Effect of weed-management practices on weed flora, soil micro-flora and yield of baby corn (Zea mays)

A field experiment was carried out during the winter seasons of 2010–11 and 2011–12 at Jaguli, West Bengal, on sandy-clay loam soil, to study the effect of different weed-control methods on weed growth, soil-microbial populations and productivity of baby corn (Zea mays L.). Besides weed-free check, the higher yield of baby corn (1, 464 kg/ha) was recorded with 2 hand-weeding done at 20 and 40 days after sowing (DAS) owing to significantly lower weed dry weight, higher weed-control efficiency (88.32%), lower weed index (4.63%) and increased nutrient uptake than the other treatments. This treatment was followed by straw mulch @ 10 t/ha and increased the yield by 68.98% over weedy check. Integrated weed-management practices like pre-emergence atrazine or metribuzin @ 1 kg/ha coupled with 1 hand-weeding at 30 DAS exhibited superiority to the respective atrazine or metribuzin @ 2 kg/ha alone. Straw-mulch treatment showed the maximum favourable effect on growth of non-symbiotic N-fixing and phosphate-solubilizing bacteria of soil. After the initial suppression, the adverse effect of herbicides on the bacterial population was recovered from 25 DAS. The maximum net returns (43, 470/ha) were obtained with hand-weeding twice, but the highest benefit: cost ratio (2.43) was recorded under atrazine-treated plots.