Assessment of the contribution of legumes to the nitrogen nutrition of sugarcane.

Field trials were conducted to assess the contribution of legumes to the nitrogen nutrition of sugarcane at the up-land sugarcane experimental field of the National Cereals Research Institute Farm, Badeggi (9°45'N, 06°07'E) in the Southern Guinea Savanna ecological zone of Nigeria in the 1997 and 1998 wet seasons. The four treatments tested consisted of sole-planted chewing cane, and chewing cane intercropped with soybean (TGM 579), Sesbania rostrata and cowpea (Ife brown). The treatments were laid out in a randomised complete block design with three replications. The legumes were ploughed into the soil at 12 weeks after sowing (WAS). At 2 months after sowing, cane intercropped with cowpea generally recorded lower values for cane height, tiller number and crop vigour, while the sole-planted cane crop gave the highest values for each of these parameters in both years. However, at 4 and 10 months after planting and at harvest (1, 6 and 9 months after the legume incorporation) sole-planted cane recorded sign...