Willow Hibbs

Grazing for CheatgrassManagement

Willow Hibbs

Habitat Extension Biologist

Natural Resources Conservation Service

Wyoming Game & Fish Dept.

Ecosystem Controls

Climate Time

Ecosystem

Topography

ParentMaterial

PotentialBiota

EcosystemProcesses

Ecosystem Processes

Defoliation

Life Strategy

Managers can usestrategies and tools

Life Strategy

Resource Acquisition

strategies and toolsto influence ecosystem

processes

Grazing management

Grazing Cheatgrass?

U.S.Department of the Interior, U.S. Geological SurveyThis page is http://gec.cr.usgs.gov/info/sw/interact/invasives_measuring.html

Cheatgrass

Natives

0-50cm

50+ cmUneven soil

moisture profileEven soil

moisture profile

Grazing Cheatgrass?

U.S.Department of the Interior, U.S. Geological SurveyThis page is http://gec.cr.usgs.gov/info/sw/interact/invasives_measuring.html

Grazing ManagementGrazing Management

•Initiated from growth points•Apical•Secondary

Grass Growth

•Secondary•Axillary

•3 main phases•Vegetative•Transition•Reproductive

Grass Growth: Vegetative PhaseYou need leaves to grow leaves!

http://www.fsl.orst.edu/forages/projects/regrowth/print-section.cfm?title=Developmental%20Phases

http://www.fsl.orst.edu/forages/projects/regrowth/print-section.cfm?title=Developmental%20Phases

Grass Growth: Transition Phase

http://www.fsl.orst.edu/forages/projects/regrowth/print-section.cfm?title=Developmental%20Phases

http://www.noble.org/ag/forage/grassmechanics101/index.htm

Grass Growth: Reproductive Phase

http://www.fsl.orst.edu/forages/projects/regrowth/print-section.cfm?title=Developmental%20Phases

http://www.caf.wvu.edu/~forage/growth.htm

Carbohydrate Reserves%

avai

lab

leca

rbo

hyd

rate

sin

roo

tsan

dcr

ow

n%

avai

lab

leca

rbo

hyd

rate

sin

roo

tsan

dcr

ow

n

http://www.ext.colostate.edu/pubs/natres/06108.html

http://www.agron.iastate.edu/moore/434/grass.html

Ecological Sites

Key Points

Questionable benefits to targeted cheatgrassgrazing

Increases pressure on natives

Uneven soil moisture profile already existsUneven soil moisture profile already exists

Proper grazing management is key to aresistant, resilient system

Key PointsGrass stages

Vegetative : resilient, but leave adequateleaf arealeaf area

Transition to boot stage: sensitive

After Reproductive: can graze, allow timefor carbohydrate reserves to replenishafter

Key Points

Growth has priority over carbohydratestorage

Carbohydrate storage increases when:- Leaf area is large- Leaf area is large- Growth rate is slow

Carbohydrate storage decreases when:- Leaf area is small- Growth rate is fast

Key Points

Leave residual cover

Cool versus warm season grassesCool versus warm season grasses

Ecological sites

Questions?