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Controlled traffic/permanent bed farming reduces GHG emissions. Jeff Tullberg


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A presentation from the WCCA 2011 event held in Brisbane, Australia.

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Controlled traffic/permanent bed farming reduces GHG emissions. Jeff Tullberg

  1. 1. Controlled traffic/permanent bedfarming reduces GHG emissions. Jeff Tullberg , Jack McHugh, Boorzoo Ghareel Khabbaz, University of Southern Queensland, Toowoomba and CTF Solutions, Brisbane. Clemens Scheer, Peter Grace Queensland University of Technology, Brisbane.
  2. 2. Australian controlled traffic (no-till) farmingHarvesting, Seeding, Spraying,From same permanent traffic lanes
  3. 3. China Controlled Traffic ResearchHarvesting, Seeding, Spraying,From same permanent traffic lanes
  4. 4. Controlled Traffic Farming (CTF)• Permanent traffic lanes for all heavy wheels. Permanent no-till crop beds.• Layouts designed for drainage and logistics. Timeliness, precision, better soil and agronomy* *opportunity crops, optimised inputsMany characteristic shared with – Permanent Raised Bed (PRB) in Mexico and Asia – Permanent bed, reduced-till intensive cropping. Impact?
  5. 5. TComparison of wheeled and non-wheeled soilParameter Units Australian Vertosol China, Loess Wheeled Non-wheeled Wheeled Non-wheeledWheel Load t/axle 4-5 1-2Rainfall ( 5year mean) mm/yr 907 (incl. irrigation) 558Runoff ( 5year mean) mm/yr 193 112L 32 18WInfiltration (80mm/h, 1h) mm/h 27 97L 12 41WAvailable Top mm 29 47M 27 30Wwater 300mmBulk density 1.36 1.28M 1.51 1.59WEarthworms/m2 # 40 108Fuel use, seeding l/ha 5.6 3.0T / /Grain yield( 5year mean) t/ha 3.70 4.05T 3.05 3.25WL Li et (2007); W Wang et al(2009): T Tullberg et al(2007); M McHugh et al(2009) Why?
  6. 6. Annual Tractor Wheel Impact in Zero Till Black = Soil Solids, White = Air or Water (from D.McGarry ) 24 cm 4- Years CTF Annually Wheeled Non-Wheeled (5t Tractor). Greenhouse Impact?
  7. 7. Greenhouse gas emissions (not Carbon)• Inputs • Fuel, Machinery • Herbicides • Fertilisers } Easily Quantified For Known Systems Energy• Outputs • Nitrous oxide & methane • Nitrate in runoff and drainage • Nitrate in eroded soil } Highly Variable, Less Well-Understood Wasted Energy In practise: Greenhouse Impact = Economic Impact
  8. 8. Soil Emissions – Nitrous Oxide, NO3 (+ Methane)Literature: N loss and emissions associated with waterloggingNO3emissions occur when: Water- filled porosity <75%, >65%., Nitrate +C present in surface 10 cm.Management Impact ?Till v. no-till: less NO3 emissions in well-drained soils. (Rochette 2009) more NO3 emissions in poorly drained soils. (measurements rarely taken in wheel tracks)Wheel effect: wheeled soil emissions 5 x non wheeled (Russer 1998)(potato fields) wheeled soil emissions 5 x non wheeled (Thomas 2003) Common thread– wheel effects?
  9. 9. Pilot trial, 2010 Wheat seeded + 80kg/ha N as anhydrous ammomia, interrow 4-year of 3m CTF heavy vertosol, disk seeder, tine fertiliser. 3m Emission Chambers Permanent Traffic Lane (T.Lane) Permanent Bed Non-Wheeled Permanent (P.Bed) Permanent Bed + Traffic Lane 1 Pre-seeding Wheeling (T.Lane) (Rand)
  10. 10. Emissions N2O-N T Lane 400 ug.m-2.h-1 Rand 350 P Bed 300 250 200 150 100 50 0 0 10 20 30 40 50 Days after planting Wheel Impact: N2O increased significantly on 3 occasions after rain CH4 increased significantly on 1 occasion after rain
  11. 11. Cumulative Emissions Emissions (6 weeks post-seeding) kg CO2-e/ha Source T Lane Rand P Bed kg kg kg N2O 324.6 369.5 58.2 CH4 0.33 0.41 -0.43 Total 324.6 369.5 58.2 Ratio 5.57 6.35 1.00Wheeltrack emissions probably greater by a factor of 5.0 – 7.0
  12. 12. Conclusions1. Pilot trial confirms the literature: wheel track emissions 5-7 times greater than bed emissions.2. Permanent traffic lanes in CTF occupy 10– 20% area. but minimum of 50% area is wheeled in non—CTF.3. This suggests that CTF should reduce soil emissions by >50% possibly more with precise, split N application. plus a substantial impact on input-related emissions.4. Improved agronomy, soil health and precision also increase WUE indicating possibility of greater biomass and C input. Needs investigation in different environments