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Options and new innovations required to improve nitrogen use efficiency in grazing systems
 

Options and new innovations required to improve nitrogen use efficiency in grazing systems

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This is the presentation given by Cameron to the PICCC Strategic Science Think Tank - Nitrogen efficiency

This is the presentation given by Cameron to the PICCC Strategic Science Think Tank - Nitrogen efficiency

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    Options and new innovations required to improve nitrogen use efficiency in grazing systems Options and new innovations required to improve nitrogen use efficiency in grazing systems Presentation Transcript

    • Nitrogen use efficiency in grazing systems: options and new innovationsCameron Gourley and Kevin Kelly (Department of Primary Industries Victoria), Helen Suter (University of Melbourne), Cecile de Klein (AgResearch NZ), Michael Russelle (USDA)
    • • Nitrogen flows and transformations • using dairy farms as our model • Where are the major flows and transformations?• How efficiently do we currently use nitrogen? • Nitrogen efficiency at a range of scales• Where are the opportunities for improved N efficiency? • Future innovative and integrated approaches
    • Nitrogen flows and transformations Whole - Farm Within - FarmINPUTS OUTPUTSFeed Dairy MilkAnimals cows AnimalsBedding Seed Pasture / crops Manure ManureFertilizer Crops Silage, hayN fixationIrrigationPrecipitationManure Soil Leaching Soil accumulation Gaseous Runoff LOSSES
    • INPUTS OUTPUTS 160 336 Dairy Feed 97 Milk 160 cows Animals 0 4 Animals 380 Bedding 0 Seed Pasture / crops Manure 0 ManureVictoriandairy farm Fertilizer 34 0 Crops 180 storage Silage, hay• 167 cows N fixation 8 11• 67 ha Irrigation 1• 2.9 cows/ha 335• 29% reliant Precipitation 1imported feed Manure 0 Soil Whole-farm N surplus = 250 kg N/ha/year N use efficiency = 29%
    • Whole-farm N Use Efficiency Total Farm N Inputs Farm Inputs : Farm OutputsUSA 215 to 568 kg ha-1 14 to 55 Rotz et al., 2006Canada Not available 25 to 64 Hristov et al., 2006Europe 235 to 870 “ “ 19 to 40 Raison et al., 2006New Zealand 150 to 550 “ “ 18 to 37 Ledgard et al., 2004Western Australia 63 to 840 “ “ 8 to 55 Ovens et al., 2008Australia-wide 88 to 808 “ “ 14 to 49 Gourley et al., 2012
    • 55 N Balance (g/L milk produced) 45 45 g N/L 35 25 21 g N/L 15 7 g N/L 5 60Whole-Farm N Efficiency (%) 40 Whole-farm NUE • 41 commercial dairy farms 14 – 49% • Differing production systems 20 Median 28% • National dairy regions • Stocking rates Gourley et al. 2012, Animal Production Science • Reliance on imported feed 0 • N fertiliser use 0 10000 20000 30000 40000 Milk Production (L/ha)
    • Whole-farm N Use EfficiencyImpact of stocking rate on nitrogen use efficiency (NUE) and nitrogenlosses on a grazing dairy farm in Western Australia (M. Staines, 2009)Parameter Stocking rate (cows ha-1) 1.25 1.50 1.75 2.00 2.25Surplus N (kg ha-1) 57 125 189 298 385Whole-farm NUE (%) 53 36 32 24 20
    • DPI Farm Monitor data – Courtesy Andrew Smith] 2500Milk solids (kg/ha/yr) Operating profit ($/ha/year) 2000 $3,000 Dairy $2,000 1500 cows $1,000 1000 $0 Pasture / crops Manure -$1,000 y = 289 + 2.84x R² = 0.05 500 Fertiliser -$2,000 0 100 200 300 400 0 Soil N fertiliser use (kg/ha/year) 0 100 200 300 400 500 N fertiliser use (kg N/ha/yr) WA dairy farms 2005 to 2008 (Red Sky Agricultural).
    • Feed Nitrogen Use Efficiency Input to Output Parameters N Input Range NUE Range Source (%) Feed to Milk 512 to 666 g cow-1d-1 26 to 33 Powell et al., 2006a (Feed-NUE) 289 to 628 “ “ “ 22 to 29 Kebreab et al., 2001 200 to 750 “ “ “ 21 to 32 Castillo et al., 2000 496 to 897 “ “ “ 21 to 36 Chase, 2004 838 to 1360 “ “ “ 16 to 24 Aarts et al., 2000 1 0.40 0.35 Vic - Spring MilkFeed N Use Efficiency Dairy 0.30 Vic - Summer Purchased cows Feed 0.25 Pasture / crops Manure 0.20 y = -0.0003x + 0.398 0.15 y = -0.0003x + 0.3547 Soil 0.10 300 400 500 600 700 800 900 N intake (g cow -1 day -1)
