THE EFFECTS OF INTERCROPPING KALE WITH BEANS ON YIELD AND SUPPRESSIONOF REDROOT PIGWEED UNDER HIGH-ALTITUDE CONDITIONS IN KENYA

Two studies were conducted in Kenya during 1993 and 1994 to determine the yield responses of kale (Brassica oleracea var. acephala D.C.) int ercropped with beans (Phaseolus vulgaris L.) under different redroot p igweed (Amaranthus retroflexus L.) densities. Redroot pigweed signific antly reduced both kale and bean yields, the reduction being greater i n 1993 than in 1994, and being greater for beans than for kale. Redroo t pigweed growth was suppressed more by beans than by kale. Food outpu t per unit area, measured by Land Equivalent Ratios, was increased by 22-115% by intercropping kale with beans and the increase was greater under weedy conditions (38-115%) than under weed-free conditions (22-7 4%). The presence of beans did not affect the leaf yield of kale. The presence of kale did not affect the seed yield of beans in 1994, but c onsistently reduced it by about 50% in 1993, though the difference was not significant.