The Impact of Weeds and Two Legume Crops onEucalyptusHybrid Clone Establishment

Abstract

SYNOPSIS The relative competition imposed on Eucalyptus hybrid clone GC304 grown from establishment with either complete weed cover, intra-row weeds, inter-row weeds or legume cover crops of Mucuna pruriens and Vigna sinensis is under study in a field experiment on a high potential Zululand site. Results up to 120 days indicated that significant competition with trees occurred in the weedy control, inter-row weeded, ring weeded and cowpea cover cropped treatments from 60 days after planting. These trends remained at 120 days when complete manual and chemical weeding produced the best tree growth while treatments which were only row weeded had reduced tree leaf surface indices (LSI) by 32%, those only ring weeded by 61% and those in the weedy controls by 68%. Velvet beans were considered unsuitable because of their aggressive vining habit while cowpeas were advised for planting only in eucalypt stands of 90 days or older to avoid interspecific competition. By 120 days there were indications that the trees ...