Effects of frequency of weeding on the growth and yield of long-fruited jute (Corchorus olitorius) in a rainforest area of southwestern Nigeria

Hand weeding is still by far the most widely practised cultural weed control technique in vegetable production throughout the tropics because of the prohibitive costs of herbicides and fear of toxic residue coupled with the lack of knowledge about their use. Field experiments were conducted in 2000 and 2001 to examine the frequency of weeding conducive to optimum growth and yield of jute in Nigeria. Results indicated that weeding once as early as 2, 3 or 4 weeks after sowing (WAS) was not as beneficial to the growth and yield of jute as two weedings conducted at 2 and 5 WAS or 3 and 6 WAS. Weeding once every week throughout the duration of crop growth significantly (P<0.05) enhanced all growth and yield parameters over most of the treatments. Both the final and cumulative weed weights at harvest were found to be negatively correlated with increasing frequency of weeding with an average correlation coefficient (r) of −0.73 in both years. In contrast, all growth and yield parameters were linearly and positively correlated with increasing frequency of weeding (r=+0.78). Bearing in mind the economics of labour input and yield, two weeding operations at 2 and 5 WAS was the most promising of all the treatments.