Cropsmith Jenners 45 Feb 08

Managing N usingThe Illinois Soil Nitrogen Test

Tim SmithCropsmith Inc.

Nitrogen Testing, Consulting

Don’t be mislead focus on what is important

Why all the interest in nitrogen?

• For Nitrogen Rates 140 lbs to 220 lbs• 140-220 lbs NH3 spring 08 $60.20-94.60• 140-220 lbs 28% Solution Spring $84.00-132.00

• For each 10 lbs of NH3 saved $4.50

• For each 10 lbs of 28% saved $6.00

Year of University Research Shows

60-90% of Crop N comes from soilFertilizer needed to supplement soil N

typically ranges from 80 to 220 lbs of N Variable Rate Nitrogen is about redistribution

of N from where less is need to where more is needed.

How much N do you need?

Yield 126

Yield 227

0

N Rate

210lb

N

On-Farm trial Champaign

County Illinois 2003

How little N do you need?

Yield 177

Yield 193



0

N Rate

210lb

PY Rate 192 lbs N

At today's NH3 prices each bushel gain cost $5.16 in N

Corn yield at the zero-N rate as a percent of yield at EONR.

Previous Crop

State Corn Soybean

---------- % -----------

Illinois 54 64

Iowa 45 75

Minnesota 60 76

Wisconsin 75 80

Economic Optimum Nitrogen Rate

• EON is the rate of applied N where the last dollar of your N cost returns more slightly more than a dollars worth of grain. With more N than the economic rate you may get more yield but you will earn less money.

IPNI Crop Nutrient Response tool

• How can you determine Economic Optimum N Rate?

Example of Nitrogen Response Trial

20080120400

016020012080

12040801600

160 40 200

The Closer to the Economic N Ratethe more money you make

Cost of Over and Under Application Of N

101.0

46.0

30.8

53.3

20.7

36.9

0.0

20.0

40.0

60.0

80.0

100.0

120.0

Over Under Over Under Over Under

Illinois Soil Nitrogen Test MRTN Proven Yield

lbs over or under

Ave

rag

e lb

s o

ver

un

der

Corn @ $4.80/buN fert @ .48 cents/lb

$13.63

$2.88

$25.20

$10.48

$48.00

$23.13

Within $8 of best N rate

$26.70 from best N rate

Cropsmith Recommendation

University Recommendations

Why Soil Based N Management?

• If soils differ in there response to N, them so should our management of them.

• The soil supplies a majority of the nitrogen that plants take up during growing season.

• Other solutions (such as Greenseeker) exist but may have limited acceptance due to logistics.

What is the Illinois Soil Nitrogen Test?

• This New test Developed at the University of Illinois measures potentially available nitrogen that is released from the organic matter in the soil

What kind of nitrogen release do your soils have?

IPNI-Crop Nutrient response tool

EON 130 lbs N EON 180 lbs N

Both fields yielded 200 bushels

Is the Economic N Rate Stabile Year to Year?

Jack Meisinger InfoAg presentation 2007

ISNT Soil Test Map

Cropsmith Variable Rate Application Map

Results from 2007

ISNT 175-225 ISNT 270-304

Corn $3.35 Fert. N $.50

MRTN Recommendation 147lbs N

2007 ISNT Values

2007 ISNT Nitrogen Recommendations

2007 Results

ISNT 175-225 ISNT 270-304

Corn $3.35 Fert. N $.50

MRTN Recommendation 147lbs N

How much N do you need?

Soil Test ISNT 192 PPM

Experimental Best N Rate 180 lbs

Yield 126

Yield 227

0

N Rate

210lb

N Rate


169 lbs N



How little N do you need?

Yield 177

Yield 193



Soil Test ISNT 225 PPM

Experimental Best N Rate 126


147 lbs N

58 Plots in Illinois from three years

For every .45 lb of N increase, Yield increases 1 bushel

For every 350 plant increase, Yield increases 1 bushel

(.45 * lbs of N )+ (.0035 * population) = Yield

.45* 188# N+ .0035*31236 plants = 192 bu/AActual yield 188 bu/a

Why haven’t nitrogen soil tests worked?

• Past soil test have measured Nitrates which are not stable in the soil.

• ISNT measure the part of organic matter with is one source of nitrate in the soil.

Fertilizer N

Organic Matter

Or maybe old ones

Sources of N to Plants

Fertilizer N –Less Efficient

Organic Soil N –More Efficient

How much N does your corn crop need?200 lbs corn

• Corn takes up 1.1 lb of N per bushel yield• Corn removes from field only .68 lbs N per bu.

