kansas fertilizer research 2016 - agronomy · i contents 3 precipitation data 5 agricultural...

KansasFertilizer Research

2016

Kansas State University Agricultural Experiment Station and Cooperative Extension Service

I

Contents3 Precipitation Data

5 Agricultural Research Center-Hays5 Nitrogen and Sulfur Fertilization Effects on Camelina Sativa

in West Central Kansas

10 Evaluating the Effectiveness of Iron Chelates in Managing Iron Deficiency Chlorosis in Grain Sorghum

18 Department of Agronomy18 Grain Sorghum Response to Band Applied Zinc Fertilizer

21 Evaluation of Phosphorus Source and Chelate Application as Starter Fertilizer in Corn

25 Evaluating the Interaction Between Chelated Iron Source and Placement on Phosphorus Availability in Soybean

29 Southeast Agricultural Research Center29 Nitrogen, Phosphorus, and Potassium Fertilization

for Newly Established Tall Fescue

32 Tillage and Nitrogen Placement Effects on Yields in a Short-Season Corn/Wheat/Double-Crop Soybean Rotation

33 Response of Soybean Grown on a Claypan Soil in Southeastern Kansas to the Residual of Different Plant Nutrient Sources and Tillage

35 Southwest Research-Extension Center35 Long-Term Nitrogen and Phosphorus Fertilization

of Irrigated Corn

40 Long-Term Nitrogen and Phosphorus Fertilization of Irrigated Grain Sorghum


2016

2

ContributorsP. Barnes, Associate Professor (Retired), Dept. of Biological and Agricultural

Engineering, K-State, Manhattan

H.D. Bond, Assistant Scientist, Southwest Research-Extension Center, Tribune

C.L. Edwards, Graduate Student, Dept. of Agronomy, K-State, Manhattan

M. Knapp, Service Climatologist, Weather Data Library, Dept. of Agronomy, K-State, Manhattan

J.L. Moyer, Professor, Forage Research, Southeast Agricultural Research Center, Parsons

N.O. Nelson, Associate Professor, Soil Fertility and Nutrient Management, Dept. of Agronomy, K-State, Manhattan

E. Obeng, Graduate Research Assistant, Dept. of Agronomy, K-State, Manhattan

A. Obour, Assistant Professor of Soil Science, Dept. of Agronomy, Agricultural Research Center, Hays

R. Perumal, Sorghum Breeder, Dept. of Agronomy, Agricultural Research Center, Hays

G. Pierzynski, Department Head and Professor, Soil and Environmental Chemistry, Dept. of Agronomy, K-State, Manhattan

D.A. Ruiz Diaz, Assistant Professor, Soil Fertility and Nutrient Management, Dept. of Agronomy, K-State, Manhattan

A.J. Schlegel, Agronomist, Southwest Research-Extension Center, Tribune

D.W. Sweeney, Soil and Water Management Agronomist, Southeast Agricultural Research Center, Parsons

A. Tonan Rosa, Graduate Student, Dept. of Agronomy, K-State, Manhattan

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Precipitation Data

Month ManhattanSWREC, Tribune

SEARC, Parsons

ECK Experiment Field, Ottawa

------------------------------------------ in. ------------------------------------------2014

Aug. 3.22 2.82 1.81 1.81Sept. 2.06 1.33 8.70 5.63Oct. 2.70 1.61 5.93 6.08Nov. 0.09 0.21 1.20 0.44Dec. 1.96 0.84 1.59 2.42

Total 2014 30.69 16.31 36.13 32.09Departure from normal -4.11 -1.03 -5.96 -7.12

2015Jan. 0.16 0.26 0.47 0.31Feb. 1.25 0.63 0.62 0.53Mar. 0.34 0.12 1.70 0.61Apr. 3.25 1.86 6.95 3.91May 10.72 6.16 10.41 12.36June 6.04 1.14 4.18 4.77July 5.43 3.95 5.50 5.67Aug. 3.62 2.48 4.76 2.69Sept. 3.83 0.32 2.99 2.72

4

Month

NCK Experiment

Field, Belleville

KRV Experiment

Field

SCK Experiment Field,

Hutchinson ARC-Hays------------------------------------------ in. ------------------------------------------

2014Aug. 5.40 3.23 5.40 1.64Sept. 2.59 2.52 2.59 5.94Oct. 4.06 4.00 4.06 2.12Nov. 0.05 0.41 0.05 0.05Dec. 0.53 2.05 .53 0.73

Total 2014 24.70 26.47 24.70 25.27Departure from normal -6.19 -9.17 -5.62 +1.78

2015Jan. 0.05 0.87 0.05 0.46Feb. 1.30 0.45 1.30 0.71Mar. 0.50 0.59 0.50 0.09Apr. 3.32 2.28 3.32 0.96May 5.78 10.31 5.78 6.44June 5.77 4.40 5.77 0.76July 4.62 6.07 4.62 4.28Aug. 3.89 2.72 3.89 0.44Sept. 0.83 5.52 0.83 0.48

SWREC = Southwest Research Extension-Center; SEARC = Southeast Agricultural Research Center; ECK = East Central Kansas; HC = Harvey County; NCK = North Central Kansas; KRV = Kansas River Valley; SCK = South Central Kansas; and ARC = Agricultural Research Center.

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Agricultural Research Center–Hays

Nitrogen and Sulfur Fertilization Effects on Camelina Sativa in West Central KansasE. Obeng, A.K. Obour, and N.O. Nelson

SummaryCamelina sativa is early maturing and possesses characteristics that make it a good fit as a rotation crop in dryland wheat cropping systems. Nitrogen (N) and sulfur (S) play very important roles in oilseed production, including camelina. This study was conducted over 3 years to determine N and S rates necessary for optimum camelina production in west central Kansas. The experiment was set up as randomized complete blocks with four replications in a split-plot arrangement. Treatments were two sulfur rates (0 and 18 lb/a) as the main plots, and four N rates (0, 20, 40, and 80 lb/a) as the sub-plot. Sulfur application did not affect stand count, biomass yield, harvest index, seed yield, oil and protein content. However, stand count, biomass yield, seed yield, and protein content were affected by N application (P < 0.05). Average oil and protein content were 28.1% and 33.9% respectively. The optimum N rate for yield was 20 lb N/a, which produced around 680 lb/a seed yield. Based on soil test levels of 25 lb N/a, N requirement for camelina production is 45 lb N/a.

IntroductionCultivation of Camelina sativa in Europe dates as far back as 1000 BC. The crop has been referred to as “gold of pleasure,” linseed dodder, and large-seeded false flax. Inter-est in camelina as a potential crop in the Great Plains has increased because of its lower requirements for inputs such as water, pesticide, and fertilizer compared with other crops. Another advantage is that it is early maturing, requiring only 85 to 100 days to mature. Camelina seed has high oil content with unique properties for both industrial and nutritional applications. The oil contains about 60% polyunsaturated fatty acids, mainly linolenic (18:2n-6) [about 15 and 40% α-linolenic acid (18:3n-6)], 30% mono-unsaturated, and 6% saturated fatty acids. Compared with other oilseed crops, camelina oil is very high in α-linolenic acid, an omega-3 fatty acid that is essential in human and animal nutrition. Because of its higher omega-3 fatty acid content, camelina oil has been promoted as a dietary supplement in human and animal nutrition. In addition to these applications, the oil has agricultural uses (seed coating, animal feed), industrial applica-tions (biolubricants), and may be used as biofuel. Research has shown that camelina yield ranges from lows of 300 lb/a to highs of 1,800 lb/a depending on biotic and abiotic factors influencing production in the growing locations.

Nitrogen plays an important role in plant physiological functions and is a component of chlorophyll, protein, and enzymes. Previous studies indicate that camelina has a lower N requirement than other oilseed crops such as sunflower and canola. Another nutrient of importance in oilseed production is sulfur, which is associated with protein and chlorophyll development and resistance to cold and water stress. Nitrogen and sulfur are strongly correlated with protein content in oilseed crops. Camelina responds to N and S with high yields and seed quality. Past findings on camelina N and S require-

6


ments have been location specific. This study was conducted to determine the N and S requirements for optimum yield of camelina grown in west central Kansas.

ProceduresThe experiment was conducted at Kansas State University Agricultural Research Center near Hays, KS (38° 51’ N/99° 20’ W; elevation: 2005 ft.) on no-till ground into wheat stubble in 2013 and 2015, and sorghum in 2014. The experimental design was a randomized complete block with four replications in a split-plot arrangement. Indi-vidual plot sizes were 30 ft × 10 ft. Fertilizer treatments were 0, 20, 40, and 80 lb/a N, and S rates of 0 and 18 lb/a. Sulfur was the main factor, and N was the sub-plot factor. Blaine Creek, a released spring camelina variety, was planted in this study at 5 lb/a. Half-doses of the N fertilizer treatments were applied at the time of planting, and the remaining half-doses were applied after emergence. In the course of the season, data collected included stand count, biomass yield, and seed yield (adjusted to 8% moisture). Oil content was analyzed after seed harvest using FT-NIR Near-Infrared spectropho-tometer (NIRS). Seed N was analyzed using Leco CN Analyzer and then used to deter-mine the protein content.

ResultsStand count at maturity was statistically different among N treatments. The control had the highest stand count and was significantly different from 20, 40, and 80 lb N/a treatments (Table 1). Stand count at maturity was higher in 2014 than 2015 (Table 2). Biomass production was higher for 40 and 80 lb N/a treatments, and was significantly different from the control (Figure 1). Biomass production was not different when 20 and 40 lb N/a was applied. Average biomass yield was 3,100 lb/a. Sulfur application had no significant (P > 0.05) effect on seed yield. Camelina seed yield was positively affected by N application.

Nitrogen application increased yield, but not beyond 40 lb N/a treatment. Yield was highest when N was applied at 20 and 40 lb/a, and they were significantly different from 0 lb N/a (Figure 2). Seed yield in 2014 and 2015 was around 750 lb/a and was significantly different from yield of 400 lb/a in 2013 (Figure 3). The difference in yield between years may be due to variation in precipitation among years. The study loca-tion received cumulative rainfall of 6.8 in., 11.2 in., and 8.5 in. in 2013, 2014, and 2015 respectively, during camelina growing season (April 15 to July 18). Harvest index was higher in 2014 and was significantly different from 2015 (Table 2).

