Developing Nitrogen BMPs from Field Research
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C onclusions • Fall application ofurea and am monium sulfate produced low ercorn yield and greater nitrate losses than w hen spring-applied. • Averaged across N rates,fallapplication of am m onium sulfate increased nitrate loss by 36% (8 lb/A)w hile reducing netreturn to fertilizerby 16% ($23/A). Developing Nitrogen BMPs from Field Research Gyles W. Randall* and Jeffrey A. Vetsch, Univ. of Minnesota, Waseca, MN Abstract Best management practices (BMPs) for nitrogen (N) and their implementation are critical to achieving profitable crop production while minimizing nitrate losses to ground and surface waters. Nitrogen BMPs for corn (Zea mays) grown after soybean (Glycine max) in south-central Minnesota were developed from long-term, subsurface tile drainage research conducted at the University of Minnesota’s Southern Research and Outreach Center at Waseca. A four-year study showed significantly greater nitrate losses in tile drainage accompanied by no increase in corn yield or profitability when applied N rates exceed the University’s recommended rate. A 15-year study indicated that spring application of ammonia produced greatest yield and profit while minimizing nitrate loss to drainage compared with fall-applied ammonia without N-Serve, and thus is a preferred BMP. Fall application of ammonia with N-Serve also significantly reduced nitrate losses but is considered a BMP with RISK because yields and economic return were lower in years when May and/or June were very wet. Results from these studies clearly show application rates in excess of University recommendations and fall application of ammonia without N-Serve are not BMPs for south-central Minnesota. Experimental Procedures Soil: Canisteo clay loam, Typic Endoaquoll Years: 1987 – 2003 Tile plots: 36; 16 corn, 16 soybean and 4 grass Plot size: 30 ft. by 20 ft. simulating 50 ft. tile spacing. Isolated to a depth of 6 ft. by 12 mil plastic sheeting. Tile depth: 3.5 ft. Slope: 0 – 1 % Tile drainage research facility at Waseca. Schematic diagram of drainage plot details. 20’ 30 ’ 5’ Collection sump Rate and Time of Application Nitrogen Source and Time of Application Time of N Application and Nitrification Inhibitors R egion Specific BM Ps forN Date 10 15 20 25 30 35 40 Nitrate Conc (mg/L) 80 lb N/A 120 160 Effect of N rate for corn after soybean on NO 3 -N concentration in tile drainage water in 2001. Purpose •To determine the effect of N rate, time of application, and nitrapyrin (N-Serve) on nitrate losses to subsurface, tile drainage and on corn production. •To develop best management practices (BMPs) for N for south-central Minnesota based on long-term field research. Proposed B M Ps forSouth- C entralM innesota • R ecom m ended – Spring preplantapplications ofam m onia or urea and splitapplications ofam monia,urea, orU AN are highly recom m ended. • Incorporate broadcasturea orU A N w ithin three days. • A pply sidedress application before corn is 12 inches tall. • Injectorincorporate sidedress applications of urea orU A N to a m inim um depth of3 inches. • R ecom m ened,butw ith greaterrisk – Fallapplication ofA A+N -Serve aftersoil tem perature at6-inch depth is below 50°F. – S ingle,spring preplantapplication ofU AN . – S ide dressing allN before corn is 12 inches tall. • N otrecom m ended – Fallapplication ofurea,am m onium sulfate, U AN ,oranhydrous am m onia w ithout N -Serve. References Randall, G.W., and D.J. Mulla. 2001. Nitrate-N in surface waters as influenced by climatic conditions and agricultural practices. J. Environ. Qual. 30:337-344. Randall, G.W., and J.A. Vetsch, and J.R. Huffman. 