Methods to Improve Nutrient Use Efficiency in Rice Timothy W. Walker, Ph. D. Associate Agronomist 662 822 2291 6R 2/Room 4 Tuesday 11:10 11:56 Wednesday 10:10 10:56
Nitrogen Use Efficiency NUE = Grain yield (lb/acre) Nitrogen applied (lb/acre)
Nitrogen Use Efficiency Yield Genetics Management Variety Selection Breeding Agronomic Pest
Nitrogen Use Efficiency N Rate Decrease N Rate Maintain N Rate Account for Soil Supply Account for Plant Need Prevent Loss N ST*R (U of A) Rate Response Chlorophyll Plant Area Board Sensorbased Ammonia Nitrate Agrotain Water Water Nitrification Inhibitors
Nitrogen Use Efficiency Maintain N Rate Prevent Loss Ammonia Nitrate Agrotain Water Water Nitrification Inhibitors
Urea s Reaction Produces NH 3 Gas 2 NH 3 ammonia gas on soil surface or in flood -H 2 O & CO 2 CO(NH 2 ) 2 (NH 4 ) 2 CO 3 2 NH 4 + + 2 OH - urea urease (ph ~ alkaline) ammonium salt in soil Note: Urea s reaction in soil initially is alkaline and increases soil ph causing ammonia volatilization loss if not incorporated in soil quickly. Slide borrowed from R. Norman
Ammonia Volatilization of Urea Applied to a Conventional Tilled and a Stale-Seedbed Silt loam soil (RREC, 2001) [N source LSD0.05 = 3.1% of applied N] Volatilization (% of applied N) 35 30 25 20 15 10 5 0 Ammonia Volatilization Ends at ~10 Days 0 5 10 15 20 25 Griggs etal., 2007; SSSAJ Time (days) Stale-Seedbed Conventional Till Slide borrowed from R. Norman
Ammonia Volatilization Losses (Clay soil) Ammonia Volatilization of 15 N-labeled Urea and Ammonium Sulfate From a Perry Clay Soil 14 Days before Flooding (SEREC, 2000) Volatilization (% of applied N) 30 25 20 15 10 5 Ammonium Sulfate Flood Urea Ammonium Sulfate Urea 0 0 2 4 6 8 10 12 14 16 18 20 22 Griggs et al., 2007; SSSAJ Time (days) Slide borrowed from R. Norman
9500 9000 y = 520.4x + 6697.5 a Yield (lb/a) 8500 8000 7500 7000 i a-d e-h 1238 lbs 15 % a-d d-h a-e 581 lbs 7 % a-c Urea Agrotain-Urea Linear (Urea) 6500 6000 5500 5000 10 DPF 7 DPF 4 DPF 1 DPF Rice Research Station fertility and Agronomy Project Application time (Days Prior to Flooding)
NH4 N loss (% of total applied) 25 20 15 10 5 0 3 6 9 12 15 18 21 Time (days) Urea AS Urea AS Super U Agrotain Urea Rice Research Station fertility and Agronomy Project
9000 (Urease inhibitor only) (Urease and nitrification inhibitors) 8500 a-d c-g a-d b-f a-e b-f a-c a-c 8000 Yield (lb/a) 7500 7000 6500 Agrotain-Urea Super-U 6000 5500 5000 10 DPF 7 DPF 4 DPF 1 DPF Application time (Days Prior to Flooding) Rice Research Station fertility and Agronomy Project
Ammonia Volatilization 12 10 NH3 Volatilization Loss % of applied 8 6 4 2 urea ams agrotain 0 0 5 10 15 20 Days Data from Tunica clay. Dillon and Walker, unpublished
Urea vs Agrotain lb/acre 8800 Source x Timing (P = 0.0024) LSD = 453 8600 8566 8400 8361 8224 8200 8000 7806 7800 LSD = 7 8269 8500 8599 8452 Agrotain Urea 7600 7400 10 7 4 1
Urea vs Agrotain 8000 7800 Source x Timing (P = 0.0024) LSD = 361 7818 7860 LSD = 7 7710 7600 7586 7400 7200 7420 7155 Agrotain Urea 7000 6800 10 7 2
