Rapeseed yield as influenced by fertilizer placement methods and weed control practices under rainfed conditions

A study was conducted to investigate the effect of integrated use of fertilizer placement methods and various weed control practices on the seed yield of rapeseed during 2005-07 in Pothwar, Punjab at two locations i.e., Rawalpindi (receiving high rainfall) and Chakwal (receiving medium rainfall). Rapeseed cultivar Con-II was planted as a test crop. The experiment was conducted in randomized complete block design (RCBD) split plot arrangement with three replications. The net plot size was 4.5 m x 3.5 m. Fertilizer treatments were applied in vertical strips that were further divided to assign weed control treatments at random. Data regarding weed control treatments showed that hand weeding, inter-row hoeing and herbicide control in combination with below seed placement of fertilizer showed significant effect on weed mortality in Rawalpindi. Hand weeded plots where fertilizer was placed below the seed resulted in highest weed mortality (78%). While at Chakwal, the highest weed mortality percentage was recorded in the interaction herbicide application + once inter-row hoeing + below seed placement of fertilizer. The highest seed yield of 2325.74 kg ha(-1) was recorded in plots where inter-row hoeing was done twice and fertilizer was placed below the seed rows at Rawalpindi. At Chakwal, the highest seed yield of 1542.14 kg ha(-1) was obtained in hand weeded plots when fertilizer was applied below the seed. Weedy check treatment was at the bottom with the lowest seed yield at both locations during study period. Economic analysis indicated that farmers should use inter-row hoeing (twice) with below seed placement of fertilizer to get maximum returns at Rawalpindi. At Chakwal the interaction of herbicide application + once inter-row hoeing + below seed placement of fertilizer was very cost effective.