Dryland pasture yields and botanical composition over 5 years under sheep grazing in Canterbury

Abstract

Annual dry matter (DM) production and botanical composition of six dryland pasture combinations, grown under sheep grazing at Lincoln University for 5 years, are presented. In 4 years, lucerne produced the highest DM yields (13.1-18.5 t/ha/yr) through higher daily growth rates, compared with grass based pastures, particularly during periods of water stress in summer and autumn. Of the grass based pastures, cocksfoot sown with subterranean clover produced yields of 9.9-12.9 t DM/ha/yr which were greater than, or similar to, all other pastures (8.0-12.9 t DM/ha/yr). Cocksfoot established with white clover produced >9.7 t DM/ha/yr in years with wetter than average summers. Over the 5 years the contribution of perennial ryegrass to total DM yield declined by ~0.7 t/ha/yr, from 70% in Year 1, to 44% in Year 5. It was replaced by unsown dicotyledonous weeds and grasses which increased from 4% in Year 1 to 24% by Year 5. Overall results show a dryland pastoral system that includes both lucerne and cocksfoot with subterranean clover pastures is likely to produce more feed in dry years than perennial ryegrass/white clover pastures. The inclusion of white clover with cocksfoot and subterranean clover may allow utilisation of variable and unpredictable rainfall in moist summers.