There was significant difference in protein content among N treatments. Nitrogen applied at 80 lb/a had the highest protein content and was significantly different from the other N treatments (Table 1). Protein content was different among the lower N rate treatments. Camelina protein content was higher in 2015 than 2014 (Table 2). There was a difference in oil content between years (Figure 4). Camelina seeds had more oil content in 2014 than in 2015. Average protein and oil content were 33.9% and 28.1% respectively.

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Table 1. Effect of nitrogen treatment on stand count and protein content

Nitrogen rate (lb/a)Stand count at maturity

(per sq. ft.) Protein (% db)0 9.3a 33.7b

20 8.2b 33.6b

40 8.5b 33.9b

80 8.2b 34.1a

Standard error 0.5 0.2 Treatment means within the same column followed by same letter(s) are not significantly different (P < 0.05).

Table 2. Stand count, seed harvest index (HI), protein and oil content (%) of camelina in 2014 and 2015

Year

Stand count at maturity (per sq. ft.)

Harvest index (HI) Protein (% db) Oil (%)

2014 9.7a 0.2a 33.1b 29.5a

2015 7.5b 0.1b 34.6a 26.7a

Standard error 0.4 0.01 0.2 0.2 Treatment means within the same column followed by same letter(s) are not significantly different (P < 0.05).

4,000

3,500

3,000

2,500

2,000

1,500

1,000

500

0

Biom

ass

yiel

d, lb

/a

Nitrogen rate, lb/a

80400 20

aab

cb

Figure 1. Effect of nitrogen application on biomass yield. Means followed by the same letter(s) are not significantly different at P>0.05.

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800

600

400

200

0

Seed

yie

ld, l

b/a

Nitrogen rate, lb/a

80400 20

bcab

c

a

100

Figure 2. Effect of nitrogen application on seed yield. Means followed by the same letter(s) are not significantly different at P>0.05.

1,000

800

600

400

200

0

Seed

yie

ld, l

b/a

Year

20152013 2014

a

b

a

Figure 3. Average camelina yield in year 2013, 2014, and 2015, Agricultural Research Center–Hays. Means followed by the same letter(s) are not significantly different at P>0.05.

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35

30

25

20

15

10

5

0

Oil

cont

ent,

%

Year

20152014

ba

Figure 4. Average camelina oil content in 2014, and 2015. Means followed by the same letter(s) are not significantly different at P>0.05.

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Evaluating the Effectiveness of Iron Chelates in Managing Iron Deficiency Chlorosis in Grain SorghumA. Obour, A. Schlegel, R. Perumal, and D. Ruiz Diaz

SummaryGrain sorghum production in alkaline or calcareous soils is frequently affected by iron (Fe) chlorosis. Soil conditions such as high pH, high free calcium carbonate (lime), and low organic matter favor development of Fe deficiency chlorosis (IDC), which can delay crop maturity and reduce yields. Field experiments were conducted in the summer of 2014 and 2015 to determine the effectiveness of Fe chelate application in alleviating IDC in grain sorghum. Treatments were four Fe chelate application rates (0, 3, 6, and 9 lb product/a) applied either in-furrow with the seed at the time of planting or 2 weeks after planting in 2014. A split treatment of 3 lb/a applied at planting and another 3 lb/a applied 2 weeks after planting was included. The study in 2015 had four Fe chelate rates (0, 3, and 6 lb product/a, and split treatment of 3 lb/a applied at planting and another 3 lb/a applied 2 weeks after planting) as main plots and five commercial sorghum hybrids as sub-plots. Results in 2014 showed IDC scores among the treatments were significant only in the early stages of growth. Iron chelate application did improve sorghum yield, with the highest yield occurring when Fe chelate was split-applied at 6 lb product/a. Grain sorghum hybrids differed in their response to IDC in 2015. Application of Fe chelates suppressed IDC and increased grain yield, particularly in susceptible hybrids in both dryland and irrigated sites. Our findings indicate that sorghum hybrids 86G32 and 87P06 showed promise for tolerance to IDC and that Fe chelate application to reduce IDC is economically feasible at current grain prices.

IntroductionGrain sorghum is susceptible to iron (Fe) deficiency chlorosis (IDC) when grown on high-pH soils in the Great Plains. High pH and free calcium carbonate associated with calcareous soils reduce the availability of Fe to the sorghum plant. This results in IDC with delayed crop maturity and reduced yields. The general approach to alleviating Fe deficiency in sorghum has been the application of foliar or soil amendments; however, these amendments have not been economically feasible on the field scale. Available Fe chelate products that are reported to correct Fe deficiency are too expensive to use on low-value field crops like grain sorghum.

Several studies have attempted to develop alternative, cheaper strategies for managing IDC in sorghum. These include breeding and selecting for Fe-efficient sorghum culti-vars and application of Fe-containing fertilizer products.Managing IDC is complicated by the temporal and spatial heterogeneity of IDC in sorghum fields. Heterogeneity in soil chemical composition within sorghum fields causes spatial development of IDC in sorghum fields, which creates a major challenge to managing IDC on a field scale. An effective management strategy for preventing IDC in grain sorghum should be a comprehensive approach that considers soil heterogeneity, application of chelated Fe products, and selection of IDC-tolerant sorghum cultivars.

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Previous research has documented that in-furrow application of ortho-ortho-EDDHA Fe can reduce IDC in soybean and dry edible beans. Research extending this technol-ogy to managing IDC in grain sorghum has been limited. The objectives of this study were to 1) determine the effectiveness of ortho-ortho Fe-EDDHA in alleviating IDC in grain sorghum, and 2) screen grain sorghum hybrids for their tolerance to IDC.

ProceduresA field experiment was conducted in the summer of 2014 on a producer’s field near Holcomb, KS, to evaluate the effectiveness of iron chelate in alleviating IDC in grain sorghum. Treatments were four ortho-ortho-EDDHA Fe chelate application rates (0, 3, 6, and 9 lb product/a) applied either in-furrow with the seed at the time of plant-ing or two weeks after planting as foliar treatment. A split application treatment of 3 lb product/a applied at planting and another 3 lb product/a applied 2 weeks after planting was included. The study was expanded in 2015 to include sites at Southwest Kansas Agricultural Research Centers (SWREC) in Garden City and Tribune, and at a producer’s field near Garden City, KS. The study in Tribune was under irrigated conditions. Treatments were four application rates of ortho-ortho Fe-EDDHA (0, 3, and 6 lb product/a, and split treatment of 3 lb/a applied at planting and another 3 lb/a applied 2 weeks after planting) as main plots and five commercial sorghum hybrids (Pioneer hybrids 86G32, 87P06, 85Y40, Golden Acres hybrid GA5613, and Northrup King hybrid NK5418) as sub-plots. The Fe chelate was applied in-furrow at planting except the split treatment where the chelate was applied at planting plus additional Fe chelate application 2 weeks after planting.

All plots received equal amounts of nitrogen (N) and phosphorus (P) applied at 100 and 30 lb/a, respectively. Before planting, three soil core samples were taken from 0- to 15-cm depths from individual plots (individual plots were 10 ft × 30 ft), combined to form a composite sample for each block, and analyzed for soil chemical properties.

SPAD (chlorophyll meter) readings, IDC scores (a score of 1 means non-chlorotic leaves, 5 means plants with complete leaf chlorosis), and plant height information were taken 30 and 60 days after planting. The plots were harvested in mid-November in 2014 to determine grain yield. Harvesting in 2015 was done in October in Garden City, and mid-November in Tribune.

ResultsResults in 2014 showed IDC scores among the treatments were significant only in the early stages of growth. Split application of Fe chelate at 6 lb product/a did better at suppressing IDC compared to the other chelate treatments (Table 1). At 60 days after planting, IDC was similar among the Fe chelate treatments. In general, severity of IDC tends to decrease over the growing season, confirming the ability of sorghum hybrids to grow out of IDC under favorable environmental conditions. Similarly, relative leaf chlorophyll content (SPAD readings) and plant height at 30 days after planting were greatest when 6 lb/a Fe chelate was split applied. As the growing season progressed, no differences in SPAD readings and plant height were observed among the treatments. Iron chelate application did improve sorghum yield compared to the control. The high-est yield occurred when Fe chelate was split applied at 6 lb product/a. SPAD readings, IDC, and grain yield were not affected by Fe-EDDHA application method.

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Results in 2015 showed that IDC differed among the sorghum hybrids studied. Iron chelate application suppressed IDC, particularly in the highly susceptible hybrids (85Y40 and NK5418) at both the dryland (Table 2) and irrigated locations (Figure 1). Severity of IDC decreased as the growing season progressed at SWREC (Table 2) in Garden City and in Tribune (data not shown) but not in the producer’s field (Table 2). Greater severity of IDC at the producer’s farm may be due to high carbonate concen-trations in the soil and the drought experienced in July. Although Fe concentrations in the soil at the two dryland locations were similar (2.5 mg/kg at SWREC in Garden City, and 2.3 mg/kg at producer’s field), calcium carbonate equivalence (CCE) in the soil at the producer’s field was 82 g/kg and that in the soil at SWREC was 25 g/kg. In general, sorghum hybrids 87P06, 86G32, and GA5613 were more tolerant to IDC than NK5418 and 85Y40. Similar to IDC scores, SPAD readings were greater with hybrids that showed tolerance to IDC (data not shown).

Grain yields were different among the sorghum hybrids at both dryland and irrigated sites. At the dryland sites, yields averaged across Fe treatments were generally greater at SWREC than the producer’s field (Figure 2). This may be due to reduced incidence of IDC observed in the later part of the growing season at SWREC. Sorghum hybrid 86G32 produced the greatest yield among the hybrids evaluated at SWREC. However, 87P06 had the highest grain yield at the producer’s field (Figure 2). This is due to rela-tively lower IDC scores observed in 87P06 at the producer’s field, particularly in treat-ments where Fe chelate was split applied at 6 lb/a. Similarly, grain yield of 86G32 was greatest among the hybrids under irrigation in Tribune when averaged across Fe chelate application rates (Figure 3).

Averaged across Fe treatments, grain yields with GA5613 and NK5418 were similar to 86G32 under irrigation compared to the dryland sites. When moisture was not limited, grain yields in NK5418 were not significantly affected by Fe chelate (Figure 4). This suggests that in good growing conditions when water is not limited, these hybrids (NK5418 and GA5613) will grow out of IDC and produce decent grain yields. However, 85Y40 consistently produced the lowest grain yield at all sites, confirming greater susceptibility to IDC.

