Effect of agroforestry prunings on seed yam yield and size of seed yam

Abstract

The study investigated effect of agroforestry prunings on seed yam yield and size of seed yam. Fresh plant pruning from 4 multipurpose tree species- Dactyladenia barteri, Gliricidia sepium, Pentaclethra macrophylla, and spondias mombin were applied and two yam minisetts sixes (25g and 45g), were laid out in field plots of 5m x 4m in a randomized complete block design (R.C.B.D) and replicated three (3) times. Some samples were taken per plot at the beginning of the experiment and subsequently monthly for four (4) months after application of green mulch for analysis. Samples of each green mulch were taken by the time of application for nutrient content determination. The green mulch was applied two (2) weeks after planting yam minisetts at 4t /ha and was incorporated into the soil at first weeding. Yam minisetts (Cultivar Obiaoturugo) was planted in the month of June at 40,000 stands ha-1 and harvested in December. At harvest, the total seed yam yield was measured. Application of Spondias mombim mulch resulted in the highest number of tubers having weights greater than 200g, while the least number of seed yams weighing greater than 200g was obtained with the control. Application of prunings resulted to significantly higher seed yam yield over the control (no application) in both 2000 and 2001 cropping seasons. In the year 2000, the highest seed yam yield of 4.87t ha-1 was obtained with Gliricidia sepium.