agronomy for practicing professionals

FeatureGoing organic: Are organic foods really healthier and better for the environment? 8SoilSEarn a CEU: Response to starter fertilizer on no-till grain sorghum in Nebraska 20

CropSEarn a CEU: Time of weed removal with glyphosate affects corn growth, yield components 33teChnologyNew herbicides offer lower costs, toxicity and more flexibility 39Company StrategieSProcessors, farmers stay ahead of nutrition demands 42

An American Society of Agronomy Publication

Volume 40 n Issue 1 Spring 2007

&agronomy for practicing professionals

8

39

42

40

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6 FeatureSICCA Chair Tom Kemp and ASA Presi-dent Jerry Hatfield introduce the new Crops & Soils. Plus, organic food has been the fastest-growing segment of the retail food industry, but are the perceived benefits by consumers well founded?

15 regional newSNews from Canada East, Canada West, and the U.S. Southeast.

18 regulatory newSNews from the USDA-ERS, EPA, and state regulations.

19 induStry newS Headline fungicide claims credit in national contest, Pioneer announc-es pre-launch of corn with increased resistance to anthracnose stalk rot, inventor of Roundup to be inducted in the National Inventors Hall of Fame, and Gregory Page is named CEO of Cargill.

20 SoilSEarn a CEU in Nutrient Management: Response to starter fertilizer on no-till grain sorghum in Nebraska. Earn a CEU in Soil & Water Management: How do pesticides behave in nursery recycling ponds?

29 CropSEarn a CEU in Crop Management: Corn types respond to population density and nitrogen levels differently. Earn a CEU in Pest Manage-ment: Time of weed removal with glyphosate affects corn growth and yield components.

39 teChnologyNew herbicides offer lower costs, toxicity and more flexibility.

40 new produCtS

42 Company StrategieSProcessors and farmers stay ahead of nutrition demands.

44 CertiFiCationMeet Ed Ruff, 2006 CCA of the Year. Plus, Director of Certification Programs Luther Smith discusses professionalism.

Volume 40 n Issue 1 n Spring 2007

Spring2007|Crops & Soils �

Crops & Soils, the magazine for practicing professionals in agronomy, is published quarterly (March, June, September, and December) by the American Society of Agronomy. Visit us online at www.agronomy.org/cropsandsoils.

Editorial staffDirector of Publications: Fran Katz (608-268-4974 or fkatz@

agronomy.org)Director of Certification Programs: Luther Smith (608-268-

4977 or [email protected])Managing Editor: matt niLSSon (608-268-4968 or mnilsson@

agronomy.org)Contributing Editor: Bruce ericKSon

Advisory boardcharLeS ruSSeLL Duncan, Clemson Extension Service, Manning, SCSuSan FitzgeraLD, Fitzgerald and Co., Elmira, ON, CanadaDaLe F. LeiKam, Kansas State University, Manhattan, KSLiSa martin, Martin and Associates, Pontiac, ILLarry oLDham, Mississippi State University, Mississippi State, MSJameS PecK, ConsulAgr Inc., Newark, NYKim r. PoLizotto, Potash Corp. of Saskatchewan, Greenfield, INgeorge SimPSon, Jr., Yara North America Inc., Beaufort, NCDaLe L. SoFtLey, Forensic Agronomy/Consultant, Lincoln, NEFreDricK F. VocaSeK, Servi-Tech Laboratories, Dodge City, KSharoLD WatterS, The Ohio State University Extension,

Raymond, OHJohn W. zuPancic, Agronomy Solutions, Sheridan, WY

Contributions/correspondenceCrops & Soils welcomes letters, comments, and contributions, published on a space-available basis and subject to editing. The deadlines are February 15 (spring issue), May 15 (summer issue), August 15 (fall issue), and November 15 (winter issue). Address correspondence or questions to: Crops & Soils, 677 S. Segoe Rd., Madison, WI 53711-1086 ([email protected] or 608-268-4968) For general inquiries not related to Crops & Soils, please email [email protected] or call 608-273-8080.

AdvertisingContact Alexander Barton ([email protected] or 847-698-5069). For a rate card, see www.agronomy.org/ sponsors_advertising.html.

PostagePeriodical postage paid at Madison, WI. USPS 009740. ISSN Number 0162-5098. POSTMASTER: Send address change to Crops & Soils, 677 S. Segoe Rd., Madison WI 53711-1086.

The views in Crops & Soils do not necessarily reflect endorse-ment by the publishers. To simplify information, Crops & Soils uses trade names of some products. No endorsement of these products is intended, nor is any criticism implied of similar products that are not mentioned.

&agronomy for practicing professionals 8

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An old name with a new beginning

rops & Soils is a magazine that for many years could be found on the desk of almost all agronomists. We now hope that this new version of Crops & Soils will also be a staple for every practic-ing CCA and other certified professionals. The CCA program has

been a part of several magazines in the past, and we hope to continue these relationships. However, the ASA and the CCA program have decided to redesign Crops & Soils in hopes of better meeting the needs of CCAs and other practicing professionals. ASA will be able to identify what practices farmers use and what the government wants as best management practices. This information can then be passed along to CCAs via Crops & Soils magazine.

CCAs are constantly looking for help in acquiring good, sound advice to pass along to their growers. Crops & Soils can be a valuable resource for this advice. This magazine is not intended to be a scientific journal but a resource for CCAs and consequentially for the farmers who depend on them for information. There are daily decisions that have to be made by growers, and their livelihood may depend on receiving the best advice. This information needs to be

presented by region and be crop specific. It is our hope that Crops & Soils will be able to successfully meet these information needs.

In order to provide advisers with the best in-formation on crops and varieties, universities and industry need to work with ASA on research and development. As the crop varieties and use of crops for specific purposes change, the nutrient re-

quirements may also change. We will need more information about varieties and how different chemicals affect the crop. We are rapidly changing from producers of food and fiber to produc-ers of food, fiber, and fuel. Different cellulose crops will be a part of the fuel component. This shift in agriculture will change the dynamics of what we do and how we do it forever. This is a very exciting time for the agricultural industry with many new challenges to be faced.

The protection of our environment is another important challenge faced by the agricultural industry of today. It is imperative that we respond to these challenges with scientific facts, not hysteria. Crops & Soils will need to help CCAs stay abreast of NRCS regulations. Consultants are currently working to assist growers as they use the programs recommended by the USDA. By providing information to CCAs via Crops & Soils, growers will have a better opportunity to optimize their yields with a minimum effect on the quality of the environment.

The benefits of this magazine go on and on, but the important thing is for ASA and the CCA program to work together to put this magazine in the hands of CCAs and other certified profes-sionals. Remember that this magazine is a direct result of the relationship between ASA and the CCA program, and this means that both sides will be working toward one common goal: dis-seminating information to CCAs and other agronomists who can use it to be better at their jobs. Through the development of Crops & Soils, ASA and the CCA program are creating a toolbox for all agricultural consultants. Hopefully parts of this toolbox will one day become available on the web. An electronic version of some of these tools may provide an extra benefit to some agricultural advisers.

I don’t know about you, but I am certainly looking forward to seeing Crops & Soils on my desk. It is destined to be a tool to assist not only CCAs but all agronomists. As you take advan-tage of this resource, always remember to promote the benefits of CCA certification and help growers recognize the importance of using a certi-fied consultant. Be proud of what you do, and don’t forget to check out the new and improved Crops & Soils. X

C

By Tom KempICCA Chair843-493-2811 [email protected]

We now hope that this new version of Crops & Soils will also be a staple for every practicing CCA and other certified professionals. “

‘

� Crops & Soils|Spring2007 AmericanSocietyofAgronomy www.agronomy.org Spring2007|Crops & Soils �� Crops & Soils|Spring2007 AmericanSocietyofAgronomy www.agronomy.org Spring2007|Crops & Soils �

Serving the needs of professionals

t is exciting to be part of the beginning of a new venture for CCAs, CPAgs, CPSS/Cs, and ASA members. The restart of Crops & Soils has the potential to fulfill part of the strategic plan for ASA and to provide information to help certified professionals enhance

their knowledge base and their skills. The joint venture between the CCA program and ASA to form this magazine will further enhance both groups. Let me explain why I believe this effort will benefit both groups and most of all agronomy and agriculture.

The development of the strategic plan for ASA identified the need to provide educational, research, and scientific information for professionals. There are many ways in which we can accomplish this strategic goal; however, this is not going to be the result of just one project, but a series of combined efforts. Crops & Soils is just one project to address this critical need.

The CCA program has been an integral part of ASA since its formation, and this joint effort along with development of other programs will enhance both groups. Agronomy is a complex subject and fulfilling its definition requires that we develop a philosophy that covers everything from discovery through delivery. I am reminded of this definition as I work with producers and consultants that our science has little impact unless it can be adopted and applied as an ag-ronomic practice. Scientific and professional societies do not exist in a vacuum, and we need to discover the synergy in which we can partner toward efforts that add value to both organizations. Accomplishing this will require that we explore new and creative methods for sharing information in a timely and effective manner. I don’t believe that any one of us has the correct answer, but through our combined efforts, we can achieve solutions that will astonish all of us and increase our impact on those that we serve in a variety of settings. We need to figure out how to harness our creative talents toward a renewed goal of expanding our knowledge base.

The development of a strategic plan for ASA and the formation of various task forces, e.g., education, communications, annual meetings, and Agronomy Journal review, are evidence of the commitment toward renewing the vision of ASA as it enters its second century of existence. The Steering Committee, a joint effort of ASA and ICCA to evaluate priorities and infrastructure needs for CCAs, is indicative of the commitment of both groups to change and improve. To achieve all of these goals in the period of time that will satisfy the individuals involved in this effort will require a focus and dedication to finding solutions that will have an impact. None of this will be easy, but I believe it will be extremely rewarding.

Crops & Soils is not designed to be another scientific journal but is directed toward providing a range of information across a number of topics along with CEUs. These topic areas present information that is critical for all of us to increase our awareness of our surrounding political, regulatory, and industrial world. There are a number of topics in which we must be informed if we desire to place our research and education efforts in the proper context. Informed ASA members will have an increasing impact on the world. The linkage between ASA and the ICCA program will impact our world, and we need to try every potential method of being able to ef-

fectively help one another. I hope that you will join me as either an ASA member or a CCA, CPAg, or CPSS/C to a renewed commitment towards forging a new future that will become the envy of all scien-tific/professional societies. X

I

By Jerry HatfieldASA President515-231-7355 [email protected]

The restart of Crops & Soils has the potential to fulfill part

of the strategic plan for ASA and to provide information

to help certified professionals enhance their knowledge base

and their skills.”

‘

� Crops & Soils|Spring2007 AmericanSocietyofAgronomy

n the six years since the USDA formalized national production and process-ing rules, organic food has

been the fastest-growing segment of the retail food industry. While it started out small, organic is getting big—fast. Even Wal-Mart announced last year it is jumping onto the organic band-wagon.

Part of all the fuss is because organ-ic food has proven profitable, with re-tail price premiums ranging from 10% to more than 100%, depending on the product. Organic has also become a welcome shelter for farmers, both big and small, who have too often seen their profits squeezed by low com-modity prices and high energy prices.

But consumers are driving the trend, not retailers, and it’s worth examining what consumers think they’re get-ting (and not getting) when they “go organic.” Recent polling of residents of Ontario, Canada reveals that more than half think organic food is more nutritious; two-thirds believe organic food is safer; and 9 out of 10 believe

organic fruits and vegetables are grown without pesticides of any kind. Other recent polls show most consum-ers think organic farming methods are better for the environment and treat farm animals more humanely.

The fragile basis for these percep-tions is surprising, given that these questions have been debated and re-searched for well over 50 years.

The organic food movementThe organic food “movement”

emerged in the 1920s after farmers began using significant amounts of synthetic nitrogen fertilizer. These “ar-tificial manures” sparked a backlash among vitalist and romantic thinkers, most notably German mystic Rudolf Steiner, who claimed that such fertil-izer resulted in spiritually and nutri-tionally deficient food. As Steiner put it, if only “mineral fertilizer” is used, “your children, more particularly your grandchildren, will have very pale fac-es.” The anti-synthetic fertilizer u

Organic food has been the fastest-growing segment of the retail food industry, but are the perceived benefits by consumers well founded?

I

By Alex AveryDirector of Research Hudson Institute’s Center for Global Food Issues Churchville, VA

[continued on page 10]

Going

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stacked with Roundup Ready® Corn 2 technology. I was developed by Dow AgroSciences to protect your corn yields by providing superior insect protection with maximum herbicide flexibility.

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10 Crops & Soils|Spring2007 AmericanSocietyofAgronomy www.agronomy.org Spring2007|Crops & Soils 1110 Crops & Soils|Spring2007 AmericanSocietyofAgronomy www.agronomy.org Spring2007|Crops & Soils 11

movement gained momentum through the 1930s, leading to America’s Jerome Rodale to coin the term “organic” with the launch of Organic Farming and Gardening magazine in 1942.

In 1946, the editors of the pres-tigious British medical journal The Lancet lamented the “somewhat emo-tional reaction against modern agri-cultural methods, particularly against the use of artificial fertilizers, which are supposed to ruin the land and the crops grown on it,” and editorialized that “many of the statements made in preaching this new gospel are unac-ceptable both to the scientist and to the practical farmer.”

So has the “organic debate” pro-gressed any in the 60 years since that editorial?

NutritionOn the nutrition question, there

have been a sizeable number of stud-

ies over the past 50 years that have found no evidence for organic food being more nutritious. The Soil As-sociation, the largest organic lobby group (and certifier) in the UK, was founded in the late 1940s chiefly to answer The Lancet and other scientific critics by proving organic food’s nutri-tional superiority. In 1977 after more than 30 years of on-farm research, the group’s wealthy founder, Lady Balfour, admitted at an international organic farming conference that their research “revealed no consistent or significant differences.”

A 1997 review of more than 150 past studies also found no consistent or significant nutritional benefits in organic in any food category. A 2002 study commissioned by Canadian TV and the Globe and Mail newspaper found no nutritional differences in 135 comparisons of organic and conven-tional fruits and vegetables. Last fall, the Soil Association submitted research to the British Food Standards Agency

(FSA) showing roughly 60% higher omega-3 levels in milk from “organic” grass-fed cows versus “conventional” milk and asked to be allowed to mar-ket organic milk as “healthier.” The FSA concluded that the difference was of “limited health benefit” because “organic milk consumed in volumes consistent with a healthy diet would not provide sufficient amounts of long-chain omega-3 fatty acids to provide significant health benefits, over and above those associated with conven-tional milk.” The FSA recommended eating oily fish such as salmon, which are 100 times richer in long-chain omega-3s.

Today, the industry-funded Organic Center for Education and Promotion (OCEP) highlights evidence indicat-ing organic produce may have higher levels of antioxidants, polyphenolic compounds, and other plant “second-ary metabolites”—which may (or may not) provide protection against cancer and other age-related diseases. But so

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Going Organic | from page �


far this research is preliminary, and we have little understanding of these compounds and their role (pro or con) in our diet. Consider that a study of smokers taking moderate doses of an-tioxidant vitamin E and beta-carotene was stopped early after initial results revealed that taking the supplements resulted in 18% more lung cancers and 8% more deaths.