Applying Fe chelate to grain sorghum increased grain yield compared to the control at both dryland sites near Garden City and the irrigated site at Tribune (Figure 5 and 6). At Tribune, there was a significant chelate × hybrid (P = 0.08) effect on grain yield. This interaction occurred because of the substantial increase in grain yield when Fe chelate was applied to GA5613 and 85Y40. The increase in grain yield due to Fe chelate application was nominal in other sorghum hybrids (Figure 4). Averaged across sorghum hybrids, application of 3 lb/a Fe chelate caused a 2-fold increase in grain yield above the control at the dryland site. At $3.22/bu current grain sorghum sale price, the increase in gross revenue generated with 3 lb/a Fe-EDDHA application is $86.94/a ($3. 22/bu × 27 bu/a) for dryland and $54.74/a ($3.22/bu × 17 bu/a) for the irrigated site. The cost of 3 lb/a Fe-EDDHA at a retail price of $8 product/lb is $24. It is therefore economi-cally feasible to apply Fe-EDDHA to grain sorghum at current grain prices.

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Table 1. Grain sorghum yield, iron (Fe) deficiency chlorosis (IDC) scores, and relative leaf chlorophyll content (SPAD) as affected by Fe chelate application

IDC score SPAD readings Grain yield, bu/aFe chelate treatment 30 DAP1 60 DAP 30 DAP 60 DAP

Check 1.9 1.2 29.1 32.1 88.83 lb/a in-furrow 1.6 1.2 29.8 33.7 101.26 lb/a in-furrow 1.5 1.2 29.7 30.3 104.59 lb/a in-furrow 1.4 1.2 30.3 32.1 91.53 lb/a postemergence 1.6 1.2 31.0 34.6 106.56 lb/a postemergence 1.5 1.1 32.1 33.2 101.89 lb/a postemergence 1.6 1.2 31.5 33.4 109.56 lb/a split 1.1 1.1 37.4 33.9 109.8Standard error 0.1 0.1 1.9 2.1 6.51 Days after planting.

Table 2. Iron chelate application and grain sorghum hybrid effects on iron (Fe) deficiency chlorosis (IDC) scores in grain sorghum at 30 and 60 days after planting at SWREC and a producer’s field, Garden City, KS, in 2015

Fe chelate rate, lb/a

IDC scores at 30 DAP1

SWREC, Garden City Producer's field, Garden CityGA5613 NK5418 85Y40 86G32 87P06 GA5613 NK5418 85Y40 86G32 87P06

Check 2.9 3.8 4.1 2.5 2.8 2.2 2.8 2.7 1.6 1.93 2.5 2.6 2.3 1.8 2.0 1.3 1.6 2.3 1.8 1.46 2.2 2.9 2.7 1.5 1.9 2.2 2.0 1.4 1.0 1.16 split 3.0 2.7 2.8 2.3 2.5 1.1 1.0 1.5 1.0 1.2Standard error 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4

IDC2 scores at 60 DAPCheck 3.2 3.8 4.5 1.4 2.2 3.5 3.5 3.8 3.2 3.23 1.8 2.0 2.2 1.1 1.7 3.3 3.8 3.9 3.3 3.26 2.4 2.7 2.6 1.4 1.6 3.3 3.3 3.3 3.0 2.86 split 2.6 2.0 3.0 1.2 1.3 2.5 2.5 3.5 2.7 2.3Standard error 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.41 Days after planting.2 Iron deficiency chlorosis score (IDC), a score of 1 means non-chlorotic leaves and 5 means plants with complete leaf chlorosis.

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Figure 1. Application of Fe chelate suppressed IDC in susceptible hybrids (e.g. Pioneer 85Y40). The control treatment (top) and a plot that received 3 lb/a Fe chelate (bottom) show the difference between treatments. Photos were taken on August 4, 2015 (60 days after planting at Tribune, KS).

3 lb/a

Check plot

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100

90

80

70

60

50

40

30

20

10

0

Gra

in y

ield

, bu/

a

Sorghum hybrid

NK541885Y40 GA5613 87P06 86G32

SWREC

Producer

Figure 2. Grain yield of sorghum hybrids at the two dryland sites at SWREC and a producer’s field in Garden City, KS. Means are averaged across Fe chelate.

160

140

120

100

80

60

40

20

0

Sorg

hum

gra

in y

ield

, bu/

a

Sorghum hybrid

NK541885Y40 GA561387P06 86G32

Figure 3. Grain yield of sorghum hybrids under irrigation at SWREC in Tribune, KS. Means are averaged across Fe chelate treatments.

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180

160

140

120

100

80

60

40

20

0

Sorg

hum

gra

in y

ield

, bu/

a

Sorghum hybrid

NK5418 85Y40GA5613 87P0686G32

0 lb/a

3 lb/a

6 lb/a

6 lb/a split

Figure 4. Sorghum grain yield as affected by iron chelate application and sorghum geno-type under irrigation at Tribune, KS.

80

70

60

50

40

30

20

10

0

Gra

in y

ield

, bu/

a

Iron chelate application rate, lb/a

6 split0 63

Figure 5. Sorghum grain yield as affected by iron chelate application across the two dryland locations in Garden City, KS.

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160

140

120

100

80

60

40

20

0

Sorg

hum

gra

in y

ield

, bu/

a

Iron chelate application rate, lb/a

6 split0 63

Figure 6. Sorghum grain yield as affected by iron chelate application under irrigated conditions in Tribune, KS.

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Department of Agronomy

Grain Sorghum Response to Band Applied Zinc FertilizerA. Tonan Rosa, N. Nelson, and D. Ruiz Diaz

SummaryZinc (Zn) is one of the micronutrients found to be deficient in Kansas. The objective of this study was to evaluate the response of grain sorghum to Zn fertilization using strip trials. The experiment was set up in Manhattan, KS, in 2015. The experimental design consisted of two strips, one with Zn fertilizer and the other without, with five replica-tions. Zn fertilizer was applied as starter in combination with ammonium polyphos-phate at the rate of 0.5 lb Zn/a. Plant tissue samples were collected to determine Zn content. Grain yield was recorded by combine equipped with yield monitor. No signifi-cant differences were found for sorghum grain yield. Grain Zn content increased with Zn fertilization. Zn fertilization may be considered for future studies in food biofortifi-cation.

IntroductionKansas consistently produces more grain sorghum than any other state in the U.S., representing approximately 46% of the country’s total production with an average yield of 74 bu/a (USDA, 2014). Fertility issues can be a limiting factor for high yields. Producers question the effectiveness of micronutrient fertilization and the ability to impact significant grain yields. Zinc (Zn) is one of the micronutrients found to be deficient in Kansas. Involved in the chlorophyll synthesis, Zn is also essential for the synthesis of proteins needed for the production of auxins, a growth hormone (Havlin, 2014). Zn availability to plants is affected mainly by its total content in the soil, soil pH and organic matter (Hawkesford and Barraclough, 2011). According to the Kansas Fertilizer Recommendation, the critical soil level for Zn is 1 ppm; anything below this value is likely to have a response to Zn fertilizer (Leikam, 2003). Band applications of 0.5 to 1 lb/a would correct crop deficiency for the season but the soil deficiency will likely remain. Although sorghum is an important crop in Kansas, there is very little data on sorghum response to Zn fertilizer. The objective of this study was to evaluate the response of grain sorghum to starter zinc fertilization using strip trials at a farm level.

ProceduresA strip trial study was established in the Agronomy North Farm in Manhattan, KS. Grain sorghum (DKS53-67) was planted on June 22, 2015 at 70,000 seeds/a. Strips were 15 ft wide (6 rows planted at 30 in spacing) and 1,070 ft length on average. The experimental design consisted of two strips, no Zn fertilization and with Zn fertilizer, replicated five times. Fertilizer was applied as starter 2 ✕ 2 (2 in below and 2 in to the side of the seed) at 27.4 lb/a of P2O5 as ammonium polyphosphate (10-34-0) and 0.5 lb/a of Source Zinc 10 (microSource, East Peoria, IL), a citric acid chelated zinc solu-tion. Nitrogen application was side-dressed at 94 lb/a of N as urea ammonium nitrate (28-0-0). All strips received the same rate of N and P. Thirty above-ground plant samples were collected at V6 stage (six leaf collar), oven dried at 65° C and analyzed for Zn content. Yields were recorded by the combine’s yield monitor using AgLeader

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Technology. Two sections of each strip were selected to analyze using SMS software. Sections were selected based on a straight pass of the combine, one in the west side of the field and another in the east. Statistical analyses were conducted with a paired t-test to determine if there was a difference between yield of strips that received Zn and strips without Zn fertilization.

ResultsZinc fertilization response was expected since the soil test results showed levels of Zn below the critical level in the field (Table 1). However, Zn tissue concentration analyses were 46 ppm on average which is within the sufficiency range for grain sorghum (15-70 ppm) (Walsh and Beaton, 1977). No significant differences were found among treat-ments in grain sorghum yields (Table 2). This suggests that the current soil test, Zn crit-ical level of 1 ppm, may be too high for sorghum. These results also agree with Gordon and Pierzynski, (1997) and B. G. Hopkins et al., (1992), who didn’t find any difference in yields when Zn was applied in studies in Kansas. Zn grain concentration increased 3 ppm when Zn fertilizer was added, statistically higher than strips without Zn (Table 2). The results show that Zn fertilizer application was effective in increasing Zn uptake by sorghum and allocation of Zn to the grain. Future studies with Zn fertilization can contribute in food biofortification helping to solve zinc deficiency in human diets.

ReferencesB. G. Hopkins, D. A. Whitney, Lamond R.E. (1992) Zinc Fertilization of Grain

Sorghum. Kansas Fertilizer Research. Report of Progress 670. Kansas State Univer-sity, Manhattan.

Gordon W.B., Pierzynski G.M. (1997) Responses of Corn and Grain Sorghum Hybrids to Starter Fertilizer Combinations. Kansas Fertilizer Research. Report of Progress 800. Kansas State University, Manhattan.

Havlin J.L., Tisdale, S.L., Nelson, W.L. and J.D., Beaton (2014) Soil Fertility and Fertil-izers: An Introduction to Nutrient Management. Pearson Education.