    • Feed N use efficiency and daily loads excreted by lactating cows from 43 dairy farms over 5 visits N use N Excreted efficiency (g N/cow/day) Average 20.8 432 Min 10.5 199 South west Victoria Max 35.1 792 Gippsland Aarons et al., 2010 Northern irrigation North eastCrude protein content of perennial pastures inVictoria throughout the year. Doyle et al. (2000)
    • 6 - 25% 40 - 85% 8 - 45%
    • SW Victoriandairy farm•540 cows•460 ha•1.2 cows/ha•42% reliantimported feed
    • Identify and train group leadersPredict location of stock camps Targeted mitigation (Nitrification Inhibitors) Slide courtesy Keith Betteridge, AgResearch NZ
    • Conclusion Surpluses of Nitrogen in modern agricultural production systems are inevitable and likelyto increase with increasing inputs Opportunities to improve nitrogen use efficiency through: Prominent role of ‘whole-farm’ N balances and use efficiencies Milk Strategic fertiliser nitrogen inputs  variability in pasture response; Purchased Dairy cows Feed  Fertiliser forms, rates, timing and placement Fertiliser Pasture / crops Manure Pasture growth stimulants (greater DM/unit N applied) Reducing feed N intakes, reduced excreta concentrations Soil Greater capture, reuse and redistribution of excreted N  Separate dung and urine; reduce loss, improved application Restricting grazing (avoid treading damage)  Mop-up crops Nitrification inhibitors
    • NZ CATCHMENT STUDY•Farm survey results + 39% Rate of efficiency gain < Rate of productivity increase•OVERSEER farm lossestimates – 17 % de Klein & Monaghan (2011)
    • PACKAGE OF OPTIONS – “MORE FOR LESS”Aim Potential optionsMore milk per cow • Higher genetic merit cowsor per unit DM • Lower replacement ratesintake • Better feeding to improve animal condition • Better quality pasture/crops/supplementsMore DM per unit • Low N feedof N input • Restricting grazing (avoid treading damage) • Mop-up crops • Exploit variability (pasture response) • Fertiliser/manure management • Nitrification inhibitors or growth stimulantsReduce N loss risk • Nitrification/urease inhibitors • Restricted grazing • Exploit variability • Feeding to divert N to dung • Riparian and wetland management
    • BUT – NOT JUST A SOIL ISSUEBeukes et al (2011) Rate of efficiency gain > Rate of productivity increase
    • NITRIFICATION INHIBITORS (DCD) –N LEACHING LOSS FROM GRAZED PASTURE 41% reduction Monaghan et al (2009)
    • MITIGATING SOIL N LOSS CAN HELP! e.g. Nitrification inhibitorsN2O emissionsAverage reduction: 57% de Klein et al (2011)
    • MUN Mirrors BUN (Gustafsson & Palmquist, 1993) MUN (Weighted avg.) = MUN 17.0 mg/dl (PM) BUN MUN MUN (AM/PM avg.) = 20.7 mg/dl (FQ)MUN(AM) Courtesy Glen Broderick,of Milk Urea Nitrogen Values WI Application USDA-ARS-USDFRC, Madison,
    • MUN & Dietary CP Content (Nousiainen et al., 2004)Courtesy Glen Broderick,of Milk Urea Nitrogen Values WI Application USDA-ARS-USDFRC, Madison,
    • If you can track MUN, you can predict Urinary N output (g/d) (Nousiainen et al., 2004) Kauffman & St. Pierre Nousiainen et al.Urinary N (g/d) Jonker et al. Application of Milk Urea Nitrogen Values
    • You can predict Urinary N output (g/d) even better from MUN Output (g/d) & Dietary CP (%) (MTT Data) Huhtanen et al., 2007 500 Predicted Urinary-N (g/d) = -178 + 12.4*MUN Output (g/d) + 2.08*CP (g/kg)Urinary N = Feed Urinary-NN – Fecal N (RMSE = 9.0) 400 adjusted N – Milk (g/d) 300 200 (r2 = 0.972) r2 = 0.972 100 (Urinary-N = NI - -178 + Fecal-N) Urinary N = Milk-N - 12.4*MUN output + 2.08*[CP] 0 0 100 200 300 400 500 predicted Urinary-N (g/d) Urinary N = -178 + 12.4*MUN output + 2.08*[CP] Courtesy Glen Broderick,of Milk Urea Nitrogen Values WI Application USDA-ARS-USDFRC, Madison,
    • MUN Suggestions for the Farm (AgSource Coop.)1. Establish MUN Baselines.• 2. Get MUN Values Under Standard Conditions• (Same Milking; Group Means; Same Assay).• 3. Exclude Cows with Mastitis & < 30 DIM.4. Number of Cows to Test for MUN: a. > 50% of Each Group or Herd (AgSource advice) b. 4 Cows, ± 2 Units; 16 Cows, ± 1 Unit (Broderick & Clayton, 1997)5. Follow MUN Trends in Archived Data. Courtesy Glen Broderick,of Milk Urea Nitrogen Values WI Application USDA-ARS-USDFRC, Madison,