Suggestions for Fertilizing Spring Wheat and Soybean 2020

Dave Franzen, PhDProfessor Soil Science

NDSU Extension Soil SpecialistFargo, ND

Spring wheat-- Recommendations not yield-based- Starter P is important- Chloride of minor importance- Micronutrients not important

unless you farm where soil OM is>10%

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y = -0.0007x2 + 0.1904x + 18.888R² = 0.156

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at Y

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Total Known Available N, lb/a

West Wheat Yield Under Conventional Tillage

y = -0.0007x2 + 0.2601x + 23.085r² = 0.19

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West Wheat Yield Under Long-term No-Till

Why is the aggregated relationship of yield and available N so ‘diffuse’, when the relationships within sites are so highly related?

Yiel

d

Total known available N

Combining all sites with actual yield at N rate looks like this

Yiel

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Total known available N

When it really looks like this-

To get a better idea of what the data look like without showing all thecurves is to ‘Standardize’ the data- putting it all in the same scale

For example-A wheat site with high yield 80 bu/acre, divide all yields by80, and we end up with values from 0 to 1

A wheat site with high yield 40 bu/acre, divide all yields by40, and we end up with values from 0 to 1

A wheat site with high yield 60 bu/acre, divide all yields by60, and we end up with values from 0 to 1

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Total known available N

Normalizing yields at all sites ends up looking like this-

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y = -0.0007x2 + 0.1904x + 18.888R² = 0.156

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Total Known Available N, lb/a

West Wheat Yield Under Conventional Tillage

y = -3E-05x2 + 0.0066x + 0.5416R² = 0.5428

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Total Known Available N, lb/acre

West Normalized Wheat Yield Conventional Tillage

Western ND No-Till wheat sites raw yields

Western ND No-Till wheat sites normalized yields

y = -0.0007x2 + 0.2601x + 23.085r² = 0.19

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Total Known Available N, pounds per acre

y = -1E-05x2 + 0.0041x + 0.5842r² = 0.62

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Total Known Available N, pounds per acre

Low yield environment-usually drier (sometimes excessive wetness)

Lower N use efficiency and crop uptakeLess N mineralization

High yield environment-Moisture near ideal- not too wet or too dryHigher N use efficiency and crop uptakeGreater N mineralization

Net result is that rate to produce economic max yieldis similar in both environments.

There is an app for Android andIphones for the 3 N calculators, including wheat.

Go to app store and search for North Dakota Crop Nitrogen Calculator follow the instructions.

It’s free to download.

Yield-Goal

RIP

Don’t forget starter P for wheat

Chloride not important for wheat as itis for malting barleyespecially if soil test is low (

Summary-

-Use of the N calculator for wheat for mostprofitable N rates. Use common sense todetermine the rate best suited to your farmand variety.-Yield goal is not a factor in N rate-Band apply P

SOIL FERTILITY OF SOYBEAN - RECENT ND RECOMMENDATION CHANGES

Iron chlorosis is common in eastern North Dakota

•Iron chlorosis - yellowing between veins of youngest leaves.

•Chlorosis not seen until the 1st tri-foliate. •Iron is mobile in the plant through the mono-foliate stage.

The main form of iron (Fe) in soil isoxidized iron (Fe+3).

Fe+3 is a trillion times less soluble than Fe+2

Soybean roots secrete organic acids and H+

They also secrete a protein (enzyme) thatreduces Fe+3 to Fe+2, increasing itsavailability to the soybean by a factorof 1,000,000,000.

But the protein is only effective if the pHis acid around the root!

If the soil pH is > 7, that means that the soilis dominated by carbonates.

(If soil pH > 7, carbonates are present)

CaCO3 ↔ Ca+2 + CO3-2 [Neutralizes root acidity]

H2O + CO3-2 ↔ HCO3-1 + OH-

(water plus carbonate goes to bicarbonate and hydroxyl ions)

Additional stress causes increased IDC ifcarbonates are present and environment supports IDC development

(Wet soils, cooler soil temps, herbicide stress).

