Ecological aspects of Mob Grazing 2012

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PowerPoint about the Ecological Aspects of Mob Grazing, by Prof. Edward Rayburn for the Greenbrier Valley Pasture Network, 2012

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Ecological aspects of Mob Grazing 2012

  1. 1. Ecology ofHigh Density or Mob Grazing Ed Rayburn Appalachian Grazing Conference March 4-5, 2011 Morgantown, WV
  2. 2. Pasture-Based Livestock Producers• In business harvesting solar energy.• Converting solar energy into food and fiber products for people.• Manage – plants to optimize harvest of solar energy, – animals to transfer that energy into livestock products, – cycling of mineral nutrients in the landscape – to make business socially, economically, and environmentally sustainable.• Are pasture ecosystem managers.
  3. 3. What we will cover• Pasture Ecosystem• Ecological principles/tools – Light interception with height and date – Tolerance to shading – Selective grazing – Stocking density• Management Goals – Toxic tall fescue management – Legume establishment – Developing soil organic matter – Substitution for bush-hogging – Animal performance (now vs. long term)
  4. 4. Pasture Ecosystem• Climate (average weather)• Weather (this year)• Plants• Grazing animals• Soil• Humans
  5. 5. Pasture Ecosystem• Plants – producers harvest sunlight fix nitrogen cycle nutrients – forage quality & anti-quality – plant morphology grass, legume, forb, shrub, tree (succession) tall vs. short rhizome vs. bunch fibrous vs. tap root “plastic” growth habit – plant life history; perennial vs. annual
  6. 6. Pasture Ecosystem• Grazing animals – primary consumers (cows, sheep, goats, others) – age, production rate (maintenance, milk, finishing)• Grazing preferences – animal species vs. learned behavior – ability to selectively graze – rumen size : body size and forage preference or tolerance• Movement while grazing; cows walk 4 ways – in file / cow-path – grazing “front” at low stock densities – quite, tight “mob” at high stock density – stampede
  7. 7. Pasture Ecosystem• Soil – parent material, landscape position – depth, texture, surface and internal drainage – organic matter – soil critters; consumers, decomposers, pests, diseases
  8. 8. Pasture Ecosystem• Humans – predators – managers: intentional & unintentional – fire • for 10,000 yrs. • savanna & prairie vs. forest • bison vs. cattle – fences • stocking rate • stocking density – grazing management (2 independent factors) • grazing timing – length of regrowth interval, plant growth cycle, time of year • (CHO cycle, tiller production, seed production) • grazing intensity - degree of defoliation – pasture management and plant species equilibrium • grazing, multi species grazing, fertilization/liming, fire, herbicides,
  9. 9. Ecological principles/tools• Light interception with height and date• Tolerance to shading• Selective grazing• Stocking density
  10. 10. Light Interception by Pasture Height and Season 1.20 1.00Light Interception 0.80 Apr & Jun May 0.60 Jul & Aug Sep & Oct 0.40 0.20 0.00 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 Ruler Height inches
  11. 11. Species Differ in Tolerance to Long Regrowth Periods/ShadingTolerant (hay type) Intolerant (pasture type) – Smooth bromegrass – Tall fescue – Timothy – Orchardgrass – Reed canarygrass – Perennial ryegrass – Quackgrass – Kentucky bluegrass – Red clover (+/-) – White clover – Alfalfa – Birdsfoot trefoil – Native WS grasses
  12. 12. Selective Grazing• The ability of animals to select and consume forage of higher quality than the average forage quality in the pasture.
  13. 13. Forage Mass vs. HeightRuler Ht FM/In.Ht. FM/acre 1 382 382 2 371 741 3 359 1076 4 347 1387 5 335 1674 6 323 1938 7 311 2178 8 299 2394 9 287 2586 10 275 2754 11 264 2899 12 252 3019
  14. 14. Diet Selection Based onInitial Pasture Quality and Utilization Pasture Utilization Whole Pasture 0.20 0.40 0.60 0.80 TDN 60 68 65 63 60 65 73 71 68 66 70 79 77 74 72
  15. 15. Management Goals• Toxic tall fescue management• Legume establishment• Developing soil organic matter• Substitution for bush-hogging• Animal performance (now vs. long term)
  16. 16. Application to toxic tall fescue management• Establish a long regowth period to open tall fescue stand through self-shading• Over-seed forage species that tolerate long regrowth periods (may already be in stand)• Use high stock density grazing to utilize the forage, walk-in the seed or just open the stand for the desired species needed to reduce the toxic tall fescue
  17. 17. Species Differ in Tolerance to Long Regrowth Periods/ShadingTolerant (hay type) Intolerant (pasture type) – Smooth bromegrass – Tall fescue – Timothy – Orchardgrass – Reed canarygrass – Perennial rye grass – Quackgrass – Kentucky bluegrass – Red clover – White clover – Alfalfa – Birdsfoot trefoil – Native WS grasses
  18. 18. Application to legume establishment• Establish a long regowth period to open forage stand at soil level through shadingOr• Use normal rotation cycle• Overseed legume species adapted to soil and planned long-term management (at “proper” time of year)• Use high stock density grazing to utilize the forage and walk the seed into the soil