Hawkesford M.J., Barraclough P. (2011) The molecular and physiological basis of nutri-ent use efficiency in crops. Wiley-Blackwell.

Leikam D.F., Lamond, R.E. and Mengel, D.B. (2003) Soil test interpretation and fertil-izer recommendation. MF 2586. Kansas State Univ. Ext., Manhattan.

USDA. (2014) Crop Production 2014 Summary. United States Department of Agri-culture (USDA), National Agricultural Statistics Service.

Walsh L.M., Beaton J.D. (1977) Soil Testing and Plant Analysis. Soil Science Society of America, Madison, Wisconsin.

Table 1. Soil test values1

pH Buffer pH OM STP Zn% ------------ ppm ------------

5.5 6.2 3.1 15.6 0.651pH and Zn values from strips, other data from field average soil samples.Abbreviations: OM, organic matter; STP, soil test phosphorus; and Zn, zinc.

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Table 2. Effects of band applied zinc in grain yield and sorghum grain concentrationGrain yield Grain zinc concentration

Parameters + Zn - Zn Difference + Zn - Zn Difference----------- bu/a ----------- ----------- ppm -----------

Mean 95 91 4 20.9 17.9 3.0Standard deviation 11.9 6.8 13.6 1.5 0.80 1.9Standard error 3.8 2.2 4.3 0.65 0.36 0.86P-value from t-test 0.392 0.025

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Evaluation of Phosphorus Source and Chelate Application as Starter Fertilizer in CornC.L. Edwards and D.A. Ruiz Diaz

SummaryThe differences between common phosphorus (P) fertilizers as a starter in corn produc-tion have been studied for many years. However, little research has been conducted showing which P fertilizer sources are most effective with varying compositions of ortho- and poly-phosphate. The objectives of this study were to evaluate three commer-cially available P fertilizers, 0-16-19, 10-34-0, and 0-18-18 (N-P2O5-K2O) as starter band with and without the addition Cee*Quest-70 (CQ-70), a glucoheptonate chelate. The study was conducted at two locations, Scandia and Rossville, in 2014 and 2015. Experimental design was a randomized, complete block with four replications and a factorial treatment arrangement. Whole plant corn tissue samples were taken at V-6 and weighted for biomass. Tissue samples were analyzed for P. Yield, V-6 biomass, and V-6 P uptake were analyzed for treatment differences. Results show that there were no yield differences between P fertilizers with or without the addition of CQ-70. Phos-phorus fertilizer was found to have a significant effect on P V-6 tissue concentration at the Rossville location. However, there was no effect on P uptake. Fertilizer source was found to have a significant effect on V-6 biomass and P uptake.

IntroductionStarter fertilizers usually consist of P and potassium (K) since seedling uptake of P and K are greatest in early growth. Starter fertilizers placed in proximity of the root zone enhance nutrient availability (Jokela, 1992), especially P and K (Barber and Kovar, 1985). The most common fertilizers used as starters consist mainly of P and K; however, some research has shown the addition of N placed with P results in greater uptake of P (Olson and Drier, 1956; Kamprath, 1987). The effects of starter fertilizer have shown an increase in early nutrient uptake (Randall and Hoeft, 1988; Rehm and Lamb, 2009). However, yield effects are inconsistent, even with an increase in early season growth (Vetsch and Randall, 2002).

ProceduresThe study was conducted at two locations in 2014 and 2015, Rossville and Scandia, Kansas. The experimental design was a complete, randomized block design with four replications. Plots were 10 ft wide by 30 ft long (4 rows of corn). A total of 9 treatments were included at each location and are described in Table 1. The treatment structure includes a control with a factorial arrangement of fertilizer source by CQ-70. Three phosphorus fertilizer products, 0-16-19, 10-34-0, and 0-18-18, were applied at 30 lb P2O5 per acre with and without the addition of CQ-70 at 3 gallons per acre. Liquid products 0-16-19, 10-34-0, and 0-18-18 were applied using a backpack sprayer imme-diately after planting in a surface band. The addition of CQ-70 was mixed with liquid sources prior to banded application.

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Initial soil samples were collected in spring 2014 by collecting one composite sample at 6 inches deep per plot. Samples were analyzed for pH, Mehlich-3 P, ammonium acetate K, and organic matter (Table 2). Plant tissue samples were collected at specific growth stages for corn, and seed grain were analyzed after harvest. The center two rows of corn were used for sampling and harvest. Ten whole plant samples were collected at growth stage V-6 (Pedersen, 2009). All plant tissue samples were dried in a forced air oven at 60°C for a minimum of 4 days. After drying, plant samples were ground with a Wiley Mill grinder to pass a 2 mm screen and digested using a sulfuric acid and hydrogen peroxide digest (Thomas et al., 1967). Phosphorus concentrations were then deter-mined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The center two rows of corn were machine harvested. Grain weights were recorded at the end of the growing season and adjusted for 15.5% moisture. Corn grain moisture and test weight were monitored at harvest.

Data were analyzed by location and across locations, using location as a random variable for analysis. Corn parameters were analyzed using SAS® PROC GLIMMIX (SAS Insti-tute, Cary, NC, 2010) to determine if there was a significant (P = 0.10) response to fertilizer source, addition of CQ-70, and the interaction between fertilizer and CQ-70. Main effects of fertilizer and CQ-70 and the interaction on least square means of corn parameters were tested.

ResultsThe Rossville and Scandia locations in both 2014 and 2015 can be considered high yielding and are categorized above the “critical level” for soil test P (Table 2) (Liekam et al., 2003). Therefore, both locations should not be expected to show response to P fertilization. The chelate addition CQ-70 had no effect on early corn growth, nutrient uptake, or yield. Corn yield was found to be significantly affected by fertilizer source at Scandia and Rossville in 2015 and averaged across locations (Table 3). Highest yields were observed with applications of 0-16-19 with the addition of Cee*Quest 70 prod-uct. Greater accumulation at growth stage V-6 was observed with 0-16-19 applications in Rossville in 2015. There were no differences averaged across site years. Phosphorus uptake at V-6 tissue was greatest with 0-16-19 with CQ-70 and 10-34-0 and 0-18-18 without the addition. Neither fertilizer source nor CQ-70 affected yield or other parameters due to the high levels of P already in the soil and the fact that application rates were as starter.

ReferencesBarber, S. A., and J. L. Kovar. 1985. Principles of applying phosphorus fertilizer for

greatest efficiency. J. Fert. Issues 2:91-94.Jokela, W. E. 1992. Effect of starter fertilizer on corn silage yields on medium and high

fertility soils. J. Prod. Agron. 2:233-237.Kamprath, E. J. 1987. Enhanced phosphorus status of maize resulting from nitrogen

fertilization of high phosphorus soils. Soil Sci. Soc. Am. J. 6:1522-1526.Liekam, D. F., R. E. Lamond, and D. B. Mengel. 2003. Soil test interpretations and

fertilizer recommendations. Kansas State University. MF-2586.Olson, R. A., and A. F. Drier. 1956. Fertilizer placement for small grains in relation to

crop stand and nutrient efficiency in Nebraska. Soil Sci. Soc. Am. J. 1:19-24.

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Randall, G. W. and R. G. Hoeft. 1988. Placement methods for improved efficiency of P and K fertilizers: A review. J. Prod. Agron. 1:70-79.

Rehm, G. W. and J. A. Lamb. 2009. Corn response to fluid fertilizers placed near the seed at planting. Soil Sci. Soc. Am. J. 4:1427-1434.

Vetsch, J. A., and G. W. Randall. 2002. Corn production as affected by tillage system and starter fertilizer. Agron. J. 94:532-540.

Table 1. Description of treatmentsCQ-70 Fertilizer†

Without 0-16-19 (Ortho 80/Poly 20)10-34-0 (Ortho 60/Poly 40)

0-18-18 (Ortho 100)With 0-16-19 (Ortho 80/Poly 20)

10-34-0 (Ortho 60/Poly 40)0-18-18 (Ortho 100)

† Fertilizer application rate was 30 lb P2O5 per acre for all treatments.

Table 2. Initial soil test results taken in early spring in 2014 and 2015 in Rossville and ScandiaLocation Year pH Phosphorus Potassium Organic matter

------------ mg/kg ------------ %Rossville 2014 6.68 23 342 2.0Scandia 2014 6.20 26 598 3.1Rossville 2015 7.4 24 225 1.7Scandia 2015 5.8 32 513 2.1

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Table 3. Average corn yields as affected by phosphorus fertilizer source with and without additions of Cee*Quest 70 (CQ-70) in 2014 and 2015, and across locations

Rossville† ScandiaCQ-70 Fertilizer 2014 2015 2014 2015 Average‡Yield (bu/a)

Without 0-16-19 253 154 ab 238 220 b 216 ab10-34-0 266 146 abc 230 250 a 223 ab0-18-18 269 141 abc 226 231 ab 217 ab

With 0-16-19 248 169 a 230 255 a 225 a10-34-0 255 116 bc 238 236 ab 211 b0-18-18 266 131 bc 232 246 a 219 ab

V-6 Biomass (g/plant)Without 0-16-19 60.5 11.5 bc 179 16.7 67.0

10-34-0 60.8 12.3 ab 174 16.4 65.90-18-18 62.7 12.3 ab 184 17.1 69.0

With 0-16-19 71.6 13.4 a 182 16.4 70.810-34-0 65.0 10.9 bc 186 18.0 70.00-18-18 67.3 10.6 c 174 17.7 67.3

V-6 phosphorus uptake (mg/plant)Without 0-16-19 219 32.6 b 587 70.4 227

10-34-0 217 34.8 ab 612 72.2 2340-18-18 227 38.4 a 644 77.2 247

With 0-16-19 267 39.6 a 587 72.3 24110-34-0 232 31.7 b 599 70.8 2330-18-18 253 30.7 b 566 70.3 230

† Different letters in each column by parameter signify treatment differences at alpha=0.1 level.‡ Average over years and locations.