PesticidesWhat about pesticides? One

wrinkle in this debate is the lack of residue tests for several organic pesti-cides, such as rotenone, and the lack of toxicity data for these “botanical” pesticides. As for synthetic pesticide residues, the evidence for lower expo-sure from organic foods is quite clear, though based on a surprisingly small amount of organic samples. The most comprehensive comparison—conduct-ed by Dr. Charles Benbrook (currently director of the OCEP) and Ned Groth of Consumers Union—compared resi-

due data from 194 samples of organic produce with more than 26,000 non-organic produce samples. They con-cluded that, overall, organic produce contained about one-sixth the amount of synthetic pesticide residues as non-organic. This assessment has been bol-stered by more recent work showing that switching children to organic fruits and vegetables results in the rapid disappearance of trace metabolites of organophosphate (OP) pesticides from the children’s urine.

However, it is not clear that there are any health benefits from this lower residue exposure. Most pesticides are found at only parts per billion levels, and essentially all are found below U.S. and World Health Association reference doses. These reference doses are set at fractions (1/100 to 1/1,000th) of the “No Observable Adverse Effect Level” seen in the most sensitive ani-mal studied.

Research is also progressing on organic farming’s agronomic and sus-

tainability performance. Last year the pro-organic Rodale Institute reported the results from 22 years of field study of an organic corn–soy–wheat rotation with cover crops. The organic rotation got “similar” corn and soybean yields to the conventional at lower produc-tion costs, though the wheat rotation reduced total grain output 25% com-pared with the conventional corn–soy rotation. John Teasdale’s group at the USDA, using the same organic rotation as Rodale, also reports “similar” yields for specific crops but that the organic suffers five times more soil erosion than a conventional no-till system.

Food safetyFinally, what about food safety?

With this year’s multiple outbreaks of deadly E. coli O157:H7 in leafy greens and the increased anxiety among con-sumers, this issue has received more than its fair share of political spin.

Initial reports in the E. coli outbreak from September indicated that u

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12 Crops & Soils|Spring2007 AmericanSocietyofAgronomy

organic spinach had been implicated. But further investigation by the Centers for Disease Control and the California Department of Food and Agriculture concluded that the spinach was non-organic. The field was likely contami-nated by bacteria from a neighboring grass-fed, free-range beef ranch on which they found the same E. coli se-rotype, speculating that wild boars may have carried it into the spinach fields.

While organic activists have often claimed that O157:H7 was created in and primarily spread by “industrial” cattle feedlots, it is found in virtually all ruminants and is a natural part of the intestinal flora of cattle.

Organic proponents cite several reasons why their food is less likely to contain illness-causing bacteria. First, organic rules do not allow application

of uncomposted “raw” manure to food crops less than 120 days prior to har-vest. Second, organic composting rules mandate specific time and temperature requirements that significantly reduce pathogen loads.

However, every state has rules against applying raw manure on crops consumed raw, and data from a re-cent University of Minnesota study found no differences in generic E. coli prevalence between organic and conventional lettuce, leafy greens, or cabbage. They did find salmonella on organic green pepper and organic lettuce and not on any conventional produce samples, but the conventional sample sizes were too small to con-clude this was a significant difference.

Perhaps more interesting was the group’s finding that “organic samples

from farms that used manure or com-post aged less than 12 months had a prevalence of E. coli 19 times greater than that of farms that used older ma-terials.” This may mean that manure composting methods need to be ad-justed to assure food safety. Consumer groups are already clamoring for greater regulatory oversight over ma-nure and water on farms, and produce growers are joining the call in hopes of putting an end to nationwide food scares.

As organic food sales continue to grow rapidly and as consumers be-come comparatively more affluent and health conscious, the debate over the merits of organic farming methods versus non-organic methods will con-tinue. And with non-organic farming technology evolving at an even more rapid pace, let us hope that this debate leads all farmers—and their consum-ers—toward a more productive, sus-tainable, and healthy future. X

Alex Avery is author of the new book, The Truth About Organic Foods.

As organic food sales continue to grow rapidly and as consumers become comparatively more affluent and health conscious, the debate over the merits of organic farming methods versus non-organic methods will continue.”

‘

14 Crops & Soils|Spring2007 AmericanSocietyofAgronomy www.agronomy.org Spring2007|Crops & Soils 15

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Regional news

Canada EastNitrogen recommendations for corn in Ontario

Accurate prediction of optimum nitrogen (N) rates for corn production is important both economically and environmentally. Under-applying N fertilizer will result in lost income due to low yields. Over-applying N will result in expense for fertilizer that does not create a net return, as well as an increased risk of off-site movement of the excess N into surface or ground water or to the air as nitrous oxide. The general N recommendations for corn in Ontario were reviewed to improve their precision.

A database was compiled of all the corn N response trials that could be found from 1962–2002 (41 years). This database comprised 1,631 ob-servations, representing 448 unique experimental sites. Of this total, 1,024 observations included three or more rates of N fertilizer, so a yield response curve could be fitted to a quadratic-plateau function. From the equations for these curves, maximum economic rates of N (MERN) could be calculated for each plot.

Sites where urea or urea-ammoni-um nitrate solution (UAN) was applied without incorporation were excluded from further analysis, since these re-sults reflected the loss of ammonia

rather than the response to fertilizer rates. Sites where corn was grown following cover crops other than red clover were also excluded, since their number was too few to be statisti-cally valid. Preliminary analysis of the data indicated that there were no differences in N response between dif-ferent forms of N. Sites that included multiple hybrids or multiple forms of N were averaged to provide a single MERN value for each experiment. Similarly, sites with response measure-ments at several different locations within a field were averaged, so these sites did not carry more weight in the analysis than was appropriate.

The 595 remaining observations were subjected to a step-wise multiple regression to determine which factors had a significant impact on optimum N rates (Table 1). Significant factors (P > 0.05) in the model were yield at MERN, soil type, previous crop, ap-plication timing (within soil type), crop heat unit rating, and relative price of corn and fertilizer. There was also a significant difference between the Ot-tawa Valley (Eastern Ontario) and the rest of the province.

Optimum fertilizer rates increased with increasing yield at a rate of 0.8 lb/bu. This is very close to the amount of N removed with the harvested grain.

The lowest N requirements were found on silt loam soils, with higher MERN values in the sandy- or clay-tex-tured soils. We speculate that this may be due to increased losses to denitri-fication in the clay soils and reduced mineralization from the sandy soils.

The highest N requirements were found in corn following grain corn.

Corn following silage corn or cere-als with the straw removed needed 11–13 lb/acre less, and corn following soybeans or edible beans needed 27 lb/acre less. The credit for a red clover cover crop was significantly larger than had previously been allowed, and there was a greater apparent N avail-ability from clover that had been tilled than from clover that was chemically killed. This is the only instance where tillage system changed the N recom-mendations.

Sidedress N requirements were 20% less than preplant on loam to clay soils, and about 10% less on sandy loam soils. There was no apparent ad-vantage to sidedress N application on loamy sand or sand soils.

Nitrogen requirements increased slightly from the cooler to the warmer areas of the province. The difference in recommendation between Guelph and Chatam is about 21 lb/acre.

Optimum N rates declined as the ratio between the price of N and the price of corn increased. The require-ments were initially calculated for a price ratio of 5 (i.e., it took 5 lb of corn to purchase 1 lb of N), and the opti-mum N rate declined by 6 lb/acre for each unit increase in the price ratio.

The Corn N Calculator worksheet, which includes details of all the fac-tors, can be found at www.omafra.gov.on.ca/english/crops/facts/ nitroratescorn.htm.

The model only explains about 32.6% of the total variability in MERN, since variations in weather and man-agement cannot be accounted for. One interesting finding, however, is that the economic return to N fertilizer is not as sensitive to slight variations in N rate as yield. With slight over-fertilization, there is an increase in yield (although not enough to pay for the extra N completely), while with slight under-fertilization, the decline in fertilizer cost is almost enough to com-pensate for the reduction in yield. At a corn price of $4.06/bu and a N price of $$0.58/lb, the actual N rate applied could be up to 18 lb/acre less or 13 lb/acre more than the MERN, and over 80% of the fields will still be within $5/acre of the maximum return to N.

u Table 1. Percentage of variability in maximum economic rates of nitrogen (MERN) explained by general corn N recommendations.

Source df Percent F P > F

Expected yield 1 9.8 52.67 0.0001

Previous crop 7 12.7 15.39 0.0001

Soil & Heat Unit rating

6 9.0 0.0001

Application timing 2 1.1 4.32 0.0139

By Keith Reid and Greg Stewart (On-tario Ministry of Agriculture, Food and Rural Affairs) and Ken Janovicek (De-partment of Plant Agriculture, Univer-sity of Guelph)

1� Crops & Soils|Spring2007 AmericanSocietyofAgronomy www.agronomy.org Spring2007|Crops & Soils 1�1� Crops & Soils|Spring2007 AmericanSocietyofAgronomy www.agronomy.org Spring2007|Crops & Soils 1�

Regional news

Cut soybean seeding rates with caution!

Seed costs have become the largest input expenses for soybean produc-tion. Glyphosate-tolerant varieties cost in excess of $50 per acre. This has lead to reduced seeding rates by some producers. But do lower seeding rates sacrifice yield and profit?

Current Ontario Ministry of Agricul-ture Food and Rural Affairs (OMAFRA) seeding rate recommendations are based on research with conventional varieties, untreated seed, and with less precise planting equipment than is now available. These recommenda-tions are:

225,000 seeds/acre in 7.5-inch rows,

200,000 seeds/acre in 15-inch rows,

170,000 seeds/acre in 22-inch rows, and

160,000 seeds/acre in 30-inch rows. In 2005, large-scale replicated

field trials were initiated to assess the most profitable seeding rates when taking into account new technology such as glyphosate-tolerant varieties, seed treatments, soil types, and earlier planting dates.

If recommended seeding rates could be reduced (e.g., from 225,000 to 200,000 seeds/acre in 7.5-inch rows)

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while still achieving maximum yields, a significant savings could be realized. This reduced seeding rate would repre-sent a savings of approximately $5.92 per acre, assuming a $32 per unit cost for glyphosate-tolerant seed with 2,700 seeds/lb.

Plant stand counts taken at 30 days after seeding showed that between 73 and 80% of the seed emerged and survived to 30 days after planting. The highest seeding rate (225,000 seeds/acre) produced the lowest percent-age of surviving plants. Seventy-four percent of planted seed survived to 30 days after planting (166,000 plants of the 225,000 seeds that were planted). The lowest seeding rate (150,000 seeds/acre) produced the highest per-centage of surviving plants 30 days af-ter planting. Eighty percent of planted seed survived to 30 days after planting. The difference in survival may be a result of early-season competition that reduced seedling survival at higher seeding rates.

In the two years of this experiment, the highest yields resulted from the fol-lowing three seeding rates:



200,000 seeds/acre in 15-inch rows.

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The following treatments all resulted in statistically lower yields compared with the treatments listed above:




150,000 seeds/acre in 15-inch rows. Results were similar for soil type,

planting date, tillage practice, and CHU area. There was also no differ-ence in the results based on whether the seed was treated with a fungicide. Glyphosate-tolerant and conventional varieties behaved the same in this study. These results indicate that seed-ing rates could be reduced to 200,000 seeds/acre when planting in either 7- or 15-inch rows. A saving in seed cost of approximately $5.92 per acre could be realized by reducing seeding rates from 225,000 to 200,000. When aver-aged across the two row widths, a re-duction of 1.2 bu/acre occurred when reducing seeding rates to 175,000 seeds/acre, and another 0.8 bu/acre reduction occurred when rates were reduced to 150,000 seeds/acre.

Rows that were 7.5 inches some-times yielded higher than 15-inch rows. This study found that under poor growth conditions such as late plant-ing, heavy soils, and low fertility, solid

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u Left: Seeding of various row widths and seeding rates. Right: Soybean emergence of 7.5-inch vs. 15-inch rows.


section HeadRegional news

Canada WestCongratulations to Lisa Britz, from

Saskatchewan Wheat Pool, Regina, SK, Canada, on being selected as the 2006 Prairie CCA of the Year. Britz is committed to personal train-ing through her professional status and continued education in the CCA Program. She provides agronomic expertise to more than 20 fellow CCAs within the Pool network. Most importantly, she is also an active field agronomist providing constant personal contact with farmers. She works daily with her customers to make good agronomic decisions for their farm—and the farm economy. The link from research to CCA to farmer is encapsulated in her career! Britz is a strong supporter of the CCA Program, offering over 23 accred-ited training sessions to the industry since 2002.

SoutheastThe annual Crop College was

held on the Mississippi State Univer-sity (MSU) campus February 13–15, 2007. About 160 agronomy profes-sionals, including 130 CCAs from Mississippi and surrounding states, participated in this opportunity. Sub-jects in the 23 hours of educational programming included: off-target pesticide application, climatology and agriculture, web soil survey, soil test recommendation philosophies, and recent GM rice issues.

This event is sponsored by the MSU Extension Service, Mississippi Agricultural Industrial Council, and the Mississippi Chapter of ASA. At the Mississippi Chapter’s annual meeting during the Crop College, Dr. David Roberts, CCA from Amory, MS, was recognized as the Agrono-mist of the Year. X

seeding provided slightly higher yields than 15-inch rows (1–3 bu/acre).

This study found that a plant stand taken at 30 days after seeding of 150,000 plants per acre produced the highest yield and the highest economic return. In the study, 200,000 seeds/acre were required to achieve a plant stand of 150,000 plants/acre. When emergence conditions are excellent (warm soils, no crusting, etc.), it is often possible to achieve 150,000 plants/acre with a lower seeding rate than 200,000 seeds/acre. Some producers may be able to seed 175,000 seeds/acre while others will need to seed 200,000 seeds/acre depending on the equipment used, the conditions following planting, residue levels, etc.

Although the yield losses associated with reduced seeding rates are relatively small, they are real. A seeding rate of 200,000 seeds/acre provided the highest economic return as well as the highest yields. When using a seed drill to plant soybeans in Ontario, significantly cutting seeding rates lowers yields and profits. Got regional news to share? Send it to [email protected]

1� Crops & Soils|Spring2007 AmericanSocietyofAgronomy www.agronomy.org Spring2007|Crops & Soils 191� Crops & Soils|Spring2007 AmericanSocietyofAgronomy www.agronomy.org Spring2007|Crops & Soils 19

RegulatoRy news

USDA-ERSOrganic produce, eggs, and poultry

retain price advantage. The USDA Eco-nomic Research Service (USDA-ERS) reports that organic broccoli fetched $13.55 per case of about 26 lb, while conventional price for the same quan-tity was $5.47 (February 2006). Fresh produce has long been an important component of the organic food sector. Despite higher prices for organic prod-ucts, the number of consumers purchas-ing organic produce is growing. Price premiums for organic products have contributed to growth in certified or-ganic farmland and, ultimately, market expansion. The report contains a num-ber of products, including organic poul-try and eggs. See www.ers.usda.gov/ publications/vgs/may05/VGS30801/.

