Effect of herbicides with and without manual weeding on weeds and yield of rainfed pigeonpea (Cajanus cajan L. Millsp.)

摘要

A field experiment was conducted during rabi 1993 and 1994 to study the efficacy of herbicide and/or manual weeding on weed control in rainfed pigeonpeas. Metolachlor 1.0 kg ha-1 + manual weeding (MW) effectively controlled weeds and maximized pigeonpea seed yields to 832 and 893 kg ha-1 in 1993 and 1994 respectively. Application of metolachlor or alachlor alone each at 1.5 kg ha-1, alachlor or pendimethalin each at 1.0 kg ha-1 + MW and manual weeding twice produced similar seed yields to metolachlor + MW. Pre-emergence application of oxyfluorfen and clomazone were phytotoxic to the crop and this was more pronounced with higher doses, especially of oxyfluorfen. Untreated control plots produced 55 to 60% yield losses compared with metolachlor + MW.Maximum economic advantage (benefit:cost ratio) was achieved with metolachlor or alachlor applied at higher dose (2.38 to 2.65) or at lower dose in combination with manual weeding (2.31 to 2.58).