EFISIENSI PUPUK DAN

PEMUPUKAN NITROGEN

Bahan kajian MK PemupukanBahan kajian MK Pemupukan

Dosen: Prof Dr Ir Soemarno MSDosen: Prof Dr Ir Soemarno MS

Jur Tanah FP UB, 2011Jur Tanah FP UB, 2011

NITROGEN EFFICIENCY AND

FALL N APPLICATIONS

Larry G. BundyLarry G. Bundy

Department of Soil ScienceDepartment of Soil Science

University of WisconsinUniversity of Wisconsin

NITROGEN FERTILIZER EFFICIENCY

Crop uptake of fertilizer NCrop uptake of fertilizer N

Amount of N fertilizer Amount of N fertilizer appliedapplied

% NFE = x 100

Improved N Management

Higher Crop Recovery of Available N

Reduced Risk of N Loss

Nitrogen Management Decisions

Rate Rate SourceSourceTimingTimingNitrification inhibitorsNitrification inhibitors

Nitrogen Loss Processes

Leaching Leaching DenitrificationDenitrification Ammonia volatilizationAmmonia volatilization

Nitrogen ReactionsNitrogen Reactions

Mineralization (Ammonification):

Soil Organic NH4-NN

+

Ammonium

Soil Organic Matter Most Midwest soils = 1-5% Most Midwest soils = 1-5% Organic soils = 20-50+ % Organic soils = 20-50+ % Nitrogen Content (O.M.) = 5% NNitrogen Content (O.M.) = 5% N About 2-3% of O.M. decomposes About 2-3% of O.M. decomposes

annuallyannually

Nitrogen ReactionsNitrogen Reactions

Nitrification:

NH4+ NO2

- + H+

NO2- NO3

- NitrateNitrite

(Nitrosomonas)Ammonium

(Nitrobacter)

Nitrite

Nitrogen ReactionsImmobilization:

NO3- or NH4

+ Organic N

InorganicNitrogen

organisms

Carbon : Nitrogen ratio Carbon : Nitrogen ratio effects on N releaseeffects on N release

Expected N EffectExpected N Effect C : N rangeC : N range

Release NRelease N < 20< 20

Depends on Depends on CompositionComposition

20 – 5020 – 50

Immobilize (Tie up) NImmobilize (Tie up) N > 50> 50

Carbon: Nitrogen Ratios Carbon: Nitrogen Ratios of Organic Materialsof Organic Materials

MaterialMaterial C : N RatioC : N Ratio

Soil microorganismsSoil microorganisms 88

Soil organic matterSoil organic matter 1010

AlfalfaAlfalfa 1212

Rotted manureRotted manure 2020

Corn residueCorn residue 6060

Grain strawGrain straw 8080

SawdustSawdust 300300

Nitrogen ReactionsDenitrification:

NO3- N2 + N2O

Gases lost to Atmosphere

organisms

Wet SoilsLow OxygenNitrate

Nitrogen Timing Options

FallFallPreplantPreplantSidedressSidedressPost-emergencePost-emergenceSplitSplit

Timing of Nitrogen Uptake by Corn

0

30

60

90

120

150

180

210

240

Time during growing season

N u

ptak

e, lb

N/a

cre

Apr. May June July Aug. Sept. Oct.

FALL N APPLICATIONS AND RESIDUE DECOMPOSITION

Objectives

Determine the influence of pre-season (fall) Determine the influence of pre-season (fall) N fertilization at low rates (30 and 100 lb N fertilization at low rates (30 and 100 lb N/acre) on corn residue decomposition in N/acre) on corn residue decomposition in no-till corn production.no-till corn production.

Monitor the effects of pre-season (fall) N Monitor the effects of pre-season (fall) N treatments and residue chopping on residue treatments and residue chopping on residue quantity, carbon and nitrogen composition, quantity, carbon and nitrogen composition, and soil temperature.and soil temperature.

Treatments

Times and rates of N (UAN and Times and rates of N (UAN and ammonium sulfate)ammonium sulfate)

Sulfur as gypsum applied to Sulfur as gypsum applied to equalize sulfur equalize sulfur

Residue fall chopped or not Residue fall chopped or not chopped. chopped.

