Nitrogen Mineralization and Uptake, and Effects of Cropping Systems on Nitrogen and pp g y g

Phosphorus AvailabilityClain Jones, Soil Fertility Extension Specialist, y p(406) 994-6076; clainj@montana.edu

Prepared for Glacier and Liberty p yCounties: February 28, 2007

Questions for youQuestions for you

• What crops do you grow?• What crops have you considered growing?What crops have you considered growing?• Are your nitrate-N levels on fallow any

different this year than last few?different this year than last few?

Factors increasing ‘Nitrogen mineralization’ (Conversion of organic N to plant available N)

• Warm Temperature How did last late spring/summer compare to

• High Moisture

• Legumes as previous crop (vs small grain stubble)

spring/summer compare to ‘normal’?

g p p ( g )

• High Organic Matter

• Tillage - Why?

Take home message: soil N will vary year to yearTake home message: soil N will vary year to year making soil testing essential for determining N needs

Timing of N UptakeTiming of N Uptake

• Relevance: Affects Yield and ProteinRelevance: Affects Yield and Protein

What makes yield?What makes yield?

Heads/area x Kernels/heads x Weight/kernel

Wh i ld t “ t”?When are yield components “set”?Weight/kernelWeight/kernelset

Head/acre set

Kernels/head set

Nitrogen lateWeight/kernel

Impacts of nitrogen

Nit l

Higher grain proteinImpacts of nitrogen

Nitrogen earlyNumber of tillers and kernels/head

Grain protein fromGrain protein fromremobilized N

Spring Wheat N UptakeSpring Wheat N Uptake

Jacobsen et al.1992

Effect of Slow Release N FertilizerEffect of Slow Release N Fertilizer

• CAN increase establishment if N seed-CAN increase establishment if N seedplaced (due to less seed germination problems esp in dry sandier soils)problems, esp. in dry sandier soils)

• CAN increase proteinCAN d i ld (if il N i l )• CAN decrease yield (if soil N is low)

• CAN decrease N losses (volatilization, leaching), possibly increasing yield

Effect of N Rate and Source on Spring Wheat Protein

G J k 1993 WTARC A l R tG. Jackson, 1993, WTARC Annual Report

1546-0-0N fertilizer topdressed after flowering

13

14

(%)

46-0-0

34-0-0

N fertilizer topdressed after flowering

12

prot

ein

(

Cut Bank

10

11

Gra

in p

No significant N source effects at these 2

8

9

G

Joplingsites nor at Inverness or Loma

80 30 60

Topdress N (lb/acre)

QUESTIONS?

As diversity of cropping system iincreases:

Efficiency of fertilizer use increases Why?Efficiency of fertilizer use increases. Why? Different rooting depths scavenge nitrogen and phosphorus at different depthsphosphorus at different depthsDeep rooted crops can bring nutrients from subsurface to surface for use by shallow rootedsubsurface to surface for use by shallow rooted crops (winter wheat pea)

Some basics on effects of cropping il i (N)systems on soil nitrogen (N)

Previous crop affects:Previous crop affects:- Amount of N

Small grain and oilseed stubble ties up Ng pLegumes release N

- Vertical distribution of Ne t ca d st but o oDepends on rooting depth and fallow frequency

- Timing of N releaseSpring vs winter cropSpring vs winter cropLegumes decompose quickly. Affected by harvest timingSmall grain and oilseed stubble slowlySmall grain and oilseed stubble slowly

Effect of Previous Crop on N Needed to Optimize Wheat Yield

60

70

40

50

60

% m

oist

)

chem fallow

30

40

bu/a

c (1

2% winter pea

spring pea

barley

10

20b barley

00 45 90 135

Fertilizer N rate (lb/ac) P MillerFertilizer N rate (lb/ac)

Wheat needs less N when grown on fallow or winter pea than on barley.

