Effects of stubble management on quality and yield of regrowth after hay : A dissertation submitted in partial fulfillment of Bachelor of Agricultural Science Honours in the University of Canterbury

Abstract

A trial sited on an irrigated Wakanui silt loam at Lincoln College, Canterbury was used to evaluate the effects of different stubble managements on the quality and yield of regrowth after a pasture was taken for hay. The stubble was either trimmed to 2cm or left intact (10cm) and spelled for 4 or 8 weeks. Herbage yield, botanical composition, digestibility and light interception were all measured. Digestibility of the regrowth was maximised by the initial trimming of the stubble. Lower overall digestibilities were caused by an increase in either the amount or age of the dead material. Both the ryegrass and white clover had a similar digestibilities in all treatments (78.7 and 79.6 respectively). Of the green herbage the proportions of white clover and ryegrass were 60 and 40% respectively in all treatments. Dead material was significantly higher in the regrowth when the stubble was left intact. Total yield and green herbage yield were maximised by leaving the stubble intact and harvesting at 4 weekly intervals. These results show that stubble should be left intact and the regrowth severely defoliated after 4 weeks to maximise production. The causes for differences in quality and yield are discussed.