Record agriculture exports. The value of U.S. agriculture exports for calendar year 2006 is a record $70.993 billion. This is nearly $8 billion higher than in 2005. Grains accounted for most of the increase, notably from corn as the value of corn exports rose 47% over 2005. Red meat exports showed the next strongest growth over last year, at just over 20%. The volume of corn shipments rose 27% above 2005 levels, with Japan, Mexico, and South Korea continuing to account for more than half of U.S. corn shipments; more than

half the December shipments went to Japan and Mexico. See http://usda.mannlib.cornell.edu/usda/current/FAU/FAU-02-15-2007.pdf.

Ten-year projections for global ag-riculture. Demand for biofuels, par-ticularly in the U.S. and the European Union (EU), is expected to increase in the next decade. U.S. agricultural projections reflect large increases in corn-based ethanol production, which affects production, use, and prices of farm commodities throughout the sec-tor. Expansion of biodiesel use in the EU raises demand for vegetable oils in global markets. Steady domestic and international economic growth in the projections supports gains in consump-tion, trade, and prices. Rising produc-tion expenses and lower government payments offset some of the gains in cash receipts and other sources of farm income, but overall net farm income remains strong through the projections. Consumer food prices are projected to rise more slowly than the general rate of inflation over the next decade, although increases in meat prices push food pric-es up faster in some years. See www.ers.usda.gov/Publications/OCE071/.

EPAEPA seeks public comment. The EPA

is seeking comment on the paperwork and regulatory burdens associated with the proposed extension of an Informa-tion Collection Request regarding the use of dispersants in the management of oil spills in U.S. waterways. Com-ments should be filed by April 16, 2007. The request is titled “Renewal of Information Collection Request for the National Oil and Hazardous Substanc-es Pollution Contingency Plan Regula-tion Subpart J.” The EPA notes that “The Clean Water Act ... requires a prod-uct schedule, identifying ‘dispersants, other chemicals, and other spill miti-gating devices and substances, if any, that may be used in carrying out’ the National Contingency Plan (NCP).” The EPA says that those potentially affected by this action are “... manufacturers of bioremediation agents, dispersants, sur-face-collecting agents, surface-washing agents, and other chemical agents and

biological additives used as counter-measures against oil spills ...” Publicly available documents are to be posted in EPA Docket Identification Number EPA-HQ-OPA-2007-0042 at www. regulations.gov.

State regulationsState legislatures active. According

to a report from the Pew Initiative on Food and Biotechnology, state legisla-tures have been busy. This most recent analysis identified legislative engage-ment on issues identified in prior fact sheets, such as liability and contracts, but also highlighted some new areas of action, such as coexistence among genetically modified (GM) crop, con-ventional, and organic farmers and producers.

Twenty-nine percent of introduced legislation addressed the regulation of seeds and crops; 22% were in sup-port of agricultural biotechnology; 16% sought to impose moratoria on GM crops and animals; and 15% ad-dressed rights and responsibilities of farmers and biotech seed producers by establishing liability for damages caused by GM crops.

The fact sheet, entitled “State Leg-islative Activity Related to Agricul-tural Biotechnology in 2005–2006,” chronicles and catalogues state and federal legislative activity relating to agricultural biotechnology in 2005 and 2006. It is accompanied by Leg-islation Tracker, a database that ar-chives legislation. These items update a similar fact sheet and database pre-pared last year.

Of the 134 pieces of legislation introduced in state legislatures, 27 were adopted (20%) compared with 37 bills (22%) in 2003–2004 and 45 (28%) in 2001–2002.

A new development emerged in 2005–2006 that focused on local lawmaking with 16 bills introduced to preempt (disallow) local and county regulations on GM seeds and crops. Hawaii and New York introduced the most bills, respectively generating 44 and 13 pieces, with Hawaii adopting the most bills (seven). X

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industRy news

BASF’s Headline fungicide claims credit in national contest

Fourteen of the 27 recently an-nounced 2006 National Corn Yield Contest winners applied Headline fungicide to their winning corn field. “What’s even more telling is that while only 9% of the 3,157 fields entered across the country applied Headline, 52% of the winning fields used Head-line,” said Gary Fellows, Technical Mar-keting Manager for corn and soybean fungicides and herbicides at BASF. “So when growers ask, ‘Does Headline pay off in yield?,’ the answer is a resound-ing ‘Yes!’ ”

Pioneer announces pre-launch of corn with increased resistance to anthracnose stalk rot

Pioneer says the new corn will help growers reduce direct yield loss and lower the risk of damage due to lodg-ing, which will improve overall harvest efficiency and increase overall farm

profitability. Stalk rot is the most com-mon disease found in corn fields world-wide, creating estimated yield losses of more than $1 billion in North and South America alone.

Through traditional breeding, Pio-neer has commercialized hybrids with the gene for anthracnose stalk rot resis-tance in Latin America. The trait should be commercially available in North America sometime in 2008.

Inventor of Roundup to be inducted into National Inventors Hall of Fame

Monsanto’s John Franz will be in-ducted into the National Inventors Hall of Fame in Akron, OH on May 5, 2007. He joins other leaders of the agricultur-al industry, including Eli Whitney, John Deere, and George Washington Carver, who were previously inducted to the Hall of Fame.

In 1970, Dr. Franz discovered that a chemical, later named glyphosate, had the amazing ability to block the growth

of vegetation. Be-cause of his dis-covery, glyphosate soon became the active ingredient in Roundup her-bicides, now the world’s most effec-tive and top-selling herbicides.

The National Inventors Hall of Fame “honors the women and men responsible for the great technological advances that make human, social, and economic progress possible.”

Page named CEO of CargillCargill announced in February that

its board of directors has elected Greg-ory Page, 55, chief executive officer and president, effective June 1, 2007. Page will succeed Warren Staley when he retires as CEO on June 1. Staley will continue to serve as chairman of the Cargill board of directors until its an-nual meeting on September 11. X

John Franz


orghum production under no-till is common in south-ern Nebraska. In the high-residue environments of

no-till, cooler soil temperatures can slow germination and root growth and reduce nutrient availability during early plant growth. Using starter fertilizer involves the application of relatively small amounts of nutrients with or near the seed, usually during planting, to accelerate early plant growth. Studies have shown that using starter fertilizer in high-residue environments can in-crease both the early growth and grain yield of grain sorghum. Starter fertilizer may also reduce sorghum grain water content at harvest as has been observed for corn. The probability of response to S in starter fertilizer may be greater for no-till than for tilled conditions or vary with soil properties such as soil test P. Some researchers have found topographic position to be important, with corn response to application of starter fertilizer on eroded shoulder and backslope positions but not for the bottomland position, which often has more soil organic matter. The objective of this research was to determine grain sorghum response to starter fertilizer for different combinations of nutrients and placement methods and how these responses are affected by topographic position within fields.

Materials and methodsSite characteristics, treatments, and

experimental design. Trials were con-ducted in Nebraska near Pickrell and Beatrice in 2002 and near Firth and Beatrice in 2003 on three topographic positions per location. Four soil series were represented, and slopes ranged from 1 to 5.5%. Continuous no-till had been practiced for at least five years for all locations. All trial locations had a history of sorghum–soybean rotation except for one where the previous crop was sorghum.

The trials had eight starter fertilizer treatments—one factor consisted of dif-ferent combinations of N, P, and S fertil-izers. The second treatment factor was starter fertilizer placement method: 2 inches deep and 2 inches to the side of the seed (2 by 2 inches), over the row, and in the seed furrow. Additional treat-ments were the control with no starter fertilizer applied, in furrow with ammo-nium sulfate as the S source (N + P + Sas), and ammonium thio-sulfate as the S source (N + P + Sats). Fertilizer solu-tions were prepared using ammonium nitrate, ammonium sulfate, monoam-monium phosphate, and ammonium thio-sulfate. The N, P, and S application rates were 20.0, 8.7, and 10.0 lb/acre, respectively, for 2- by 2-inch and over-the-row application. Only half of these rates were applied for in-furrow appli-cation to minimize risk of salt damage during germination. Potassium was not included in the starter fertilizer as soil test K was always very high.

The hybrids used in the study were all of medium- to late-maturity rating for southern Nebraska and included DKC53–11 (Monsanto Co., St. Louis, MO) at Pickrell and Pioneer 84G62 (Pi-oneer Hi-Bred Int., Inc., Johnston, IA) at Beatrice in 2002 and Pioneer 83G66 at Firth and Pioneer 84G62 and Pioneer 83G66 at Beatrice in 2003. The cooper-ating producers selected the hybrid for their fields. In 2003, a second variety of similar maturity as the first was selected by the researchers and included as a split-plot treatment in the three trials at Beatrice to evaluate the hybrid × starter fertilizer treatment interaction effect.

The base preplant N application rates were determined and applied by the cooperating producers. Nitrogen as anhydrous ammonia was applied at 105 and 100 lb/acre at Beatrice in 2002 and 2003, respectively, and at 100 lb/acre at Firth in 2003. At Pickrell, 100 lb/acre of N as urea ammonium nitrate was applied to the soil surface in 2002. No P fertilizer was applied regardless of

soil test P except for the P in the starter fertilizer treatments.

ResultsSite characteristics. Ground cover

by crop residue after planting ranged from 44 to 73%. Soil test P ranged from low to very high. Soil test K was very high, and mean soil organic matter was 2.7%. Soil temperatures were similar for the west and southwest slopes at Firth and for the north and east slope aspects at Beatrice in 2003. Thus, any treatment × topographic position inter-action effect was not likely because of soil temperature differences. Soil wa-ter deficits constrained crop growth in both years at all locations.

Grain sorghum plant biomass and stand density at V6 to V8 growth stage. Early plant growth was affected by the topographic position × treatment inter-action at Beatrice in 2003, only. This in-teraction was because of less response and inconsistent treatment effects for the trial on the east slope compared with the other two trials at this loca-tion. Treatment effects were significant for all trials. In-furrow application of N + P + S resulted in increased plant growth more frequently than the other starter fertilizer treatments. The mean effect of the starter fertilizer treatments compared with the control increased growth by a mean of 48% in five out of seven trials that had Bray-P1 ≤ 15 ppm but did not increase growth at the higher soil test P sites. The effects of N + P and N + P + S were similar. The differ-ence in S fertilizer sources was signifi-

Response to starter fertilizer on no-till grain sorghum in Nebraska

soils

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cant for two trials but with contrasting results (Table 1).

Placement at 2 by 2 inches was su-perior to over-the-row placement in stimulating early growth for six out of the seven trials with Bray-P1 ≤ 15 ppm. The results indicate that crop response was primarily because of P in the start-er fertilizer as growth was increased in cases of relatively low soil test P and in treatments that placed the fertilizer within reach of early root growth. Plant densities were not consistently affected by starter fertilizer treatments.

Sorghum grain yield. The topo-graphic position × treatment interaction

affected grain yield at all locations ex-cept Firth. At Pickrell, mean yield with starter fertilizer applied was greater than for the control for only the hillside posi-tion, and yield with N + P was greater than with N + P + S at the bottomland position. At Beatrice in 2002, starter fertilizer did not increase yield at any topographic position, but the response to N + P relative to N + P + S varied with position. Response to S source and placement also varied by topographic position at Beatrice in 2002. The posi-tion × treatment interaction at Beatrice in 2003 was attributed to lower yield with the 2- by 2-inch placement com-

pared with other placements at one hillside position, but otherwise there was little treatment effect at this loca-tion (Table 2—next page). There were no treatment effects at Firth.

The frequency of yield increases with starter fertilizer application was low, but increases occurred most frequently for 2- by 2-inch placement of N + P. The positive effects of starter fertilizer on early growth that occurred in soils with low soil test P did not translate to higher grain yields. The control treat-ment produced lower yield compared with the mean of the starter fertilizer treatments in only 1 of 12 trials, and this trial had relatively high soil test P compared with most other trials.

The N + P application produced high-er yield than N + P + S for two trials and lower yield for another trial. Yield was higher with S from ammonium thiosul-fate compared with ammonium sulfate at one site. The 2- by 2-inch placement had higher yield than the mean of in-furrow and over-the-row placements for two trials and lower yield for another trial. Yield was similar for in-furrow and over-the-row placement except for one location where yield was more with over-the-row placement.

Sorghum grain water content at har-vest. The treatment × position interac-tion effect was significant at Beatrice in 2003 because of reduced grain water with starter fertilizer applied compared with the control at one of the hillside positions but not at the other positions. In the hilltop trial at Beatrice in 2003, grain water content was higher with ammonium thio-sulfate compared with ammonium sulfate as the S source. Wa-ter content was higher with over-the-row placement than with other place-ments for the hillside trials at this loca-tion. Four of the 12 trials showed a 7% decrease in grain water when using the N + P/2- by 2-inch treatment compared with the control. Grain water content was similar for N + P and N + P + S treatments in all trials. Grain was drier at one trial for ammonium sulfate com-pared with ammonium thio-sulfate and for 2- by 2-inch and in-furrow place-ment compared with over-the-row placement. There is no evidence that starter fertilizer effect on grain water u

u Table 1. Starter fertilizer effect on grain sorghum growth at V6 to V8 in southeast-ern Nebraska.

Beatrice 2003

TreatmentsPickrell 2002

Beatrice 2002 East North Top

Firth 2003

Plant weight, g/plant

Control 6.2 4.7 14.0 5.8 8.9 5.9

N + P2 by 2 inches

6.4 5.5 15.4 9.7 18.4 6.4

N + Pover the row

6.9 5.1 13.6 6.9 10.8 6.3

N+ Pin furrow

6.2 5.1 18.0 10.6 13.7 6.1

N + P + Sas

2 by 2 inches6.7 5.6 14.6 10.5 12.4 6.3

N + P + Sas

over the row6.2 4.9 13.7 7.1 11.2 6.4

N + P + Sas

in furrow6.8 5.9 16.6 8.3 15.0 7.1

N + P + Sats

in furrow6.5 5.2 17.7 10.5 16.2 6.7

Contrasts and mean differences

Starter vs. control 0.4 0.6 1.3 3.1 4.7 0.5

N + P vs.N + P + S

0 –0.2 0.7 0.4 1.4 –0.4

Sas vs. Sats 0.2 0.6 –1.0 –2.2 –1.1 0.4

2 by 2 inches vs.over the row

0 0.3 –0.5 1.8 2.7 –0.1

Furrow vs. overthe row

–0.1 0.5 3.7 2.4 3.3 0.2

22 Crops & Soils|Spring2007 AmericanSocietyofAgronomy www.agronomy.org Spring2007|Crops & Soils 2�

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content at harvest was affected by soil test P.

DiscussionTreatment × topographic position

interaction effects were significant for early growth and grain water content at Beatrice in 2003 and for grain yield at all locations except Firth. The interactions were not consistent, however, across measured traits, treatments, and com-binations of treatments. When soil test P < 15 ppm, starter fertilizer increased V6 to V8 biomass of grain sorghum in all but one trial. Starter fertilizer place-ment at 2 by 2 inches or in furrow was important for increasing early growth. Seminal and lateral root uptake of the

surface-applied P with over-the-row application was probably too little and too late, respectively, to stimulate early growth. In-furrow application often re-sulted in increased early plant growth but did not consistently affect plant density. Plant density loss with in-fur-row application may be greater if wa-ter deficits occur shortly after planting, even with only 9 lb/acre of N applied.