P Miller

Moccasin Cropping System/Tillage Study

Previous crop: Winter Pea (forage) Spring Wheat Spring Pea (grain)

Photo by C. Chen

Winter Wheat

Effect of Previous Crop and N on 2006 Winter Wheat Grain Yield (NT)

60

2006 Winter Wheat Grain Yield (NT)Moccasin, MT

50

/acr

e) Fallow

30

40

Yiel

d (b

u/

Spring Wheat

20

30

W G

rain

Y

g

10WW

Data from C. Chen0

0 20 40 60 80 100 120Nitrogen Units (lb N/acre)

Effect of Previous Crop and N on 2006 Winter Wheat Grain Yield (NT)2006 Winter Wheat Grain Yield (NT)

Moccasin, MT60

50

/acr

e) Fallow

Spring Pea

Winter Pea

30

40

Yiel

d (b

u/

Spring Wheat

Spring Pea

20

30

W G

rain

Y

p g

10WW

Data from C. Chen

Note: There was good moisture in 2006

00 20 40 60 80 100 120

Nitrogen Units (lb N/acre)

Effect of Previous Crop on Residual Nitrate-N

60

70C. Chen

50

60

-N (l

b/ac

) Why different?

30

40

oil N

itrat

e-

20

Sprin

g So

0

10

S

Fallow Winter Pea Spring Pea Spring Wheat

Previous Crop

Nitrogen Benefits from LegumesNitrogen Benefits from Legumes• Peas and lentils CAN ‘fix’ about 2-4 lb N/bu.Peas and lentils CAN fix about 2 4 lb N/bu.

Ex: 50-100 lb N/acre for 25 bu crop.• Over 1/2 of this is removed at harvest.• N credit for NEXT CROP is between 0 and 20 lb

N/acre. Where did rest go?• If replacing a small grain or oilseed with a legume,

bigger N savings will be in legume year.• If replacing fallow with legume, bigger N savings

will be in long-term.

Effect of Lentil on Spring Soil Nitrate N LevelsNitrate-N Levels

140Swift Current SK

100

120

acre

)

Fallow

Swift Current, SKZentner et al. 2004

80

100

te-N

(lb/

a FallowLentilGreen

ManureLentilGreen

40

60

rng

Nitr

a Manure

Fallow

GreenManure

20

40

Spir

01988-1993 1994-1999

QUESTIONS?

Some basics on effects of cropping il h h (P)

• Previous crop affects:

systems on soil phosphorus (P)Previous crop affects:-Soil moisture. Dry soil decreases available P.

Sunflowers, safflower, corn, wheat, barley can use substantial amounts of waterLegumes use similar amounts of water atLegumes use similar amounts of water at shallow depth, but very little at deeper depth

-Available P can be increased by:Available P can be increased by:Legumes, buckwheat, and some mustards through root zone acidificationthrough root zone acidification

Maximum Rooting Depths (M d N h D k )(Mandan, North Dakota)

Crop Maximum rooting depth (ft.)

Dry Pea 3.0

Canola 3.5

Spring Wheat 4.0

Sunflower 4 5*Sunflower 4.5*

* 6 ft. in Montana (Miller, pers. comm.)Merrill et al. 2002

6 ft. in Montana (Miller, pers. comm.)

What is More Important than Max. Root Length for Nutrient Uptake?

Root Density

0

Dry pea will use more nutrients

th (f

t.)

0

1

2

3

nutrients from surface;

Dep 4

5

6

canola will use more from depth

0

1t.)

p

1

2

3

4epth

(ft

Merrill et al4

5

6

De Merrill et al.

2002

P can accumulate near surface in both no-till and tilled systems

.)

0

Chen and

P banded with seed

Why i t t?rfa

ce (i

n.

2

4

Chen and Jones

important?

Shallow rootedm s

oil s

ur 4

6

Shallow rooted crops can

scavenge P from near surfacept

h fro

m

8

10NTNTNTCT

Moccasin

near surface, increasing

efficiency of P fertilizer.0 2 4 6 8 10 12 14 16 18 20

De 10

12

NTCTCTNTCTCT

Olsen P (ppm)0 2 4 6 8 10 12 14 16 18 20

Crop Species that Acidify RootzoneCrop Species that Acidify Rootzone

Buckwheat Legumes Some MustardsBuckwheat Legumes Some Mustards

Root zone pH of four cropsRoot zone pH of four crops

QUESTIONS?

