The effect of undersowing euca!yptus (Euca/ypfus Camaldulensis L.) with maize (Zea mays L) and cowpeas (Vigna unguiculata L.) on tree growth and crop performance

Abstract

Maize (Zea mays L.) hybrid R201 and cowpea (Vigna unguiculata L.) variety IT82D- 875 were separately inter-row interplanted with gum-tree (Eucalyptus camaldulensis L.) during the 1995-96 cropping season at Domboshava Training Centre. Planting E. camaldulensis with cowpeas and maize had no marked effect on the yields of the two annual crops. Sole clean-weeded E. camaldulensis had significantly thicker circumference than the Eucalyptus in the other treatments, but was comparable to Eucalyptus interplanted with the annual crops in terms of branching habit. However, E. camaldulensis interplanted with maize showed a slightly higher performance (branching and circumference) than that interplanted with cowpeas. This was probably related to the fertilizer added to the maize/£. camaldulensis intercrop since no fertilizer was added to the cowpea/£. camaldulensis intercrop. Management factors such as clean weeding in sole Eucalyptus markedly increased tree performance as observed through parameters of stem circumference and branching compared to those of the unweeded sole Eucalyptus situation. Neither tree branching pattern, height growth nor soil moisture were significantly affected by intercropping with annual crops. Undersowing annual crops to E. camaldulensis will facilitate maximum utilization of land and light in the early years of E. camaldulensis woodlot establishment. This approach will also allow better tree growth when compared to the unweeded situation which is common in small-holder farming.