What New Equipment Is Available to Improve N-Use Efficiency?

Global Issues and the Fate of Nitrogen

W.R. RaunRegents ProfessorPresented By: Jacob P. VossenkemperO K L A H O M A S T A T E U N I V E R S I T YO K L A H O M A S T A T E U N I V E R S I T Y1Population and Food ProductionIncreasing population needing to be fed will fuel interest in finding and developing new practices to improve food productionInterest in improved soil nutrient management today as world population growsO K L A H O M A S T A T E U N I V E R S I T Y2World Population

O K L A H O M A S T A T E U N I V E R S I T Y3World FoodCurrent world food supplies are estimated to be more than adequate at about 2,500 to 3,000 calories per day per person. Nonetheless, hunger is still quite common in developing countries because of the lack of resources to purchase and/or redistribute available foodstuffs. O K L A H O M A S T A T E U N I V E R S I T Y4World Food (www.fao.org)Grain SourceCal/kgProduction, Mt, 2004Total CaloriesWheat grain, whole3394624,093,3062.11802E+15Cornmeal, whole3625705,293,2262.55682E+15Rice, white, cooked1219608,496,2847.41497E+14Soybeans1734206,409,5253.57837E+14Potatoes1092328,865,9363.59195E+14Total6.13336E+15World Population6,500,000,000/ 6.5 billion / 365Calories per person/day from grain2585O K L A H O M A S T A T E U N I V E R S I T Y5

CO2 levels in the atmosphere have increased from 260 to 360 ppm in the last 150 years

Global Warming?

What % of the increase (100 ppm) has been due to cultivation?25 ppm or 25%O K L A H O M A S T A T E U N I V E R S I T Y6Organic food productionThere are groups within our society that believe food should be raised organic, meaning without the benefit of external inputs of synthetic materials (e.g. chemical fertilizers),

The soundness of this approach can be quickly examined by considering the amount of animal manure required to replace the current 300,000 tons of N, from commercial inorganic fertilizer, used in Oklahoma to maintain current crop production levels. O K L A H O M A S T A T E U N I V E R S I T Y7Using beef manure, the tons of manure required would be300,000 tons N x 2,000 lb/ton = 6 x 108 lb N required6 x 108 lb N required 1 ton (2000 lbs) has 20 lb N6 x 108 lb N required/20 lb N /ton= 3.0 x 107 tons of manureAverage manure production of 1,000 lb steers in a confined feedlot will produce 3.212 tons per year.3.0 x 107 ton manure x 1.0 animals/3.212 ton per year = 9,339,975 steersThe Oklahoma Agricultural Statistics 430,000 cattle on feed as of January 1, 1998 O K L A H O M A S T A T E U N I V E R S I T Y8Cattle ManureThe Oklahoma Agricultural Statistics for 1997 reported 430,000 cattle on feed as of January 1, 1998 (this does not mean the number was constant throughout the year).

A 21X increase in feedlot beef cattle to produce the required N in the form of animal manure. What would we do with all the meat?

It is also important for the promoters of organic farming to realize that even the best recycling efforts are not 100% efficient. O K L A H O M A S T A T E U N I V E R S I T Y9SCIENCE MagazineExcess nitrogen flowing down the Mississippi each year is estimated to be worth $1,000,000,000 (Science, Malakoff, 1998)

NUE in cereal production

30% or 80% ?O K L A H O M A S T A T E U N I V E R S I T Y10

O K L A H O M A S T A T E U N I V E R S I T Y11Large Scale Application

O K L A H O M A S T A T E U N I V E R S I T Y12NUE in CerealsAuthorCropMethodYearLocationNUE (grain)VarvelCorn15N1990NE43-53%RusselleCornDiff.1981NE46%RaunCornDiff.1989NE30-40%OlsonWheat15N1984KS27-33%BronsonWheat15N1991CO53%RaunWheat15N1999OK21-32%LeesWheat15N2000OK38-41%WestermanSorghum15N1972IL51%VarvelSorghum15N1991NE48%DeDattaRice15N1988Asia37-47%

O K L A H O M A S T A T E U N I V E R S I T Y13ReviewYield Goals: average of last 3-5 years +30%

Nebraska study showed that farmers overestimated yield by 2 Mg ha-1 (32 bu ac-1), resulting in an excess of 35 kg N ha-1 (Schepers et al., 1986)

Over-optimistic yield goals were the largest contributor to excess N applications with average yield goals exceeding actual yields by over 15%, only about 30% of the fields were within 5% of the yield goal (Daberkow et al., 2001)O K L A H O M A S T A T E U N I V E R S I T Y14

ReviewFor all systems, it is important to account for N contributed from other sourcesManures, legume residues, irrigation water, rainfall (mass balance) The Sensor takes advantage of this natural Nitrogen

O K L A H O M A S T A T E U N I V E R S I T Y15

O K L A H O M A S T A T E U N I V E R S I T Y16

VolatilizationpH >7.0>50FLeaching50FMoisture StressDenitrification>50FanaerobicImmobilizationPlant Uptake

