Integrated weed management in brinjal (Solanum melongena L.)

Abstract

A field experiment was conducted at the Instructional Farm, College of Agriculture, Vellayani, Thiruvanantbapuram to study the technical and economic feasibility of different weed management practices for brinjal. The study was carried out during the period from August to November, 1999. The experiment was laid out in Randornised Block Design with fourteen treatments and three replications. The treatments consisted of physical, cultural and chemical methods of weed control alone or in combination. Unweeded check and completely weed free check were included as control treatments. 'Swetha' was the variety of brinjal used for the study. Results of the study revealed that grasses, broadleaved weeds and sedges competed with the brinjal crop. The weed intensity and distribution was found significantly influenced by the weed management practices included in the study. It was evident that weeds failed to emerge under the black polythene mulching and the few weeds recorded were those emerging from the planting hole. There was no distinguishable weed growth even from the planting hole beyond 30 days after transplanting (OAT). The farmers practice of giving two manual weeding at 15 and 30 OAT allowed unchecked weed growth upto 15 OAT, but had comparatively high weed control efficiency at later stages. Application of fluchloralin as pre-plant incorporation (PPI) was found to inhibit early emergence of grasses and broadleaved weeds, but gave poor control of sedges. Fluchloralin + one hand weeding at 20 OAT was found to give season long control of weeds and was a better option than fluchloralin alone and fluchloralin + smother cropping.

The cultural practices of stale seed bed technique and smother cropping gave early season weed control but allowed weed emergence later and gave improved weed control efficiency when integrated with one hand weeding. The effect of glyphosate application also was found to respond in similar lines. The weed management practices were found to exert considerable influence on growth and yield characters of the crop. Under weed free situation the plant produced the highest number of branches and leaves and had the maximum number of flowers and fruit also. The crop yield was found to bear a direct positive correlation with the weed control efficiency of the management practices. Weedy check recorded the lowest yield and the yield losses worked out was 58.43 per cent. Excluding the weed free check, the yield loss was minimum under black polythene mulching followed by fluchloralin + one hand weeding. The most remunerative treatment was found to be fluchloralin + one hand weeding (T9) followed by two manual weeding (T3). The herbicides were found non persistent leaving little toxic residue in the soil after the experiment.