Measurements

Soil nitrate (Fall, PPNT, PSNT)Soil nitrate (Fall, PPNT, PSNT)Residue quantity and Residue quantity and

compositioncompositionSoil temperature, 4 in. depthSoil temperature, 4 in. depthCorn silage and grain yieldCorn silage and grain yield

TreatmentsN timing, source, & rate (lb N/a)

FallFall SpringSpring TotalTotal

00 00 00

30 UAN30 UAN 00 3030

30 AS30 AS 00 3030

100 AS100 AS 00 100100

00 100 AS100 AS 100100

30 UAN30 UAN 160 UAN160 UAN 190190

30 AS30 AS 160 AS160 AS 190190

00 190 UAN190 UAN 190190

00 190 AS190 AS 190190

100 AS100 AS 90 UAN90 UAN 190190

Nylon mesh bag for residue quantity & composition measurements

Dry matter amounts at several times in the chopped residue treatment,

Arlington, WI 1998-2001 SamplingSampling

timetime

---- Residue (lb dry matter/acre) -------- Residue (lb dry matter/acre) ----

1998-991998-99 1999-20001999-2000 2000-20012000-2001

NovemberNovember 70307030 56675667 60236023

AprilApril 61216121 51025102 49584958

JuneJune 54175417 47244724 47994799

SeptemberSeptember ------ 18901890 36213621

Effect of N treatment on corn residue decomposition, Arlington, 1999-2000.

DateDate

Fall NFall N 30 Apr 0030 Apr 00 27 Jun 0027 Jun 00 26 Sep 0026 Sep 00

-lb N/acre--lb N/acre- -- % residue remaining ---- % residue remaining --

00 92 a92 a 8787 3131

30 UAN30 UAN 94 a94 a 9090 2929

30 AS30 AS 97 a97 a 7979 3535

100 AS100 AS 76 b76 b 7878 3535

Carbon/nitrogen ratio and N content of

corn residue at various dates, Arlington, WI, 1999-2000.

N contentN content

DateDate C/N ratioC/N ratio -- lb N/acre ---- lb N/acre --

10 Nov 9910 Nov 99 7474 3333

30 Apr 0030 Apr 00 4747 4848

27 Jun 0027 Jun 00 3737 4545

26 Sep 0026 Sep 00 2828 2222

Nitrogen timing, source, & rate effects on corn grain yield, Arlington, 1999-2001

N timing & rateN timing & rate

(lb N/acre)(lb N/acre)

Yield Yield 19991999

Yield Yield 20002000

Yield Yield 20012001

FallFall SpringSpring -------------- bu/acre --------------------------- bu/acre -------------

00 00 167 b167 b 63 e63 e 105 e105 e

30 UAN30 UAN 00 180 b180 b 60 e60 e 126 d126 d

30 AS30 AS 00 178 b178 b 66 e66 e 126 d126 d

100 AS100 AS 00 209 a209 a 112 d112 d 175 c175 c

00 100 AS100 AS 216 a216 a 128 cd128 cd 171 c171 c

Nitrogen timing, source, & rate effects on corn grain yield, Arlington, 1999-2001

N timing & rate N timing & rate

(lb N/acre)(lb N/acre)

Yield Yield 19991999

Yield Yield 20002000

Yield Yield 20012001

FallFall SpringSpring ---------------- bu/acre --------------------------- bu/acre -----------

00 00 167 b167 b 63 e63 e 105 e105 e

30 UAN30 UAN 160 UAN160 UAN 219 a219 a 146 abc146 abc 191 b191 b

30 AS30 AS 160 AS160 AS 220 a220 a 158 a158 a 202 ab202 ab

00 190 UAN190 UAN 219 a219 a 148 ab148 ab 194 b194 b

00 190 AS190 AS 216 a216 a 160 a160 a 208 a208 a

100 AS100 AS 90 UAN90 UAN 220 a220 a 136 bc136 bc 207 a207 a

Summary

About 60 to 70% of corn residue About 60 to 70% of corn residue decomposed during the subsequent decomposed during the subsequent growing season.growing season.

C/N ratio of residue usually decreased C/N ratio of residue usually decreased from the initial November value from the initial November value through the following September. through the following September.

Most of this change was due to carbon Most of this change was due to carbon loss.loss.

Summary For production, fall N additions to promote For production, fall N additions to promote

residue decomposition do not appear to be residue decomposition do not appear to be justified. justified.

Improvements in yield or other agronomic Improvements in yield or other agronomic benefits were not observed in this study.benefits were not observed in this study.

Fall N can increase potential for over winter N Fall N can increase potential for over winter N loss.loss.

