Interactive effect of moisture conservation and integrated nutrient management on yield and nutrient utilization efficiency of rainfed Bt cotton (Gossypium hirsutum)

A continuous decline in rainfall in the area of rain dependant crop like cotton, there remains a critical need for much more appropriate water conservation research with integrated nutrient as viable option. A field experiment was conducted during kharif season of 2007, 2008 and 2009 to study the effect of different rainwater conservation practices with integrated nutrient through different sources on seed cotton yield and nutrient utilization efficiency (NUE) of Bt cotton (Gossypium hirsutum L.). Results of three years revealed that the intercropping system in Bt cotton hybrid with greengram (Phaseolus radiatus L.) enhanced the seed cotton as well as seed cotton equivalent yield significantly over sole cotton. Higher seed cotton equivalent yield (2.07 tonnes/ha) was also recorded with cotton intercropped with greengram followed by in-situ mulching of sunnhemp (Crotolaria juncea) and opening of furrows in alternate row of cotton (1.68 tonnes/ha) as compared to conventional method (1.33 tonnes/ha). Higher available soil moisture was recorded in intercropping and mulching system resulted in higher seed cotton and NUE. Among the different N sources, Bt cotton produced the highest seed cotton yield with 75% N through inorganic+ 25% N through FYM and 100% N through inorganic + micronutrients over 100% N through inorganic only. Bt cotton with greengram intercrop recorded higher production efficiency (12.16 kg/ha/day), net returns (30 842/ha) with B: C ratio of 2.35 when compared to flat bed system production efficiency 7.82 kg/ha/day, net returns 12 054/ha, and B: C ratio 1.54.