• 200 bushel would take up 220 lbs of N • 200 bu corn would remove 136 lbs of N

• 75% of N comes from soil (organic N)

• Applied N is only 40% efficient

• 220 lbs N needed 165 from soil 55 needed from Fertilizer• 137 lbs of Fertilizer N needed

• 83 lbs of N in corn stover left to be recycled ( organic N)

How much N does your corn crop need?150 bu Corn

• Corn takes up 1.1 lb of N per bushel yield• Corn removes from field only .68 lbs N per bu.

• 150 bushel would take up 165 lbs of N • 150 bu corn would remove 102 lbs of N

• 50% of N comes from soil (organic N)

• Applied N is only 40% efficient

• 165 lbs N needed 82 from soil 82 needed from Fertilizer• 205 lbs of Fertilizer N needed

• 63 lbs of N in corn stover left to be recycled (organic N)

N cycle

50-90%

10-50%

Top Ten Important Nitrogen Factors

1. Amount of N from soil2. Rotation-amount, type of residue from previous crop3. Population of current crop4. Weather (moisture, temp, timing)5. Source and timing of N6. Hybrid response to N7. Past N applications (especially from manure)8. Drainage 9. pH and nutrient levels Nutrient interactions P, K and S10. Cost of N, Price of Crop

17 Sites Indiana

With x-int estimate of soil N

0

0.2

0.4

0.6

0.8

1

1.2

0 50 100 150 200 250 300 350 400

Total N supply, lb/a

Rel

ativ

e yi

eld

100 to 140 bu/a 141 to 180 bu/a 181 to 220 bu/a

Purdue (Camberato, Nielsen)

Corn after Soybeans 2005

190 Acre field in McLean County (C.U. Williams Farm)Average yield 189 bu.

Ave.135 lbs of N Yield 189 Bushel

Average N Rate 146# N

Soil is more efficient at delivering N to plants

Yield by N Rate and ISNT

170

175

180

185

190

195

200

205

210

215

220

90 110 120 130 150 180 210

N Rates

Yiel

d

ISNT>300

ISNT280

ISNT260

ISNT240

ISNT220

ISNT200

ISNT<180

U of I C.U. Williams Field 2006

Ave yield 191.3 bu.

• Green test strips 165 lbs N

• Increased N in test strips marginally increased yield in some places

How and when to sample

• We sample 0-12 an 12-24 inches deep

• Sample can be taken Fall, Winter, Early Spring

• Maps can be used for 6-8 years

• Sample have some special handling requirements

Cost of Nitrogen Soil Testing

• We have complete programs from $8.30 to $15 per acre

• For $8.30 you get whole field N rates with two zones per field

• $15 includes intensive sampling 0-12 and 12-24 inch at all sample sites and complete variable rate recommendations

Conclusions

• Having an ISNT map of your field can save money maintain high yield for many years

Cropsmith IncTim Smith

(217) [email protected]

www.cropsmith.com

Fall 2007 results

Yield by N Rate

Cs Nrec

Avg Corn

12

01

99

12

02

11

12

02

13

12

02

04

14

02

05

16

02

05

12

02

11

60

21

1

0

50

100

150

200

250

120 120 120 120 140 160 120 60

2006 DataNorthern and Central Illinois

Corn Soybean Rotations

y = -0.5883x + 285.87

R2 = 0.5221

100

120

140

160

180

200

220

240

100 120 140 160 180 200 220 240 260 280 300

ISNT

Eco

no

mic

O

pti

mu

m N

175 N

192

2006 DataNorthern and Central Illinois

Corn Soybean Rotations

y = -0.5883x + 285.87

R2 = 0.5221

100

120

140

160

180

200

220

240

100 120 140 160 180 200 220 240 260 280 300

ISNT

Eco

no

mic

O

pti

mu

m N

155 N

225

What kind of nitrogen response does your soils have?

Southern Illinois

Economic N Rate 192

ISNT 95

Central Illinois

Economic N Rate 124

ISNT 265

QP EON vs MRTN 06 from N Rate Calc.3 outliers removed

y = -0.5343x + 244.93

R2 = 0.076

0

50

100

150

200

250

300

0 50 100 150 200 250

MRTN from N Rate Calc.

QP

EO

N

3 Outliers Removed one each , Rotation, Variability, Flooded field

CC

N

orth

CS

B N

orth

CC

Central

CS

B S

outhC

SB

Central

Nafziger 2006 MRTN

Documents

Cropsmith Jenners 45 Feb 08