Grazing Management For Healthy Watersheds

Dr. M. Karl WoodDirector

Water Resources Research Institute

New Mexico State University

What is a healthy watershed?

Desired Functioning Condition?

What are the Goals?

Are the Goals Obtainable and Sustainable?

Watershed Goal?

ResourceExploitation

Sustainable Use

ResourceProtection

Exploitation Sustainable Protection

Use

Watershed Goal?

The extremes result in attitudes of supremacy

From: Thompson, P.B. 1995. The Spirit of the Soil - Agriculture and Environmental Ethics. Routledge Publ. New York, New York

New Mexico Historical PerspectiveWild Ungulates native to New Mexico

Cous deer

Mule deer

Whitetail deer

Pronghorn

Desert bighorn

Rocky Mountain bighorn

Elk

Bison

Javelina

Domestic and Wild Ungulates Introduced in last 500 years

Cattle

Swine

Sheep

Horses

Burros

Goats

Barbary sheep Oryx

Ibex

Grazing Effects on Plants

Land Management Practice

Plant and RockCover

Plant Volume

Animal Grazing, Trampling,and Burrowing

Soil Surface Roughness

Soil SurfaceConfiguration

Soil MoistureEvaporative

Loss

SoilOrganic Matter

Content

Soil Particle Sizes

Soil Structure

Soil Bulk Density and Porosity

Runoff andInfiltration

Grazing Effects on Plants

1. Grazing reduces plant cover and volume

Little Great StimulationResistance Resistance Response

2. Plants species respond differently to grazing

Antelope bitterbrushBlack grama Blue grama

Grazing Effects on Plants

2. Plants species respond differently to grazing continued…

Moderate to No GrazingBunchgrass

Heavy GrazingSodgrass

Blue grama Blue grama

Reduced Plant Cover and Plant Volume Effects the Watershed

1. Decreased interception and transpiration

3. Decreased water infiltration into soil surface

4. Increased runoff and erosion

2. Decreased organic matter additions to soil, which affect soil structure and porosity

5. Increased runoff and erosion lead to loss of sustainability after about 50% utilization of present year’s growth

Grazing Effects on Plants Continued…

Grazing can retard or stop invasion of salt cedar

Observed on:

1. Capitan Creek on the Pecos River

2. Middle Fork of the Gila River

3. Redstone Allotment of the Gila River

Trampling or Hoof Action Effects on Plants

1. Trampling reduces plant cover and volume.

2. Plant cover and volume reductions may:

a. Decrease Interception and Transpiration

b. Damage or kill the plants

c. Stimulate plant growth

Trampling or Hoof Action Effects on Soils

Trampling Effects on Soils

Soil Surface Runoff and Roughness Erosion

Wet Soil Dry Soil

Southwestern soils are usually dry!

Increases

Decreases

Decreases

Increases

Trampling Effects on Soil

Runoff and Trails Erosion

Up & Down Slopes

Across Slopes

Configuration

Increases

Decreases

Trampling Effects on Soil

Bulk Density Porosity Water Holding Runoff and Capacity Erosion

Bulk Density and Porosity

Bulk Density increases are usually mitigated with cold-weather freeze-and-thaw conditions.

Increases Decreases Increases Increases

Trampling Effects on Soils

When ungulates are removed

from watersheds, pocket gopher

populations often increase, even

exponentially.

Gopher mounds may add up to 5 tons/acre/yr of sediment into streams!

Trampling Effects on Soils

Gopher tunnels often lead to piping and eventually a side gully!A benefit of trampling is control of pocket gophers!

Animal Wastes and Nutrient Cycling

Soil Runoff and Erosion

Wind

Animal Wastes and Water Pollution

Fisheries in high fertility watersheds won’t benefit much from dung and urine additions but may suffer from over-enrichment.

Only that dung deposited on bare ground connected to a runoff system is expected to be eroded from a watershed.

Fisheries in watersheds of low fertility may benefit from accelerated erosion and elevated nutrient levels

Livestock and Wild Ungulate Management Strategies

Fences

It is easy to fence out livestock

It is difficult to fence out wildlife

Total number of ungulates may not change from fencing out livestock

Livestock and Wild Ungulate Management Strategies

Fences and exclosures may be problematic because they:

Lead to aesthetic considerations

Are expensive

Have annual maintenance hassles

Create problems with animal movement

Often result in unused forage

Livestock and Wild Ungulate Management Strategies

Stocking Rates

Extreme 100% Utilization - Rarely sustainableHeavy 75 “ - “ “ Moderate 50 “ - Usually sustainableLight 25 “ - “ “Exclusion 0 “ - “ “

Livestock and Wild Ungulate Management Strategies

Livestock and Wild Ungulate Management Strategies

Grazing systems

Grazing Systems – Example from Texas Rolling Plains

Stocking Infiltration Sediment System Rate Rate Production cm/hr kg/ha

Exclosure None

Deferred-Rotation Moderate

Continuous Moderate

Short Duration Moderate

Continuous HeavyWood and Blackburn. 1981. J Range Manage. 34:228-231; 331-335

11 b

14 b

28 ab

40 ab

114 a

15.2 a

13.9 ab

11.4 bc

8.2 c

8.1 c

Grazing Systems – Example from Fort Stanton, New Mexico

Stocking Infiltration Sediment System Rate Rate Production cm/hr kg/ha

Exclosure None

Continuous Moderate

Short Duration Heavy after resting

Short Duration Heavy after grazing

Continuous Heavy Weltz and Wood. 1986. JRM 39:365-368; J Soil & Water Cons. 41:262-266.

65 b

307 a

221 a

565 a

334 a

7.4 a

4.9 b

3.9 c

2.3 d

2.6 d

Grazing Systems – Example near Fort Sumner, New Mexico

Stocking Infiltration Sediment System Rate Rate Production cm/hr kg/ha

Exclosure None

Continuous Moderate

Short Duration Heavy after resting

Short Duration Heavy after grazing

Weltz and Wood. 1986. JRM 39:365-368; J Soil & Water Cons. 41: 262-266.

20 c

80 b

25 c

268 a

6.3 ab

5.5 b

7.0 a

3.8 c

Livestock and Wild Ungulate Management Strategies

Range Improvements

Plant Control

Biological

Burning

Herbicides

Mechanical

Livestock and Wild Ungulate Management Strategies

Range Improvements

Plant Enhancements

Seeding Fertilizing Waterspreading

Livestock and Wild Ungulate Management Strategies

Monitoring

Explore

Evaluate

Keep Records

Measure

Observe

ConclusionsFour noteworthy points can be made regarding the question: Can we graze watersheds?

4th If we don’t get our management act together, the public won’t let us graze watersheds because of high resource value and potential for damage from improper grazing!

1st Yes, we can graze these areas!

2nd We should be able to increase forage produced without damaging other uses!

3rd We don’t know yet how to do this in all areas!

If on the other hand the prime objective is watersheds, we should restore the grass, which all the evidence indicates is a better watershed cover than either brush or woodland.” Aldo Leopold

“If the prime objective is wood products, we may continue to overgraze, letting in the woodland and sacrificing watershed values.

A Good Quote

God Bless America!