MSc

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.