Effects of Diversified No-till Cropping pp gSystems on Soil Nutrient Status

by Clain Jones and Perry Miller

Bozeman Crop Rotation StudyWinter Wheat Grain Yield

Bozeman Crop Rotation Study

60

70

50

60

bu/a

cre)

Organic (PM-WW-L-B)

WW based

30

40

Yiel

d (b WW based

(WP/L-WW-C-WW)

Diverse (P/L-WW-M/C-S)

10

20

Gra

in

Continuous (SW-WW)

014 Year Average Following Legume* P Miller

QuestionQuestion

Are yield differences partly due to theAre yield differences partly due to the effects of rotation on nutrient levels?

RotationsRotationsCrop Diversification Rotation Study (Miller) 2000-2003p y ( )

System Year 1 Year 2 Year 3 Year 4Organic AWP fallow WWheat Lentil Barley

DormantNT Winter Winter Pea WWheat RR Canola WWheatNT Winter Winter Pea WWheat RR Canola WWheat

NT Spring Pea SWheat RR Canola SWheat

NT Diverse Pea WWheat Hybrid Corn Sunflower

NT CW SWheat WWheat SWheat WWheat

Dormant canolaDormant canola

Yellow peaYellow pea

RESULTS

NitrateNitrate

160

1800-6 in.

b

120

140

160

ac)

6-12 in.12-24 in.

b

b

80

100

120

e N

(lb/

a

aa

ab

40

60

80

Nitr

ate a

0

20

40

Organic NT WW-based

NT SW-based

NTDiverse

NT CW

Olsen POlsen P25

bbCritical Level

20

kg) a a

abCritical Level

15

P (m

g/k

5

10

Ols

en

0

5

Organic NT WW-based

NT SW-based

NTDiverse

NT CW

Effect of Available N on WW Yield

80

90ac

)

60

70

80

ield

(bu/

a

40

50

at g

rain

y

NTD2 H

20

30

nter

whe

a NTD2-HNTD2-LNTW2-HNTW2-LPFP2

0

10

0 50 100 150 200 250 300

Win PFP2

Org2

0 50 100 150 200 250 300

Fertilizer N + March nitrate-N (lb/ac)

Effects of other Nutrients on Yield

Other nutrients also had no effect on winter wheat yield.

So what was causing large yield differences?So what was causing large yield differences?

Effect of Plant-Available Water on WW Yi ldWW Yield

90

70

80

d (b

u/ac

)

50

60

grai

n yi

eld

Best fit line for NT rotations

P <0 01

30

40

ter w

heat

NTD2-HNTD2-LNTW2-HNTW2 L

P <0.01

10

20Win

t NTW2-LPFP2Org2

2 3 4 5 6 7April Available H2O by Brown Probe (in.)

Study SummaryStudy Summary1) Some small but measurable differences were observed1) Some small but measurable differences were observed

in soil nutrient concentrations between no-till rotations after 4 yr.

2) Spring based rotations may require somewhat higher fertilizer levelsfertilizer levels.

3) Nutrient concentrations did not appear to substantially affect winter wheat grain yield in 2004.

4) Grain yield was highly influenced by water and hence4) Grain yield was highly influenced by water, and hence water use of previous crop.

ConclusionsConclusions• Legumes can increase soil N, though mainly aLegumes can increase soil N, though mainly a

long-term effect.

• Legumes oilseeds and buckwheat can acidify• Legumes, oilseeds, and buckwheat can acidify root zone, increasing P availability

C t ti h l ti l ll ff t• Crop rotations have relatively small effects on nutrient availability in a 4 year period, but effects likely increase with timeeffects likely increase with time.

• Diverse cropping systems can help use fertilizer more efficiently especially when crops withmore efficiently, especially when crops with different rooting depths are grown.

For additional information:For additional information:

• Soil Fertility Website:Soil Fertility Website:http://landresources.montana.edu/soilfertilityC i S t W b it• Cropping Systems Website:http://scarab.msu.montana.edu/CropSystems/

QUESTIONS?