THE EFFECT OF DEFOLIATION ON SEED YIELD OF COWPEAS (VIGNA UNGUICULATA (L.) WALP.) AND ANALYSIS OF THE LEAF HARVEST FOR DRY MATTER AND NITROGEN CONTENT
Cowpeas are widely grown in the drier parts of East Africa. The leaves are eaten as a substitute for spinach and the green pods and dry seeds provide food for many people. Current work at the Makerere University Farm involves the investigation of the adaptation of cowpeas to environments other than those in which the crop is traditionally grown in East Africa.
In the Teso and Lango districts of Uganda, the cowpea is one of the main grain legume crops. During 1968, approximately 185 000 hectares were devoted to cowpea cultivation in Uganda, either in pure stands or in mixtures with other crops (Anon., 1969). Purseglove (1943) pointed out that in Teso and Lango districts, the green tender leaves are cooked as a spinach with other vegetables; surplus leaves are either sold in the markets or dried and preserved in the form of powder which is used during dry periods when fresh leaves are unobtainable. The cultivars grown in Uganda have an indeterminate growth habit and produce young leaves continuously over a period of at least two months.
In view of the importance of cowpeas as a source of protein and income to the peasant farmer it was considered necessary to investigate:
- The number of times the young leaves could be picked during the period of maximum vegetative growth without affecting the dry seed yield.
- The stage of growth at which the picking should begin.
- The nutritional value of the leaves.