Agrotain vs Super U 8700 8600 8500 8400 8300 8200 8100 8000 7900 7800 7700 Source x Timing (P = 0.0024) LSD = 453 8566 LSD = 7 8599 8488 8331 8224 8269 8113 8056 10 7 4 1 Agrotain Super U
Testing the Mechanism Product Evaluation Agrotainis the only urease inhibitor recommended in Arkansas. Other products unproven to inhibit NH 3 loss include Nutrisphere N Zone Extend Upgrade
Lab Evaluation Upgrade Urea Agrotain Urea Upgrade Urea Cumulative NH 3 Loss (% of applied N fertilizer) 45 40 35 30 25 20 15 10 5 0 0 5 10 15 Time (days) Source: Norman and Roberts (unpublished data)
Lab Evaluation N Zone Cumulative NH 3 Loss (% of applied N fertilizer) 64 56 48 40 32 24 16 8 0 Urea Agrotain Urea N Zone Urea 0 5 10 15 Time (days) Source: Norman and Roberts (unpublished data)
Lab Evaluation Nutrisphere Cumulative NH 3 Loss (% of applied N fertilizer) 64 56 48 40 32 24 16 8 0 Urea Agrotain+Urea Nutrisphere+Urea Ammonium Sulfate 0 5 10 15 Time (days) Source: Franzen et al. (2011, in press) J. Plant Nutr. 0.25% Nutrisphere added
Lab Evaluation Extend Urea Agrotain Urea Extend Urea Cumulative NH 3 Loss (% of applied N fertilizer) 45 40 35 30 25 20 15 10 5 0 0 5 10 15 Time (days) Source: Norman and Roberts (unpublished data)
Nitrification/Denitrification Nitrosomonas 2NH 4+ + 3O 2 2NO 2 + 2H 2 O + 4H + Nitrobacter 2NO 2 + O 2 2NO 3 Permanent Flood NO 3 + H 2 O NO, N 2 O, N 2 (gases)
Nitrogen Stabilizers 180 170 160 164 150 bu/ac 140 137 60 130 131 120 120 110 100 113 10 DBF 2 DBF
Urea Conversion to NO 3 NH 4 remaining (% of initial) 110 100 90 80 70 60 50 40 30 20 10 0 0 3 6 9 12 15 18 21 24 27 Time (days) Dulaney F13S F14 Walker CircleH LA Davis
Urea Conversion to NO 3 Soil A K T 1/2 R 2 % d 1 d Unit less LA 106.3244 (8.6832) 0.1046 (0.0187) 6.6 0.945 F13S 98.1749 (5.0216) 0.0840 (0.0095) 8.3 0.971 Dulaney 92.3076 (8.0813) 0.0708 (0.0139) 9.8 0.910 Davis 101.8352 (7.4631) 0.1353 (0.0218) 5.1 0.961 CircleH 103.3625 (7.8772) 0.1447 (0.0242) 4.8 0.960 F14 105.0458 (7.1418) 0.1573 (0.0236) 4.4 0.970 Walker 96.3323 (5.5211) 0.1672 (0.0212) 4.1 0.977
Nitrification Rate of Urea 120 Nitrification of Urea in two Soils 100 % urea-n as NO3-N 80 60 40 20 Calhoun soil Dewitt soil 0 0 5 10 15 20 25 30 35 Days Unpublished data: Golden et al. (2009) Slide borrowed from R. Norman
Grain Yield 8400 8200 8000 7800 7600 7400 7200 7000 Source x Timing (P = 0.0024) 8235 8218 7467 LSD = 7 8071 8041 8069 7994 7642 7858 43% Urea ENTEC Super U Agrotain Data collected at DREC 2010 Sharkey clay soil LSD = 421 2DBF 10DBF
Nitrification Inhibitor Nutrisphere Soil Inorganic N (ppm) 50 45 40 35 30 25 20 15 10 5 0 NO3 N NH4 N Source: Franzen et al. (2011, in press) J. Plant Nutr. 90 lb urea N/acre; LSD0.05 (8.4 ppm for NO 3 and 4.5 ppm for NH 4 ) Data from Hazelton, North Dakota)
Sensor based
1 NUE Fixed = 35% NUE Sensor = 38% $ Fixed = $447 $ Sensor = $446
Commercially Available Active Sensors Photo courtesty of B. Tubana
Rice Info on the Web www.rice.msstate.edu
Dr. Dustin Harrell Dr. Brenda Tubana Mr. Kevin Dillon Mr. Paxton Fitts Dr. Rick Norman Dr. Nathan Slaton Dr. Bobby Golden Dr. Trent Roberts Special Thanks
Special Thanks