  19. 19. Clover seedlings about 9 weeks old
  20. 20. August walk-in seeding 1-year latter
  21. 21. Developing soil organic matter
  22. 22. Why Is SOM Important? 50Avail. Water Holding Capacity% 45 40 35 30 25 20 15 10 5 0 0 2 4 6 8 10 SOM%
  23. 23. Soil Organic Matter Affected by:• Past management (fertility and grazing) – Adequate fertility (applied, recycled) stimulates plant growth – Rotational grazing to proper height stimulates SOM• Local environment (temperature rainfall) – High elevations (further north) have low temperature high rainfall beneficial to development of SOM – Low elevations (further south) have higher temperatures more SOM loss hard to keep high SOM.
  24. 24. Soil Organic Change with Adoption of Rotational Grazing Soil Organic Matter % 0.0 2.0 4.0 6.0 8.0 10.0 12.0 0Soil Depth Inches 6 1995 12 1999 1995est 18 24
  25. 25. What in the soil do we want to feed? (feed them and they will come)• Night crawlers for • Bacteria and fungus aeration and bacteria for soil structure – Legumes – Grass – Young grass – Older high fiber – Roots material – Roots
  26. 26. Application to developing SOM• Establish an appropriate regowth period to maximize root health and optimize forage growth and quality for the local environment• Use high stock density grazing at density appropriate for livestock production goals to utilize the forage, compress thatch to the ground, and distribute manure and urine evenly over landscape
  27. 27. Substitution for bush-hogging or herbicide
  28. 28. Bracken fern in no-tilled pasture.
  29. 29. Bracken fern not in no-tilled pasture.
  30. 30. Application to bush-hogging• Use high stock density grazing at heavy stocking density to utilize the forage, walk thatch and seed heads into the ground, and distribute manure and urine evenly over landscape• Know life history of plants being worked with• Consider multispecies grazing
  31. 31. Animal performance (now vs. long term)• Increasing nutrient requirement – Dry cow mid-trimester – Dry cow last-trimester – Early lactation cow – Stocker steer – Backgrounding calf – Dairy cow• First 4 can be made to work at times• Make animals work strategically to develop better forage for the future
  32. 32. Forage Mass vs. HeightRuler Ht FM/In.Ht. FM/acre 1 382 382 2 371 741 3 359 1076 4 347 1387 5 335 1674 6 323 1938 7 311 2178 8 299 2394 9 287 2586 10 275 2754 11 264 2899 12 252 3019
  33. 33. Stocking Density and Time vs. Grazing Pressure/Utilization• 31 animals at 1450 lbs avg. wt.• ~45,000 lbs LW on 1.25 acres• ~36,000 lbs LW/acre• 900 lbs DMI / 24 hr at 2.5%BW DMI• 1800 lbs DMI / 48 hrs• Entry ht 10” or 2754 lbs/a• Exit FM 954 lbs/a or 2.6”
  34. 34. Stock Density for 24 Hours at 2.5% DMI on 10” Tall Pasture (2750 lbs DM/acre) and its Affect on Utilization and Residual Forage Height Residual Residual forage Stocking forage heightForage Ht density mass Utilization est. 10 40000 1750 0.36 5.2 10 50000 1500 0.45 4.4 10 60000 1250 0.55 3.5 10 70000 1000 0.64 2.8 10 80000 750 0.73 2.0
  35. 35. Healthy Soil Ecology Balance of• Food supply (organic matter with adequate macro- and micro mineral nutrients)• Physical environment above and below ground (cover and habitat at all scales)• Healthy consumers, omnivores, predators, and predators of predators (diversity)• Chemical environment (soil oxygen, pH, fertility)• Thermal and moisture environment
  36. 36. Management Needed to Help the System (a)• Soil pH 6.0-7.0 depending on the legume• Adequate not excessive soil P and K• Inoculate legume seed with proper bacteria• Manage nutrients on the farm – (recycle manure, urine, and organic residues)• Proper grazing management – timing and intensity suitable for the forage mixture• Proper fall grazing – develop tillers in grasses and stolons of white clovers – reduce adult clover root curculio activity
  37. 37. Take Home• Above ground we manage plants with animals to capture solar energy, convert it into marketable livestock products, cycle nutrients so that our pasture system can be sustainable.• This management influences soil organic matter to feed macro- and microorganisms in the soil.• This affects the soil’s physical condition, availability of macro- and micronutrients and soil moisture to plants.• Understanding how management affects the soil community assists us in our management of the entire pasture ecosystem.
  38. 38. High Density or Mob Grazing Can Be a Useful Management Tool• To accomplish management goals – Toxic tall fescue management – Legume establishment – Developing soil organic matter – Substitution for bush-hogging• Keep in mind animal performance (now vs. long term)• Using ecological principles/tools – Light interception with height and date – Tolerance to shading – Selective grazing – Stocking density and hoof action/treading• Stock density, utilization, and regrowth period are independent management practices with their own outcome.

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