Cotton (Gossypium hirsutum) establishment methods based system-intensification: Effects on Bt cotton growth, weed suppression, system crop and water productivity, system-profitability and land-use efficiency in Indo-Gangetic plains region

摘要

A field experiment was conducted at IARI, New Delhi during 2014-15 and 2015-16 to study the effect of Bt cotton (Gossypium hirsutum L.) establishment methods (CEMs) and planting geometry on plant growth, yield and weed suppression behaviour in Bt cotton vis-a-vis system productivity, profitability, water-productivity, production-efficiency, economic-efficiency and land use efficiency. The experiment was laid out in split-plot-design with four replications comprising two CEMs [transplanted-cotton (TPC) and direct-seeded-cotton (DSC)] and three planting geometries/plant densities [(90x60 cm (18,518 plants/ha); 75 x 45 cm (29629 plants/ha) and 60x45 cm (37,037 plants/ha)] and four cropping systems viz. TPC-wheat-mungbean; TPC-onion-fodder cowpea + maize; DSC-wheat; and DSC-onion cropping system under above two CEMs. Among CEMs, the DSC-cotton resulted in higher plant growth though the seed yield and lint yield were respectively higher by similar to 9.54% and similar to 15% under TPC-cotton over DSC-cotton due to better plant stand in TPC-CEM. On an average, the significantly highest system productivity in terms of seed-cottonequivalent-yield (SCEY) was registered in TPC-wheat-mungbean/TPC-onion-fodder cowpea + maize cropping systems (mean of both systems) during 2014-15 (6.75 t/ha) and 2015-16 (6.96 t/ha), respectively. In general, the legume-intensification in TPC-based cropping systems exhibited about 25 to 27% higher system yield (SCEY) over DSC-based cropping systems. The TPC-based cropping systems exhibited additional net economic gains of (sic)43000/ha vis-a-vis higher weed suppression, system crop and water productivity, system economic-efficiency and land-use efficiency over the DSC-based systems. Likewise, planting geometry/planting density of 60 x 45 cm (37037 plants/ha) exhibited significantly higher system productivity (SCEY) (6.58 t/ha), system net returns ((sic) 178450/ha), system water-productivity and system economic-efficiency over other two planting geometries viz. 75 x 45 cm and 90 x 60 cm. In nutshell, system-intensification through transplanted Bt-cotton based cropping systems (TPC-wheat-mungbean/TPC-onion-fodder cowpea + maize) and planting geometry/planting density of 60 x 45 cm (37037 plants/ha) led to higher weed suppression, system productivity, system economic-efficiency, system water-productivity and land-use efficiency in Indo-Gangetic plains region.