Theme 08: Grazing Ecology

Description

The botanical composition of mixed grass pastures may change during grazing due to the various grazing period/recovery period lengths associated with multiple-paddock grazing strategies. This 4-year study compared changes in relative species composition and basal plant cover of a C4 grass mixture grazed using a nested paddock design to simulate 2, 4, 6 and 12- paddock grazing cells in eastern Nebraska. Total basal plant cover declined from 11.6% prior to grazing to 7.3% after one year of grazing and then remained nearly constant thereafter. Neither relative species composition nor basal density were affected greatly by grazing strategy. Within grazing strategies, however, some changes occurred although high variability made it difficult to detect significant differences among plant species. Across all grazing strategies, switchgrass [Panicum virgatum L.] frequency was inversely related to big bluestem [Andropogon gerardii Vitman] and indiangrass [Sorghastrum nutans (L.) Nash.] while sideoats grama [Bouteloua curtipendula (Michx.) Torr.] was inversely related to little bluestem [Schizachyrium scoparium (Michx.) Nash.] and indiangrass.

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Response of Mixed C4 Grasses to Various Multiple Paddock Grazing Strategies

The botanical composition of mixed grass pastures may change during grazing due to the various grazing period/recovery period lengths associated with multiple-paddock grazing strategies. This 4-year study compared changes in relative species composition and basal plant cover of a C4 grass mixture grazed using a nested paddock design to simulate 2, 4, 6 and 12- paddock grazing cells in eastern Nebraska. Total basal plant cover declined from 11.6% prior to grazing to 7.3% after one year of grazing and then remained nearly constant thereafter. Neither relative species composition nor basal density were affected greatly by grazing strategy. Within grazing strategies, however, some changes occurred although high variability made it difficult to detect significant differences among plant species. Across all grazing strategies, switchgrass [Panicum virgatum L.] frequency was inversely related to big bluestem [Andropogon gerardii Vitman] and indiangrass [Sorghastrum nutans (L.) Nash.] while sideoats grama [Bouteloua curtipendula (Michx.) Torr.] was inversely related to little bluestem [Schizachyrium scoparium (Michx.) Nash.] and indiangrass.