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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