Richard Teague - Grazing Down the Carbon: The Scientific Case for Grassland Restoration

Improving Life through Science and Technology

Grazing Down the Carbon: The Scientific Case for Grassland Restoration

Biodiversity for a Livable Climate15th November 2014

Boston

Richard Teague, Texas A&M AgriLife Research, Vernon

Overview

Need to improve ecosystem function

Big problems and big opportunities

Testing a ranch scale hypothesis

Published research results

Conclusions

Importance for climate change mitigation

Regenerative management to mitigate agriculture’s Carbon footprint

Restore Ecosystem Function

• Soil formation

• Soil retention

• Biodiversity

• Primary production

• Water cycling

• Nutrient cycling

• Habitat provision

• Fresh water

• Food, fiber

• Water purification

• Climate regulation

• Temperature moderation

• Biological control

• Soil maintenance

• Erosion control

• Flood mitigation

• Seed dispersal

• Pollination

How sustainable is current agriculture?

Modern agriculture has greatly increased human well-being and wealth

But production of food has come at considerable environmental and social cost

Negative effects include: disruption of hydrological and biogeochemical processes, soil erosion and impoverishment, excessive water use and aquifer depletion, contamination of soil and water by fertilizer and biocides, air pollution from aerosols, loss of pollinators loss of habitat and biodiversity, and increased GHG emissions

The role of forages and grazers

In contrast, ecologically sensitive, regenerative management of ruminants in crop and grazing agriculture contributes positively to critical ecosystem benefits

Conservation management measures and inclusion of perennial forages in cropping systems have been demonstrated to reduce negative impacts

My Goal

Find out : Why there is a discrepancy between some

research and rancher achievements

What is the best that management can achieve to sustain: livelihoods

delivery of ecosystem goods and services

Infiltration with Vegetation CompositionThurow 1991

90% of Soil function is mediated by microbes

Microbes depend on plants

So how we manage plants is critical

Indicator: Soil Temperature

At 70 oF, 100% of Soil moisture is used for growth.

At 100 oF, 85% of Soil moisture is lost and 15% is used for growth.

At 115 oF, microbes begin to breakdown, and

At 140 oF they die.

Essential 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 resilience and productivity.

Improving Rangeland Soil Health

Improve soil microbe function by:

• Improving plant cover• Perennial plants rather than annuals

• Manage for most productive plants

• Leave adequate plant residue

• Minimizing bare ground - plant and litter cover

• Grow plants for as many months 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

Grazing PatternNovember to March < 10

10-50

50-150

> 150

Days present

Water point

Senft et al. 1985320 acres10-12 stockers

Previous research on multi-paddock grazing

Teague et al. 2011; 2013

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

Animals: Graze more of the whole landscape Select a wider variety of plant species

Planned multi-paddock grazing

Ranch road

Landscape impact of continuous grazing

Existing fenceElectric fence

Water point

Restoration using multi-paddock grazing

Degraded tallgrass prairie18 paddocks + water pointManaged to improve plant species

Noble Foundation, Coffey Ranch

Restoration using multi-paddock grazingNoble Foundation, Coffey RanchCharles Griffith, Hugh Aljoe, Russell Stevens

Summary of Managing for Desired Outcomes

Match animal numbers to available forage

Spread grazing over whole ranch

Defoliate moderately in growing season

Short grazing periods

Adequate recovery before regrazing

Graze again before forage too mature

Adaptively change these elements according to changing conditions

Teague et al. 2013

Managing proactively for best results

% Leaf Volume Removed

10%

20%

30%

40%

50%

60%

70%

80%

90%

% Root Growth Stoppage

0%

0%

0%

0%

2-4%

50%

78%

100%

100%

Range ConditionExcellent Good Poor

0

10

20

30

40

50

60

70

80

0 5 10 15 20 25

days of grazing in cycle

kg

gain

/he

ad

fo

r s

eas

on Low SR

High SR

Barnes and Denny cited by Norton 2003

Days of grazing before recovery

Managing high animal performance

0

10

20

30

40

50

60

70

80

0 50 100 150

days of rest in cycle

kg

gain

/he

ad

fo

r s

eas

on

Barnes and Denny cited by Norton 2003

Days of recovery in cycle

Managing high animal performance

High-density grazing

Low-density, light continuous grazing

What we need to know:

What are the mechanisms causing degradation?

What management reverses degradation?

How good is Planned Holistic Management as a restoration and management tool?

Where does it work and not work?

How does it need to be managed to make it work as well as it can?

Understanding causal mechanisms is critical to knowing how to manage to regenerate from a degraded situation.

Equilibrium of soil formation

and soil erosion

Decreased cover, productivity and SOC

Deteriorated soil structure

Decreased infiltration and water

holding capacity

Degradation Spiral

Decreased cover and SOC

We know what causes this at

the small scale

Increased cover and SOC

Regeneration Spiral

Increased cover, productivity and SOC

Enhanced soil structure

Enhanced infiltration and water holding

capacity

How to manage for this at the ranch scale?