Grain yield response was significant for the mean of the starter fertilizer treat-ments at one trial only, and this trial had relatively high soil test P. Increases in early growth did not consistently trans-late into increased grain yield. Similar results have been noted in corn. Grain water content at harvest was reduced in 4 of 12 trials. Fertilizer N + P was as ef-

fective as N + P + S for increasing yield and decreasing grain water.

Grain yield responses were deter-mined to be sufficient to pay for the in-furrow application of starter fertilizer if yields were increased by more than 2.4 bu/acre. For N + P + S applied 2 by 2 inches from the seed, yield increases of greater than 5.6 bu/acre were re-quired. Economic grain yield response occurred most frequently with 2- by 2-inch placement of N + P and with in-furrow placement of N + P + S. Eco-nomic response was too infrequent to confirm the profitability of any starter fertilizer treatment under these condi-tions, regardless of soil test P level. The occasional effect of reduced grain wa-ter at harvest was a small contribution

u Table 2. Starter fertilizer effect on grain sorghum yield under no-till conditions in southeastern Nebraska.

Pickrell 2002 Beatrice 2002 Beatrice 2003

Treatments Bottom Side Top West East Top East North Top Firth

Yield, bu/acre

Control 113 78 105 110 114 70 94 45 76 107

N + P2 by 2 inches

116 84 102 113 121 81 81 41 86 114

N + Pover the row

114 94 99 107 113 83 105 46 80 105

N+ Pin furrow

113 86 102 110 114 72 102 46 78 108

N + P + Sas

2 by 2 inches103 94 103 103 122 80 95 51 76 105

N + P + Sas

over the row108 91 102 103 118 75 87 43 80 107

N + P + Sas

in furrow108 92 108 97 121 65 100 46 86 110

N + P + Sats

in furrow110 86 103 99 119 80 92 54 80 110

Contrasts and mean differences

Starter vs. control –2 13 –2 –3 5 6 2 0 3 2

N + P vs.N + P + S

8 –3 –3 8 –5 5 2 –2 0 2

Sas vs. Sats 2 6 5 0 3 –14 8 6 6 0

2 by 2 inches vs.over the row

–2 –2 0 5 5 6 –10 0 0 2

Furrow vs.over the row

0 –3 5 0 3 –10 6 2 2 3


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toward profitability of starter fertilizer use.

It is possible that response would have been greater with earlier planting as the young plants would have been exposed to a longer period of low temperature stress. The trials were planted at typi-cal times for grain sorghum planting in southeast Nebraska. The frequency and magnitudes of response were less than for corn, which was planted earlier than the sorghum planting dates. The grain sorghum crops did experience soil wa-ter deficits that constrained grain yield. In both years, there was a two-month period during the season where the to-tal rainfall was less than 4 inches. Mean

grain yields were, however, above the long-term county averages for rainfed grain sorghum for 11 of 12 trials. Under more favorable soil water conditions, frequency and magnitude of increased grain yield might have been greater as has been observed for irrigated corn in southeastern Nebraska.

ConclusionsEarly grain sorghum growth increases

with application of N + P starter fertiliz-er are common under no-till conditions for soils with low to medium soil test P. Including S in the starter fertilizer may increase the frequency of early growth

response. The early growth responses, however, generally do not translate into increased yield or decreased grain water content at harvest time. Increased grain yield and decreased grain water content at harvest may not be sufficient to make starter fertilizer use profitable for dry-land grain sorghum. Research is needed for earlier-planted grain sorghum where seedlings are exposed to a longer period of low soil temperature. X

Adapted from “No-till row crop re-sponse to starter fertilizer in eastern Nebraska: II. Rainfed grain sorghum,” by C.S. Wortmann, S.A. Xerinda, and M. Mamo. 2006. Agron. J. 98:187–193.

Response to starter fertilizer on no-till grain sorghum in Nebraska (no. SS 03660)

Spring 2007 Self-Study Exam This exam is worth 1 CEU in Nutrient Management. A score

of 70% or higher will earn CEU credit. The International CCA program has approved self-study CEUs for 20 of the 40 CEUs required in the two-year cycle. An electronic version of this test is also available at www.certifiedcropadviser.org. Click on “Continuing Education” and then “Self-Study CEUs.”

Directions1. After carefully reading the article, answer each question by

clearly marking an “X” in the box next to the best answer.

2. Complete the self-study exam registration form and evalu-ation form on the back of this page.

3. Clip out this page, place in envelope with a $15 check made payable to the American Society of Agronomy (or provide your credit card information on the form), and mail to: ASA c/o CCA Self-Study Exam, 677 S. Segoe Road, Madison, WI 53711. You can also complete the exam and pay online at www.certifiedcropadviser.org ($12 charge).

5. Factors consistently affected by fertilizer treatments in-cluded

q a. plant stands.

q b. yields.

q c. early growth where soil test P levels were low.

q d. the yield boost from adding S to the starter.

6. Economic analyses of these trials indicated that

q a. drier grain at harvest significantly impacted profitabil-ity.

q b. an additional yield of 2.4 bu/acre was necessary to pay for in-furrow treatments.

q c. paying less for cheap starter fertilizer is not advisable.

q d. variable-rate starter applica-tions can minimize input costs.

1. An objective of this research was to

q a. test sorghum hybrid responses to fertilizer placement.

q b. evaluate different forms of sulfur used for starter.

q c. compare irrigated and dryland systems for nutrient responses.

q d. rank the comparative advantage of various brands of starter products.

2. An advantage of using a starter fertilizer in grain sor-ghum might include all of the following EXCEPT

q a. increased grain yields.

q b. lower grain water at harvest.

q c. decreased input costs.

q d. improved early growth.

3. The research methods of this study included

q a. different ratios of N and K fertilizers.

q b. tillage interactions.

q c. two different forms of sulfur.

q d. farm strip trials for comparison.

4. The difference between N + P + Sas and N + P + Sats fertilizers is the

q a. form of sulfur.

q b. amount of N.

q c. presence of micronutrients.

q d. chelation of sulfur.

Exam Continues

Next Page

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7. Responses to starter fertilizers might be greater with

q a. higher soil test P values.

q b. earlier planting.

q c. droughty conditions.

q d. conventional tillage.

8. The starter fertilizer placement least favorable for achiev-ing early growth was

q a. 2 by 2 inches.

q b. in-furrow.

q c. over the row.

q d. pop-up.

9. The lack of consistent responses in topographic positions may be related to

q a. no differences in early soil temperatures among posi-tions.

q b. the relative uniformity of soils regardless of position.

q c. low soil test K at all locations.

q d. ideal growing conditions masking possible plant stresses.

10. A conclusion of this research might be that

q a. starter fertilizer use is nearly always cost-effective in sorghum.

q b. sulfur in starters should be avoided if applying in-fur-row.

q c. hybrids react differently to starter fertilizer placement.

q d. early growth increases do not always result in yield increases.

Self-Study exam RegiStRatioN foRmName:

Address: City:

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ifferent pesticides react differently when used in fields drained into nursery recycling ponds. The use

of container production, where single plants are grouped in containers and placed on packed gravel beds or other surfaces, is considered a preferable way to manage these plants. The containers are frequently treated with pesticides and fertilizers during the early grow-ing season to improve quality and ap-pearance of the plants. The plants are normally watered using an overhead irrigation system, and as much as 70 to 75% of the irrigation water runs off the packed beds. To recycle fertilizers and irrigation water and to reduce runoff to downstream water bodies, recycling or collection ponds are used to cap-ture irrigation runoff. This is especially

true in large-scale nurseries. Recycling ponds are considered the primary best management practice (BMP) to reduce pollution to downstream water bodies. However, pesticides may accumulate in recycling ponds, causing phytotoxic-ity during water reuse and can harm the water quality of downstream rivers if discharges occur during pond cleaning or storm events. Pesticides can exist in the reused water or in runoffs depend-ing on their distribution between the water and sediment phases, and their persistence in the recycling pond.

Once in recycling ponds, pesticides distribute between the water and the sediment, and the amount of pesticides in the water depends on how they ab-sorb in the sediment and how persistent they are in the water. A number of stud-ies have produced information about

the persistence of pesticides in agricul-tural fields and surface water, but the bi-ological conditions of recycling ponds are often very different from these en-vironments. The recycling ponds often have high concentrations of nutrients (nitrogen and potassium) and other ap-plied chemicals (such as pesticides), and are high in salt contents, organic matter, and are often turbid. u

D

How do pesticides behave in nursery recycling ponds?

Earn 1 CEU in Soil & Water Manage-ment by reading this article and com-pleting the exam at the end. CCAs may earn 20 CEUs per two-year cycle as board-approved self-study articles. Fill out the attached questionnaire and mail it with a $15 check (or provide credit card information) to the American So-ciety of Agronomy. Or, complete the exam online at www.certifiedcropad-viser.org ($12 charge).



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Previous studies showed that the persistence of diazinon and chlorpyri-fos were prolonged in recycling pond waters compared with surface stream water. No studies have reported on pesticide persistence in nursery pond sediments. Researchers sought to in-vestigate the sorption and distribution of pesticides between the sediment and water column in nursery recycling ponds and to evaluate the degradation rate of four heavily used pesticides in recycling pond sediments under aero-bic and anaerobic conditions. The four pesticides were diazinon (insecticide), chlorpyrifos (insecticide and nemati-cide), chlorothalonil (fungicide), and pendimethalin (herbicide). These are widely used pesticides for outdoor con-tainer nursery production and are high-ly toxic to aquatic organisms.

Nursery pond sedimentsFindings showed that nursery recy-

cling pond sediments have two unique characteristics that include high or-ganic matter content and high salinity. Sediment samples from recycling ponds were collected from two representative commercial nurseries in southern Cali-fornia. The first sample was collected from the recycling pond of a large nurs-ery with about 247 acres of plant pro-duction area (Nursery A) located in Ir-vine, CA. The second sample was from the recycling pond of a small nursery (Nursery B) with 37 acres of plant pro-duction area. This recycling pond is about 10,600 cu ft.

The sediment from the pond of Nurs-ery A had organic matter content of 6.1%, and its gravity-drained water had an electrical conductivity (EC) of 3.3 mmho/cm; the sediment from Nursery B had organic matter content of 17.8% and an EC of 1.2 mmho/cm. The or-ganic matter in recycling comes from plant residues and potting mixes that are washed into the recycling ponds during nursery operation, and the salts generally are fertilizer residues. Be-cause water in the recycling ponds is continuously reused, sediment and water in recycling ponds usually con-tain high concentrations of nutrients including nitrate, phosphorus, and po-

tassium. Pesticide content of water can trigger unique microbial environments that are different from those in natural sediments. Testing for the amount of the four pesticides showed only an insignif-icant amount of residual pesticides in the two selected sediment samples.

Sorption of pesticidesThe sorption isotherms of the four

pesticides in the two nursery sediments are generally linear over the range of equilibrium concentrations, which were up to 40 ppm for pendimethalin and chlorpyrifos and 120 ppm for chlo-rothalonil and diazinon. Degradation compounds of pesticides were mea-sured by incubating pesticide-fortified sediment samples at room temperature (22°C ) or 10°C under either aerobic or anaerobic conditions. In a nurs-ery recycling pond, most of the pesti-cides will reside in the bulk sediment or with suspended sediment. Overall persistence of pesticides in the pond mainly depend on the sediment phase. The strong sorption of these pesticides into the sediment tells us that runoff recycling using sedimentation ponds may keep the pesticides on the prop-erty and minimize the potential runoff input into downstream surface water bodies. However, the pesticides can accumulate, and reuse of water with-out additional makeup water can cause phytotoxicity if the quantity of pesticide in the water increases too much.

Sediment of Nursery B was approxi-mately 3.1-, 3.2-, 1.4-, and 1.3-fold, respectively, of that for Nursery A sedi-ment for the same compound. For di-azinon and chlorothalonil, the stronger sorption in Nursery B sediment may be mainly caused by its higher organic matter content. For pendimethalin and chlorpyrifos, other factors, such as a difference in organic carbon structure content appeared to have influenced sorption. In addition, the texture of the sediments might also contribute to the difference between the two sediments as sorption of pendimethalin and chlor-pyrifos was found to correlate positively with the amount of clay in the soil (the texture of sediment in Nursery A was much finer than in Nursery B).

The high KOC (soil organic carbon distribution coefficient) values of pen-dimethalin and chlorpyrifos indicate that these pesticides distributed them-selves into the sediment of the recycling pond. In a nursery recycling pond, the majority of these pesticides will prob-ably reside in the bulk sediment or with suspended sediment. Persistence of pesticides in the sediment phase will determine the overall persistence of pesticides in the pond environment. The strong sorption of these pesticides suggests that the practice of runoff re-cycling using sedimentation ponds may effectively keep the pesticides on the property and minimize the potential runoff into downstream surface water bodies. The strong sorption also sug-gests that other mechanisms can be used to remove suspended solids, such as constructed wetlands, sedimenta-tion basins, and the use of flocculants (such as polyacrylamide) and that these methods can reduce pesticide loads in nursery runoff.

Degradation of pesticides in nursery ponds

The chemical structure of pesticides is the most important factor for how they persist, as it determines how the material is affected by microbial me-tabolism. Depending on temperature conditions, the four pesticides tested in this study followed the order of chlor-pyrifos > diazinon> chlorothalonil > pendimethalin in speed of degradation in pond sediment. The degradation rate varied with the characteristics of sedi-ment, the availability of oxygen, and temperature.

Sediment of a nursery collection pond will have higher amounts of or-ganic matter than natural streams, and the sediment will be higher in salinity. Two of the organophosphate pesticides (diazinon and chlorpyrifos) were mod-erately persistent in the pond sediment. At temperatures below 22°C and under aerobic conditions, the half-life of di-azinon was 8.6 days in Nursery A sedi-ment and 10.2 days in Nursery B sedi-ment, while the half-life of chlorpyrifos was 23.3 days in Nursery A sediment and 31.5 days in Nursery B sediment.


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These organophosphate compounds can be degraded by both biotic and abiotic action in soil and in water, and the rate of degradation depends on pesticide application rates, as well as temperature, pH, moisture, and oxygen action.

Temperature effects can increase degradation of the organophosphate pesticides, accelerating the abiotic chemical reactions and speeding up microbial activities. The pesticide ac-tivity remains active in pond sediment in the case of all four tested pesticides for a significantly longer time at lower temperatures, depending on the nature

of the sediment as well as the tempera-ture. Colder seasons will reduce deg-radation activity and could cause pes-ticide accumulation to increase, and the degradation activity will increase in the summer months, degrading the pesticides more rapidly from the pond water.

