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5. Cover Crops - Adame Hayes and Jake Munroe

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How to maximize nutrient benefits from cover crops.

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5. Cover Crops - Adame Hayes and Jake Munroe

  1. 1. Adam Hayes Soil Management Specialist Field Crops, OMAFRA Ridgetown Jake Munroe Soil Fertility Specialist Field Crops, OMAFRA Stratford Managing Cover Crops for Nutrient Benefits 1
  2. 2. Overview • Cover crop nutrient benefits – Erosion & phosphorus – Nitrogen – fixing and scavenging – Organic matter contribution – Reconnecting topsoil and subsoil • Management strategies to maximize benefits & minimize risk • Putting the pieces together 2
  3. 3. The original reason for cover crops Ditch Wind-blown soil Colin Little, LTVCA 3
  4. 4. Ditch Wind-blown soil Colin Little, LTVCA 9.4% OM 37 ppm P 282 ppm K 683 ppm Mg The original reason for cover crops 4
  5. 5. Soil isn’t moving on this field 5
  6. 6. 1/4 inch of rain in 10 minutes April 20, 2017 Craig Merkley, UTRCA 6
  7. 7. 1/4 inch of rain in 10 minutes April 20, 2017 Craig Merkley, UTRCA 7
  8. 8. 8
  9. 9. Cover Crops and Phosphorus Loss radish Rye + radish control rye vetch oat 9
  10. 10. Cover Crops and Phosphorus Loss • Light freeze thaw cycling – Cereal rye, hairy vetch & volunteer wheat • No increase in phosphorus leaching – Oats • Increase in water extractable P • P losses remained elevated over time • Harsh freeze thaw cycling – Oilseed radish • Greatest P concentrations released from root tissues 10
  11. 11. Cover Crops and Phosphorus Loss • Cereal rye and oilseed radish – Radish had more gradual leaching in mixture – Root samples P concentration not as high as in monoculture samples • 11 way mixture – Groups of frost susceptible species may act as a large source of P – More frost tolerant species in the mix could limit the potential for P leaching 11
  12. 12. Cover Crops and Phosphorus Loss • Phosphorus pool held in cover crops was much smaller than the surface soil pool • Overland flow P concentrations did not correlate with cover crop P 12
  13. 13. Cover Crops and Nitrogen 13
  14. 14. -40 -20 0 20 40 60 80 100 Red Clover-Fall Control -40 -20 0 20 40 60 80 100 Red Clover-Spring Control 1 2 -40 -20 0 20 40 60 80 100 No Cover LSD=27.99 LSD=28.99 Actual Nitrate Actual Ammonium Relative Nitrate Relative Ammonium -40 -20 0 20 40 60 80 100 -40 -20 0 20 40 60 80 100 Red Clover-Fall Control -40 -20 0 20 40 60 80 100 -40 -20 0 20 40 60 80 100 Red Clover-Spring Control 1 2 -40 -20 0 20 40 60 80 100 -40 -20 0 20 40 60 80 100 No Cover LSD=27.99 LSD=28.99 LSD=27.99 LSD=28.99 Actual Nitrate Actual Ammonium Relative Nitrate Relative Ammonium Actual Nitrate Actual Ammonium Relative Nitrate Relative Ammonium -40 -20 0 20 40 60 80 100 Perennial Ryegrass -40 -20 0 20 40 60 80 100 Oilseed Radish -40 -20 0 20 40 60 80 100 16/9/03 6/10/03 23/10/0314/11/03 12/4/04 26/4/04 10/5/04 26/5/04 9/6/04 21/6/04 19/7/04 1/9/04 29/11/04 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 Oats -40 -20 0 20 40 60 80 100 -40 -20 0 20 40 60 80 100 Perennial Ryegrass -40 -20 0 20 40 60 80 100 -40 -20 0 20 40 60 80 100 Oilseed Radish -40 -20 0 20 40 60 80 100 -40 -20 0 20 40 60 80 100 16/9/03 6/10/03 23/10/0314/11/03 12/4/04 26/4/04 10/5/04 26/5/04 9/6/04 21/6/04 19/7/04 1/9/04 29/11/0416/9/0316/9/03 6/10/036/10/03 23/10/0323/10/0314/11/0314/11/03 12/4/0412/4/04 26/4/0426/4/04 10/5/0410/5/04 26/5/0426/5/04 9/6/049/6/04 21/6/0421/6/04 19/7/0419/7/04 1/9/041/9/04 29/11/0429/11/04 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 0 200 100 Oats Oats Perennial Ryegrass Oilseed Radish Red Clover Spring Control Red Clover Fall Control No Cover Timing of Kill and Timing of N Release Mid Sept 03 mid Nov 04 14
  15. 15. 186 157 175 217 202 217 190 191 198 162 184 214 228 225 200 200 100 120 140 160 180 200 220 240 GrainYield(bu/ac) 2010 2011 Corn Yields after Wheat +/- Red Clover Ridgetown 2010-16 +RC 2012 Ave Hooker (UG Ridgetown) Fertilizer N applied to all plots @ 180-240 lbs N/ac (N sufficient) * = difference significant at P=0.05 2013 +RC +RC +RC +RC @cropdoc2 +RC +RC +RC 2014 2015 2016 * 15
  16. 16. 16
  17. 17. Nitrogen Credit from Legume Mixture? 17
  18. 18. Cover Crop Rating ARG Barley, oats, wheat (W & S). triticale Millet Rye Sorghum–Sudangrass, Sudangrass Buckwheat Mustards Oilseed radish Canola, forage turnip Legumes 18 Nitrogen Scavengers
