Long-term Trend in Pre-grazing Horizontal Distribution of Herbage Mass in Bahiagrass Pasture (Paspalum notatum Flügge)

Abstract

Grazing by cattle plays a main role in development of spatial heterogeneity in pasture and through it, as well, in stability of particular grazing system. In this study the first five years (1995-1999) of a long-term trial in pre-grazing distribution of herbage mass in bahiagrass pasture, utilised under the same repeated grazing management are shown. Herbage mass was non-destructively estimated with an electronic capacitance probe at 182, 50 by 50 cm locations along 2 permanent line transects. The changes in pre-grazing horizontal distribution of herbage mass during five grazing seasons were measured always on the same position on two transects just before the beginning of each grazing period (27 occasions). The pre-grazing herbage mass shows spatially heterogeneous distribution, as it was indicated by the coefficient of variation in the range from 0.221 (August 1998) to 1.107 (September 1995) for all measurement dates. This research had also the aim to quantify the stability of sward in a long-term distribution of pre-grazing herbage mass in bahiagrass pasture, and the calculated correlation coefficient of multilinear regression (r=0.612) was highly significant (p < 0.001). Anyway, it is difficult to say weather this pasture is going to maintain the same spatial pattern of herbage mass in, for example, next five years. That is, to continue this research in the future is necessary task in obtaining more information about spatial heterogeneity of vegetation in bahiagrass pasture, and implication of agro ecological advantages to grazing systems.