It should be noted that laboratory ex-periments are not directly applicable to field conditions but can provide general information. For instance, this carefully controlled experiment indicates that chlorothalonil and pendimethalin will generally not accumulate in nursery recycling ponds because they dissipate

rapidly, while diazinon and chlorpyrifos may be persistent to varying degrees. All four pesticides are most likely to remain in sediment phases. Runoff can be reduced by practices that retain the suspended sediments, such as the use of flocculants, and this can help protect downstream water bodies. X

Adapted from “Sorption and Degrada-tion of Pesticides in Nursery Recycling Ponds,” by Jianhang Lu, Laosheng Wu, Julie Newman, Ben Faber, Donald J. Merhaut, and Jianying Gan. J. Environ. Qual. 35:1795–1802.

1. Which condition will most likely speed degradation of pesticides in pond sediment?

q a. freezing and thawing.

q b. high levels of pesticide applications.

q c. use of flocculants.

q d. higher temperatures.

2. What conditions speed up microbial activity on pesticide-containing sediment?

q a. low temperatures.

q b. low pH.

q c. high temperatures.

q d. low oxygen activity.

3. This study compared the activity of two nursery recycling ponds under what conditions?

q a. container nursery production with ditch-type irrigation.

q b. container nursery production with overhead irrigation.

q c. container production with drip irrigation.

q d. seedling flat production with bottom irrigation.

4. The pesticides used included

q a. a fungicide, an insecticide, a herbicide, and an antivi-ral agent.

q b. an insecticide and nematicide, a herbicide, and a fun-gicide.

q c. a bloom enhancer and an insecticide.

q d. a fungicide and nematicide.

5. In the ponds used for this experiment, the amount of pes-ticide found initially was

q a. low but significant.

q b. very high.

q c. variable.

q d. insignificant.

6. How does nursery pond sediment differ from natural stream sediment?

q a. less organic matter.

q b. lower salinity.

q c. greater density.

q d. higher organic matter and more salinity.

How do pesticides behave in nursery recycling ponds? (no. SS 03670)

Spring 2007 Self-Study Exam This exam is worth 1 CEU in Soil & Water Management. A

score of 70% or higher will earn CEU credit. The International CCA program has approved self-study CEUs for 20 of the 40 CEUs required in the two-year cycle. An electronic version of this test is also available at www.certifiedcropadviser.org. Click on “Continuing Education” and then “Self-Study CEUs.”



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7. Which two pesticides showed moderate and variable per-sistence in recycling pond sediments?

q a. diazinon and chlorpyrifos.

q b. diazinon and chlorothalonil.

q c. chlorpyrifos and chlorothalonil.

q d. chlorothalonil and pendimethalin.

8. What are practices that can reduce pesticide runoff?

q a. Use flocculants to keep sediment on the ponds.

q b. Use more pesticide.

q c. Increase temperature of the holding ponds.

q d. Decrease size of holding ponds.

9. Nursery container operations use

q a. a mix of pesticides to provide acceptable products.

q b. mostly insecticides.

q c. a standard mix, the same each year.

q d. mostly fungicides.

10. The degradative capacity of a recycling pond is reduced by

q a. cooler weather.

q b. higher temperature or seasonality.

q c. combinations of pesticides.

q d. unusual bacterial environments.


Earn 1 CEU in Crop Management by reading this article and completing the exam at the end. CCAs may earn 20 CEUs per two-year cycle as board-ap-proved self-study articles. Fill out the attached questionnaire and mail it with a $15 check (or provide credit card information) to the American Society of Agronomy. Or, complete the exam online at www.certifiedcropadviser.org ($12 charge).


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inding the right population density of corn plants for a given area of land depends on several things: hybrid

type, soil fertility, and agronomic man-agement. Leafy hybrids, grown primar-ily for silage, have been around for a while, but specific information about the precise agronomic practices to op-timize production of silage hasn’t been available. To provide this needed infor-mation, a study was undertaken at the Eastern Cereal and Oilseed Research Centre of Agriculture and Agri-Food Canada in Ottawa, Ontario, to identify the appropriate plant density for leafy hybrids, compared with conventional hybrids, under different nitrogen fertil-ization rates.

Looking at the specifics about appro-priate hybrids for silage, there is diver-

gence of thought between the appro-priateness of a grain hybrid and a leafy hybrid. Leafy corn plants have more leaves above the ear compared with standard corn hybrids. The plants look bigger, and some seed corn producers maintain that these plants provide more and better silage per acre than conven-tional corn varieties. Other producers suggest that leafy hybrids may lodge more often and produce less silage and/or less quality silage. For this trial, two hybrids were chosen: a leafy hybrid designated as Maizex LF850 RR and a conventional hybrid, Pioneer 3893.

Whether a farmer prefers to plant the “leafies” to conventional hybrids can depend on his or her perception of the “look” of the field. The additional leaves that grow above the ears can cause the field to look quite robust. The leafy hy-brid chosen for this test generally pro-duces 20 to 25% more leaf area on an individual plant basis. Crop growth rate depends on several factors, including

the amount of light available through the canopy and used by the leaves to convert into photosynthates or biomass. The leaf area index (LAI; the amount of leaf surface per unit of ground) is at its maximum around silking, so early growth is important. The plant popu-lation density affects both leaf area u

u Abbreviations: LAI, leaf area in-dex; PAR, photosynthetically active radiation.

F

Corn types respond

to population density

and nitrogen levels

differently

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and biomass yield, and balancing these two parameters determines the value of silage and its amount. In this paper, amount of silage was also measured.

To optimize dry matter yield from the leafy hybrid, and to compare its ac-tual performance with the conventional hybrid, the two hybrids were planted at three densities: 24,300 plants/acre, 30,365 plants/ acre, and 36,440 plants/ acre.

Fertilizer was used in four regimes: at 0 additional nitrogen, 66.8 lb nitro-gen/acre, 133.6 lb nitrogen/acre, and 200 lb nitrogen/acre. To test the extent to which plant density and fertilizer af-fected the yields, plant canopy light in-terception, plant dry matter, silage, and grain yield were measured.

This test presumably provides in-formation that may be specific to the northern tier of states and the southern part of Canada. Growing conditions for both 2003 and 2004 produced normal amounts of rainfall, and air tempera-tures were similar and normal. Rain-fall was evenly distributed throughout both growing seasons, and plants ex-perienced little or no stress. The 2004 growing season had better rainfall dur-ing the grain-filling period. The month of May was a little warmer in 2004 than 2003, but the late season of 2003 was warmer (in August and September).

The effect of canopy light interception

The amount of light that penetrates the canopy affects photosynthesis, so the measurement called “intercepted photosynthetically active radiation (PAR)” is estimated on the basis of the leaf area per unit ground area (LAI). The relationship between leaf area and the light that filters through to the ears of grain is measured as a variation in LAI caused by plant architecture and envi-ronment. Increased plant density and nitrogen fertilizer rates can increase LAI. Increased plant density promotes light attenuation within the canopy, ac-cording to a study published in 2003, but decreases grain protein content.

It has been reported that higher plant density allows capturing more of the intercepted PAR early in the season,

but crowding increases as the canopy closes because of midseason growth. Grain yield in each unit area increases as plant density increases, but only un-til the yield per plant decreases, caused by reduced light conditions. When the plant density proceeds past optimal, the number of kernels per ear, weight of the individual kernels, and length of the cob are all reduced, and total yield drops.

A word about the methods used: leaf greenness, which measures the amount of usable light reaching the plants, was measured with a chlorophyll meter (SPAD-502 Chlorophyll Meter, Minolta Camera Co., Ltd, Tokyo, Japan), and canopy reflectance was measured with a hand-held radiometer (MSR-16 Crop-Scan Inc., Rochester, MN). The spectral readings from the CropScan were used to derive a normalized difference veg-etative index. Leaf area index was mea-sured using a leaf area meter (LI-300, LI-COR, Inc., Lincoln, NE).

The role of nitrogen Nitrogen fertilizer influences leaf

area development and maintenance and increases dry matter production. The need for more or less nitrogen is a function of hybrid type, population density, soil, and other environmen-tal conditions. There have been many studies relating nitrogen concentration and corn yield, but few have consid-ered the effect of nitrogen on different hybrid types, row spacing, and plant densities. This study investigated how the two types of corn hybrids differ in response to nitrogen concentration and plant density for grain or silage produc-tion, and whether any hybrid response is consistent across years.

Nitrogen appeared to have major ef-fects on silage yields and did not ap-pear to interact with hybrids or plant density.

ResultsIn this study, the leafy hybrid had

20 leaves per plant, while the con-ventional hybrid had 16. Ten of the leafy hybrid leaves were above the ear compared with five above the ear in the Pioneer hybrid. Highest ni-

X

trogen addition levels produced the most leaf area, especially for the leafy hybrid, which was less tolerant of low nitrogen stress than the conventional hybrid.

However, plant greenness, as mea-sured by the chlorophyll meter, was consistently higher in the convention-al hybrid, and the greenness scores were highest for the lower plant den-sities.

Nitrogen treatment affected the number of ears and barren plants in 2003. Treatments that added no nitro-gen produced the fewest ears and had the most barren plants (up to 15%). The three levels of nitrogen treatment produced little difference in the num-ber of ears or barren plants, so in this case, additional nitrogen produced little additional value, as far as grain yield was concerned.

There was a clear nitrogen interac-tion with the selected hybrids, with the leafy hybrid showing no ears in about 10% of the plants grown with no nitrogen supplementation, while only 2.6% of the Pioneer 3893 hy-brid plants were barren. High plant densities produced the greatest num-ber of barren plants, when given no supplemental nitrogen, especially in the leafy hybrid.

Leafy hybrids had more barren plants when planted at high densities without nitrogen addition, while the conventional hybrid responded simi-larly regardless of plant densities and nitrogen additions. For the leafy hy-brid, as the plant density increased, so did the number of barren plants despite greater fertilizer application, indicating that crowding in the cano-py affected ear development.

Silage-specific hybrids vs. all-purpose varieties (or hybrids)

If a farmer is sure he or she wants more silage from a field of corn, this study indicated that, for biomass alone, the leafy hybrids produced greater dry matter than the Pioneer hybrid. It was clear that the two hybrids differed in several parameters. The leafy hybrid produced a large amount of biomass

X

X

X

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and greater LAI but had smaller grain yield than the conventional hybrid. So, it depends on the purpose for which the plants are grown. It is clear that higher plant densities yielded better silage than grain when good nitrogen levels were maintained. However, the study did not attempt to test the quality of the resulting forage produced.

Grain yield of the two hybrids both increased exponentially at the high-est nitrogen addition levels, regardless of plant density or hybrid. However, the leafy hybrid produced lower grain

yields, possibly because of a higher number of barren plants. The differenc-es were relatively small, however.

Silage yield increased linearly as plant density increased, for both hy-brids tested. Plant densities above the tested densities appeared to produce still more silage. Silage moisture varied: because of a slightly delayed harvest in 2003, the moisture level of the un-fermented silage was between 63 and 65% in 2004 and 53 to 59% in 2003.

The value of silage is generally con-sidered part of the formula when it is

integrated into the diet of animals. In the case of dairy cows, silage is part of the total formula but can be estimated as a part of the “milk per acre” formulas used to optimize crop yields. X

Adapted from “Response of a Leafy and Non-Leafy Maize Hybrid to Population Densities and Fertilizer Nitrogen Lev-els,” by K.D. Subedia, B.L. Ma, and D.L. Smith. Crop Sci 46:1860–1869.

1. What is a “leafy” hybrid?

q a. A corn plant that produces more leaves below the ear shoots.

q b. A corn plant that has little or no tassel.

q c. A barren corn plant.

q d. A corn plant with more leaves, especially above the ear node.

2. How does a leafy hybrid react to nitrogen stress?

q a. It produces less leaf area at high plant densities.

q b. It producers more ears.

q c. It produces more leaf area.

q d. It produces more tillers.

3. Leafy hybrids produce

q a. the greatest amount of plant biomass at high plant densities and higher nitrogen levels.

q b. more grain than standard hybrids at high plant densities.

q c. less lodging than standard hybrids as tested.

q d. better grain than silage.

4. Silage production increased in both hybrids tested

q a. at the highest plant density levels.

q b. at the highest nitrogen levels.

q c. at the lowest plant density levels.

q d. at low density, low nitrogen levels.

5. Grain yield was lowest in the leafy hybrids because

q a. ears were smaller.

q b. kernels were smaller.

q c. more plants were barren.

q d. fewer plants emerged.

6. How many leaves were above the ear node on the leafy hybrid in this test?

q a. 12.

q b. 10.

q c. 8.

q d. 2.

Corn types respond to population density and nitrogen levels differently (no. SS 03690)

Spring 2007 Self-Study Exam This exam is worth 1 CEU in Crop Management. A score

of 70% or higher will earn CEU credit. The International CCA program has approved self-study CEUs for 20 of the 40 CEUs required in the two-year cycle. An electronic version of this test is also available at www.certifiedcropadviser.org. Click on “Continuing Education” and then “Self-Study CEUs.”





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7. How many fewer leaves did the conventional hybrid have compared with the leafy hybrid?

q a. 2.

q b. 4.

q c. 7.

q d. They were the same.

8. Leafy hybrids are more affected by nitrogen stress than conventional ones, measured by the number of barren plants. What was the average of barren plants for both hybrids in this test?

q a. 10% leafy, 2.6% conventional.

q b. 5% leafy, 2% conventional.

q c. 15% leafy, 1% conventional.

q d. 12.6% leafy, 3.8% conventional.

9. If nitrogen is not added to fields for silage, which plant densities will yield fewest barren plants?

q a. lowest plant densities of leafy hybrid.

q b. moderate densities.

q c. High densities of leafy hybrid.

q d. low densities of conventional hybrid.

10. What attributes produce high leaf greenness?

q a. light, nitrogen, plant density, and hybrid.

q b. plant density and water.

q c. insect pressure.

q d. number of leaves.


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orn develops leaf area slow-ly and competes poorly with early emerging weeds in the normally cool conditions of

the northeastern USA. Corn growers who plant glyphosate-resistant corn need to know when to initiate their weed control program to prevent yield loss from early-season weed competi-tion. Hall et al. (1992) reported that the critical period of weed control in corn occurred from the third to 14th leaf stage. This indicates that corn tolerated early-season weed competition with-out yield loss only until the third leaf stage in the cool spring conditions of Ontario, Canada. The results from the Canadian study suggest that glypho-sate may have to be applied as early as the V3 stage (Ritchie et al., 1993) to prevent yield losses from early-season weed competition in regions with cool spring conditions. Gower et al. (2003) reported that the optimum timing for weed control and corn yields for an ini-tial application of glyphosate generally occurred by the V4 stage in the north-central USA when weeds were less than 4 inches high. Dalley et al. (2004), however, reported that the optimum timing for weed control and corn yields depended on specific annual growing conditions in Michigan. In highly com-petitive conditions (high weed densities and below-normal precipitation), opti-mum glyphosate application for weed control and corn yield occurred by the V4 stage. In less competitive condi-tions, optimum glyphosate application for weed control and corn yield oc-curred as late as the V9 stage. Gower et al. (2002) reported that glyphosate should be applied before weeds are 6 inches high to avoid yield losses in Ohio. They concluded that reinfestation of weeds after an early application had less potential to reduce yield than de-

laying application and allowing weeds to compete with corn for too long a pe-riod before removal.

