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Conservation Agriculture, Emissions and Resilience: Opportunities and Dangers

Conservation Agriculture, Emissions and Resilience: Opportunities and Dangers. J. N. Tullberg, CTF Solutions, Brisbane, Australia. jeff@ctfsolutions.com.au. Summary. Conservation agriculture has big environmental benefits, but is it climate-friendly? Factors: Soil carbon

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Conservation Agriculture, Emissions and Resilience: Opportunities and Dangers

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  1. Conservation Agriculture, Emissions and Resilience: Opportunities and Dangers J. N. Tullberg, CTF Solutions,Brisbane, Australia.jeff@ctfsolutions.com.au

  2. Summary Conservation agriculture has big environmental benefits, but is it climate-friendly? Factors: • Soil carbon • (CA better, but still not always positive) • Energy • (CA better on fuel, often not better overall) • Soil emissions • (CA often negative from nitrous oxide and methane) Answer: not always. System & Climate Dependent.

  3. Emission Mechanisms • Inputs: (energy) • Fuel, Machinery • Herbicides • Fertilisers • Outputs: (losses) • Gaseous nitrous oxide & methane • Nitrate in runoff and drainage • Nitrate in eroded soil } Easily Quantified For Known Systems. Substantial System Effects } Highly Variable, Poorly Understood. Very Large System Effects, Systems and Effects

  4. Generic Systems • Stubble mulching, 1 - 3 minimum-inversion tine or sweep tillage operations, and 1 – 3 herbicide weed control operations per crop. (most common). Tilled, Random Wheels • Zero tillage, herbicide weed control, soil disturbance at seeding, but occasional chisel tillage after wet harvests. (less common). Minimum Tillage, Random Wheels • Controlled traffic farming (CTF), herbicide weed control, minimal soil disturbance at seeding, all heavy wheels on permanent traffic lanes oriented for surface drainage, opportunity cropping. (least common, growing). Minimum Tillage, Precise Wheels

  5. Random Traffic Wheeling? >20% at Harvest >20% at Seeding ~ 5% at Spraying ~ 5% Logistics 50% Field Area Wheeled/Crop -- In Zero Tillage Wheel Effect Lasts >2 years at 20cm in cracking clay

  6. Header Width 9m,12m. CTF, Australia 2cm GPS Autosteer Track Width 3m Tyre Width 0.5m 20 Mg Axle Harvesters Track Width 3m Tyre Width 0.5m

  7. CTF Shanxi, China 2 Mg Axles (similar effects in top 10cm ) • CTF Planting Shanxi 1.2m Permanent Raised Bed Systems: Mexico Gansu, 1.2m

  8. Spreadsheet Assessment --Basis • Fuel energy CO2 • Herbicide energy CO2 • Fertiliser energy CO2 • Soil emissions. N2O, CH4 CO2-e =  {CO2 + (300 x N2O) + (23 x CH4) • Soil carbon, • Runoff, drainage water Quantified as } Comment Only Context: water limited, dryland grain production……… ….. but probably relevant to most cropping systems.

  9. Relative Performance, Generic Systems Comparing just the Seeding Operations Tullberg J.N. (2000) Traffic Effects on Tillage Energy. Journal of Agricultural Engineering Research 75(4).375-382. What happens to 50% wasted power?

  10. Profiles – White = Soil Solids Black = Air or Water Random Traffic Effects – Zero Tillage Plots Coarse Aggregates 24 cm Massive Structure Impact of Tractive Power Loss. Wheeled (4t Axle Once/year) Non-Wheeled 4- Years CTF .

  11. Relative Performance, Generic Systems Tullberg J.N., Yule D.F. and McGarry D. (2007) Controlled traffic farming— From research to adoption in Australia. Soil & Tillage Research 97 272–281 Side-by-side experiments don’t capture system effects.

  12. System Operations *Improved timeliness increases herbicide effectiveness. ** In-crop fertiliser more common in CTF DPIF (2008) Selection and matching of tractors and implements. http://www2.dpi.qld.gov.au/thematiclists/9155.html

  13. System Fuel Requirements DPIF (2008) Selection and matching of tractors and implements. http://www2.dpi.qld.gov.au/thematiclists/9155.html G.F. Botta, O. Pozzolo, M. Bomben, H. Rosatto, D. Rivero, M. Ressia, M. Tourn, E. Soza, J. Vazquez (2007) Traffic alternatives for harvesting soybean (Glycine max L.) Effect on yields and soil under a direct sowing system Soil & Tillage Research 96 145–154 Peter Bradley, P (2008) Contract Harvesting and Controlled Traffic Expenses and Costs. 6th Australian Controlled Traffic Farming Conference, 2008 32

