Pasture production and liveweight gain from cocksfoot-subterranean clover pastures grazed at two stocking rates and closed at different times during spring

Abstract

The effect of stocking rate (8.3 (low) and 13.9 (high) ewes + twin lambs/ha) and time of closing in spring on lamb liveweight gain, pasture production and subterranean clover seedling densities was monitored over 2 years for a dryland cocksfoot-subterranean clover pasture in Canterbury. In both years, lambs grew faster (g/head/d) in spring at low (327; 385) than high (253; 285) stocking rate. Subterranean clover seedling populations (per m²), measured in autumn after grazing treatments in the previous spring, were greater at low (2850) than high (2500) stocking rate and declined with later closing dates (3850, 2950, 2100 and 1700 at 2, 4, 6, 8 weeks after early flowering). Seedling populations measured in autumn after grazing treatments in the second spring were unaffected by stocking rate (1290 low and 1190 high) but declined with later closing dates (1470, 1320 and 940). The effect of stocking rates and closing dates in spring of year 1 on pasture and clover production in the following autumn was similar to the effects on seedling numbers. However, clover production in the following spring was not affected by stocking rates or closing dates imposed a year earlier.