Basic Civil Engineering first year Notes- Chapter 4 Building.pptx
Ecological aspects of Mob Grazing 2012
1. Ecology of
High Density or Mob Grazing
Ed Rayburn
Appalachian Grazing Conference
March 4-5, 2011
Morgantown, WV
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. 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)
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. 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
17. Management Goals
• Toxic tall fescue management
• Legume establishment
• Developing soil organic matter
• Substitution for bush-hogging
• Animal performance (now vs. long term)
18. 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
19. Species Differ in Tolerance to Long
Regrowth Periods/Shading
Tolerant (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
20. Application to legume
establishment
• Establish a long regowth period to open forage
stand at soil level through shading
Or
• 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
24. Why Is SOM Important?
50
Avail. Water Holding Capacity%
45
40
35
30
25
20
15
10
5
0
0 2 4 6 8 10
SOM%
25. 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.
27. 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
28. 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
32. 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
33. 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
36. 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”
37. 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 height
Forage 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
38. 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
39. 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
40. 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.
41. 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.