Soybean yield is reduced to about 85% even without IDC at EC 1.5

Chart1

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RY1

Soil 1:1 EC

Percent Relative Soybean Yield

y = -13.972x2 + 16.749x + 89.361

R² = 0.279

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Sheet1

ECRY1RYECRY

0.210892.30769230770.292.3076923077

0.211295.72649572650.295.7264957265

0.2511396.58119658120.2596.5811965812

0.2511194.87179487180.2594.8717948718

0.2510892.30769230770.2592.3076923077

0.210186.32478632480.286.3247863248

0.410993.16239316240.493.1623931624

0.511598.29059829060.598.2905982906

0.29782.9059829060.282.905982906

0.28270.08547008550.270.0854700855

0.26858.11965811970.258.1196581197

0.28471.79487179490.271.7948717949

0.28875.21367521370.275.2136752137

0.28774.3589743590.274.358974359

0.258270.08547008550.2570.0854700855

0.257664.95726495730.2564.9572649573

0.36757.2649572650.357.264957265

0.39682.05128205130.382.0512820513

0.38875.21367521370.375.2136752137

0.38068.37606837610.368.3760683761

0.38572.64957264960.372.6495726496

0.38270.08547008550.370.0854700855

0.49379.48717948720.479.4871794872

0.59177.77777777780.577.7777777778

0.51171000.5100

0.68370.94017094020.670.9401709402

0.68471.79487179490.671.7948717949

0.610085.47008547010.685.4700854701

0.77866.66666666670.766.6666666667

0.710791.4529914530.791.452991453

0.810589.74358974360.889.7435897436

0.810488.88888888890.888.8888888889

0.88673.50427350430.873.5042735043

0.910488.88888888890.988.8888888889

1.111598.29059829061.198.2905982906

1.18068.37606837611.168.3760683761

1.26757.2649572651.257.264957265

1.26555.55555555561.255.5555555556

1.410589.74358974361.489.7435897436

1.49076.92307692311.476.9230769231

1.47059.82905982911.459.8290598291

1.46858.11965811971.458.1196581197

1.59076.92307692311.576.9230769231

1.65547.00854700851.647.0085470085

1.69682.05128205131.682.0512820513

1.68370.94017094021.670.9401709402

1.69581.19658119661.681.1965811966

1.76555.55555555561.755.5555555556

1.87059.82905982911.859.8290598291

1.910287.17948717951.987.1794871795

26858.1196581197258.1196581197

2.28370.94017094022.270.9401709402

2.24034.1880341882.234.188034188

2.24235.89743589742.235.8974358974

Sheet1

RY

RY1

Soil 1:1 EC

Percent Relative Soybean Yield

y = -13.972x2 + 16.749x + 89.361

R² = 0.279

Field selection-

1. Fields with low carbonates or slightlyacid soils preferred. (

New Soybean Fertility Circular 2019available on-line

Search for

Inoculating virgin soybean ground

aa

b b

Forster, 2015

If soybean had good nodulation, you’ll likely not see a response from inoculation

Time since last soybean crop

Bradyrhizobium cells per gram

of soil1 year 19,5342 years 3,7183 years 2,4644 years 2,234

Soybean Soil Fertility, Franzen et al., 2019

Soybean Soil Fertility, Franzen et al., 2019

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Inoculation is not necessary or helpfulif the field has been in a successfullynodulated soybean field within the past 4 years.

Supplemental N is not helpfulunless the nodulation is a totaldisaster and the leaf tissue indicatesN deficiency.

Rescue N application only profitable on virgin ground or no nodulation. R3 N application

Treatment Yield (bu/ac)100 lbs N/ac as urea 34.5a100 lbs N/ac as UAN 32.9a50 lbs N/ac as UAN 29.0ab50 lbs N/ac as urea 25.9bcUntreated 21.9cLSD 5% 6.2

Endres, Aberle, and Henson, 2002

P is only needed for yield increase whensoil test is 7ppm or less.

Broadcast or band-seed separatedP is best.

Seed-placed P does not increase yieldin most trials and can decrease yieldespecially if the soil becomes dry afterseeding.