Kernel number is the yield compo-nent that most influences grain yield of corn (Tollenaar, 1977; Otegui, 1997; Andrade et al., 1999). Maddonni and Otegui (2004) suggested that the physi-ological state of the corn plant resulting from interplant competition between corn plants may determine the kernel number of corn as early as the V7 stage. The objective of this study was to eval-uate how early-season weed competi-tion in relation to the timing of an ini-tial glyphosate application affects the growth, development, yield, and yield components of corn.

Materials and methodsField experiments were conducted

in 2003 and 2004 on a silt loam soil at a Cornell University research farm near Aurora, NY. In the experimental year, the sites received an application of 0.75 lb/acre of glyphosate and 0.50 lb/acre of 2,4-D ester in late April for control of perennial weeds. The ex-perimental sites were then disked and harrow-cultipacked before planting. Soil tests of the experimental sites in-dicated a pH of 7.9 in 2003 and 7.8 in 2004 with medium concentrations of P and K in both years. DeKalb brand ‘DKC42-70RR’, 92-day Relative Matu-rity (RM), and ‘DKC53-33RR’, 103-day RM, were planted on May 5, 2003 and May 11, 2004 with a four-row planter at a 30-inch row spacing and 35,600 kernels/acre with 200 lb/acre of the starter fertilizer 10–20–20. All plots re-ceived about 100 lb/acre as a 32% (w/v) N solution of urea/ammonium nitrate at the V5 stage of corn growth in both years.

Weed control treatments included an untreated control, a weed-free plot, and three postglyphosate treatments. The weed-free plot received a mixture of atrazine and S-metolachlor applied pre-emergence followed by a later glyphosate application. Glyphosate

treatments were 1 lb/acre (applied as 0.8 qt/acre of Roundup ULTRAMAX) at the V3–V4 stage of corn growth (EP-OST), the V5–V6 stage (MPOST), and the V7–V8 stage (LPOST). The EPOST and MPOST treatments also received a second glyphosate application at LPOST. All herbicides were applied with a tractor-mounted sprayer with flat fan nozzles at 20-inch spacing. The sprayer was calibrated to deliver 20 gal/acre at 34-psi pressure at a ground speed of 20 mph. Boom height was 20 inches above the soil surface for the pre-emergence application, 22 inches for the EPOST, 28 inches for the MPOST, and 36 inches for the LPOST herbicide applications.

The experimental design was a ran-domized complete block in a split-plot arrangement with five replications. Hy-brids were the main plots, and weed control treatments were the subplots. Subplots measured 10 by 40 ft.

Results and discussionWeed populations. The 2003 and

2004 growing seasons were mostly stress-free for corn growth, and the weed-free treatments provided similar yields in 2003 and 2004. Weed popu-lation density totaled 1,630 weeds/sq yd in the untreated control at the V5 stage in 2003, with most weeds emerg-ing with corn or a few days thereaf-ter. Population densities totaled 771/ sq yd for common lambsquarters and 517/sq yd for green foxtail in 2003 (Table 1—next page). Such high densi-ties of both weeds can significantly re-duce corn yields in untreated u

Time of weed removal with glyphosate affects corn growth, yield components

C

u Abbreviations: DM, dry matter; EPOST, V3–V4 stage of corn growth; LAI, leaf area index; LPOST, V7–V8 stage of corn growth; MPOST, V5–V6 stage of corn growth.

Earn 1 CEU in Pest Management by reading this article and completing the exam at the end. CCAs may earn 20 CEUs per two-year cycle as board-ap-proved self-study articles. Fill out the attached questionnaire and mail it with a $15 check (or provide credit card information) to the American Society of Agronomy. Or, complete the exam online at www.certifiedcropadviser.org ($12 charge).



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control plots as indicated by a 44% yield reduction with population densi-ties of 38 lambsquarters/sq yd (Sikkema et al., 2004) and up to a 40% yield re-duction with population densities of 60 green foxtails/sq yd (Cathcart and Swanton, 2004) in Ontario, Canada. Also, wild mustard, which measured 14 inches high, 1 inch taller than corn, to-taled 160/sq yd at the V5 stage in 2003. Dalley et al. (2004) reported that weed height as well as weed population den-sity were equal factors in reducing corn yields, so the height and density of wild mustard had the potential to reduce corn yields in this study.

Weed population density in 2004 totaled 781 weeds/sq yd in the untreat-ed control at the V6 stage, with most weeds emerging with corn or a few days thereafter. Population densities to-taled 252/sq yd for common ragweed, 185/sq yd for green foxtail, and 129/sq yd for common lambsquarters. In addi-tion, the population density of yellow nutsedge, which measured 7 inches high at the V6 stage, totaled 84/sq yd. Thomas et al. (2004) reported that yel-low nutsedge population densities of 60/sq yd, which measured 6 to 8 inch-es high at the V5 to V6 stage, reduced corn yields by 85% in North Carolina. Although weed population densities were more than 50% less in 2004 vs. 2003, the untreated control yielded similarly in both years. Visual estimates both years at the R1 stage indicated

greater than 95% weed control in the three postemergence glyphosate treat-ments and 100% control in the weed-free treatment.

Plant development. Corn given the weed-free and EPOST treatments silked on the same date. A delay in glyphosate application until MPOST or LPOST re-sulted in slight silking delays. A two- to three-day delay in silking can negative-ly impact corn in northern latitudes be-cause it increases the risk of a fall frost before corn attains physiological ma-turity. The untreated control silked five days later vs. the weed-free treatment, which is consistent with the four-day delay reported by Evans et al. (2003a) in a Nebraska study.

The weed-free and EPOST treatments averaged similar leaf area index (LAI) values and dry matter (DM) accumu-lation at the V8 and R1 growth stages. Under the environmental conditions of this study, significant weed competition before the V3–V4 stage did not affect vegetative growth of corn. The MPOST treatment, however, averaged 46% less LAI and 56% less DM accumulation at the V8 stage and 35% less LAI and 39% less DM accumulation at the R1 stage compared with the weed-free treat-ment. Maddonni and Otegui (2004) recently reported that the physiological state or size of the plant at the V13 stage or earlier can significantly influence kernel number of corn. Weed compe-tition up to the V5 to V6 stage in this

study may have reduced DM accumu-lation at the V8 stage to such an extent that potential biomass allocation to the developing ear and subsequent kernel number were impaired (Maddonni and Otegui, 2004).

The LPOST treatment had a 61% re-duction in LAI and a 65% reduction in DM accumulation at the V8 stage and a 47% reduction in LAI and a 55% reduction in DM accumulation at the R1 stage compared with the weed-free treatment. The 47% reduction in LAI greatly exceeded the 24% reduction in maximum LAI in a LPOST treatment (glyphosate application at the V9 stage) in a Nebraska study in which weed population densities ranged from 96 to 435 weeds/sq yd (Evans et al., 2003a). In fact, the LPOST and untreated con-trol had the same LAI at the R1 stage in the current study, whereas the untreat-ed control had only a 33% reduction in maximum LAI in the Nebraska study and a 4 to 35% reduction in maximum LAI in a Canadian study (Cathcart and Swanton, 2004). Apparently, higher weed population densities and perhaps taller weeds in the current study com-pared with the Nebraska and Canadian studies resulted in greater reductions in vegetative growth in the LPOST and un-treated control, despite no water stress during vegetative development.

Yields. The weed-free and EPOST treatments yielded the same, whereas u

u Table 1. Date, height, and leaf stage of corn, and height of the major weed species at the time of early (EPOST), mid- (MPOST), and late (LPOST) postemergence applications.

Treatment Date Corn Lambsquarters Foxtail Ragweed Nutsedge Mustard

Height, inches

2003

EPOST June 2 10, V3 0.4 0.8 – – 2

MPOST June 17 33, V5 3 4 3 – 14

LPOST June 30 38, V7 6 6 8 – 24

2004

EPOST June 7 25, V4 2 4 2 3 2

MPOST June 21 43, V6 3 5 5 7 11

LPOST June 28 61, V8 4 13 9 7 16

[continued on page 36]


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the MPOST treatment yielded 25% less (Table 2). Significant weed competition before the V3 to V4 stage did not influ-ence growth, development, and yield, but significant weed competition up to the V5 to V6 stage significantly influ-enced development and reduced grain yield by 25%. The critical weed control period under the environmental condi-tions of this study began shortly after the V3 to V4 stage. This finding agrees with the findings of Hall et al. (1992) in their pioneering study in Ontario, Canada. The 25% yield reduction in the MPOST vs. the weed-free treatment, however, far exceeds results from other studies with similar environmental conditions in which the V4 stage marked the be-ginning of the critical weed-free period. A glyphosate application at the V5 to V6 stage vs. a weed-free treatment resulted in an 11% yield reduction in a Michi-gan study in which giant foxtail was the dominant species, with population densities of 658 to 837/sq yd (Tharp and Kells, 1999). In an Ohio study, in which giant foxtail was the dominant species with population densities of 4,066/sq yd at one site and 2,213/sq yd at another site, yield reductions were 13 and 0%, respectively, with a glypho-sate application at the V5 to V6 stage (Gower et al., 2002). In a multistate study in the north-central USA in which giant foxtail was among the dominant weed species at 31 of 35 sites, common lambsquarters was among the dominant at 23 sites, and common ragweed was

among the dominant at 13 sites, yield reductions averaged only 8% with a glyphosate application at the V5 to V6 stage (Gower et al., 2003). Dalley et al. (2004), however, found that weed height plus weed population density predicted yield reductions better than weed population densities alone.

The LPOST treatment yielded 42% less, and the untreated control yielded 71% less compared with the weed-free treatment. Although the LPOST and untreated control had similar LAIs and DM accumulation at the R1 stage, the untreated control yielded 50% less than the LPOST treatment. Obviously, the critical weed-free period extended far beyond the V7 to V8 stage in this study. The relationships between LAI and DM accumulation at the R1 stage and grain yield were curvilinear rather than lin-ear in this study, which agrees with the findings of Evans et al. (2003a). Weed control treatments did not affect ear number per plant. Evans et al. (2003b) also reported that ear number had min-imal effect on yield losses associated with weed interference in a weed con-trol timing study.

Yield components. The EPOST and weed-free treatments averaged similar numbers of rows per ear, kernels per row, and kernels per plant. The MPOST treatment averaged 0.8 less rows per ear, 6.2 less kernels per row, and 118 less kernels per plant vs. the weed-free treatment. The LPOST treatment av-eraged 1.8 less rows per ear, 9.1 less kernels per row, and 188 less kernels per plant compared with the weed-free

treatment. Despite similar LAI values and DM accumulation at the R1 stage, the LPOST treatment averaged 9.6 more kernels per row and 147 more kernels per plant compared with the untreated control. Apparently, weed interference during the three-week period after silk-ing contributed to kernel abortion in the untreated control.

Kernel weight was much less sensi-tive to weed interference than kernel number, findings that agree with those of Evans et al. (2003b). A reduction in postsilking crop growth rates from two to six weeks after silking reduces kernel weight in corn (Maddonni et al., 1998), which Cathcart and Swanton (2004) attributed to an 8 to 12% reduction in kernel weight when green foxtail popu-lation densities exceeded 60/sq yd. All treatments except for the untreated con-trol had mostly weed-free conditions during the grain-filling period, which probably contributed to their similar kernel weights.

ConclusionsThe critical period for weed control

began shortly after the V3–V4 stage of corn growth when all weed species were 4 inches or less in height. A de-lay in glyphosate application until the V5–V6 stage, when wild mustard mea-sured 14 inches high in 2003 and yel-low nutsedge measured 7 inches high in 2004, delayed silking by two days, reduced LAI at silking by 35% and DM accumulation by 39%, kernel num-ber by 21%, and grain yield by 25%. Maddonni and Otegui (2004) reported

u Table 2. Leaf area index, grain yield, and yield components averaged across two hybrids and the 2003 and 2004 growing seasons under different weed control treatments.

Treatment LAI at V8 Yield Ears/plant Rows/ear Kernels/row Kernels/plant Kernel weight

bu/acre mg

Weed-free 1.57 177 1.00 15.8 34.9 549 216

EPOST 1.52 177 1.00 15.7 33.6 528 248

MPOST 0.84 132 1.00 15.0 28.7 431 239

LPOST 0.62 102 1.00 14.0 25.6 361 205

Untreated 0.61 51 0.98 13.2 16.2 214 180

LSD 0.05 0.14 8 NS 0.5 3.1 50 50

Time of Weed Removal | from page 34

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that interplant competition among corn plants began at the V4 to V6 stage. The delay in glyphosate application from the V3 to V4 stage until the V5 to V6 stage resulted in 0.7 less rows per ear, which indicates that weed interference between the V4 to V6 stage may have directly affected reproductive devel-opment in corn. The results from this study indicate that growers should ap-ply glyphosate by the V3 to V4 stage to avoid yield losses from early-season weed competition in the cool spring conditions in the northeastern USA. X

ReferencesAndrade, F.H., C. Vega, S. Uhart, A. Cirilo, M.

Cantarero, and O. Valentinuz. 1999. Ker-nel number determination in maize. Crop Sci. 39:453–459.

Cathcart, R.J., and C.L. Swanton. 2004. Ni-trogen and green foxtail (Setaria viridis) competition effects on corn growth and development. Weed Sci. 52:1039–1049.

Dalley, C.D., J. Kells, and K. Renner. 2004. Effect of glyphosate application timing and row spacing on corn (Zea mays) and soy-bean (Glycine max) yields. Weed Technol. 18:165–176.

Evans, S., S. Knezevic, J. Lindquist, and C. Shapiro. 2003a. Influence of nitrogen

and duration of weed interference on corn growth and development. Weed Sci. 51:546–556.

Evans, S., S. Knezevic, J. Lindquist, C. Shap-iro, and E.E. Blankership. 2003b. Nitrogen application influences the critical period for weed control in corn. Weed Sci. 51:408–417.

Gower, S.A., M. Loux, J. Cardina, and S.K. Harrison. 2002. Effect of planting date, residual herbicide, and postemergence application timing on weed control and grain yield in glyphosate-tolerant corn (Zea mays). Weed Technol. 16:488–494.

Gower, S.A., M. Loux, J. Cardina, S.K. Harri-son, P.L. Sprankle, N.J. Probst et al. 2003. Effect of postemergence glyphosate appli-cation timing on weed control and grain yield in glyphosate-resistant corn: Results of a 2-year multistate study. Weed Tech-nol. 17:821–828.

Hall, M.R., C.L. Swanton, and G.W. Ander-son. 1992. The critical period of weed control in grain corn (Zea mays). Weed Sci. 40:441–447.

Maddonni, G.A., and M.E. Otegui. 2004. Intra-specific competition in maize: Early establishment of hierarchies among plants affects final kernel set. Field Crops Res. 85:1–13.

Maddonni, G.A., M.E. Otegui, and R. Bon-hommie. 1998. Grain yield components in maize: II. Postsilking growth and kernel weight. Field Crops Res. 56:257–264.

Otegui, M.E. 1997. Kernel set and flower syn-chrony within the ear of maize: II. Plant population effects. Crop Sci. 37:448–455.

