Influence of planting pattern and weed control practices on weed growth, nutrient uptake and productivity of sweet corn (Zea mays L.)

摘要

A field experiment was conducted during two consecutive seasons of rabi 2004-05 and 2005-06 at S. V. Agricultural College Farm, Tirupati in the southern agro-climatic zone of Andhra Pradesh to study the effect of different planting patterns (75 x 16 cm, 60 x 20 cm, 75 x 20 cm and 60 x 25 cm) and weed control practices [weedy check, hand weeding (HW) twice at 15 and 30 clays after sowing (DAS), pre-emergence application of atrazine@1 kg/ha+HW at 30 DAS, pre-emergence application of atrazine @ 1 kg/ha+post-emergence application of paraquat @ 0.5 kg/ha at 30 DAS] on the weed growth and performance of sweet corn. Results revealed that planting pattern of 60 x 20 cm recorded the lowest density, dry weight and nutrient uptake of weeds with the highest leaf area index, dry matter production and nutrient uptake of sweet corn. It was, however, on par with 75 x 16 cm. Though the yield attributes viz., cob length, green cob weight (with husk) and number of kernels/cob were significantly higher with 60 x 25 cm, the narrow row spacing and higher number of 83,333 plants/ha with 60 x 20 cm resulted in the highest yield of green cob (13.9 and 13.1 t/ha) and green fodder (17.6 and 16.7 t/ha) with enhanced monetary returns (benefit : cost ratio of 3.43 and 3.23) during 2004 and 2005, respectively. All the three weed control practices were more or less equally effective in suppressing the weed growth and were superior to weedy check. Integrated weed management practice of pre-emergence application of atrazine @ 1 kg/ha+HW at 30 DAS recorded distinctly lower weed count, dry weight and nutrient uptake of weeds, improved the crop growth stature, yield attributes, in turn resulted in the highest green cob (14.2 and 13.4 t/ha) and fodder yield (18.0 and 17.1 t/ha) of sweet corn, which were found to be at par with pre-emergence application of atrazine @ 1 kg/ha+post-emergence application of paraquat @ 0.5 kg/ha and HW twice at 15 and 30 DAS. Weeds in the best treatment as pre-emergence of atrazine+HW at 30 DAS recorded 42.3, 54.0 and 46.2% lesser uptake of nitrogen, phosphorus and potassium, respectively, over weedy check during 2004-05, whereas it was lesser to the extent 0147,4, 65.4 and 44.2% during 2005-06.