Vegetation Cover, Composition, and Yield as Influenced by Soil, Litter and Grazing Intensity

Three pastures located 2.5 miles southwest of Hays were selected to determine the relationship of vegetation to depth of soil and different intensities of grazing. The pastures were classified as non-grazed, moderately-grazed, and heavily-grazed according to past use. Sites with deep and shallow soil were selected in each pasture to study in detail vegetational variations with respect to differences in soil and grazing intensity. When soil depth was less than 12 inches, soils were considered shallow and depths greater than 12 inches were considered deep. Ten quadrats, one square meter each, were selected on deep and shallow soil of each pasture. A detailed study of vegetation and soil differences was made by studying the following factors: basal cover and composition, monthly yield of vegetation, growth of grasses in height, counting of forbs with three feet by one foot rectangle, textural classification of soil, amount of organic matter and soil pH, amount of mulch, and utilization of vegetation by livestock. Basal cover increased with increased intensity of grazing. Deep and shallow soils of the heavily-grazed pasture had the highest basal cover when compared with the same type of soils of the non-grazed and moderately-grazed pastures. Composition of the species also varied according to the depth of soil and intensity of grazing. On deep soil of the non-grazed pasture, big bluestem was dominant while little bluestem dominated the shallow soil. On deep soil of both moderately- and heavily-grazed pastures, buffalo grass, blue grama, and side-oats grama were the dominants. Blue grama, hairy grama, and side-oats grama were dominant on shallow soils. Production of vegetation, mulch, and per cent organic matter was greater on deep and shallow soils of the non-grazed pasture as compared to the moderately- and heavily-grazed pastures. Deep soil of all three pastures produced higher vegetation, mulch, and organic matter than the shallow soil. Percentage of organic matter was higher in the 0-to-6-inch layer than the lower 6-to-12-inch layer of soil in each type of soil and pasture. Organic matter content was greatest in deep soil than in shallow soil of each pasture. Utilization of vegetation by livestock than the mode rarely-grazed pasture was 54.8 per cent while in the heavily-grazed pasture utilization was 77.8 per cent