Weed management in sugarcane intercropped with arable crops in Nigeria

Field experiments were conducted during the wet seasons of 1996 and 1997 at the Research Farm of National Cereals Research Institute (NCRI), Badeggi (9° 45’; 6° 7’E and 70.57m above sea level) in the Southern Guinea Savannah Zone of Nigeria. The study was carried out to evaluate weed competition and management strategies in sugarcane intercropped with soybean (Glycine max L. (Merrill), sesame (Sesamum indicum L), Okra (Abelmoschus esculentus L.) and Sole sugarcane. Five weed control measures consisting of combinations of hoe-weeding regimes with pre-emergence application of diuron (N’-(3,4-dichlorophenyl)-N, N-dimethylurea) and post emergence application of dimethametryn (2-(1,2-dimethylproplamino)-4-ethylamino-6-methylthio-1, 3,5-triazine) were tested under the intercrop systems. The experiment was laid out in a split-plot design with three replications in both years. The weed control treatments were allotted to the main plots while the inter crops were in sub plots. The result obtained show that a pre-emergence application of diuron (2.0 kg a.i./ha) combined with a post emergence application of dimethametryn (3.0 kg a.i./ha) at 12 WAP provided comparable efficiency in weed control to the monthly hoe-weedings. Growth and biomass production of weeds were significantly depressed under sugarcane + soybean and sugarcane + sesame intercrop systems. Similarly, growth of sugarcane was depressed by soybean and sesame intercrops but the vigour of cane increased after the harvest of the intercrops at 12 WAP. Intercropping sugarcane with soybean or sesame under the application of diuron + dimethametryn increased the land utilization based on farm returns by 31 and 11%, respectively.