improving soil health with grazing - leon...
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Improving Life through Science and Technology
Improving Soil Health with Grazing
Soil Health Workshop
Gatesville, TX 2015 Richard Teague, Texas A&M AgriLife Research, Vernon
90% of Soil function is mediated by microbes Microbes depend on plants So how we manage plants is critical
Infiltration with Vegetation Composition Thurow 1991
The Four Ecosystem Processes
1. Energy flow - Maximize the flow of solar energy through plants and soil.
2. Water cycle - Maximize capture and cycling of water
through plants and soil. Reduce export and import.
3. Mineral cycle - Maximize cycling of nutrients through plants and soil.
4. Community dynamics - High ecosystem biodiversity with more complex mixtures and combinations of desirable plant species leads to increased stability and productivity
To improve Soil Health
Improve soil microbe population by:
• Keeping the 4 ecosystem processes functioning
• Improving plant cover • Perennial plants rather than annuals
• Manage for most productive plants
• Leave adequate plant residue
• Minimizing bare ground
• Manage for plant growth for as many days each year as possible
Edwards Plateau Ranch 3-D View w/ GPS Locations
1. 39% area used
2. 41% GPS points on 9% area
3. SR: 21 ac/cow
4. Effective SR: 9 ac/cow
Landscape impact of continuous grazing
Previous research on multi-paddock grazing
Many Grass farmers use MP grazing successfully
Most conservation award winners use MP grazing
Planned multi-paddock grazing
Manager can control: How much is grazed The period of grazing, and The length and time of recovery Use livestock to enhance wildlife habitat
Animals: Graze more of the whole landscape Select a wider variety of plant species
Landscape impact of continuous grazing
Go-back field 18 paddocks + water points Managed to IMPROVE plant species
Noble Foundation, Coffey Ranch
Restoration using Holistic grazing
Restoration using multi-paddock grazing Noble Foundation, Coffey Ranch Charles Griffith, Hugh Aljoe, Russell Stevens
Restoration using Holistic grazing
Managing for Desired Outcomes
Match animal numbers to available forage
Spread grazing over whole ranch
Defoliate moderately in growing season
Use short grazing periods
Adequate recovery before regrazing
Graze again before forage too mature
Planned multi-paddock grazing
Ranch road
Landscape impact of continuous grazing
Existing fence Electric fence
Water point
Jack county
Parker county
Cooke county
Influence of multi-paddock grazing on soil and vegetation
Influence of multi-paddock grazing on soil and vegetation
Neighbouring ranches in each county: Planned HM graze @ heavy SR (± 10 ac/AU) Continuous graze @ heavy SR (± 10 ac/AU) Continuous graze @ light SR (± 20 ac/AU)
Grazing treatment at least 10 years
0
5
10
15
20
25
30
35
40
Heavy Continuous Heavy Rotation Light Continuous
Bare
gro
und (%)
Bare Ground
a
b b
P = 0.0006
Heavy Multi-camp
Parameter
Grazing Management Heavy
continuous Light
continuous Multi-
paddock Grazing
exclosure
Total bacteria (g m-2) 82a 74a 78a 98a
Total fungi (g m-2)
97b 98b 174a 105ab
Fungi to Bacteria ratio 1.2b 1.1b 3.1a 0.7b
Soil Microbes
Importance of Fungi
Fungi provide: Access and transport nutrients
Extend root volume and depth
Exude glomalin to enhance soil C
Increase water and nutrient retention
Increase drought resistance
Plant growth highest with highest fungal – bacterial ratio
Killham 1994; Leake et al. 2004; Averill et al. 2014; Johnson 2014
Penetration Resistance
0
50
100
150
200
250
300
Heavy Continuous Heavy Rotation Light Continuous
Energ
y (Joules)
a
c
b
P = 0.0005
Heavy Multi-camp
Aggregate Stability
0
20
40
60
80
100
120
Heavy Continuous Heavy Rotation Light Continuous
%P = 0.295
b ab a
Heavy Multi-camp
0
5
10
15
20
25
30
g /
m2 (fo
r 1 h
our)
Sediment loss
P = 0.05
Heavy Continuous
Light Continuous
Heavy Rotation
ab
b
a
Heavy Multi-camp
