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Effects of Livestock Grazing on Infiltration Rates, Edwards Plateau of Texas

1984; University of Arizona; Volume: 37; Issue: 3 Linguagem: Inglês

10.2307/3899153

2162-2728

G. R. McCalla, W. H. Blackburn, L. B. Merrill,

Plant Water Relations and Carbon Dynamics

The influence of short duration grazing (SDG), moderate continuous grazing (MCG), heavy continuous graxlnr (HCG).and communities was evahtated over a 2Ormonth pe& on the Texas Agricultural Research Station, located near Sonora in the Edwards Plateau, Texas.A combination of cattle, sheep, and goats were used in each grazing treatment.Infiltration rates were consistently less in the midgrass (bunchgrass) than in the shortgrass (sodgrass) community.The HCG pasture was severely overgraxed and htfiltration rates were reduced to about one-half those in the MCG pasture.The mldgrasses in this pasture were destroyed after 26 months of overgrazing.Infiltration rates in the SDG pasture, stocked at double the recommended rate, decreased during the study period.Infiltration rates in the SDG pasture shortgrass community, near the end of the study, approached those in the HCG pasture.The greatest infiltration rates for both communities were maintaIned in the MCG pasture.Infiltration rates for the midgrass community remained relatively stable during the study when the general trend in the SDG and HCG pastures was toward reduced infiltration rates.The nongrazed pasture subsequent to the 1980 drought had a general increase in inflltratlon rates.Infiltration rates vary naturally in time and space because of normal variations in climate, vegetation, and intensity and duration of livestock use.Few studies have attempted to account for these natural variations.The literature is filled with examples of the adverse impact of heavy or abusive grazing on infiltration rates.Few research projects have studied seasonal or long-term impacts of grazing systems or proper grazing management on infiltration rates (Blackburn et al. 1982).Much interest has been generated by specialized grazing systems and their potentials.Short duration grazing and its potential economic benefits to the ranching industry have become extremely popular (Savory 1978).Little information is available, however, to support many of the claims concerning specialized grazing systems.Gifford and Hawkins (1978) found no published evidence to show that any single grazing system consistently or significantly increased plant and litter cover on watersheds.Other reviews (Van Pollen and Lacey 1979, Beck 1980) of the impacts of grazing support Gifford and Hawkins' conclusions.Most of the information on the impact of specialized grazing systems on infiltration rates come from studies conducted in the Rolling Plains and Edwards Plateau of Texas.The results of these studies indicate that infiltration rates of pastures grazed under a deferred-rotation system (4-3: 12:4 mo)i were similar to those of livestock exclosures and greater than high intensity, low frequency pastures (8-1:17:119 days) or moderate or heavy continuously grazed pastures (McGinty