Spatial Distribution of Herbage Mass in Bahiagrass (Paspalum notatum FLUGGE) Pasture under Grazing, Resting and Mowing

Abstract

This study investigated the spatial distribution of herbage mass in a paddock of a bahiagrass pasture grazed rotationally by beef cattle and mown for hay. With a single-probe electronic capacitance meter, the herbage mass was estimated non-destructively in 5036 fixed places in a 0.61 ha paddock on nine dates during a period of about four months. The statistical parameters of the frequency distributions of herbage mass showed variable responses to grazing, resting and mowing. From the results of the present and past studies, the increase in the coefficient of variation (CV) with grazing, the increase in the mean and decrease in the CV with resting, and the decrease in the mean, maximum and standard deviation (SD) with mowing were regarded as the general phenomena. In the paddock, the areas of lower herbage mass and those of higher herbage mass tended to aggregate in particular parts of the paddock. Furthermore, there were some similarity and dissimilarity in the distribution patterns. The causes for such phenomena were partly cleared by evaluating the comparative contributions of the preceding distribution of herbage mass, grazing equipment and mowing to the herbage mass distribution. The preceding distribution of herbage mass was more important than the grazing equipment in a heterogeneous herbage mass environment. The period for which the effect of the preceding distribution continued was estimated at about 10 to 50 days. The mowing did not always cancel the effect of the preceding herbage mass distribution.