Ritchie, S.W., J.J. Hanway, and G.O. Benson. 1993. How a corn plant develops. Coop. Ext. Serv. Spec. Rep. Iowa State Univ., Ames. IA.

Sikkema, P.H., C. Shropshire, A.S. Weaver, and P.B. Cavers. 2004. Response of com-mon lambsquarters (Chenopodium album) to glyphosate application timing and rate in glyphosate-resistant corn. Weed Tech-nol. 18:908–916.

Tharp, B.E., and J.J. Kells. 1999. Influence of herbicide application rate, timing and interrow cultivation on weed control and corn (Zea mays) yield in glufosinate-resis-tant and glyphosate-resistant corn. Weed Technol. 13:807–813.

Thomas, W.E., I.C. Burke, and J.W. Wilcut. 2004. Weed management in glyphosate-resistant corn with glyphosate, halosul-furon, and mesotrione. Weed Technol. 18:826–834.

Tollenaar, M. 1977. Sink-source relation-ships during reproductive development in maize. A review. Maydica 22:49–75.

Adapted from “Time of Weed Removal with Glyphosate Affects Corn Growth and Yield Components,” by W.J. Cox, R.R. Hahn, and P.J. Stachowski. Agron. J. 98:349–353.

1. A goal of this research was to

q a. test different weed control products.

q b. compare glyphosate efficacy among different cropping systems.

q c. examine the susceptibility of different weed species in becoming resistant.

q d. determine how weed control timing affected corn growth and yield.

2. A situation increasing the competition between corn early growth and weeds might include any of the following EXCEPT

q a. droughty weather. q b. high weed populations.

q c. low-fertility soils. q d. cool conditions.

3. A characteristic of the research methods was that

q a. herbicide treatments were subplots.

q b. multiple test locations were located near upstate New York.

q c. different formulations of glyphosate were used.

q d. corn was planted in a range of dates each year to obtain dif-ferential development information.

time of weed removal with glyphosate affects corn growth, yield components (no. SS 03680)

Spring 2007 Self-Study Exam This exam is worth 1 CEU in Pest Management. A score of

70% or higher will earn CEU credit. The International CCA program has approved self-study CEUs for 20 of the 40 CEUs required in the two-year cycle. An electronic version of this test is also available at www.certifiedcropadviser.org. Click on “Continuing Education” and then “Self-Study CEUs.”





Exam Continues

Next Page

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4. Compared with early postglyphosate treatments, late post-treat-ments yielded about

q a. 50% more. q b. 25% more.

q c. 25% less. q d. 50% less.

5. The characteristic of weeds most associated with yield loss is

q a. allelopathic factors. q b. rooting volume.

q c. weed population density. q d. weed seed size.

6. A factor little-affected by herbicide timing was

q a. kernel weight. q b. ears/plant.

q c. grain yield. q d. kernel thickness.

7. Compared with more southern locations, the impact of early weed pressure in the northern corn growing areas is generally

q a. more.

q b. less, because of different hybrid genetics.

q c. less, because of the ability of corn to grow relatively faster than weeds.

q d. about the same.

8. The factor most indicating that early weed pressure may have interfered with early reproductive development in corn is

q a. ears/plant. q b. rows/ear.

q c. kernel weight. q d. leaf area index (LAI).

9. According to Table 2, there was a significant difference in the early post-treatments compared with the weed-free checks for

q a. leaf area index (LAI). q b. kernels/plant.

q c. kernel weight. q d. none of the above.

10. To avoid yield losses, growers should make glyphosate applica-tions by the

q a. V4 stage. q b. V9 stage.

q c. V11 stage. q d. R4 stage.


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tecHnology

he cost of keeping weeds out of fields continues to grow, and the growth not only represents cost-per-unit, but

also the costs of contaminating ground-water, and the problems of reducing effectiveness. Several new herbicides have been introduced to the market re-cently and offer some of the attributes needed by growers of modern crops.

Concerns about herbicides have in-creased in recent years. Some of the concerns include: activity levels appro-priate for specific crops, broad appli-cation levels for different weeds, cost, and dealing with herbicide-resistant crops in a way that will prevent major weeds from becoming glyphosate resis-tant quickly.

The rapid adoption of glyphosate-resistant hybrids may pose problems in the future, according to crop scientists. New herbicide-resistant crops have provided growers with an easy-to-use, low-cost, and effective weed control program that does not harm their crops. In addition, the new herbicide-resistant crops, developed with modern biotech-nology, have significantly increased growers’ profits by decreasing their input costs, increasing yields, or both, in some cases. New herbicide-resistant crops have increased no-till and mini-mum-tillage agriculture in the U.S. by 35%, which saves 1 billion tons of soil material from erosion annually.

According to DuPont, the result of these benefits to growers led glypho-sate-resistant soybeans to become available to U.S. growers in 1996, and within five years, 70% of the soybeans grown in the U.S. were glyphosate-resistant biotech varieties. The rate of increase in Argentina was even more rapid. Within the same time frame, the country moved from zero acres of glyphosate-resistant soybeans to more than 29 million acres, which is 98% of its total soybean acres. Currently, over 60% of the global soybean acres are herbicide-resistant, primarily glypho-sate-resistant, varieties. In 2005, 71% (157 million acres) of the 222 million acres of biotech crops planted globally were herbicide-resistant varieties of

corn, soybean, canola, and cotton. The majority of the corn, canola, and cotton varieties were resistant to glyphosate

How do some new herbicides stack up against the concerns of producers?

Status herbicide from BASFIt’s a broad-spectrum herbicide with

three active components: dicamba and diflufenzopyr, plus a patented safener, isoxadifen. According to Mike Owen, a researcher from Iowa State University, Status makes a good tank-mix partner with glyphosate, as it can be used on Roundup Ready corn and conventional crops for broadleaf weed control, help-ing to reduce the possibility of increased glyphosate resistance. The addition of the safener decreases the possibility of phytotoxicity.

The recent appearance of glypho-sate-resistant giant ragweed in Ohio and Indiana means that growers in those states cannot depend on glypho-sate alone to control the 15-ft weed that grows fast and towers over crops. Researchers have reported yield loss of 70% when three to four giant ragweeds occupy a square yard in a field. It was registered by the EPA last December.

LibertyLink keeps herbicide-tolerant hybrids viable longer

Liberty herbicide combined with LibertyLink hybrids offer corn growers who want to manage weed-resistance concerns without giving up the con-venience of a non-selective herbicide system an economical system. Liberty users can receive up to $6.25 per acre from Bayer CropScience. The Liber-tyLink trait is available in Herculex and Agrisure CB/LL hybrids. By alternat-ing LibertyLink hybrids with Roundup Ready hybrids, weed resistance issues can be minimized, extending the pe-riods when such hybrids can be used successfully.

The 32 oz/acre rate of Liberty con-trols up to 120 tough grasses and broad-leaf weeds—that includes glyphosate-resistant and tolerant weeds and even Roundup Ready volunteers. Liberty is effective on tough-to-control weeds like woolly cupgrass, waterhemp, cocklebur, lambsquarter, foxtail, vel-vetleaf, and many others. Liberty and the LibertyLink system also offer rota-tion alternatives to Roundup Ready and conventional corn.

Resolve DF herbicide is a good tank partner for atrazine

Used as a residual pre-emergent her-bicide, Resolve DF by Dupont keeps spring fields clean until canopy. A Re-solve DF plus atrazine tank-mix pro-gram provides a broad-spectrum corn herbicide treatment that can be applied before crop emergence to up to 12-inch corn as a setup for Roundup Ready corn. This program provides more consistent performance, even under cool condi-tions, and residual with reach-back on small grasses and broadleaf weeds—even if they emerge before an activating rainfall. Resolve DF herbicide is a wa-ter-dispersible granule containing 25% active ingredient rimsulfuron by weight. The Resolve DF plus atrazine program may be used in a one-pass, soil-applied or planned two-pass herbicide program in conventional field corn or as a setup for Roundup. X

New herbicides offer lower costs, toxicity and more flexibility

T

u Giant ragweed (Ambrosia trifida L.). Photo by Ted Bodner, Southern Weed Science Society, www.ipmimages.org.


new pRoducts

Alfalfa varietyGarst Seed Company recently

added Garst brand 6417 alfalfa variety to its 2007 lineup. The company says it delivers outstanding forage yield potential and an excellent disease package, including high resistance to Aphanomyces race 2. This new variety will be available in limited quantity for planting this spring.

6417 is a multileaf variety with a disease rating index (DRI) of 30, which includes high resistance to the six ma-jor alfalfa diseases. This variety has a late-fall dormancy with a winter hardi-ness score of 1.3. Garst says it recovers fast after cutting and is widely adapted and performs well in all the traditional dormant alfalfa markets of much of the United States.

“Garst’s alfalfa lineup is working to solve specific, difficult issues, and pests and diseases are always a con-cern for growers,” says Phil Kunz, al-falfa product manager for Garst. “Both pests and diseases can cost growers by reducing yields, lowering quality, and reducing stand life. With the introduc-tion of 6417, growers have an excel-lent option in fighting several costly diseases.”

For more information, call 1-888-464-2778 or visit www.garstseed.com.

Combined pressure, humidity, and temperature transmitter

Vaisala recently introduced a new generation barometric pressure, rela-tive humidity, and temperature trans-mitter series, the Vaisala Combined Pressure, Humidity, and Temperature Transmitter PTU300. The PTU300 features fully digital measuring elec-tronics for all three parameters, several small RH&T sensor heads for different applications, and calculated humid-ity variables. The new backlit display shows three-hour graphical trends and up to one year of historical data. The recorded measurement data can be viewed on the display or transferred to a PC. Seven languages options are also available.

The PTU has four different probe options: PTU301 for laboratories,

PTU303 for outdoor use, the warmed PTU307 probe for demanding meteo-rology, and the PTU30T for pressure and temperature measurement only.

The Vaisala BAROCAP sensor is used for pressure measurement, and the Vaisala HUMICAP sensor measures humidity. The temperature sensor is a platinum RTD sensor.

Applications include environmental monitoring in calibration laborato-ries, GPS meteorology, and weather stations. For more information, call 1-888-824-7252 or see www.vaisala.com/instruments/PTU300.

Planter hitchDandi Products has a new planter

hitch designed to increase row unit clearance for John Deere model 7000, 7200, and 1770 front-fold planters. The company says that the hitch virtu-ally eliminates the costly damage to row units that can be caused by enter-ing and exiting fields or when crossing railroad tracks as well as other terrain challenges. The Dandi Planter Hitch fits category 2 and 3 hitches and 12-, 16-, and 24-row planters.

For more information, call 260-347-6830 or visit www.dandiproducts.com.

Potato Virus Y ImmunoStripAgdia, Inc. has released to the pota-

to industry a PVY ImmunoStrip that al-

lows for rapid and universal detection of all strains of potato virus Y (PVY), including yet unclassified isolates of the virus such as the NTN isolates.

Agdia designed the ImmunoStrip test for on-site determination of sus-pect PVY-infected plants, but it can also be used in laboratory settings. The company says no prior testing experi-ence or laboratory training is required to use the test.

Agdia recommends the PVY Im-munoStrip for testing nonsymptomatic leaf tissue and confirming presence of PVY in symptomatic leaf tissue. The testing process involves grinding the suspect plant sample in the special bag that contains the extraction buffer (in-cluded with the kit) and inserting the ImmunoStrip into the bag. Results can be seen in 10 to 15 minutes.

“Agdia was the first to develop this type of ImmunoStrip technique for several plant viruses, and we’re excited about the positive impact the PVY Im-munoStrip test will have in advancing the early and rapid detection of the virus in the worldwide agricultural community,” says Dr. Luis Salazar, Agdia’s Scientific Director. “Potato vi-rus Y is now the most common potato virus in nearly all regions of the world. Because almost all cultivars planted are susceptible to the virus, it creates

u The Vaisala PTU300.

u Dandi Planter Hitch.

u Agdia PVY ImmunoStrip.


new pRoducts

a huge economic impact on crops worldwide.”

For more information about the PVY ImmunoStrip and other Agdia products and services, call 574-264-2014 or visit www.agdia.com.

Soil moisture smart sensorsOnset Computer Corporation, a

supplier of battery-powered data log-gers and weather stations, recently an-nounced the release of two new plug-and-play Soil Moisture Smart Sensors for use with HOBO Weather Stations.

The new sensors measure volumet-ric water content in soil and integrate Decagon ECH2O dielectric probes for precise, long-term soil moisture moni-toring.

Onset says the new sensors are suit-able for a wide range of applications including agricultural research and

irrigation management and provide a number of key features, including:

Low sensitivity to temperature and saline effects—broadens the range of soil types, including sandy and high-salinity soils, which can be monitored with HOBO Weather Stations.

Compact form factor—enables easy installation in pots, greenhous-es, and other environments.

Smart Sensor design—enables the sensors to be plugged into HOBO Weather Stations and Micro Stations and automatically recognized with-out complicated wiring, program-ming, or calibration requirements. The new Soil Moisture Smart Sen-

sors work with Onset’s 15-channel HOBO Weather Station and 4-channel HOBO Micro Station. These systems

X

X

X

can be configured to measure the user’s choice of a wide range of pa-rameters and are powered for one year using only four AA batteries.

For more information, call 1-800-564-4377 or see www.onsetcomp.com. X

advertiser Index For advertising opportunities in Crops & Soils, contact Alexander Barton at [email protected] or 847-698-5069.

Advertiser Page Web address Phone

BASF 10–11 www.corporate.basf.com 800-526-1072

Bayer CropScience 13 www.bayercropscienceus.com 866-992-2937

Decagon Devices 19 www.decagon.com 800-755-2751

Delta-T Devices 25 www.delta-t.co.uk +44 1638 742922

Dow AgroSciences 9 www.dowagro.com 317-337-3000

Gamma Design Software 18 www.gammadesign.com NA

John Deere 48 www.deere.com 309-765-8000

LI-COR Biosciences 14 www.licor.com 800-447-3576

Mosaic 5 www.mosaicco.com 800-918-8270

Mycogen Seeds 4 www.mycogen.com 800-692-6436

Regent Instruments 2 www.regentinstruments.com NA

Spectrum Technologies 17 www.specmeters.com 800-248-8873

Stevens Water Monitoring Systems 12 www.stevenswater.com 800-452-5272

TeeJet 47 www.teejet.com 630-665-5000

Vaisala 46 www.vaisala.com 888-824-7252

u Soil Moisture Smart Sensors from Onset Computer Corporation.


company stRategies

ith a remarkable lack of the stick-your-head-in-the-sand technique, a number of oil-pro-

cessing companies are staying ahead of the demand for trans fats–free oils. Specialty soybeans with low amounts of linolenic acid (one of the amino acids naturally found in grains) offer growers a ready market, sometimes a growers’ bonus, and often contracted acres. In exchange for these economic benefits, the soybeans must be identity preserved (IP), so they can’t be stored in a common bin, and equipment must be cleaned out before planting and har-vesting. Growing “low-lin” beans has become a special deal, as more oil pro-cessors demand the IP beans to meet their customers’ needs.