N TreasureO K L A H O M A S T A T E U N I V E R S I T Y17Thief #1 Ammonia Volatilization

If pH and temperature can be kept low, little risk exists for the loss of N as ammonia (urea or anhydrous N sources)Influenced by Soil pHTemperatureUrease ActivityApplication MethodCEC

50FpH 7.0DenitrificationLeachingLeachingVolatilizationNitrificationNitrification

LeachingLeachingO K L A H O M A S T A T E U N I V E R S I T Y18Thief #2 Nitrate LeachingUsually takes place in the winterExcess N applied in-season that is not usedTemperatures below 50F (microbial pools not active)

50FpH 7.0DenitrificationLeachingLeachingVolatilizationNitrificationNitrification

LeachingLeachingO K L A H O M A S T A T E U N I V E R S I T Y19Thief #3, Denitrification

Burford and Bremner, 1975

50FpH 7.0DenitrificationLeachingLeachingVolatilizationNitrificationNitrification

LeachingLeachingO K L A H O M A S T A T E U N I V E R S I T Y200.040.050.060.070.080.090.1040801201602000.40.50.60.70.80.9TSNOC#406Total Soil N, %Organic Carbon, %N Rate, kg/haSED TSN = 0.002SED OC = 0.03Raun, W.R., G.V. Johnson, S.B. Phillips and R.L. Westerman. 1998. Effect of long-term nitrogen fertilization on soil organic C and total N in continuous wheat under conventional tillage in Oklahoma. Soil & Tillage Res. 47:323-330.O K L A H O M A S T A T E U N I V E R S I T Y21Thief #4, Plant N Lossphotosynthesiscarbohydratescarbon skeletonsaminoacidsNH3reducing powernitritereductasenitratereductaseferredoxinsirohemeNO2NO3NADH or NADPHrespiration

O K L A H O M A S T A T E U N I V E R S I T Y22Total N uptake in winter wheat with time and estimated loss following flowering.

Thief #4, Plant N LossO K L A H O M A S T A T E U N I V E R S I T Y23R-NH2NO3- + 2e (nitrate reductase) NO2- + 6e (nitrite reductase) NH4+NH3R-NH2NO3NH4REPRODUCTIVEVEGETATIVEmoistureheatTotal NTotal NaminoacidsNH3nitrite reductasenitrate reductaseNO2NO3

O K L A H O M A S T A T E U N I V E R S I T Y24Nitrogen TreasureWhere did all the Nitrogen Go?Magruder Plots1892: 4.0 % organic matter = 0.35+ 1.8 OCOC = 2.03TN = 0.16Pb = 1.623 (0-12")lb N/ac = Pb * ppm N * 2.7194= 1.623 * 1600 * 2.7194 = 7061+ 10 lbs N/year in the rainfall = 1050 (105 * 10)= 81111997OC = 0.62TN = 0.0694 lb N/ac = 1.623*694 * 2.7194=3063

Difference: 8111 - 3063 = 5048 lbs N

NO K L A H O M A S T A T E U N I V E R S I T Y25N Rich Strip Apply lower rates at PlantingBase Topdress Rates off predicted yield potential and N ResponsivenessApply N when it is needed

NHow to Keep the Leaching, Volatilization, Plant N Loss, and Denitrification Thieves Away from our Nitrogen Treasure?Only way to know how big the treasure is how far we have to dig to find it

O K L A H O M A S T A T E U N I V E R S I T Y26Dry, Cool Winter0-N MineralizedGood Stand30 bu/ac Yld Potential60 bu/ac Yld Potential with NTopdress N = 60 lb N/acSize of the TreasureWet, warm Winter40 lb N in rain + MineralizedGood Stand45 bu/ac Yld Potential65 bu/ac Yld Potential with NTopdress N = 40 lb N/ac Dry, Cool Winter0-N MineralizedPoor Stand20 bu/ac Yld Potential40 bu/ac Yld Potential with NTopdress N = 40 lb N/ac

Wet, warm Winter40 lb N in rain + MineralizedPoor Stand35 bu/ac Yld Potential45 bu/ac Yld Potential with NTopdress N = 20 lb N/ac

What Unlocks the Mystery of the Nitrogen Treasure? N Rich Strip and Yld Potential

NNNN

O K L A H O M A S T A T E U N I V E R S I T Y27Evidence

O K L A H O M A S T A T E U N I V E R S I T Y28Extreme Soil Variability

Apply more N

Apply less NHigher NUE

LowerNUEO K L A H O M A S T A T E U N I V E R S I T Y29Improving Nitrogen Use Efficiency for Cereal ProductionPotential Improvements Crop RotationsForage Production SystemsHybrid or CultivarConservation TillageNH4-N SourceIn-Season and Foliar-Applied NFertigationHigh Resolution Precision ManagementOSU Has developed a tool the GreenSeekerO K L A H O M A S T A T E U N I V E R S I T Y30

SummaryCereal NUE < 50%N Rich Strip (RI), SBNRC, RAMP can improve NUE and profitHave to be committed to increasing NUE

Questions? O K L A H O M A S T A T E U N I V E R S I T Y31