MANAJEMEN NITROGEN

TANAMAN JAGUNG

Bahan Kajian MK. Manajemen Kesuburan Tanah

Smno.agroekotek.fpub.sept2013

Tanaman jagung memerlukan sejumlah besar nitrogenProper nitrogen fertilizer

application Good nitrogen management is essential for protecting groundwater quality.

Proper nitrogen management includes

managing nitrogen rate, source, timing, and

placement. The primary goal of nitrogen best

management practices is attaining high nitrogen

use efficiency. This assures the most

effective use of nitrogen fertilizer.

Nitrogen Rate

Yield

Economic Optimal N Rate (EONR)The sufficiency range is the nutrient level at which the plant has enough nutrients

to function and develop properly, but not so much that it is poisoned. This is reported as "medium" or "high" on soil tests.

Nitrogen Rate

Yield

Economic Optimal N Rate (EONR)

Oran00 Rep1 Block6

0

4

8

12

16

0 100 200 300

N rate (kg ha-1)

Yie

ld (M

g ha

-1)

Nopt

Oran00 Rep3 Block26

0

4

8

12

16

0 100 200 300

N rate (kg ha-1)

Yie

ld (M

g ha

-1) Nopt

Economic Optimum Nitrogen Rate

Eco

nom

ical

ly O

ptim

al N

Rat

e, k

g ha

-1

RA

TE

300

250

200

150

100

350

300

DL00 DL01MD00 MD01CP00 CP01 DL02 MD02

** *

*

* *

**

0

50

100

150

200

250

0 50 100 150 200 250Sensor N Rate with MO Algorithm (lbs N/acre)

EON

R (l

bs N

/acr

e)

0

50

100

150

200

250

0 50 100 150 200 250Sensor N Rate with MO Algorithm (lbs N/acre)

EON

R (l

bs N

/acr

e)

B C w/o C with D H P S W

0

50

100

150

200

250

0 50 100 150 200 250Sensor N Rate with MO Algorithm (lbs N/acre)

EON

R (l

bs N

/acr

e)

C w/o C with P W

0

50

100

150

200

250

0 50 100 150 200 250Sensor N Rate with MO Algorithm (lbs N/acre)

EON

R (l

bs N

/acr

e)

B D H S

1. EONR prediction is not easily accomplished, and is more of a challenge in rainfed environments.

2. If one could reliably predict yield, this factor alone does not do a good job of predicting EONR.

3. In 2004 and averaged over all sites, we achieved ~$5/acre more profit when using the sensors when compared to the farmer’s single blanket rate. (average of 30 lbs/acre less N).

4. Data needs to be collected to test current and yet-to-be developed algorithms.

Research supported in part by the USDA- NRI, IFAFS, and CIG Grant Programs. Assistance also given by OSU, NTech, and Holland Scientific

Instruments.

The corn N recommendations are based on:- Yield potential

- soil type and drainage

- Soil N supply- soil type and drainage

- N fertilizer uptake efficiency- soil type and drainage

- N credits from sods- % legume/grass in the sod

- N credits from manure- application method + timing

N Recommendation for corn

(yield potential * 1.2) – soil N – sod N N requirement =

(fertilizer efficiency/100)in lbs N/acre

in lbs N/acre

in %

in bushels/acre

= soil series specific

Cornell Corn N Recommendations

- soybean N or manure N credits

y = 126.36 + 4.0944x - 0.0199x 2

r 2 = 0.9851; n = 33

0

50

100

150

200

250

300

350

400

0 20 40 60 80 100 120

Organic matter (g kg-1)

ISN

T-N

(mg

kg-1

)

NONRESPONSIVE

RESPONSIVE

Critical Values

y = 126.36 + 4.0944x - 0.0199x 2

r 2 = 0.9851; n = 33

0

50

100

150

200

250

300

350

400

0 20 40 60 80 100 120

Organic matter (g kg-1)

ISN

T-N

(mg

kg-1

)

NONRESPONSIVE

RESPONSIVE

Critical Values

Loss-on-ignition (g kg-1)

Initial Field Calibration

Factors relating to BMP’s for N

1. Cropping systems

2. N rate applied3. Time of

application4. Nitrification

inhibitors5. N source6. Tillage7. Cover crops

Established Gliricidia-maize intercropping system in Southern Malawi. Photo: T. Breedy

http://climatecolab.org/plans/-/plans/contestId/18/planId/1304331

CROPPING SYSTEMS

http://www.cirad.fr/en/research-operations/research-results/2009/no-tillage-with-cover-crops-for-the-brazilian-cerrados

Effect of CROPPING SYSTEM on drainage volume, NO3-N concentration, and N loss in subsurface tile drainage during a 4-yr period (1990-93) in

MN.