Ammonium sulfate provided more consistent Ammonium sulfate provided more consistent crop responses than UAN solution.crop responses than UAN solution.

Improving Fall N Effectiveness

Use ammonium forms of N. Use ammonium forms of N. Use a nitrification inhibitor Use a nitrification inhibitor

(N-Serve) with fall N. (N-Serve) with fall N. Delay N application until soil Delay N application until soil

temperature remains below temperature remains below 5050o o F.F.

INHIBITION OF NITRIFICATION

NH4+ NO2 NO3

Inhibitor action

Ammonium(Held by soil)

Nitrite Nitrate(Subject to loss)

Improving Fall N Effectiveness

Use ammonium forms of N. Use ammonium forms of N. Use a nitrification inhibitor Use a nitrification inhibitor

(N-Serve) with fall N. (N-Serve) with fall N. Delay N application until soil Delay N application until soil

temperature remains below temperature remains below 5050o o F.F.

Time of anhydrous ammonia application and N-Serve effect on corn grain yield. Waseca, MN

TimingTiming

YearYear FallFall Fall +Fall +N-SN-S SpringSpring Signif.Signif.

------------- bu/acre ------------------------- bu/acre ------------

19971997 186186 189189 180180 NSNS

19981998 199199 207207 195195 NSNS

19991999 109109 154154 187187 ****

20002000 135135 139139 160160 ****

14-yr ave 14-yr ave 11// 144144 153153 15515511/ 1987-2000 ave., 135 lb N/a, Soybean-Corn rotation (Randall, / 1987-2000 ave., 135 lb N/a, Soybean-Corn rotation (Randall, 2000)2000)

Soil nitrate to ammonium ratios as affected by date of anhydrous ammonia application and N-Serve

Application dateApplication date11//

Sampling Sampling datedate

Oct. 28Oct. 28w/o N-Sw/o N-S

Oct. 28Oct. 28w/ N-Sw/ N-S

Nov. 19Nov. 19w/o N-Sw/o N-S

-------- Nitrate:Ammonium ratio ---------------- Nitrate:Ammonium ratio --------

Apr. 20Apr. 20 0.80.8 0.40.4 0.10.1

May 15May 15 2.52.5 1.21.2 0.20.2

May 30May 30 3.63.6 1.91.9 0.50.5

11/ Soil temp. (6 in. depth) = 47/ Soil temp. (6 in. depth) = 47oo on 10/28 and 34 on 10/28 and 34oo on 11/19 on 11/19 (Randall, MN, 1997).(Randall, MN, 1997).

Effect of N Rate and Time of Application on Nitrate-N Losses and Corn Yield

NitrogenNitrogen Annual Loss ofAnnual Loss of 5-Yr Yield 5-Yr Yield

RateRate TimeTime NONO33-N in Drainage-N in Drainage AverageAverage

lb/Alb/A - lb/A/yr -- lb/A/yr - bu/Abu/A

00 - -- - 77 6666

120120 FallFall 2727 131131

120120 SpringSpring 1919 150150

180180 FallFall 3434 160160

180180 SpringSpring 2626 168168

* Ammonium sulfate applied about 1 Nov. or 1 May. * Ammonium sulfate applied about 1 Nov. or 1 May. MinnesotaMinnesota

Nitrogen timing and nitrification inhibitor effects on corn yield, Fond du Lac Co., WI, 1994

M. Rankin, UW-Extension140 lb N/a as anhydrous ammonia

N timingN timing N-ServeN-Serve YieldYield

bu/acrebu/acre

NoneNone ---- 7070

FallFall nono 132132

FallFall yesyes 143143

SidedressSidedress nono 169169

SidedressSidedress yesyes 166166

Fall N Applications

Fall N has higher risk of loss. Fall N has higher risk of loss. Performance of fall N is better where Performance of fall N is better where

over winter soil temperatures retard over winter soil temperatures retard conversion of ammonium to nitrateconversion of ammonium to nitrate..

Best results with medium-textured Best results with medium-textured soils with relatively good drainage.soils with relatively good drainage.

Fall N Applications

Soil temperature history (calendar Soil temperature history (calendar date) may be more useful than date) may be more useful than daily measurements.daily measurements.

Low rates of ammonium sulfate in Low rates of ammonium sulfate in fall can provide S in combination fall can provide S in combination with P&K fertilizers application.with P&K fertilizers application.