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Evaluating the Interaction Between Chelated Iron Source and Placement on Phosphorus Availability in SoybeanC.L. Edwards and D.A. Ruiz Diaz

SummaryIn agriculture, chelating agents are used to supplement micronutrients, such as iron (Fe). However, little research has been conducted at the field-scale level to evaluate chelating agent effects on phosphorus (P). The objectives of this study were to evaluate three commercially available chelated Fe sources on early soybean growth and nutrient uptake. The study was conducted at six locations in 2014 and 2015. The experimental design was a randomized, complete block with a factorial treatment arrangement. The two factors included fertilizer source and fertilizer placement. The fertilizer sources were P only, EDTA-Fe, HEDTA-Fe, and one glucoheptonate product, Cee*Quest N5Fe758 (CQ-758), with two fertilizer placements, in-furrow with seed contact and surface band at planting. Results show soybean yield was affected by chelate source and placement. Greater yields occurred with application in-furrow at Scandia in 2014 and 2015, but in-furrow was superior at Rossville in 2015. Increased yields also occurred with applications of EDTA and HEDTA. However, further analysis of tissue and grain may show chelate effects on nutrients.

IntroductionIncreasing yield with the application of chelated micronutrients has been studied extensively since the 1920s. Chelating agents are used extensively in the Great Plains and North Central regions due to widespread Fe deficiencies in soybean (Good and Johnson, 2000). The chances of increasing soybean yields with the application of micro-nutrients is highest with Fe (Liesch et al., 2011) and magnese (Mn) (Loecker et al., 2010), when compared to other nutrients. Soil application of chelated Fe has shown to decrease Mn uptake (Ghasemi-Fasaei et al., 2003) as soybeans are affected more by Fe/Mn antagonism (Ghasemi-Fasaei et al., 2003).

In addition to the effects of chelated Fe on other metals, there is potential for an effect on plant available phosphorus (P). A soil incubation study observing the effects of chelates on plant available P resulted in increased P with the application of EDTA and HEDTA (Edwards et al., 2013). Increasing chelating agent application rate was also found to increase soil test P for EDTA and HEDTA (r2=0.86 and 0.95) in a soil with high P adsorption capacity. This increase in P was attributed to EDTA binding Fe within soil colloids and decreasing the P adsorption capacity of the soil (van der Zee and van Riemsdijk, 1988).

Farmers often question the most effective application method of chelated micronu-trient and their effects on other nutrients. Little research has been conducted at the field-scale level to evaluate the effect of chelates on phosphorus and other nutrients. The objectives of this study were to evaluate four commercially available chelated Fe sources

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on early soybean growth and nitrogen (N), P, and potassium (K) uptake, comparing two common application methods.

ProceduresThe study was conducted at six locations; Rossville, Scandia, and Hutchinson in 2014, and Rossville, Scandia, and Colby in 2015. The experimental design was a complete, randomized block design with four replications. Plots were 10 ft wide by 30 ft long (4 rows of soybeans) at all locations. In 2015, the plots at Colby were 10 ft wide by 20 ft long. A total of 11 treatments were included at each location and are described in Table 1. The treatment structure includes an absolute control with a factorial arrangement of placement and fertilizer source. In-furrow and surface band fertilizer placements were compared in combination with 3 fertilizer chelate products and one phosphorus only product for each placement. Phosphorus fertilizer was applied at 20 lb P2O5 per acre

and chelates were applied in-furrow and surface banded at 3 and 6 gal per acre, respec-tively. The chelating agents used were commercially available products. Both EDTA and HEDTA were solutions of 4.5% Fe. The CQ-758 contains 5% Fe chelated as a glucoheptonate.

Initial soil samples were collected in the spring of 2014 and 2015 by collecting one composite sample at 6 inches deep per plot. Samples were analyzed for pH, Mehlich-3 P, ammonium acetate K, and organic matter (Table 2). The center two rows of soybeans were machine harvested for the total length of the plot (30 ft). Grain weights were recorded at the end of the growing season and adjusted for 13.0 % moisture. Soybean seed grain moisture and test weight were monitored at harvest.

Data were analyzed by location and across locations, using location as a random variable for analysis. Soybean parameters were analyzed using PROC GLIMMIX SAS 9.1 (SAS, 2010) to determine if there was a significant (P = 0.10) response to fertilizer source, fertilizer placement, and the interaction between fertilizer and placement using soil test P (STP) as a continuous variable. Main effects of fertilizer and placement and the interaction on least square means of soybean parameters were tested.

ResultsAll locations, except Colby, can be categorized as below the “critical level” on STP (Table 1) (Liekam et al., 2003), therefore, having a response to P fertilization. Chelate placement was found to significantly affect soybean yield in Scandia and Rossville (Table 2). Increased yields with in-furrow placement in Scandia in 2014 and 2015 could be attributed to finer texture soils. However, in Rossville, greater yield with surface band applications could potentially be due to sandy soil texture. Fertilizer appli-cation in-furrow with seed contact in soils with low CEC and organic matter could have detrimental effects on germination. Further analysis of application on popula-tion count could further explain these results. Chelate source was also found to affect soybean yield (Table 2). Highest yields were observed after applications of EDTA-Fe and HEDTA-Fe. Further analysis of tissue samples taken at V-4 and R-3 and grain samples following harvest may prove chelate and placement effects on nutrient uptake.

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ReferencesEdwards, C. L., R. O. Maguire, G. B. Whitehurst, and M. M. Alley. 2014. Using

synthetic chelating agents to decrease phosphorus binding in soils. Soil Sci. Soc. Am. J. Submitted.

Ghasemi, R., A. Ronaghi, M. Maftoun, N. Karimian, and P. N. Soltanpour. 2003. Influ-ence of iron-manganese interaction in soybean genotypes in a calcareous soil. J. Plant Nutr. 26:1815-1823.

Goos, R. J., B. E. Johnson, and M. Thiollet. 2000. A comparison of availability of three zinc sources to maize (Zea mays L.) under greenhouse conditions. Soil Fertil. Soils 31:343-347.

Liekam, D. F., R. E. Lamond, and D. B. Mengel. 2003. Soil test interpretations and fertilizer recommendations. Kansas State University. MF-2586.

Liesch, A. M., D. A. Ruiz Diaz, K. L. Martin, B. L. Olsen, D. B. Mengel, and K. L. Roozeboom. 2011. Management strategies for increasing soybean yield on soils susceptible to iron deficiency. Agron. J. 103:1870-1877.

Loecker, J. L., N. O. Nelson, W. B. Gordon, L. D. Maddux, K. A. Janssen, and W. T. Schapaugh. 2010. Manganese response to conventional and glyphosate resistant soybean. Agron. J. 102:606-611.

Pedersen, P. 2009. Soybean growth and development. PM1945. Iowa State University, University Extension, Ames, Iowa.

Thomas, R. L., R. W. Sheard, and J. R. Moyer. 1967. Comparison of conventional and automated procedures for nitrogen, phosphorus, and potassium analysis of plant material using a single digestion. Agron. J. 59:240-243.

van der Zee, S.E.A.T.M., and W.H. van Riemsdijk. 1988. Model for long-term phos-phate reaction kinetics in soil. J. Environ. Qual. 17:35–41.

Table 1. Initial soil test results taken in early spring 2014 and 2015Location Year pH Phosphorus Potassium Organic matter

------------ mg/kg ------------ %Hutchinson 2014 6.87 19 183 2.3Rossville 2014 7.07 17 218 2.1Scandia 2014 6.21 6 508 2.8Colby 2015 7.4 27 832 2.0Rossville 2015 7.2 20 256 2.0Scandia 2015 6.6 13 507 2.9

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Table 2. Soybean yields (bu/a) by site year as affected by fertilizer source and placement in 2014 and 20152014† 2015

Placement‡ Fertilizer§ Hutchinson Rossville Scandia Colby Rossville ScandiaIn-furrow P Only 42.8 ab 51.9 cd 32.8 a 56.8 bc 66.7 b 75.0 aIn-furrow CQ-758 38.3 bcd 46.2 e 32.0 ab 54.5 c 68.0 ab 70.7 abcIn-furrow EDTA-Fe 41.7 ab 54.6 abc 31.7 ab 62.6 a 67.1 b 74.5 abIn-furrow HEDTA-Fe 36.4 cd 59.0 a 31.9 ab 53.8 c 68.7 ab 74.4 abc

In-furrow placement 39.5 52.8 31.7 a 56.9 66.4 b 73.1 a

Band P Only 41.2 abc 58.2 ab 31.6 ab 60.1 ab 70.2 ab 74.2 abcBand CQ-758 35.1 d 51.2 cde 30.2 bc 56.5 bc 72.8 a 70.5 abcBand EDTA-Fe 37.9 bcd 53.1 bc 30.5 bc 59.0 abc 69.9 ab 69.6 bcBand HEDTA-Fe 41.1 abc 49.9 cde 29.2 c 62.9 a 68.7 ab 69.2 c

Surface band placement 39.8 51.8 30.3 b 59.6 69.6 a 70.5 b† Different letters in each column by parameter signify treatment differences at alpha=0.1 level.‡ Fertilizer placement as in-furrow was in contact with the seed at planting; band, surface band using a backpack sprayer on the row.§ CQ-758, Cee*Quest N5Fe758.

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SOUTHEAST AGRICULTURAL RESEARCH CENTER

Nitrogen, Phosphorus, and Potassium Fertilization for Newly Established Tall FescueD.W. Sweeney and J.L. Moyer

SummaryFirst-year production of tall fescue (Site 1 in 2013 and Site 2 in 2014) was affected by nitrogen (N) and phosphorus (P), but not potassium (K) fertilization. Environmental conditions likely influenced the growth of the fescue and the response to fertilizer N and P in the first year of production at the two sites.

IntroductionTall fescue is the major cool-season grass in southeastern Kansas. Perennial grass crops, as with annual row crops, rely on proper fertilization for optimum production, but meadows and pastures are often underfertilized and produce low quantities of low-quality forage. This is often true even when new stands are established. The objective of this study was to determine whether N, P, and K fertilization improves yields during the early years of a stand.

