The effect of rate of stocking with sheep on the botanical composition of an annual pasture in southern Victoria

Abstract

The botanical composition of an annual unirrigated pasture at Werribee, twenty miles west of Melbourne, Victoria, grazed at one, three, and six sheep to an acre was greatly influenced by level of stocking. The areas grazed at one sheep to an acre became dominated by Wimmera ryegrass and had large reserves of grass and subterranean clover seeds in the soil. In those grazed at six sheep to an acre the original Wimmera ryegrass and subterranean clover had virtually disappeared at the end of three years, and there were few grass and clover seeds in the soil. Some change in botanical composition occurred from year to year in the areas grazed at three sheep to an acre but it was not progressive and the pasture at the end of the observations was similar to that at the beginning. The reserves of grass and clover seed, although lower in these plots than in those grazed at one sheep to an acre, were considerably above the level of those grazed at six sheep to an acre. It is concluded that at their present level of productivity these pastures will not carry six sheep to the acre continuously, but they may carry more than three sheep to the acre.