Weed management in sorghum-legume intercropping systems

Abstract
The field experiments were conducted at the Indian Agricultural Research Institute, New Delhi in summer-rainy seasons of 1980 and 1981 to study the effect of different sorghum-legume intercropping systems and weed control methods on growth, yield and nutrient uptake by different crops and on weeds. The intercropping of legumes increased growth, uptake of N, P and K and yield of sorghum compared with sole sorghum. However, maximum increase was obtained when it was grown in association with fodder cow pea. All intercrops smothered the weeds but maximum suppression was by fodder cow pea. The total uptake of nutrients (N, P and K) was also greater in intercropping systems. Pre-emergence application of fluchloralin at 0·5 kg/ha was most effective in all intercropping systems followed by nitrofen at 1·0 kg/ha. Hand weeding and fluchloralin application also led to higher nutrient uptake by sorghum and the whole system than the unweeded control. Application of fluchloralin and nitrofen controlled most of the weeds and reduced nutrient removal compared with the control but was less effective than hand weeding.