Effects of mulching materials on the growth, development and yield of white yam

Abstract

Two similar experiments are described in which the effects of different mulching material and staking on the growth, development and yield of white yam ( Dioscorea rotundata ) Minisetts were studied. One white yam cultivar TDR 131 was used and the treatments were: black and white embossed polyethylene plastic (Visqeen 38 mu) with either black or white surface up; light weight black polyethylene plastic, rise straw; staking but no mulch, and no staking and no mulch. Each experiment was laid out in a randomized complete block design with four replications. Polyethylene plastic mulch with white surface up was superior to all other treatments. Total dry matter per plant and total fresh tuber yield were all consistently higher in plants grown under the white surface polyethylene plastic mulch. in 1985, mean tuber size was more than 34% larger than in the traditional staking system and nearly double the value obtained with no staking no mulch treatment. In 1986, mean tuber size was again larger with white surface plastic mulch but not significantly different from those of the staking and rice straw treatments. Plants in all treatments attained peak leaf area index (LAI) about 100 days after planting and those in the white surface plastic mulch maintained a higher LAI for most of the growing season. White surface polyethylene plastic mulch gave the larger Leaf Area Index and Greater Leaf Area Duration which ensure a high bulking rate over a comparatively longer period. It is suggested that under tropical conditions, farmers would obtain better seed yam yields through the use of white surface polyethylene plastic mulch.