Not just soybeans anymoreThey are something special, and ma-

jor users of soy oil like Kentucky Fried Chicken’s Yum Brands and Kellogg’s have jumped on the bandwagon for low-lin bean oil. The controversy about trans fatty acids, and the need for food companies to list them on the label, has forever changed the bean market. New York City has passed laws to eliminate oils that have to be hydrogenated to retain flavor stability, which produces trans fats. California cities will probably follow suit.

Development of varieties with reduced linolenic acid

Walter R. Fehr from the Department of Agronomy at Iowa State University,

Ames, answered some of our questions about low-lin beans. Fehr, considered the father of low-lin beans commented, “Soybean oil with reduced linolenic acid has been adopted by the food in-dustry as an alternative to partially hy-drogenated oils. Hydrogenation of oil generates trans fats that are undesirable for human health. Reduced linolenic acid in soybeans is controlled primarily by alleles of three major genes, desig-nated fan1, fan2, and fan3. The alleles for reduced linolenic acid were devel-oped by conventional breeding and did not involve genetic engineering. Con-ventional soybean oil has about 7% linolenic acid. By combining the fan1 and fan2 alleles, the linolenic acid is reduced to about 3%, commonly re-ferred to as a low linolenic acid oil. The combination of the fan1, fan2, and fan3 alleles results in oil with about 1% linolenic acid, referred to as ultra-low linolenic acid. Both types of oil are sold commercially.”

Why low-lin?Trans fatty acids are increased in ed-

ible oils by the addition of hydrogen, which causes bonding of fat molecules

across a central area. Using oils that are not hydrogenated is required to avoid trans fatty acids, but the inclusion of linolenic fatty acids causes the oil to turn rancid soon. If you don’t like the taste of rancid oil—it’s somewhat fishy or soapy—you want oils with only small amounts of linolenic fatty acids.

Some relatively new research in-dicates that excess linolenic acid can retard the formation of omega-3 fatty acids from fatty acid precursors in the body. It is suggested that the process favors inflammation in blood vessels, leading to aneurisms, stroke, and other dreaded diseases.

How growers benefitSoybean acres available for low-

linolenic soybean contracting through Bunge, in connection with the Bunge DuPont Biotech Alliance, will be expanded to include an estimated 200,000 acres in 2006 and 550,000 acres in 2007. In addition, growers will be able to choose from a growing lineup of low-linolenic soybean varieties from

Processors and farmers stay ahead of nutrition demands

W

u Trans fats are particularly prominent in deep-fried foods.

u Walter Fehr developed a soybean by selective breeding that includes only about 1% of linolenic acid. Photo courtesy of Iowa State University.


company stRategies

Pioneer Hi-Bred International, Inc.—two Pioneer brand soybean varieties in 2006 and up to six in 2007. This pro-gram, begun on a limited basis in Iowa and Ohio in 2005, offers premiums to growers who grow Pioneer low-linole-nic soybeans designed for healthier oils in the food industry. Contracts will be offered through Bunge North America at local participating elevators. The ex-panded acres and elevators will primar-ily be in Iowa and Ohio.

“We expect the market for low-lino-lenic soybeans to expand further in the future,” says Marv Wilson, Pioneer soy-bean marketing director. “We’re able to increase the number of soybean variet-ies for this marketplace because we’ve been working on developing these soy-beans with improved oil since 1991 and can provide growers with the com-plete genetic package needed for their production demands.”

When elevators are announced in these regions, growers can sign-up at the participating facilities and purchase low-linolenic soybeans from their local Pioneer seed representatives. Partici-pating growers must provide the grain to elevators within an IP system.

Making IP pay for the farmerBecause historically farmers have

avoided many IP situations, Pioneer and Bunge are sweetening the pot. Key points of the programs include:

Growers who contract Pioneer low-linolenic soybeans for the 2007 growing season are eligible for the re-bate if they purchase and use any of the DuPont crop protection products on their own low-lin soybean acres.

Pioneer sales reps who are also Pioneer Low-Linolenic Soybean Con-tract Growers can qualify for a rebate only as a contract grower.

Growers must submit a report list-ing their qualifying net purchases to Pioneer. More information will be available prior to the 2007 growing season on how to submit a report. In Southwest Iowa, Bunge is offer-

ing acreage contracts at elevators with some premiums and signing bonuses. The firm offers a premium of $0.35/bu + $0.10/bu signing bonus for harvest de-livery and a premium of $0.40/bu plus an extra dime for on-farm storage. The firm is planning to have delivery peri-ods between October 2007 and August 2008. Similar programs are offered in eastern Iowa, Illinois, and Wisconsin.

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Another processing firm, CHS, Inc., operates crushing plants in Mankato and Fairmont, MN, and is gearing up for a second season of selling low-lin oil. CHS, Inc. will pay a premium of $0.40/bu for on-farm stored, Pioneer brand low-lin soybeans delivered to the CHS crushing facility in Fairmont. The company also offers flexible marketing alternatives and can spread delivery pe-riods throughout the year.

One expert from CHS commented on the growth of low-lin beans: ”They are easy to grow on the right soil. If you have questions about the variety and soil that grows them best, call our agronomists.”

Getting low-lin into the marketWhen low-lin beans became avail-

able, several companies formed a soy-bean industry initiative called Qualisoy. Last October, the group announced that Yum Brands (Kentucky Fried Chicken) would switch to a Qualisoy-approved version of the enhanced oil. The 5,500 restaurants will require a major quan-tity of the special oil. The Qualisoy Board consists of 22 individuals repre-senting all components of the U.S. soy-bean industry, including 10 producers, as well as representatives from technol-ogy corporations, soybean processors and end users, academic institutions, and USDA-ARS. The United Soybean Board’s chief executive officer serves as an ex-officio member of the board. The group (a checkoff program of the United Soybean Board) works on a pro-gram called BBB (Build a Better Bean) and is looking at other specialty beans in addition to low-lin. X

u Low-linolenic oil made from Pioneer brand low-lin soybeans. Photo cour-tesy of Pioneer Hi-Bred Int., Inc.

u Chemist Gary List checks soybeans. Photo by Keith Weller (USDA-ARS).


Meet Ed Ruff, 2006 CCA of the Year

he sun is just crossing the horizon on this clear but very cold, January morning. Certified Crop Adviser Ed

Ruff navigates the hilly country roads in southwest Wisconsin on his way to evaluate a client’s farm business plans.

“The winter months are spent gath-ering information, preparing financial records and projections, and preparing crop management plans for the upcom-ing growing season,” explains Ed during the drive. Ed won the 2006 CCA of the Year Award that is sponsored by ASA and the International CCA program.

Ed works with 45 to 50 farmers in his territory for the Farm Business and Production Management program of-fered through Southwest Technical Col-lege. He provides crop production and management, livestock nutrition and management, and farm business and financial management advice through both on-farm consulting and classroom instruction. It is a somewhat unique role compared with the majority of other CCAs throughout North America who work for ag retail or farm coop-erative type businesses focused on crop production practices.

A lot of what Ed does is considered farm management, but he also utilizes

his CCA-related training and back-ground. Agronomy is a major part of Ed’s services. He does soil sampling and test interpretation for fertility plans, scouting to develop pest management plans, and trouble shooting throughout the growing season. The farm manage-ment approach pulls it all together with the financial and livestock data if ap-plicable.

“The farmer doesn’t really know how well he is doing until you collect and analyze all of the production data with the financial data,” Ed says.

He provides these services for farms, predominantly dairies, ranging in size from 80 to 1,700 acres of crops for a combined total of approximately 15,000 acres in his territory.

The CCA advantageAs with many CCAs, part of Ed’s re-

sponsibilities is to add new clients each year, and that involves cold calling. He lets his prospects and clients know at some point in the conversation that he is a CCA and what that means. Ed says being a CCA, “...gains respect with farmers and adds to their confidence that the recommendations are sound … it adds creditability.”

Ed has gained the trust and respect of his farmer clients by being a CCA and drawing on his past experiences work-ing for a farm cooperative and as an in-

dependent crop adviser prior to joining Southwest Tech.

“[Ed’s] approach to farming and what he wants us to follow is to look at all segments of production … so we can success-fully produce a good product, show a profit, and remain in compliance with all the regulations…” wrote one of Ed’s clients. Another commented, “He has advised me on a very broad range of agronomic issues … increasing annual alfalfa yields from 5 to 7.2 tons per acre. One major goal was to increase alfalfa and corn yields with soil ero-sion kept to a minimum … corn yields have increased while keeping inputs to a minimum.”

With the increased scrutiny of non-point pollution at the farm level, CCAs are increasingly involved with nutrient management plans. Ed Ruff is no differ-ent. He writes 12 nutrient management plans per year for clients to satisfy the Wisconsin NRCS 590 requirements. He also writes NRCS 595 plans that deal with pest management.

Ed likes to relate the value of using a CCA for his clients.

“For example with corn, the timing is critical with pest management when the number of rows of kernels is deter-mined … if applied properly, this could lead to increased yields … is it worth it to pay a CCA $7/acre to gain $80/acre from increased yields?”

Providing a valuable service to his clients has made Ed a trusted business partner.

“Ed is very conscientious about my operation, a very reliable CCA … He keeps me up to date on potential insect problems by sending me a simple email during the growing season,” wrote one of his clients. “I have recommended Ed’s services to everyone interested in becoming more profitable.”

We thank Ed Ruff for exemplifying the CCA profession and congratulate him on winning the 2006 CCA of the Year Award.

ceRtification

T

Recent ICCA Meetings

u Left: The ICCA Board met in Atlanta last month in conjunction with the NAICC and ASFMRA annual convention. The board discussed continuing education, exam deliv-ery, a new structure proposal for the CCA program, marketing efforts, and financial matters. Right: Members of the ASA ICCA steering committee also met in Atlanta to evaluate and develop the new structure proposal.

Ed Ruff


ceRtification

Professionalismo the logos above make you think of a professional or professionalism? They should. We often use the

word “professionalism” to describe what a certification program strives to achieve. Are you a professional? Do you consider yourself to be one? Do your clients, customers, and peers call you a professional? To answer these questions, we need to know what a professional is and what constitutes professionalism.

According to the American Heri-tage Dictionary (AHD), a professional is “having great skill or experience in a particular field or activity” and “one who has an assured competence in a particular field or occupation.” Also according to AHD, professionalism is “professional status, methods, charac-ter or standards.”

The definitions of professional and professionalism describe many in our certification programs. In fact, profes-sionalism is the number one reason why CCAs say they become and remain certified. It is used as part of the name of Certified Professional Agronomists, Soil Scientists, and Soil Classifiers.

Certification programs strive to as-sure that a person has met a set standard of practice. ASA and SSSA use exams, education, experience, and ethics to set the minimum standards for someone to become certified in the particular field. These standards also help establish and identify the profession and those who practice it. Neither the certification nor the profession is based on one as-pect—in our case, it is based on four, with “ethics” being the overriding one that holds it all together and ties to the word character in the definition of pro-fessionalism.

Can someone be a professional with-out being certified? They could act pro-fessionally, but they have not demon-strated that they have met a “standard” that defines what being a professional

is or can do. That’s what certification does. It docu-ments that an in-dividual has met the standard set by the profession and he/she has agreed to up-hold that standard by his/her conduct. It is not mandatory but voluntary. You did it to demonstrate that you could, to satisfy a requirement, or as many have said to me, “because it is what profes-sionals do.”

CCA, CPAg, and CPSS/C are vol-untary certifications that have helped establish agronomy and soil science as professions. Do you talk about your certification with peers, customers, and clients? Do you place value on it by what you say and how you conduct your business? If not, don’t expect any-one else to.

“I ask my clients why they use a CPA (certified public accountant) rather than a bookkeeper to do their taxes?” com-mented CCA Jim Smith. “They often answer with ‘because they have passed exams, demonstrated they know more, have to earn continuing education so they keep up on the latest information to do the best they can for me, and I feel better about it.’ I follow with ‘and that is why I’m a CCA.’ ”

There are 15,449 people who are cer-tified as a CCA, CPAg, CPSS, or CPSC. Can you imagine what would happen if everyone, in a one minute explana-tion, told all of their customers, clients, students, and peers how important cer-tification was to them over the next 12 months? Lack of awareness about these certifications would no longer be an is-sue. Let’s try it and see what happens!

If you are not yet certified, check out the certification requirements at: www.agronomy.org/certification. See if you can meet the standards set by the profession and join the ranks of your professional peers. It will be well worth your efforts and may lead you to more opportunities within the profession than you realized.

Livestock manure management CEUs available via webcast

Certified crop advisers seeking CEUs need only look as far as their computer. The National Livestock and Poultry En-vironmental (LPE) Learning Center of-fers a monthly webcast series on a vari-ety of topics related to livestock manure management. The webcasts started in September 2006 and are scheduled to continue through November 2007. Past webcast topics include: pathogens in animal manure, integrated nutrient management, and limits of the phos-phorus index. Future webcast topics include: nitrogen availability from or-ganic sources, value of manure in land application, and value-added process-ing of manure, among others.

The webcast series is not the only service offered by the LPE Learning Center. Expert teams in the areas of pathogens and integrated nutrient man-agement have also assembled answers to frequently asked questions (FAQs) and compiled a “best of the best” list of recommended resources. Additional teams are working on resources for the value of manure and alternative tech-nologies for manure treatment with more teams expected to begin work in the near future. These expert teams are multidisciplinary groups drawn from the EPA, USGS, USDA-NRCS, USDA-ARS, Environmental Defense, and land grant universities across the nation.

Visiting the LPE Learning Center website will connect you to webcasts, the monthly newsletter, resources as-sembled by each workgroup, a collec-tion of national resources, and a sched-ule of upcoming webcasts. It is found at http://lpe.unl.edu.

by Luther SmithDirector of Certifica-tion [email protected]

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4� Crops & Soils|Spring2007 AmericanSocietyofAgronomy4� Crops & Soils|Spring2007 AmericanSocietyofAgronomy

ceRtification

Award nominations due March 27Do you know an outstanding certified professional? One

who has positively affected associates, producers, and the public at large? Someone who deserves to be publicly recog-nized and rewarded?

We invite you to consider nominating outstanding col-leagues for several awards in the Societies’ 2007 Awards Pro-gram, several which are designed to recognize and reward certified professionals and those in private industry.

Every year the program recognizes distinguished scientists, practitioners, and students in a variety of disciplines and at all levels of the professions. Nominations are due on March 27. Reference letters and the final nomination submission are due on April 3.

Online submissionThe 2007 online Awards Program features an updated

website that walks you through the steps to complete a nomi-nation or reference letter. A highlight of the program is that you can save at any time in the process to complete it later.

Visit the Awards Program online for award, scholarship, and fellowship listings; qualifications for each; and instruc-tions. The online Awards Program also tracks the three refer-ence letters required by each award or scholarship. The sys-tem automatically emails the reference a request to submit a letter, tracks when that letter is submitted online, and emails an update to the nominator.

For information, visit: www.agronomy.org/awards, www.crops.org/awards, and www.soils.org/awards. If you have questions, contact Leann Malison at [email protected] or 608-268-4949. X

u Paul Carter, Pioneer Hi-Bred International (left), receives the 2006 Agronomic Industry Award from ASA Past President David Sleper.

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