Production potential and energy budgeting of soybean (Glycine max) varieties as influenced by weed-management practices under different crop geometries

A study was undertaken during the rainy season of 2001 and 2002 on clay loam alkaline soil at Udaipur (Rajasthan), to evaluate effect of weed control on production potential and energy budgeting of soybean [Glycine max (L.) Merr.] varieties grown in different crop geometris. Variety ‘JS 335’ recorded the maximum seed yield, additional net returns, energy gain and energy-use efficiency (EUE) compared with ‘NRC 37’ and ‘JS 7105’. There were no significant differences in density of grassy and broad-leaf weeds at 40, 60 days after sowing and at harvest among the varieties. Crop geometry could not affect the weed as well as crop parameters. All the weed-control treatments resulted in significant reduction in density of grassy weeds and helped in significant enhancement in soybean yield. Two hand-weedings 20 and 40 days after sowing and pre-emergence (PE) application of clomazone 1.0 kg/ha + hand-weeding at 40 days after sowing treatments registered around 88% weedcontrol efficiency in controlling grassy as well as brod leaf weeds. Higher seed yield, additional net returns, energy gain and EUE were recorded with 2 hand-weedings, followed by clomazone 1.0 kg/ha PE + hand-weeding at 40 days after sowing.