2003. Nitrate losses in subsurface drainage from a corn- soybean rotation as affected by time of nitrogen application and use of nitrapyrin. J. Environ. Qual. 32:1764-1772. Randall, G.W., J.A. Vetsch, and J.R. Huffman. 2003. Corn production on a subsurface-drained Mollisol as affected by time of nitrogen application and nitrapyrin. Agron. J. 95:1213-1219. Randall, G.W., and J.A. Vetsch. 2005 Nitrate losses in subsurface drainage from a corn-soybean rotation as affected by fall vs. spring application of nitrogen and nitrapyrin. J. Environ. Qual. 34(2):590-597. Randall, G.W., and J.A. Vetsch. 2005. Corn production on a subsurface- drained Mollisol as affected by fall versus spring application of nitrogen and nitrapyrin. Agron. J. 97:472-478. Acknowledgement Sincere appreciation is extended to Dow AgroSciences for their financial contribution to this research. C onclusions • Applying 120 lb N /A in the spring (a BM P) increased corn yield 5% and reduced nitrate losses in drainage w aterby 27% com pared to a fall application of160 lb N /A. • R educing the N rate from 120 lb/A to 80 lb/A reduced yield by 17% and nitrate loss by 13% . • Forty-six percentofthe nitrate lostin tile drainage from a corn-soybean rotation w as lostin the yearsoybeans w ere grow n. EffectofN rate and tim e ofapplication on nitrate-N losses to subsurface drainage and continuous corn yield. 143 160 34 Fall 180 168 150 131 66 bu/A Yield 5-YrA verage 26 19 27 7 lb N /A/yr in drainage ofnitrate Annual loss 154 Spring 180 135 Spring 120 100 Fall 120 -- -- 0 $/A lb/A N etreturn Time Rate N treatm ent* * Am m onium sulfate applied to continuous corn aboutN ov.1 orM ay 1. C orn yield and N recovery in the w hole plantas influenced by tim e ofapplication and N source,1997-99. 63 170 Yes “ “ 60 168 No Am m onia “ 47 158 Yes “ “ 8 112 182 185 152 bu/A Yield 3-YrAverage -- -- N one -- 84 No Am m onia “ LSD (0.10): 76 No Urea Spr.PP 43 No Urea Fall % N R ecovery N -Serve Source Time N M anagem ent Effectoftim e ofN application and N -Serve on corn yields aftersoybean,1987–2001. 12.0 12.2 14.1 15-YrAvg.FW NO 3 -N C onc. (mg/L) * C orn = $2.00/bu;N = $0.25/lb N (fall)& $0.275/lb (spring). ** Seven years w hen statistically significantdifferences occurred. $51.00 $22.50 --- 7-YrAvg.Econom ic return over fall N ($/A/yr)* 158 146 131 7-YrAvg.Yield (bu/A)** $18.80 $9.30 --- 15-YrAvg.Econom ic return over fall N ($/A/yr)* 156 153 144 15-YrAvg.Yield (bu/A) S pring Fall+N -Serve Fall Parameter Tim e ofN Application C orn production and nitrate loss as affected by tim e ofN application and N -Serve,1987-93. 14.6 56 145 No Split 13.7 47 139 No Spring 4 LSD (0.10): 13.7 43 139 Yes “ 16.8 34 131 No Fall -m g/L - $/A bu/A D rainage * return to N yield N -Serve Time conc.in tile Econom ic C orn N treatm ent FW NO 3 -N 7-YrAverage * Across the 4-cycle corn (1990-93)– soybean (1991-94)rotation. C onclusions • C om pared to late fall N application w ithout N -Serve overthe 15-yearperiod: – C orn yields w ere increased 9 and 12 bu/A/yr(6 and 8% )by eitherfallN +N -Serve orspring preplantN,respectively. – N itrate losses w ere decreased 14 and 15% by eitherfallN +N -Serve orspring preplantN , respectively. • S pring-applied N -Serve did notim prove w aterquality. • N o consistentevidence showing splitor sidedress application to be superiorfrom a w aterquality perspective. EffectofN rate on yield ofcorn aftersoybean, netreturn to fertilizerN ,and nitrate-N concentration in tile drainage,2000–2003. 4-YrFW N et 4-YrYield N Treatm ent 120 160 120 80 0 lb/A Rate Spr. “ “ Fall --- Time No “ “ Yes --- N -Serve 14 105 180 18 78 172 13 70 166 12 30 144 --- --- 111 mg/L $/A/Yr bu/A NO 3 -N conc. R eturn Avg.
