Weed management in cotton (Gossypium hirrutum) groundnut (Arachis hypogaea) sequence

A field experiment was conducted during 1990-91, 1991-92 and 1992-93 to study comparative performance of different methods of weed control in rainfed American hybrid cotton during the rainy season and its effect on subsequent groundnut (Arachis hypogaea L.) crop (irrigated) during summer season on Vertisols. Unchecked weeds caused an average yield loss of 89%. Pooled results indicated that application of any herbicide, i.e. pendimethalin 0.75 kg/ha, diuron (PE) 0.50 kg/ha and fluchloralin (preplant in corporation, PPI) 0.90 kg/ha, each supplemented with weeding and hoeing at 6 weeks after sowing to cotton hybrid 'NHH 44' was more effective than that of recommended cultural practices (RCP) of 3 weedings and hoeings at 3,6 and 9 weeks after sowing in controlling weeds and enhancing seed-cotton yield as well as net monetary returns. Further, these herbicides did not leave any phytotoxic effect on succeeding summer groundnut crop. Unchecked weeds in summer groundnut caused an average yield loss of 44%. The highest net monetary returns (Rs 16,745/ha) (3-year average) was with pendimethalin (PE) 0.75 kg/ha supplemented with hand-weeding and hoeing 6 weeks to cotton. Diuron (PE) 0.50 kg/ha + hand-weeding and hoeing at 6 weeks and fluchloralin (PPI) 0.90 kg/ha + hand-weeding and hoeing at 6 weeks to cotton were next best integrated methods. Two hand-weedings and hoeings at 3 and 5 weeks to groundnut controlled weeds effectively in summer season and enhanced dry-pod yield as well as net monetary returns.