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Bahan Kajian MK. Manajemen Kesuburan Tanah. MANAJEMEN NITROGEN TANAMAN JAGUNG. Smno.agroekotek.fpub.sept2013. Tanaman jagung memerlukan sejumlah besar nitrogen.

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Manajemen nitrogen tanaman jagung

BahanKajian MK. ManajemenKesuburan Tanah




Manajemen nitrogen tanaman jagung

Tanamanjagungmemerlukansejumlahbesar nitrogen

Proper 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.

Manajemen nitrogen tanaman jagung

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

Manajemen nitrogen tanaman jagung

Economic Optimal N Rate (EONR)


Nitrogen Rate

Manajemen nitrogen tanaman jagung

Economic Optimum Nitrogen Rate

Oran00 Rep1 Block6



Yield (Mg ha-1)












N rate (kg ha-1)

Oran00 Rep3 Block26






Yield (Mg ha-1)



N rate (kg ha-1)

Manajemen nitrogen tanaman jagung

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

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

  • 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).

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

Manajemen nitrogen tanaman jagung

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

Manajemen nitrogen tanaman jagung

N Recommendation for corn

  • 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

Manajemen nitrogen tanaman jagung

Cornell Corn N Recommendations

in bushels/acre

in lbs N/acre

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

N requirement =

(fertilizer efficiency/100)

in lbs N/acre

in %

- soybean N or manure N credits

= soil series specific

Manajemen nitrogen tanaman jagung

Initial Field Calibration

Loss-on-ignition (g kg-1)

Factors relating to bmp s for n

Factors relating to BMP’s for N

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

  • Cropping systems

  • N rate applied

  • Time of application

  • Nitrification inhibitors

  • N source

  • Tillage

  • Cover crops

Cropping systems


Manajemen nitrogen tanaman jagung

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.

Nitrate losses in tile drainage water from soil mineralization

Nitrate losses in tile drainage water from soil mineralization.

Established grass

Dry years

Manajemen nitrogen tanaman jagung

Cumulative Nitrogen Uptake Across the Growing Season

Cropping system has greater effect on hydrology and nitrate losses than any other management factor!

“Preventive Management”

Rate of application


Good nitrogen management requires understanding:

How nitrogen is used by the crop

When nitrogen is used by the crop

What environmental influences affect the use of soil and fertilizer nitrogen by the growing crop

How management of nitrogen and irrigation water affect the leaching of residual nitrate, which eventually affects water quality

Continuous corn 2001 03 olmsted co

Continuous Corn, 2001–03 Olmsted Co.

Effect of n rate for corn after soybean on no 3 n concentrations in tile drainage water in 2001

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

Manajemen nitrogen tanaman jagung

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).

Manajemen nitrogen tanaman jagung

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.



  • 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.

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

  • 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.

Effect of time of n application and n serve on corn yields after soybean from 1987 2001 at waseca

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

Manajemen nitrogen tanaman jagung

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

Manajemen nitrogen tanaman jagung

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



  • 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

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 mn1

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

Economic Nitrogen Management for Corn“NEW” MSU N Recommendations

How much is enough

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)



  • 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 fit

Response Data Model Fit



Yield (bu/acre)

N rate (lb/acre)

Manajemen nitrogen tanaman jagung

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.

Manajemen nitrogen tanaman jagung

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

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

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

Criteria for Soil Productivity or Yield Potential Grouping

  • Low: ≤ 120 bu/a

  • Medium:121 – 150 bu/a

  • High:151 – 180 bu/a

  • Very High:≥ 181 bu/a

  • 5 year running average!

Soil yield potential

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

N response functions

Corn following Corn

Example 1

Heavy clay soils


118 bu. average

Corn price $3.12

N price (28%) $385/T

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 # 1

Example 2

Sandy loam soils


167 bu. average

Corn price $4.04

N price (28%) $365/T

Previous crop soybeans

N:Corn Ratio = .16

Crop conditions – excellent

Population – 32,000

Soil moisture – very good

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

Example # 2

Manajemen nitrogen tanaman jagung

0 40 80 120 160

Lbs. of sidedress N applied

Mrtn plot st clair county

MRTN Plot – St. Clair County

Previous Crop – Soybeans ~ 30 lb credit

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