Soil Carbon, Nutrients and Water
Parameter
Heavy
Continuous
Light
Continuous
Multi-paddock
Soil Organic Matter
3.1b
4.4b
4.86a
Cation Exchange Capacity
24.6b
23.7b
27.4a
Water holding (Gal/acre) 55,700 79,059 87,324
Tall Grasses
0
500
1000
1500
2000
2500
3000
Heavy
Continuous
Heavy Rotation Light Continuous
Biomas
s (k
g ha-
1)
b
a
b
P = 0.003
Heavy Multi-camp
Mid Grasses
0
500
1000
1500
2000
2500
Heavy
Continuous
Heavy Rotation Light Continuous
Biomass
(kg h
a-1)
b
ab
a P = 0.188
Heavy Multi-camp
Annual Forbs
0
100
200
300
400
500
600
Heavy Continuous Heavy Rotation Light Continuous
Biomass
(kg h
a-1)
a
b b
P = 0.014
Heavy Multi-camp
Soil Carbon, Nutrients and Water
Parameter
Heavy
Continuous
Light
Continuous
Multi-paddock
Soil Organic Matter
3.1b
4.4b
4.86a
Cation Exchange Capacity
24.6b
23.7b
27.4a
Water holding (Gal/acre) 55,700 79,059 87,324
Grazing Management impact on Water Runoff
Grazing period
ET
Percolation
Groundwater flow
Surface runoff
LCA Profit Scenarios (20-year) for HC or LC farms under a CO2 price of $6 per ton
Initial Farm
management
Practice Change
Economic
Profit
($ ha-1)
Carbon
Profit
($ ha-1)
Total
Profit
($ ha-1)
Best
Choice
Initially
Practicing HC
HC unchan -2.39 0 -2.39
HC → MP 16.29 32.97 49.26 HC → LC -0.31 28.77 28.46
Initially
Practicing LC
LC unchan -0.31 0 -0.31
LC → MP 16.29 0.09 16.38 LC → HC -2.39 -28.77 -31.16
It takes a minimum of 10 paddocks just to stop overgrazing
Ranchers with 8 or fewer paddocks are not rotationally grazing, but rotationally overgrazing
To support decent animal performance takes 14-16 paddocks
The most rapid range improvement takes 30 paddocks
The biggest decrease in workload and greatest improvement has been with > 50 paddocks
Dave Pratt, Ranch Management Consultants, rancher survey
What we have learnt from ranchers…...1
The fastest, cheapest way to create more paddocks is combining herds
1 herd reduces workload a lot; checking 4 herds of 200 animals takes much longer than 1 herd of 800
Productivity per acre is improved without decreasing individual animal performance
Carrying capacity and total productivity are greatly increased at low cost
Long recovery periods are critical
Do not move to the adjacent paddock but to the paddock that has recovered the most
Dave Pratt, Ranch Management Consultants, rancher survey
What we have learnt from ranchers…...2
High Density Grazing in higher rainfall ecosystems
Neil Dennis, SE Saskatchewan
Flexible management
Temporary electric fence
Slew
Water
Low density grazing High density grazing
Earthworm castings and proliferation of forage species
Cover crop with 25 species
Bismarck, ND
Mob grazed
Moving to the next paddock
Is this wasted forage?
8-fold increase in infiltration
Jay Fuhrer, NRCS, North Dakota
Regenerative Multi-Paddock grazing can:
Build SOC levels and soil microbial function
Enhance water infiltration and retention
Build soil fertility
Control erosion more effectively
Enhance watershed hydrological function
Improve economic returns while improving the resource base
Enhances wildlife and biodiversity
Result in grazed soils being a net greenhouse gas sink
Importance for Ecosystem Function?
Successful multi-paddocks managers use:
Flexible stocking to match forage availability and animal numbers
Spread grazing over whole ranch
Moderate grazing during growing season
Short graze periods
Allow recovery before regrazing
Graze again before forage too mature
Use multiple livestock species
Conclusions
To improve pasture soil health
Improve soil microbe population by: • Perennial plants rather than annuals
• Manage for most productive plants
• Leave adequate plant residue
• Use diverse species mixes and cover crops
• Eliminate tillage
• Minimize bare ground
• Use organic soil amendments
• Reduce N-fertilizer use
• Grow plants for maximum days each year
Delgado et al 2011; Rodale 2014; Jones, 2014
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