Effect of soil treatment and grazing management on the productivity, erosion, and run-off from pasture land

This paper presents the results of an experiment conducted at the Dixon Springs Experiment Station as a cooperative project between the Illinois Agricultural Experiment Station and the Soil Conservation Service, Research Division. The purpose of the experiment is to determine the effect of intense and moderate grazing and soil treatment on soil and water losses and forage values of pastures. Four areas 1/3 acre in size were fenced and grazed with sheep. Small run-off plots 70 by 14 feet in size were located within the grazing areas and it was from these small plots that soil and water losses were measured. Intense and regulated grazing was practiced on both treated and untreated soil. Forage yields and vegetal data were obtained by random sampling of small areas by the point quadrat method. Days of pasturage with yearling ewes are reported for 1938 and 1939. In 1939, pounds of gain or loss in weight of sheep are also given. The amount of vegetative cover on treated land on which regulated grazing was practiced was from three to four times greater than on land intensively grazed. Regulation of grazing did not markedly increase the amount of cover on untreated land. Severe grazing and lack of soil treatment increased the proportion of undesirable vegetation. Soil losses from land with established vegetal cover, even under conditions of severe grazing management and low fertility, were very small. Annual weedy grasses which were abundant on untreated land under intensive grazing protected the soil against erosion. Run-off losses from intensively grazed land that was treated with limestone and phosphorus were greater than from land similarly treated that was moderately grazed. On the untreated plots, grazing management did not significantly affect the run-off losses. Under moderate grazing run-off losses from land untreated were greater than from land which was treated, but the losses were not greater under severe grazing. These results were influenced by the type of weed growth which is produced on untreated land. Number of pasture days of grazing with sheep were approximately the same on treated land under the two intensities of grazing. On land not treated, fewer days of grazing were obtained under moderate than severe grazing management. Yearling ewes gained considerably more during the grazing season on treated land when grazing was regulated than when grazing was severe.