ProceduresThe experiment was established on two adjacent sites in fall 2012 (Site 1) and fall 2013 (Site 2) at the Parsons Unit of the Kansas State University Southeast Agricultural Research Center. The soil on both sites was a Parsons silt loam with initial soil test values of 5.9 pH, 2.8% organic matter, 4.2 ppm P, 70 ppm K, 3.9 ppm NH4-N, and 37.9 ppm NO3-N in the top 6 in. at Site 1 and 6.5 pH, 2.2% organic matter, 6.7 ppm P, 58 ppm K, 6.8 ppm NH4-N, and 12.3 ppm NO3-N in the top 6 in. at Site 2. The experimental design was a split-plot arrangement of a randomized complete block. The six whole plots were combinations of P2O5 and K2O fertilizer levels allowing for two separate analyses: (1) four levels of P2O5 consisting of 0, 25, 50, and 100 lb/a; and (2) a 2 × 2 factorial combination of two levels of P2O5 (0, 50 lb/a) and two levels of K2O (0, 40 lb/a). Subplots were four levels of N fertilization consisting of 0, 50, 100, and 150 lb/a. P and K fertilizers were broadcast applied in the fall as 0-46-0 (triple super-phosphate) and 0-0-60 (potassium chloride). Nitrogen was broadcast-applied in late winter as 46-0-0 (urea) solid. First-year samplings and harvests from each site were as follows. Early growth yield as an estimate of grazing potential in early spring was taken at E2 (jointing) growth stage on May 1, 2013 at Site 1, and on May 2, 2014 at Site 2, from a subarea of each plot not used for later spring and fall harvests. Spring yield was measured at R5 (postbloom) on June 7, 2013 at Site 1, and at R4 (half bloom) on May 22, 2014 at Site 2. Fall harvest was taken on September 10, 2013 at Site 1, and on September 24, 2014 at Site 2.

ResultsThe first year of tall fescue production (Site 1 in 2013 and Site 2 in 2014) was affected by N and P, but not K fertilization. At Site 1 in 2013, early yield at the E2 (jointing)

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growth stage to estimate forage available if grazed early, taken in a subarea of each plot not used for later hay harvest, was increased by P rates up to 100 lb P2O5/a (Table 1). At R5 hay harvest in 2013, yields were high at over 3 ton/a with no P and approximately 4.5 ton/a with P additions of 25 to 100 lb P2O5/a. Adding P fertilizer increased lodging and was near 100% for P rates more than 50 lb P2O5/a. The fall harvest yield declined with increasing P rates. In contrast, increasing N rates tended to decrease yield at R5 but increased yield in the fall. For the first year at Site 2 (2014), increasing N and P rates increased measured yield at E2 and at the R5 hay harvest (Table 2). Lower rainfall amounts resulted in smaller R5 yields (Table 2) and no lodging at that stage (data not shown) compared with Site 1 in the previous year (Table 1). However, June rains in 2014 resulted in increased growth after R5 harvest and resulted in midsummer lodging. By fall harvest, the grass had recovered and measured lodging was minimal, with small amounts of lodging that were unrelated to P fertilization in the 150 lb N/a treatment (Table 2). As in 2013 at Site 1 (Table 1), fall hay yield in 2014 at Site 2 decreased with increasing P rate, but yield increased with increasing N rate (Table 2).

Table 1. Newly established tall fescue yield in the spring and fall 2013 and R5 lodging visual estimates as affected by P2O5 and N fertilization rates at Site 1

YieldSpring

P2O5, lb/a E2 (jointing) R5 (postbloom) Fall harvest R5 lodging------------------ ton/a, 12% moisture ------------------ %

0 0.30 3.41 2.05 125 0.73 4.32 1.99 5350 1.00 4.51 1.74 97100 1.70 4.47 1.48 100LSD (0.05) 0.32 0.63 0.29 19

N, lb/a0 0.86 4.48 1.61 5850 0.95 4.16 1.70 61100 0.94 4.17 1.91 67150 0.95 3.89 2.04 65LSD (0.05) NS 0.33 0.15 NS

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Table 2. Newly established tall fescue yield in the spring and fall 2014 and lodging visual estimates prior to fall harvest as affected by P2O5 and N fertilization rates at Site 2

YieldSpring

P2O5, lb/a E2 (jointing) R5 ( postbloom) Fall harvest Fall lodging------------------ ton/a, 12% moisture ------------------ %

0 0.17 1.02 1.99 725 0.38 1.25 1.89 350 0.46 1.76 1.81 4100 0.60 1.98 1.58 4LSD (0.05) 0.24 0.65 0.26 NS

N, lb/a0 0.15 0.94 0.65 050 0.41 1.30 1.32 0100 0.49 1.86 2.34 4150 0.55 1.91 3.02 13LSD (0.05) NS 0.31 0.21 5

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Tillage and Nitrogen Placement Effects on Yields in a Short-Season Corn/Wheat/Double-Crop Soybean RotationD.W. Sweeney

SummaryOverall in 2014, adding nitrogen (N) improved average wheat yields, but different N placement methods resulted in similar yields. Double-crop soybean yields were unaf-fected by tillage or the residual from N treatments that were applied to the previous wheat crop.

IntroductionMany crop rotation systems are used in southeast Kansas. This experiment is designed to determine the long-term effects of selected tillage and N fertilizer placement options on yields of short-season corn, wheat, and double-crop soybean in rotation.

ProceduresA split-plot design with four replications was initiated in 1983 with the tillage system as the whole plot and N treatment as the subplot. In 2005, the rotation was changed to begin a short-season corn/wheat/double-crop soybean sequence. Use of three till-age systems (conventional, reduced, and no-till) continues in the same areas as during the previous 22 years. The conventional system consists of chiseling, disking, and field cultivation. Chiseling occurs in the fall preceding corn or wheat crops. The reduced-tillage system consists of disking and field cultivation prior to planting. Glyphosate is applied to the no-till areas prior to planting. The four N treatments for the crop are: no N (control), broadcast urea ammonium nitrate (UAN; 28% N) solution, dribble UAN solution, and knife UAN solution at 4 in. deep. The N rate for the corn crop grown in odd-numbered years is 125 lb/a. The N rate of 120 lb/a for wheat is split as 60 lb/a applied preplant as broadcast, dribble, or knifed UAN. All plots except for the controls are top-dressed in the spring with broadcast UAN at 60 lb/a N.

ResultsIn 2014, wheat yields were low, averaging less than 30 bu/a (data not shown). Fertil-izing with N increased wheat yield by approximately 70%; however, preplant applica-tion method (broadcast, dribble, or knife) did not affect yields. Tillage had no effect on wheat yields. Average yield of soybean planted double-crop after wheat harvest exceeded 45 bu/a in 2014, but yield was not affected by tillage systems or the residual from N fertilizer treatments that were applied to the wheat.

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Response of Soybean Grown on a Claypan Soil in Southeastern Kansas to the Residual of Different Plant Nutrient Sources and TillageD.W. Sweeney, P. Barnes, and G. Pierzynski

SummaryThe residual effects of turkey litter and fertilizer amendments applied in previous years had little effect on the yield, yield components, and dry matter production of the following soybean crop grown in 2014.

IntroductionIncreased fertilizer prices in recent years, especially noticeable when the cost of phos-phorus spiked in 2008, have led U.S. producers to consider other alternatives, including manure sources. The use of poultry litter as an alternative to fertilizer is of particular interest in southeast Kansas because large amounts of poultry litter are imported from nearby confined animal feeding operations in Arkansas, Oklahoma, and Missouri. Annual application of turkey litter can affect the current crop; however, information is lacking concerning any residual effects from several continuous years of poultry litter applications on a following crop. This is especially true for tilled soil compared with no-till, because production of most annual cereal crops on the claypan soils of the region is often negatively affected by no-tillage planting. The objective of this study was to determine if the residual from fertilizer and poultry litter applications under tilled or no-till systems affects soybean yield and growth.

ProceduresA water quality experiment was conducted near Girard, KS, on the Greenbush Educa-tional facility’s grounds from spring 2011 through spring 2014. Fertilizer and turkey litter were applied prior to planting grain sorghum each spring. Individual plot size was 1 acre. A total of 10 plots with five treatments were replicated twice. The five treatments were:

Control – no N or P fertilizer or turkey litter – no tillageFertilizer only – commercial N and P fertilizer – chisel-disk tillageTurkey litter, N-based – no extra N or P fertilizer – no tillageTurkey litter, N-based – no extra N or P fertilizer – chisel-disk tillageTurkey litter, P-based – supplemented with fertilizer N – chisel-disk tillage

Starting in 2015 after the above study, soybean was planted in the plots with no further application of turkey litter or fertilizer. Prior to planting soybean, tillage operations were done in appropriate plots as in previous years. A subarea of 20 ft × 20 ft near the center of each 1-acre plot was designated for crop yield and growth measurements. Samples were taken for dry matter production at V3 (approximately 3 weeks after

34


planting), R2, R4, and R6 growth stages. Yield was determined from the center 4 rows (10 × 20 ft) of the subarea designated for plant measurements in each plot.

Results The residual effects of turkey litter and fertilizer amendments had little effect on follow-ing soybean yield, yield components, and dry matter production (Table 1). The number of pods per plant where turkey litter had been previously applied based on N needs of the former grain sorghum crop was greater than in the no-amendment control. Also, the early growth of the soybean plants at V3 appeared to respond to the residual of the high litter rate with tillage (TL-N-C) compared with either the control or the TL-N no-till residual. However, in the reproductive stages of growth (R2, R4, and R6), the residual treatments seemed to have no effect on dry matter production.

Table 1. Residual effect of turkey litter and fertilizer amendments on following soybean yield, yield components, and dry matter production in 2014

Residual amendment1 Yield

Stand (×1000)

Seed weight

Pods/plant

Seeds/pod

Dry matterV3 R2 R4 R6

bu/a plants/a mg ---------------------- lb/a ----------------------Control 31.2 118 156 24.5 2.3 60 680 2,020 2,650TL-N 37.0 121 149 39.5 2.4 60 1,100 3,200 4,970TL-N-C 38.8 121 157 37.5 2.4 280 1,570 3,680 6,160TL-P-C 26.7 118 160 29.5 2.4 120 1,050 3,140 4,750Fert-C 32.1 117 159 31.0 2.3 130 1,060 2,460 4,760

LSD (0.10) NS NS NS 8.7 NS 170 NS NS NS 1 Control, no turkey litter or N and P fertilizer with no tillage; TL-N, N-based turkey litter application with no tillage; TL-N-C, N-based turkey litter application incorporated with conventional tillage; TL-P-C, P-based turkey litter application and supplemental N applica-tion incorporated with conventional tillage; and Fert-C, commercial fertilizer only incorporated with conventional tillage.

