摘要：An experiment was carried out at Mkuranga Research Station of National Coconut Development Programme （NCDP） to study the effect of light regimes on three different crops which are sweet potato, cowpea and pineapple between 1995 and 1996. Four light intensities with nominal values of light transmission namely L0 = 100%, L 1 = 75%, L2 = 50%, L3 = 25% were provided by nylon netting materials which filtered sunlight to varying light percentages. The experiment was a split-plot on randomized complete block design, replicated four times. Growth measurements and yield were recorded at a regular interval in all crops. Leaf morphological characteristics were carried out only on sweet potato. Result on the leaf morphological characteristics showed light intensity strongly influenced growth and development of sweet potato. Specific leaf area values in full light were smaller than those in under heavy shade. The light intensity increased the cowpea seed yield significantly （P 〈 0.01） and the interaction between seasons （year） x light regimes was significant （P 〈 0.01）. In low intensity, pineapple flowered earlier and yielded more than in high intensity. These results have provided useful information in planning intercropping models in coconut based-farming systems in Tanzania.