description
Collection sump. 5’. 30’. 20’. Developing Nitrogen BMPs from Field Research Gyles W. Randall* and Jeffrey A. Vetsch, Univ. of Minnesota, Waseca, MN. Rate and Time of Application. Abstract - PowerPoint PPT Presentation
Transcript of Developing Nitrogen BMPs from Field Research
Conclusions• Fall application of urea and ammonium
sulfate produced lower corn yield and greater nitrate losses than when spring-applied.
• Averaged across N rates, fall application of ammonium sulfate increased nitrate loss by 36% (8 lb/A) while reducing net return to fertilizer by 16% ($23/A).
Developing Nitrogen BMPs from Field ResearchGyles W. Randall* and Jeffrey A. Vetsch, Univ. of Minnesota, Waseca, MN
AbstractBest management practices (BMPs) for nitrogen (N) and their implementation are critical to achieving profitable crop production while minimizing nitrate losses to ground and surface waters. Nitrogen BMPs for corn (Zea mays) grown after soybean (Glycine max) in south-central Minnesota were developed from long-term, subsurface tile drainage research conducted at the University of Minnesota’s Southern Research and Outreach Center at Waseca. A four-year study showed significantly greater nitrate losses in tile drainage accompanied by no increase in corn yield or profitability when applied N rates exceed the University’s recommended rate. A 15-year study indicated that spring application of ammonia produced greatest yield and profit while minimizing nitrate loss to drainage compared with fall-applied ammonia without N-Serve, and thus is a preferred BMP. Fall application of ammonia with N-Serve also significantly reduced nitrate losses but is considered a BMP with RISK because yields and economic return were lower in years when May and/or June were very wet. Results from these studies clearly show application rates in excess of University recommendations and fall application of ammonia without N-Serve are not BMPs for south-central Minnesota.
Experimental Procedures
Soil: Canisteo clay loam, Typic Endoaquoll
Years: 1987 – 2003
Tile plots: 36; 16 corn, 16 soybean and 4 grass
Plot size: 30 ft. by 20 ft. simulating 50 ft. tile spacing. Isolated to a depth of 6 ft. by 12 mil plastic sheeting.
Tile depth: 3.5 ft.
Slope: 0 – 1 %
Tile drainage research facility at Waseca.
Schematic diagram of drainage plot details.
20’
30’
5’
Collection sump
Rate and Time of Application
Nitrogen Source and Time of Application
Time of N Application and Nitrification Inhibitors
Region Specific BMPs for N
Date
10
15
20
25
30
35
40
Nitr
ate
Co
nc
(mg
/L)
80 lb N/A 120 160
Effect of N rate for corn after soybean on NO3-N concentration in tile drainage water in 2001.
Purpose
• To determine the effect of N rate, time of application, and nitrapyrin (N-Serve) on nitrate losses to subsurface, tile drainage and on corn production.
• To develop best management practices (BMPs) for N for south-central Minnesota based on long-term field research.
Proposed BMPs for South-Central Minnesota
• Recommended– Spring preplant applications of ammonia or
urea and split applications of ammonia, urea, or UAN are highly recommended.
• Incorporate broadcast urea or UAN within three days.
• Apply sidedress application before corn is 12 inches tall.
• Inject or incorporate sidedress applications of urea or UAN to a minimum depth of 3 inches.
• Recommened, but with greater risk– Fall application of AA+N-Serve after soil
temperature at 6-inch depth is below 50° F.– Single, spring preplant application of UAN.– Side dressing all N before corn is 12 inches
tall.• Not recommended
– Fall application of urea, ammonium sulfate, UAN, or anhydrous ammonia without N-Serve.
References
Randall, G.W., and D.J. Mulla. 2001. Nitrate-N in surface waters as influenced by climatic conditions and agricultural practices. J. Environ. Qual. 30:337-344.