35

Southwest Research-Extension Center

Long-Term Nitrogen and Phosphorus Fertilization of Irrigated CornA. Schlegel and H.D. Bond

SummaryLong-term research shows that phosphorus (P) and nitrogen (N) fertilizer must be applied to optimize production of irrigated corn in western Kansas. In 2015, N applied alone increased yields 70 bu/a, whereas P applied alone increased yields only 12 bu/a. Nitrogen and P applied together increased yields up to 129 bu/a. This is below the 10 year average, where N and P fertilization increased corn yields up to 144 bu/a. Applica-tion of 120 lb/a N (with P) produced about 98% of maximum yield in 2015, which is 5% more than the 10-year average. Application of 80 instead of 40 lb P2O5/a increased average yields only 1 bu/a. Average grain N content reached a maximum of 0.6 lb/bu while grain P content reached a maximum of 0.15 lb/bu (0.34 lb P2O5/bu).

IntroductionThis study was initiated in 1961 to determine responses of continuous corn and grain sorghum grown under flood irrigation to N, P, and potassium (K) fertilization. The study is conducted on a Ulysses silt loam soil with an inherently high K content. No yield benefit to corn from K fertilization was observed in 30 years, and soil K levels remained high, so the K treatment was discontinued in 1992 and replaced with a higher P rate.

ProceduresThis field study is conducted at the Tribune Unit of the Southwest Research-Extension Center. Fertilizer treatments initiated in 1961 are N rates of 0, 40, 80, 120, 160, and 200 lb/a without P and K; with 40 lb/a P2O5 and zero K; and with 40 lb/a P2O5

and 40 lb/a K2O. The treatments were changed in 1992; the K variable was replaced by a higher rate of P (80 lb/a P2O5). All fertilizers were broadcast by hand in the spring and incorporated before planting. The soil is a Ulysses silt loam. The corn hybrids [Pioneer 34N50 (2006), Pioneer 33B54 (2007), Pioneer 34B99 (2008), DeKalb 61-69 (2009), Pioneer 1173H (2010), Pioneer 1151XR (2011), Pioneer 0832 (2012-2013), Pioneer 1186AM (2014), and Pioneer 35F48 AM1 (2015)] were planted at about 32,000 seeds/a in late April or early May. Hail damaged the 2008 and 2010 crops (slight damage on 2015 crop). The corn is irrigated to minimize water stress. Sprinkler irriga-tion has been used since 2001. The center two rows of each plot are machine harvested after physiological maturity. Grain yields are adjusted to 15.5% moisture. Grain samples were collected at harvest, dried, ground, and analyzed for N and P concentrations. Grain N and P content (lb/bu) and removal (lb/a) were calculated.

ResultsCorn yields in 2015 were 17% greater than the 10-year average (Table 1). Nitrogen alone increased yields 70 bu/a, whereas P alone increased yields only 12 bu/a. However, N and P applied together increased corn yields up to 129 bu/a. While maximum yield was obtained with the highest N and P rate, 160 lb/a N with 80 lb/a P2O5 caused less

36


than a 2% yield reduction. Corn yields in 2015 (averaged across all N rates) were only 1 bu/a greater with 80 than with 40 lb/a P2O5.

The 10-year average grain N concentration (%) increased with N rates but tended to decrease when P was also applied, presumably because of higher grain yields diluting N content (Table 2). Grain N content reached a maximum of 0.6 lb/bu. Maximum N removal (lb/a) was greatest at the highest yield levels, which were attained with 200 lb N and 80 lb P2O5/a. Similar to N, average P concentration increased with increased P rates but decreased with higher N rates. Grain P content (lb/bu) of about 0.15 lb P/bu (0.34 lb P2O5/bu) was greater at the highest P rate with low N rates. Grain P removal averaged less than 30 lb P/a at the highest yields.

Table 1. Nitrogen and phosphorus fertilization on irrigated corn yields, Tribune, KS, 2006-2015Fertilizer Yield

N P2O5 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Mean------ lb/a ------ -------------------------------------------------- bu/a --------------------------------------------------

0 0 42 49 36 85 20 92 86 70 86 92 660 40 68 50 57 110 21 111 85 80 95 103 780 80 72 51 52 106 28 105 94 91 98 104 80

40 0 56 77 62 108 23 114 109 97 106 113 8740 40 129 112 105 148 67 195 138 125 153 164 13340 80 123 116 104 159 61 194 135 126 149 162 133

80 0 79 107 78 123 34 136 128 112 117 131 10480 40 162 163 129 179 85 212 197 170 187 195 16880 80 171 167 139 181 90 220 194 149 179 193 168

120 0 68 106 65 117 28 119 134 114 115 124 99120 40 176 194 136 202 90 222 213 204 213 212 186120 80 202 213 151 215 105 225 211 194 216 216 195

160 0 84 132 84 139 49 157 158 122 128 144 120160 40 180 220 150 210 95 229 227 199 211 215 194160 80 200 227 146 223 95 226 239 217 233 216 202

200 0 115 159 99 155 65 179 170 139 144 162 139200 40 181 224 152 207 97 218 225 198 204 214 192200 80 204 232 157 236 104 231 260 220 238 221 210

continued

37


Table 1. Nitrogen and phosphorus fertilization on irrigated corn yields, Tribune, KS, 2006-2015Fertilizer Yield

N P2O5 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Mean------ lb/a ------ -------------------------------------------------- bu/a --------------------------------------------------ANOVA (P>F)Nitrogen 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001

Linear 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001Quadratic 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001

Phosphorus 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001Linear 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001Quadratic 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001

N × P 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001

MEANSNitrogen, lb/a

0 61e 50f 48e 100e 23e 103d 88f 80e 93e 100e 75f40 103d 102e 91d 138d 50d 167c 127e 116d 136d 146d 118e80 137c 146d 115c 161c 70c 189b 173d 143c 161c 173c 147d120 149bc 171c 118c 178b 74bc 189b 186c 171b 181b 184b 160c160 155ab 193b 127b 191a 80ab 204a 208b 179ab 190ab 192ab 172b200 167a 205a 136a 199a 89a 209a 218a 186a 196a 199a 180aLSD(0.05) 15 11 9 12 9 13 10 10 10 9 8

P2O5, lb/a0 74c 105b 71b 121c 36b 133b 131c 109b 116c 128b 102c40 149b 160a 122a 176b 76a 198a 181b 163a 177b 184a 159b80 162a 168a 125a 187a 81a 200a 189a 166a 186a 185a 165aLSD(0.05) 11 8 6 9 7 9 7 7 7 6 6

*Note: Hail events on 7/23/10 and 5/28/15.

38


Table 2. Nitrogen and P fertilization on grain N and P content of irrigated corn, Tribune, KS, 2006-2015

Fertilizer Grain Grain removalN P2O5 N P N P N P

-------- lb/a -------- -------- % -------- ------- lb/bu ------- -------- lb/a --------0 0 1.02 0.233 0.48 0.110 31 70 40 0.97 0.310 0.46 0.147 35 110 80 0.97 0.318 0.46 0.151 36 12

40 0 1.16 0.185 0.55 0.087 47 740 40 0.99 0.298 0.47 0.141 62 1940 80 1.00 0.321 0.47 0.152 62 20

80 0 1.26 0.178 0.60 0.084 62 980 40 1.07 0.257 0.51 0.121 84 2080 80 1.05 0.306 0.50 0.145 83 24

120 0 1.25 0.173 0.59 0.082 58 8120 40 1.15 0.228 0.54 0.108 101 20120 80 1.12 0.296 0.53 0.140 103 27

160 0 1.26 0.178 0.60 0.084 70 10160 40 1.19 0.243 0.57 0.115 109 22160 80 1.19 0.282 0.56 0.133 113 27

200 0 1.26 0.185 0.60 0.088 82 12200 40 1.21 0.240 0.57 0.114 109 22200 80 1.20 0.296 0.57 0.140 119 29

ANOVA (P>F)Nitrogen 0.001 0.001 0.001 0.001 0.001 0.001

Linear 0.001 0.001 0.001 0.001 0.001 0.001Quadratic 0.001 0.001 0.001 0.001 0.001 0.001

Phosphorus 0.001 0.001 0.001 0.001 0.001 0.001Linear 0.001 0.001 0.001 0.001 0.001 0.001Quadratic 0.001 0.001 0.001 0.001 0.001 0.001

N × P 0.001 0.001 0.001 0.001 0.001 0.001continued

39


Table 2. Nitrogen and P fertilization on grain N and P content of irrigated corn, Tribune, KS, 2006-2015

Fertilizer Grain Grain removalN P2O5 N P N P N P

-------- lb/a -------- -------- % -------- ------- lb/bu ------- -------- lb/a --------MEANSNitrogen, lb/a

0 0.99e 0.287a 0.47e 0.136a 34f 10e40 1.05d 0.268b 0.50d 0.127b 57e 16d80 1.13c 0.247c 0.53c 0.117c 76d 18c120 1.17b 0.232d 0.56b 0.110d 87c 18bc160 1.21a 0.234d 0.57a 0.111d 97b 20b200 1.22a 0.240cd 0.58a 0.114cd 103a 21aLSD(0.05) 0.02 0.012 0.01 0.006 5 1

P2O5, lb/a0 1.20a 0.189c 0.57a 0.089c 58b 9c40 1.10b 0.263b 0.52b 0.124b 83a 19b80 1.09b 0.303a 0.52b 0.143a 86a 23aLSD(0.05) 0.01 0.008 0.01 0.004 3 1

40


Long-Term Nitrogen and Phosphorus Fertilization of Irrigated Grain SorghumA. Schlegel and H.D. Bond

SummaryLong-term research shows that phosphorus (P) and nitrogen (N) fertilizer must be applied to optimize production of irrigated grain sorghum in western Kansas. In 2015, N applied alone increased yields 66 bu/a, whereas N and P applied together increased yields up to 92 bu/a. Averaged across the past 10 years, N and P fertilization increased sorghum yields up to 76 bu/a. Application of 40 lb/a N (with P) was sufficient to produce 88% of maximum yield in 2015 which is slightly above the 10-year average. Application of potassium (K) has had no effect on sorghum yield throughout the study period. Average grain N content reached a maximum of ~0.7 lb/bu while grain P content reached a maximum of 0.15 lb/bu (0.34 lb P2O5/bu) and grain K content reached a maximum of 0.19 lb/bu (0.23 lb K2O/bu).

IntroductionThis study was initiated in 1961 to determine responses of continuous grain sorghum grown under flood irrigation to N, P, and K fertilization. The study is conducted on a Ulysses silt loam soil with an inherently high K content. The irrigation system was changed from flood to sprinkler in 2001.

