Presentation on theme: "Nitrogen Loss Research"— Presentation transcript:
1Nitrogen Loss Research Joel RansomNDSU Extension Agronomist
2BackgroundNitrogen fertilizer third most costly input in corn productionNitrogen losses can be significant (only ~1/3 of N applied is used by the crop)Off site loses are environmental concerns
3Why worry about N use efficiency? N is biologically and chemically very active in the soilEach N compound behaves differently in the soil affecting potential for lossNitrous oxide is a potent greenhouse gas (impacts climate change?)Excess nitrate in surface waters causes eutrophication and anoxia
6Principles to guide N loss reductions 4 R’s of nutrient stewardshipRight fertilizer sourceRight rateRight timeRight place
7Addressing sources of loss VolatilizationPlacement, urease inhibitors, polymer coated urea, soil moisture status (AA), application timing relative to rain (surface applications)Leaching and denitrificationDelaying the conversions from ammonium to nitrateNitrification inhibitorsSoil temperature at time of applicationPolymer coated urea or slow releaseBanding vs. broadcastingApplying nearer the time of greatest uptakeSlow release ureaSplit applications
8Urease inhibitorsNBPT is the most commonly available and widely tested (Agrotain, SuperU, etc.)Volatilization of NH3 from urea anytime moisture, urea and urease are present in temperatures that range from 11ºF to 105ºF.Urease inhibitors block the conversion of urea to ammonia for a period of one to two weeks allowing time for incorporation by rainfall or other meansUAN contains 50% urea
10Nitrification inhibitors Slow the conversion of NH4+ to NO3- by killing or reducing the activity of populations of Nitrosomonas and Nitrococcus bacteria.Two most common commercial inhibitors are nitrapyrin and DCD
15Release rate of ESN compared to corn N uptake, Manitoba (Heard and Ginter, MAFRD).
16Treatments included in recent research Standard treatment – urea pre-plant incorporatedInstinct – new formulation of nitrapyrin that inhibits nitrification (ammonium to nitrate)Polymer coated urea – (ESN) coated so that it will release gradually and when temperatures are warmer (30% of total N applied)Split application – UAN applied at the 6 lf dribbled between rowsSplit with UAN + Agrotain Plus – urease inhibitor plus nitrification inhibitor in powder form for ease of mixing with UAN
17Experimental locations 2011 two locations2012 and 2013 five locations2012 dry but productive year, limited N loss in most environments2013 excess moisture early, dry later in the season
18Effect of additive yield of corn, Fargo and Prosper, 2011.
19Effect of nitrogen management practices on yield of corn in five environments, 2012.
20Effect of nitrogen management practices at lowest N rate on yield of corn in five environments, 2012.
21Effect of nitrogen management practices on yield of corn in five environments, 2013.
22Effect of nitrogen management practices at lowest N rate on yield, all locations, 2013.
23Effect of nitrogen management practices at lowest N rate on yield of corn in Casselton, 2013.
24Prices Urea $550/ton ($60 per 100 lbs/N) ESN $675/ton ($73 per 100 lbs N = 22 lbs N)28% UAN $360/ton ($64 per 100 lbs N)SuperU ~$ /ton (~$190 over price of urea)Instinct ~$11 per acreAgrotain $56 per ton ($6 per 100 lb N)Agrotain Plus $65 per ton ($11 per 100 lb N)
27ConclusionsNo compelling evidence that additives were profitable in any of the environments includedSplit applications were both positive and negative depending on the environmentProtection of UAN with urease inhibitor in one environment in 2013Additional research would be beneficial to sample additional environmentsRate of Instinct may need adjustmentRatio of ESN may have been too low to pick up response