Cropping Total Nitrate-N System discharge Conc. Loss

Inches ppm lb/A Cont. Corn 30.4 28 194 Corn – Soybean 35.5 23 182 Soybean – C 35.4 22 180 Alfalfa 16.4 1.6 6 CRP 25.2 0.7 4

Nitrate losses in tile drainage water from soil mineralization.

87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04

Year

0

10

20

30

40

50

60

F-W

Nitr

ate-

N C

onc.

(ppm

)

Dry years

Esta

blis

hed

gras

s

Cropping system has

greater effect on hydrology and nitrate losses than any other management

factor!

“Preventive Management”

Cumulative Nitrogen Uptake Across the Growing Season

http://www.lenrd.org/nitrogen-management/

RATE OF APPLICATION

http://www.lenrd.org/nitrogen-management/

Good nitrogen management requires understanding:

1. How nitrogen is used by the crop2. When nitrogen is used by the crop3. What environmental influences affect the use of

soil and fertilizer nitrogen by the growing crop4. How management of nitrogen and irrigation

water affect the leaching of residual nitrate, which eventually affects water quality

Continuous Corn, 2001–03 Olmsted Co.

Effect of N rate for corn after soybean on NO3-N concentrations in tile drainage water in 2001.

Date

10

15

20

25

30

35

40

Nitr

ate

Con

c (m

g/L)

80 lb N/A 120 160

Effect of N rate on yield of corn after soybean, net return to fertilizer N, and nitrate-N concentration in tile drainage at

Waseca (2000–2003).

N Treatment 4-Yr Yield Net 4-Yr FWTime Rate N-Serve Avg. Return NO3-N conc.

lb /A bu/A $/A/Yr mg/L--- 0 --- 111 --- ---

Fall 80 Yes 144 30 12“ 120 “ 166 70 13“ 160 “ 172 78 18

Spr. 120 No 180 105 14

Effect of N rate applied for corn in 2003 on nitrate-N concentration and loss in tile drainage during May–

September 2004 from soybeans at Waseca.

N FW Nitrate-N Nitrate-NRate. Concentration LossLb/A mg/L Lb/A

80 9 36120 12 52160 20 81

Conclusion1. Corn yields were increased 5% and nitrate losses

in drainage were reduced by 27% when reducing the N application rate from 160 lb/A applied in the fall to the recommended 120-lb rate applied in the spring.

2. Reducing the N rate from 120 lb/A to 80 lb/A reduced yield by 17% and nitrate loss by 13%.

3. Forty-six percent of the nitrate lost in tile drainage from a corn-soybean rotation was lost in the year soybeans were grown.

TIME OF N APPLICATION

Maximum nitrogen uptake occurs

in periods of maximum growth (in

corn roughly between vegetative

growth stages V9 and V18, or from hip-high

to just before tasseling).

Risk of N loss is low during this period.

Credit: Iowa  State University Extension.

http://plantsci.missouri.edu/nutrientmanagement/nitrogen/practices.htm

Effect of time of N application and N-Serve on corn yields after soybean from 1987–2001 at Waseca.

Time of N ApplicationParameter Fall Fall+N-Serve Spring

15-Yr Avg. Yield (bu/A) 144 153 15615-Yr Avg. Economic return over fall N ($/A/yr) *

--- $9.30 $18.80

7-Yr Avg. Yield (bu/A) ** 131 146 1587-Yr Avg. Economic return over fall N ($/A/yr) *

--- $22.50 $51.00

* Corn = $2.00/bu; N = $0.25/lb N ** Seven years when statistically significant differences occurred.

Nitrate-N concentration in tile drainage from a corn-soybean rotation as influenced by time of N application and N-Serve at

Waseca.

N Treatment

Time of application N-Serve Nitrate-N Conc.*

-- mg/L --

Fall No 14.1

Fall Yes 12.2

Spring No 12.0

* 10-cycle (1990-2000) rotation average.

1999 tile water NO3-N loading at Waseca vs. NO3-N concentrations in the Le Sueur River 2.3 miles from Mankato.

7.4

16.615.7

12.0

10.8

16.215.2

12.7

15.6

14.1

11.9 11.6

Sampling Date

0

10

20

30

40

50

60

Nitr

ate-

N L

oss

(lb/A

)

6.0

8.0

10.0

12.0

14.0

16.0

18.0

Nitr

ate-

N (p

pm)

Fall AAPP AALe Sueur River

Conclusion

• Compared to late fall N application without N-Serve over the 15-year period:– Corn yields were increased 9 and 12 bu/A/yr

(6 and 8%) by either fall N+N-Serve or spring preplant N, respectively.

