Effect of deferred autumn grazing and stocking rate of sheep on pasture production in a Mediterranean-type climate

Abstract

The effect of deferred autumn grazing and stocking rate on an annual pasture was monitored for five years at Kybybolite Research Centre in the south-east of South Australia. Pasture availability, yearly production and botanical composition were measured under a series of eight stocking rates from 12.4 to 29.7 Merino wethers per hectare. Autumn deferment resulted in extra available pasture during the winter months of June, July and August. However, the continously grazed pastures reached the same level of availability as the deferred pastures in spring. By the third year of the experiment yearly pasture production irrespective of grazing management was greatly reduced at the higher stocking rates. This reduction was associated with an invasion of Poa annua and Juncus bufonius. Autumn deferment tended to favour the growth of Wimmera ryegrass at the lower stocking rates whereas continuous grazing tended to favour clover growth at these stocking rates.