Thurow 1991; Teague et al., 2011

Managed with Holistic Planned Grazing

No stock for decades

Semi-arid Karroo region in South AfricaAverage rainfall = 14”

H2O, CO2H2O, CO2

(McNaughton, 1988; Fynn, 2008)

Planned multi-paddock grazing, when adaptively managed to give best vegetation and animal performance, has the potential to produce superior long-term:

1. Conservation and restoration of resources;

2. Ecosystem goods and services; and

3. Ranch profitability

We tested the hypothesis that at the commercial ranch scale:

An Alternate Ranch Scale Hypothesis

Jack county

Parker county

Cooke county

Influence of multi-paddock grazing on soil and vegetation

Influence of multi-paddock grazing on soil and vegetation

In each county on 3 neighbouring ranches :Continuous graze @ ± 20 ac/AU (Best in class continuous)Continuous graze @ ± 10 ac/AU (Most common management)Planned multi-paddock @ ± 10 ac/AU (Best in class)

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

bb

P = 0.0006

HeavyMulti-camp

Teague et al. 2011

ParameterGrazing 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

Penetration Resistance (compaction)

0

50

100

150

200

250

300


Energ

y (Joules)

a

c

b

P = 0.0005

HeavyMulti-camp

Total Carbon Stock in Top 90 cm (t/ha)

Heavy continuous

Light continuous

Multi-paddock

Russ Conser SHELL pers comm

160

140

120

100

80

60

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

HeavyMulti-camp

Mid Grasses

0

500

1000

1500

2000

2500

Heavy

Continuous

Heavy Rotation Light Continuous

Biomass

(kg h

a-1)

b

ab

aP = 0.188

HeavyMulti-camp

Annual Forbs

0

100

200

300

400

500

600


Biomass

(kg h

a-1)

a

b b

P = 0.014

HeavyMulti-camp

Profit Scenarios for HC or LC farms (20-year scenario) 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 unchanged -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 unchanged -0.31 0 -0.31

LC → MP 16.29 0.09 16.38

LC → HC -2.39 -28.77 -31.16

Both ecological condition and profitability increase with increasing number of paddocks

Adjusting HPG management with changing conditions increases ecological condition and profitability

Short periods of grazing with adequate recovery gave the greatest profit and improved ecological condition

Profitability is decreased if recovery is too long

HPG management ameliorated impact of increasing stocking rate in proportion to number of paddocks

Journal of Environmental Management 2014

Simulation modelling results

Successful multi-paddocks managers use: Flexible stocking to match forage availability

Spread grazing over whole ranch

Moderate grazing during growing season

Short graze periods

Allow recovery before regrazing

Graze again before forage too mature

Adaptively adjust to prevailing conditions

Use multiple species

Summary

Appropriate regenerative grazing management:

Sequesters more soil carbon

Improves watershed function

Improves species composition

Stabilizes soil and soil fertility

Enhances wildlife and biodiversity

Improves economic returns while improving the resource base

Conclusions

Improving Pasture Soil Health

Improve soil microbe function 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 months each year

Delgado et al 2011; Rodale 2014; Jones, 2014

Soil health differences due to management

Christine Jones, 2014 Multi species pasture

High density grazing

Using regenerative cropping and grazing management can:

Build SOC levels and soil microbial functions

Control erosion more effectively

Build soil fertility

Reduce damaging inputs

Enhance watershed hydrological function

Increase biodiversity

Could result in agricultural soils being a net GHG sink rather than a major GHG source

Importance for Ecosystem Function?

Northern Great Plains carbon sinks and emissions of:

Light continuous grazing -0.783 tons CO2eq /ha/yr

With enteric methane of 0.176 tons CO2eq /ha/yr

Heavy continuous grazing -0.618 tons CO2eq /ha/yr

With enteric methane of 0.484 tons CO2eq /ha/yr

Liebig et al., 2010

Data from pasture and southern tallgrass prairie

Best pasture management sequestered 11 tons CO2eq /ha/yr

Best multi-paddock grazing on prairie sequestered 11 tonsCO2eq /ha/yr more than heavy continuous grazing

Teague et al., 2011

Conant et al., 2001

Importance for climate change mitigation

Soil Health for climate change mitigation?

Soil Health for Climate Change Mitigation?

EPA 2013; Lal 2003

Current Reduce Ruminants

-3.0 t C ha-1 yr-1 for 263 mil ha


Conant et al., 2001; Teague et al., 2011

25% Regenerative cropping and

grazing



-3.0 t C ha-1 yr-1 for 263 mil ha

Conant et al., 2001; Teague et al., 2011


grazing


grazing


grazing


Using regenerative cropping and grazing management to:

Build SOC levels and soil microbial functions

Control erosion more effectively

Could result in soils being a net sink for agricultural GHGs rather than a major source of GHGs as at present.

Importance for Climate Change Mitigation?

Future Management Research……………….(1)

Research needs to investigate:

How good is Holistic Planned Grazing as a restoration and management tool?

What multi-paddock management best reverses the causes of degradation?

Where does it work and not work?

How does it need to be managed to make it work as well as it can?

Include ranch-based research at scale of management

Use retrospective, remote sensing to evaluate 20-year impacts of different management at landscape scale

Develop and test theories to check conclusions for inconsistencies with evidence from other sources

Corroborate output of biological models with field results from commercial ranches under a range of management strategies

Use models to determine what combination of management choices yields superior results?

Future Management Research……………………..(2)

END