Randall, G.W., and J.A. Vetsch, and J.R. Huffman. 2003. Nitrate losses in subsurface drainage from a corn-soybean rotation as affected by time of nitrogen application and use of nitrapyrin. J. Environ. Qual. 32:1764-1772.
Randall, G.W., J.A. Vetsch, and J.R. Huffman. 2003. Corn production on a subsurface-drained Mollisol as affected by time of nitrogen application and nitrapyrin. Agron. J. 95:1213-1219.
Randall, G.W., and J.A. Vetsch. 2005 Nitrate losses in subsurface drainage from a corn-soybean rotation as affected by fall vs. spring application of nitrogen and nitrapyrin. J. Environ. Qual. 34(2):590-597.
Randall, G.W., and J.A. Vetsch. 2005. Corn production on a subsurface-drained Mollisol as affected by fall versus spring application of nitrogen and nitrapyrin. Agron. J. 97:472-478.
Acknowledgement
Sincere appreciation is extended to Dow AgroSciences for their financial contribution to this research.
Conclusions
• Applying 120 lb N/A in the spring (a BMP) increased corn yield 5% and reduced nitrate losses in drainage water by 27% compared to a fall application of 160 lb N/A.
• 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.
Effect of N rate and time of application on nitrate-N losses to subsurface
drainage and continuous corn yield.
14316034Fall180168
150131
66bu/AYield
5-Yr Average
26
1927
7lb N/A/yr
in drainageof nitrate
Annual loss
154Spring180
135Spring120100Fall120- -- -0$/Alb/A
Net returnTimeRateN treatment *
* Ammonium sulfate applied to continuous corn about Nov. 1 or May 1.
Corn yield and N recovery in the whole plant as influenced by time of application
and N source, 1997-99.
63170Yes““60168NoAmmonia“47158Yes““
8112182185
152bu/AYield
3-Yr Average
- -- -None- -84NoAmmonia“
LSD (0.10):
76NoUreaSpr. PP
43NoUreaFall%
N RecoveryN-ServeSourceTimeN Management
Effect of time of N application and N-Serve on corn yields after soybean, 1987–2001.
12.012.214.115-Yr Avg. FW NO3-N Conc. (mg/L)
* Corn = $2.00/bu; N = $0.25/lb N (fall) & $0.275/lb (spring).
** Seven years when statistically significant differences occurred.
$51.00$22.50---7-Yr Avg. Economic return over fall N ($/A/yr) *
1581461317-Yr Avg. Yield (bu/A) **
$18.80$9.30---15-Yr Avg. Economic return over fall N ($/A/yr) *
15615314415-Yr Avg. Yield (bu/A)
SpringFall+N-ServeFallParameter
Time of N Application
Corn production and nitrate loss as affected by time of N application and N-Serve, 1987-93.
14.656145NoSplit
13.747139NoSpring
4LSD (0.10):
13.743139Yes“
16.834131NoFall
- mg/L -$/Abu/A
Drainage *return to NyieldN-ServeTime
conc. in tileEconomicCornN treatment
FW NO3-N7-Yr Average
* Across the 4-cycle corn (1990-93) – soybean (1991-94) rotation.
Conclusions• Compared to late fall N application without
N-Serve over the 15-year period:– Corn yields were increased 9 and 12 bu/A/yr (6
and 8%) by either fall N+N-Serve or spring preplant N, respectively.
– Nitrate losses were decreased 14 and 15% by either fall N+N-Serve or spring preplant N, respectively.
• Spring-applied N-Serve did not improve water quality.
• No consistent evidence showing split or sidedress application to be superior from a water quality perspective.
Effect of N rate on yield of corn after soybean, net return to fertilizer N, and nitrate-N
concentration in tile drainage, 2000–2003.4-Yr FWNet4-Yr YieldN Treatment
120
160
120
80
0
lb/A
Rate
Spr.
“
“
Fall
---
Time
No
“
“
Yes
---
N-Serve
14105180
1878172
1370166
1230144
------111
mg/L$/A/Yrbu/A
NO3-N conc.ReturnAvg.