  14. System Fuel Requirements DPIF (2008) Selection and matching of tractors and implements. http://www2.dpi.qld.gov.au/thematiclists/9155.html G.F. Botta, O. Pozzolo, M. Bomben, H. Rosatto, D. Rivero, M. Ressia, M. Tourn, E. Soza, J. Vazquez (2007) Traffic alternatives for harvesting soybean (Glycine max L.) Effect on yields and soil under a direct sowing system Soil & Tillage Research 96 145–154 Peter Bradley, P (2008) Contract Harvesting and Controlled Traffic Expenses and Costs. 6th Australian Controlled Traffic Farming Conference, 2008 32

  15. Herbicides* Zentner,R.P., Lafond, G.P.,Derksen, D.A.,Nagy,C.N., Wall,D.D., May, W.E. (2004) Effects of Tillage Method and Crop Rotation on Non-Renewable Energy Use Efficiency in the Canadian Prairies. Soil and Tillage Research 77; 125 – 136.

  16. Fertiliser** *Lefroy, T.(2007) Soil biology - Trials push beyond soil quick fix. Ground Cover Issue 68 - May - June 2007 *Des McGarry 2006 Soil compaction in cropping land . Natural Resources and Water. www.nrw.qld.gov.au/factsheets/pdf/land/l84.pdf *Ruwolt, R. (2008). CTF/No till Farming 2008 -- What We Learned? 6th Australian controlled traffic conference, Dubbo NSW. Proceedings, p.50. *Robert Q, Cannell, Robert K. Belford, Kenneth Gales,Colin W. Dennisa Robert D. Prewb Effects of Waterlogging at Different Stages of Development on the Growth and Yield of Winter Wheat J. Sci. Food Agric. 1980, 31, 117-132 **Zentner,R.P., Lafond, G.P.,Derksen, D.A.,Nagy,C.N., Wall,D.D., May, W.E. (2004) Effects of Tillage Method and Crop Rotation on Non-Renewable Energy Use Efficiency in the Canadian Prairies. Soil and Tillage Research 77; 125 – 136.

  17. Soil Emissions* *Vermeulen, G.D., Mosquera, J. (2008). Soil, crop and emission responses to seasonal-controlled traffic in organic vegetable farming on loam soil. In press, Soil Tillage Res., doi:10.1016/j.still.2008.08.008 ** Assumption. Increment between zero till and CTF will be the same as that between stubble mulch and CTF (based on drainage/infiltration conditions in CTF, stubble mulch, and zero till, determining the occurrence of near-saturated conditions. (see Rochette, P. (2008) No-till only increases N2O emissions in poorly-aerated soils. Soil & Tillage Research 101 97–100)

  18. Soil Emissions -Total * Nitrous oxide production occurs when excess nitrate is available at high levels of water-filled porosity. This will normally occur over a relatively short period between fertilizing and crop assimilation: Assumption -- 30 days. ** Methane absorption/emission occurs over a wider range of soil conditions: Assumption – 150 days.

  19. Total System Emissions – CO2-e Zero Tillage alone is not the answer. We must also stop Random Wheeling

  20. Soil Carbon Sequestration Difficult/Slow at < 400mm/yr rain, but optimised in CTF by: • Maximum Biomass Production (High WUE). • Maximum Standing Residue (Min Wheels, ) • Minimum Soil Disturbance (Zero Till) Advantages of Precise Interrow Seeding

  21. Runoff & Drainage Losses Pollution & Nutrient Loss Minimized in CTF by: • Max Infiltration (Residue, No Compaction) • Max Available Water Capacity (Soil Health, SOM) • Opportunity Cropping ( Timeliness, Precision) Relay Cropping

  22. conclusions • Input-related emissions (from fuel, herbicides and fertiliser) are demonstrably 20- 40% less from CTF zero till, compared with random traffic zero tillage or stubble mulch systems. • Soil emissions from CTF zero till systems are 30- 70% less than those from random traffic zero till. Emissions from stubble mulch tillage are substantially less than those from random traffic zero till. • Major mechanisms of random traffic effects on emissions include direct compaction effects on tillage energy, fertiliser efficiency and soil porosity, and indirect effects via soil health, and timeliness. • Biomass production is improved in CTF by minimising runoff, drainage (and pollution) with minimum soil disturbance to optimise soil carbon balance.

  23. Synythesis Major , Global Challenges: • Poor Energy Efficiency • Poor Fertilizer Efficiency • Poor Water Efficiency } All Lose >50% under Random Wheel Traffic All guarantee poor carbon balance Its not difficult to fix, if we try Thank You

  24. Thank You

  25. Acarina (mites) Collembola (springtails) Earthworms • Free-living nematode Aeration, Soil Strength, SOM?? • Plant parasitic nematode

  26. Uncontrolled Field Traffic After the flood -you can see every wheel pass

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