Phosphorus rates

Olsen P test, ppmVery Low Low Medium High Very High

0-3 4-7 8-11 12-15 16+--------------------lbs P2O5/ac--------------------

52 26 0 0 0Soybean Soil Fertility, Franzen et al., 2019

Kalra and Soper, 1968Bardella, 2016

Soybean prefers broadcast P

Soybean Soil Fertility, Franzen, 2013, NDSU Extension Service

P2O5/ac Placement MethodBroadcast 2x2in Band

---Yield (bu/ac)---0 35.5 34.320 39.6 35.340 41.1 36.260 44.0 39.180 42.4 37.1

ApplicationMethod

Stand 1,000 plants/ac

Yield bu/ac

Check 187.5a 32.8a2x2 4gal/ac 188.6a 33.5aIn furrow 4 gal/ac 133.2b 24.5bIn Furrow 8 gal/ac 120.6b 18.9cLSD 5% 16.5 4.3Endres and Hendrickson, 2008

CREC In Furrow

There is no safety advantage of‘low-salt’ starters compared to 10-34-0based starters.

‘Low-salt’ starters contain urea or UAN,which is at least as harmful to the seedas salt.

Potassium rates

Ammonium acetate K test, ppmVL/VL L/L M/M H/M VH-H VH/VH0-40 41-80 81-120 121-150 151-200 201+

--------------------lbs K2O/ac--------------------90/90 60/90 60/60 30/60 0/60 0/0

Soybean Soil Fertility, Franzen et al., 2019

K rates are based on clay chemistry inNorth Dakota. The circular has a map that can serve as a guide to rates.

Smectite:Illite Potassium Thresholds

In-season foliar sprays for N, P, K are almost never effective at$ payback let alone profit.

2 treatments each site in NC andNW ND, 6 site years- no effect onyield at 2 different timings (2016-2019).

Soybean is much more able to extractS from the soil compared to wheat or corn.

Soybean may respond after a yearlike 2019 and snow like so far in 2020on SANDY, higher topography locationsoils.

Rescue of S deficient soybean is possiblein-season (soybean is an August crop).

NDSU finds no need for micronutrientsupplements in North Dakota.

Except Fe

Fe-o-o-EDDHA is the best so fariron fertilizer for soybean-in-furrow at seeding. Followlabel directions.Try to use a product with thehighest ortho component.

Take care of field selection,variety selection first beforeusing Fe fertilizer to overcome IDC

FeEDDHA Fertilizer QualityDue to differences in FeEDDHA isomer concentrations

ortho,ortho FeEDDHA ortho,para FeEDDHA

Fe3+ Fe3+

The Shuttle Effect

e-

H+

e-H+

H+

e-

Fe2+Fe3+

Fe Chelate

Chelate

Soil Fe

Fe Chelate

Soil pH

Soil pHSoil

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Soil pH – 1.0

Soil pH – 1.0

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The Shuttle Effect

e-

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o-o-FeEDDHA

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Soil pH – 1.0

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A companion crop of oats/barley mayserve to dry out the soil a little and takeup some nitrate, reducing IDC.

Without oats With oats

J. Lamb images, used with permission, U of MN

Suggestions for Fertilizing Spring Wheat and Soybean 2020Slide Number 2Slide Number 3Slide Number 4Slide Number 5Slide Number 6Slide Number 7Slide Number 8Slide Number 9Slide Number 10Slide Number 11Slide Number 12Slide Number 13Slide Number 14Slide Number 15Slide Number 16Slide Number 17Soil Fertility of Soybean - Recent ND Recommendation ChangesSlide Number 19Slide Number 20Slide Number 21Slide Number 22Slide Number 23Slide Number 24Slide Number 25Slide Number 26Inoculating virgin soybean groundIf soybean had good nodulation, you’ll likely not see a response from inoculationSlide Number 29Slide Number 30Rescue N application only profitable on virgin ground or no nodulation. R3 N applicationSlide Number 32Phosphorus ratesSoybean prefers broadcast PCREC In FurrowSlide Number 36Potassium ratesSlide Number 38Smectite:Illite Potassium ThresholdsSlide Number 40Slide Number 41Slide Number 42Slide Number 43FeEDDHA Fertilizer QualityThe Shuttle EffectThe Shuttle EffectSlide Number 47Slide Number 48