– Nitrate losses were decreased 14 and 15% by either fall N+N-Serve or spring preplant N, respectively.

Proposed BMP’s for South-Central MN

• Recommended– Spring preplant or split applications of

ammonia, urea, or UAN are highly recommended.

– Incorporate broadcast urea or preplant UAN within three days.

– Apply sidedress application before corn is 12” high.

– Inject or incorporate sidedress applications of urea or UAN to a minimum depth of 4 inches.

Proposed BMP’s for South-Central MN.

• Recommended, but with greater risk– Fall application of AA + N-Serve after soil

temperature at 6-inch depth is below 50° F.– Side dressing all N before corn is 12 inches

high.• Not recommended

– Fall application of urea, UAN, or anhydrous ammonia without N-Serve

Economic Nitrogen Management for Corn

“NEW” MSU N Recommendations

How much is enough?• Old vs. new recommendations…

Yield vs. Economic Return– Old:

• 1.2 lbs per bushel• This only applies within yield potential of soil

– New: • Based on economic return• This only applies within yield potential of soil• Use previous crop in association with field history (low – medium – high – very high)

Definitions

• MRTN – maximum return to N• EONR – economic optimum N rate• N:Corn Price Ratio• Corn Yields – 5 year averages – soil

productivity (disregard unusual hi’s or lo’s)– Low: Average yield , <120 bu/a– Med: Average yield, 121 – 150 bu/a– High: Average yield, 151 – 180 bu/a– Very High: Over 181 bu/a

Response Data Model FitYi

eld

(bu/

acre

)

N rate (lb/acre)

OptimumMaximum

http://nrcca.cals.cornell.edu/nutrient/CA3/CA0323.php

Critical value or range indicates the soil or tissue content below which the plant most likely is deficient in that specific nutrient and production could be enhanced by addition of the nutrient. Below that critical value, the nutrient levels are below

optimum.

http://nrcca.cals.cornell.edu/nutrient/CA3/CA0323.php

Luxury consumption occurs when soil nutrient levels are above optimum and plants take up more of a nutrient than needed for functioning and production.

Potassium (K) is commonly taken up in excess.

How much is right?

• National Corn Growers Contest (NCGA):

• 10 separate yield checks averaged:– 163.1 lbs of N/acre (131-210)– Average yield = 214.5 bu/acre (181-239)– .76# N/bu (.57 - .95)

• Was it economical????• It depends…………

Key points…

• Determine soil productivity…a 5 year history.

• Determine N:Corn price ratio• Evaluate crop conditions, and weather

at the time of maximum N application.– This could be at planting or at

sidedress time.

Criteria for Soil Productivity or Yield Potential Grouping

1. Low: ≤ 120 bu/a2. Medium: 121 – 150 bu/a

3. High: 151 – 180 bu/a4. Very High: ≥ 181 bu/a

5. 5 year running average!

Soil Yield Potential

• Qualitative assessment of soil productivity– Group soils with similar N response

• Tiled, non-tiled, high OM, etc.– Do Not use yield estimate to calculate N rate

• Based on soil series description

• Look at:– Water holding capacity– Drainage class– Depth of root zone– Length of growing season (> or < 2300 GDD)

N response functions

Nitrogen Rate (kg N ha-1)

0 50 100 150 200 250

Gra

in Y

ield

(Mg

ha-1)

3

4

5

6

7

8

9

10

11

12

High/Very High Yield Potential Medium/Low Yield PotentialIrrigated Sand

134

185

241Corn following Corn

Example # 11. Heavy clay soils2. Non-tiled3. 118 bu. average4. Corn price $3.125. N price (28%)

$385/T6. Previous crop -

soybeans

• N:Corn Ratio = .22• Crop condition –

excellent• Soil Moisture –

excellent • Population 32,000/a

• Recommendation: 80 Lbs. added N/a range 65 – 95 lbs/a

Example # 21. Sandy loam soils2. Tiled3. 167 bu. average4. Corn price $4.045. N price (28%)

$365/T6. Previous crop

soybeans

1. N:Corn Ratio = .162. Crop conditions –

excellent3. Population –

32,0004. Soil moisture –

very good

5. Recommendations: 105 lbs. added N range of 90 -120 lbs/a

0 40 80 120 160 Lbs. of sidedress N applied

StarterN

Sidedress

NTotal

N%

Moisture   Adj. Yield  

38 0 38 22.6 c 149.07 c38 40 78 21.6 b 195.95 b38 80 118 21.4 b 201.49 b38 120 158 20.9 a 215.93 a38 160 198 20.5 a 218.25 a

0.83 LSD 10.9

2.06% C.V. 3.05%

MRTN Plot – St. Clair County

Previous Crop – Soybeans ~ 30 lb credit