  19. 19. Phosphorus and Potassium Uptake • Canola and buckwheat – release organic acids in the root zone making insoluble phosphorus more available • Hairy vetch – good phosphorus scavenger • Sweet clover – greater ability to extract nutrients from insoluble minerals than most cover crops • Rye – good for potassium uptake • Brassicas – quick release of nutrients once plant is dead 19
  20. 20. Cover Crops and Organic Matter • Corn-soybean rotation will not maintain organic matter levels • “You really want to grow your organic matter in place.” – Dr. Ray Weil, FarmSmart 2018 20
  21. 21. New Understanding of Organic Matter 21 Soil microbes and their by-products make up a large proportion of soil organic matter Physical protection of carbon within soil aggregates is important
  22. 22. New Understanding of Organic Matter 22 Roots contribute more to soil organic matter than shoots
  23. 23. Soil Organic Matter: Inputs and Outputs Tillage Erosion Whole plant removal Poor productivity Soil conversation High productivity Cover crops 23
  24. 24. Maximizing Cover Crop Biomass • Using a post-wheat window • Finding other cover crop opportunities in rotation • Delaying spring termination 24
  25. 25. Brant SCIA Termination Timing Trial 3 replicated, randomized strips in each field • Cereal rye ahead of soybeans • 3 termination timings – 2.5 weeks before planting – 1.5 weeks – “Plant green” 25
  26. 26. Cover Crop Biomass 0 5 10 15 20 25 30 0 200 400 600 800 1000 1200 1400 %CanopyCover Drybiomass(lbs/ac) Biomass (lbs/ac) Canopy Cover % 2.5 wk 1.5 wk Plant Green 26
  27. 27. Cover Crop Biomass 0 5 10 15 20 25 30 0 200 400 600 800 1000 1200 1400 %CanopyCover Drybiomass(lbs/ac) Biomass (lbs/ac) Canopy Cover % 1.5 wk Plant Green 3X more biomass in 11 days 27
  28. 28. 0 10 20 30 40 50 60 2 week 1 week Plant Green Soybeanyield(bu/ac) Termination timing before planting a a a Effect of Termination Timing on Yield 57 bu/ac 58 bu/ac 60 bu/ac 28
  29. 29. What Does Other Research Say? Impact of rye termination timing on soy yield 29
  30. 30. 30
  31. 31. Biomass Production from Mixtures 31
  32. 32. Reconnecting Topsoil and Subsoil Topsoil (A horizon) Subsoil (B horizon) High nutrient concentration Low nutrient concentration, but large volume 32
  33. 33. Reconnecting Topsoil and Subsoil 33 100-200 lbs/acre N Subsoil nitrate that would otherwise leach over winter NO3 NO3 NO3 P P K K NO3 Nutrients moved from areas of low crop root density to topsoil (high density)
  34. 34. Restricted Rooting Limits Nutrient Uptake 34
  35. 35. 35
  36. 36. Biological Activity OM Turnover ↑Nutrient Cycling Steps to Maximum Soil Health ↑Soil Structure ↑ Water Availability Adapted from Jerry Hatfield 36
  37. 37. Fairview Farms: Bill and Earl Elgie, Dresden • Mixed farming – Steers, vegetables, field crops, maple syrup • Nearly all (700 acres) in cover crops – Rye, radish, buckwheat, red clover • Manure from off-farm, – Applied beyond home farm to maintain soil health • Reduced tillage system Soil health is high: non-responsive to N fertilizer 37
  38. 38. Terwidlen Farms: The Barrie Brothers Bowmanville
  39. 39. Terwidlen Farms: The Barrie Brothers Bowmanville • Dairy/cash crop & long-term no till • Soybean – Oats/Winter Wheat (underseeded Red Clover) – Red Clover (1st cut hay, 2nd seed) – Winter Wheat (Red Clover) – Grain corn • Nitrogen rate in corn: 100-110 lbs/ac N • Average corn yield: 170 bu/ac • Nitrogen rate in wheat: 45 lbs/ac N • Average wheat yield: 85+ bu/ac
  40. 40. Summary • Cover crops can help recycle nutrients by: – bringing them up from the subsoil – reducing erosion – building SOM and increasing soil biological activity • Cover crops reduce nitrate leaching by: – taking up available nitrate for their own needs – using soil moisture reducing the amount available to leach nutrients • Keeping P in organic form is the most efficient way to keep it cycling, so the return of plant materials helps maintain P availability 40
  41. 41. Sources of Information • OMAFRA – Cover Crop Webpage – Agronomy Guide for Field Crops, Publication 811 • Managing Cover Crops Profitably • plantcovercrops.com • Midwest Cover Crops Council http://www.mccc.msu.edu/ 41
  42. 42. 42 OMAFRA Soil Health Resources
  43. 43. Questions? 43 adam.hayes@ontario.ca 519 674 1621 jake.munroe@ontario.ca 519 301 0548

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