ProceduresThis field study is conducted at the Tribune Unit of the Southwest Research-Extension Center. Fertilizer treatments initiated in 1961 are N rates of 0, 40, 80, 120, 160, and 200 lb/a N without P and K; with 40 lb/a P2O5 and zero K; and with 40 lb/a P2O5

and 40 lb/a K2O. All fertilizers are broadcast by hand in the spring and incorporated before planting. The soil is a Ulysses silt loam. Sorghum (Pioneer 8500/8505 from 2006–2007, Pioneer 85G46 in 2008–2011, Pioneer 84G62 in 2012-2014, and Pioneer 86G32 in 2015) was planted in late May or early June. Irrigation is used to minimize water stress. Sprinkler irrigation has been used since 2001. The center two rows of each plot are machine harvested after physiological maturity. Grain yields are adjusted to 12.5% moisture. Grain samples were collected at harvest, dried, ground, and analyzed for N, P, and K concentrations. Grain N, P, and K content (lb/bu) and removal (lb/a) were calculated.

ResultsGrain sorghum yields in 2015 were 22% greater than the 10-year average (Table 1). Nitrogen alone increased yields 66 bu/a while P alone increased yields 13 bu/a. However, N and P applied together increased yields up to 92 bu/a. Averaged across the past 10 years, N and P applied together increased yields up to 76 bu/a. In 2015, 40 lb/a N (with P) produced about 88% of maximum yield, which is slightly above the 10-year average of 84%; 120 lb/a N (with P) and 160 lb/a N (with P) produced 98% and 100% of maximum yield, respectively. Sorghum yields were not affected by K fertilization, which has been the case throughout the study period.

41


The 10-year average grain N concentration (%) increased with N rates but tended to decrease when P was also applied, presumably because of higher grain yields diluting N content (Table 2). Grain N content reached a maximum of ~0.7 lb/bu. Maximum N removal (lb/a) was obtained with 160 lb N/a or greater with P. Similar to N, average P concentration increased with P application but decreased with higher N rates. Grain P content (lb/bu) of ~0.15 lb P/bu (0.34 lb P2O5/bu) was similar for all N rates when P was applied. Grain P removal was similar for all N rates of 40 lb/a or greater with P applications ranging from 19 to 23 lb/a. Average K concentration (%) and content (lb/bu) tended to decrease with increased N rates. Similar to P, K removal was similar for all N rates of 40 lb/a or greater plus K ranging from 23 to 27 lb/a.

Table 1. Nitrogen, phosphorus, and potassium fertilizers on irrigated grain sorghum yields, Tribune, KS, 2006-2015Fertilizer Grain sorghum yield

N P2O5 K2O 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Mean---------- lb/a ---------- -------------------------------------------------- bu/a --------------------------------------------------0 0 0 84 80 66 64 51 75 78 62 90 89 740 40 0 102 97 60 70 51 83 90 77 94 102 830 40 40 95 94 65 76 55 88 93 72 96 97 83

40 0 0 102 123 92 84 66 106 115 94 115 122 10240 40 0 133 146 111 118 77 121 140 114 144 160 12640 40 40 130 145 105 109 73 125 132 110 142 155 123

80 0 0 111 138 114 115 73 117 132 102 120 133 11680 40 0 132 159 128 136 86 140 163 136 151 173 14080 40 40 142 166 126 108 84 138 161 133 164 178 140

120 0 0 101 138 106 113 70 116 130 100 116 127 112120 40 0 136 164 131 130 88 145 172 137 162 177 144120 40 40 139 165 136 136 90 147 175 142 170 178 148

160 0 0 123 146 105 108 74 124 149 117 139 150 123160 40 0 145 170 138 128 92 152 178 146 171 181 150160 40 40 128 167 133 140 88 151 174 143 176 179 148

200 0 0 134 154 120 110 78 128 147 119 139 155 128200 40 0 143 168 137 139 84 141 171 136 165 177 146200 40 40 143 170 135 129 87 152 175 138 170 179 148

continued

42


Table 1. Nitrogen, phosphorus, and potassium fertilizers on irrigated grain sorghum yields, Tribune, KS, 2006-2015Fertilizer Grain sorghum yield

N P2O5 K2O 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Mean---------- lb/a ---------- -------------------------------------------------- bu/a --------------------------------------------------

ANOVA (P>F)Nitrogen 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001

Linear 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001Quadratic 0.004 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001

P-K 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001Zero P vs. P 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001P vs. P-K 0.578 0.992 0.745 0.324 0.892 0.278 0.826 0.644 0.117 0.806 0.951

N × P-K 0.210 0.965 0.005 0.053 0.229 0.542 0.186 0.079 0.012 0.002 0.035

MEANSNitrogen, lb/a

0 93d 91d 64d 70c 52c 82d 87d 70d 94e 96d 80d40 121c 138c 103c 104b 72b 117c 129c 106c 134d 146c 117c80 128bc 155b 123b 120a 81a 132b 152b 124b 145c 161b 132b120 125bc 156ab 124ab 126a 82a 136ab 159ab 126b 149bc 161b 134b160 132ab 161ab 125ab 125a 84a 142a 167a 135a 162a 170a 140a200 140a 164a 131a 126a 83a 141a 165a 131ab 158ab 170a 141aLSD(0.05) 11 9 7 11 5 8 9 8 9 8 6

P2O5-K2O, lb/a0 - 0 109b 130b 101b 99b 68b 111b 125b 99b 120b 129b 109b40 - 0 132a 151a 117a 120a 80a 130a 152a 124a 148a 162a 132a40 - 40 130a 151a 117a 116a 79a 133a 152a 123a 153a 161a 132aLSD(0.05) 7 6 5 7 4 6 6 5 6 5 4

43


Table 2. Nitrogen, phosphorus, and potassium fertilizers on grain N, P, and K content of irrigated grain sorghum, Tribune, KS, 2006-2015

Fertilizer Grain Grain removalN P2O5 K2O N P K N P K N P K

---------- lb/a ---------- ------------ % ------------ ---------- lb/bu ---------- ---------- lb/a ----------0 0 0 1.07 0.267 0.372 0.52 0.131 0.182 39 10 130 40 0 1.05 0.315 0.393 0.51 0.154 0.192 42 13 160 40 40 1.04 0.312 0.391 0.51 0.153 0.191 42 13 16

40 0 0 1.18 0.240 0.345 0.58 0.117 0.169 59 12 1740 40 0 1.14 0.317 0.378 0.56 0.156 0.185 70 20 2340 40 40 1.14 0.311 0.376 0.56 0.152 0.184 68 19 23

80 0 0 1.36 0.227 0.339 0.67 0.111 0.166 77 13 1980 40 0 1.27 0.301 0.361 0.62 0.147 0.177 86 21 2580 40 40 1.24 0.312 0.369 0.61 0.153 0.181 84 21 25

120 0 0 1.41 0.215 0.335 0.69 0.105 0.164 77 12 18120 40 0 1.36 0.288 0.356 0.67 0.141 0.174 96 20 25120 40 40 1.36 0.311 0.363 0.67 0.153 0.178 98 22 26

160 0 0 1.45 0.236 0.345 0.71 0.115 0.169 88 14 21160 40 0 1.41 0.311 0.365 0.69 0.152 0.179 104 23 27160 40 40 1.39 0.292 0.358 0.68 0.143 0.176 100 21 26

200 0 0 1.45 0.242 0.349 0.71 0.119 0.171 91 15 22200 40 0 1.42 0.294 0.365 0.70 0.144 0.179 101 21 26200 40 40 1.43 0.297 0.363 0.70 0.146 0.178 103 21 26

ANOVA (P>F)Nitrogen 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001

Linear 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001Quadratic 0.001 0.009 0.001 0.001 0.009 0.001 0.001 0.001 0.001

P-K 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001Zero P vs. P 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001P vs. P-K 0.502 0.718 0.876 0.502 0.718 0.876 0.659 0.890 0.986

N × P-K 0.705 0.014 0.221 0.705 0.014 0.221 0.118 0.002 0.019continued

44


Table 2. Nitrogen, phosphorus, and potassium fertilizers on grain N, P, and K content of irrigated grain sorghum, Tribune, KS, 2006-2015

Fertilizer Grain Grain removalN P2O5 K2O N P K N P K N P K

---------- lb/a ---------- ------------ % ------------ ---------- lb/bu ---------- ---------- lb/a ----------MEANSNitrogen, lb/a

0 1.05e 0.298a 0.385a 0.52e 0.146a 0.189a 41e 12c 15d40 1.15d 0.289ab 0.367b 0.57d 0.142ab 0.180b 66d 17b 21c80 1.29c 0.280bc 0.356cd 0.63c 0.137bc 0.175cd 82c 18a 23b120 1.38b 0.272c 0.351d 0.68b 0.133c 0.172d 90b 18a 23b160 1.42ab 0.280bc 0.356cd 0.69ab 0.137bc 0.174cd 97a 19a 25a200 1.43a 0.278bc 0.359c 0.70a 0.136bc 0.176c 98a 19a 25aLSD(0.05) 0.04 0.012 0.007 0.02 0.006 0.003 4 1 1

P2O5-K2O, lb/a0 - 0 1.32a 0.238b 0.348b 0.65b 0.117b 0.170b 71b 13b 19b40 - 0 1.27b 0.304a 0.370a 0.62a 0.149a 0.181a 83a 19a 24a40 - 40 1.27b 0.306a 0.370a 0.62a 0.150a 0.181a 83a 20a 24aLSD(0.05) 0.03 0.008 0.005 0.01 0.004 0.002 3 1 1

Copyright 2016 Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. In each case, give credit to the author(s), Kansas Fertilizer Research 2016, Kansas State University, August 2016. Contribution no. 17-020-S from the Kansas Agricultural Experiment Station.

Chemical DisclaimerBrand names appearing in this publication are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products not mentioned. Experiments with pesticides on nonlabeled crops or target species do not imply endorsement or recommendation of nonlabeled use of pesticides by Kansas State University. All pesticides must be used consistent with current label directions. Current information on weed control in Kansas is available in 2016 Chemical Weed Control for Field Crops, Pastures, Rangeland, and Noncropland, Report of Progress 1126, available from the Distribution Center, Umberger Hall, Kansas State University, or at: www.ksre.ksu.edu/ bookstore (type Chemical Weed Control in search box).

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