Effect of weed management practices on productivity, economics, quality and soil fertility of Guinea grass (Panicum maximum)-based pasture intercropped with legumes

A field experiment was conducted during 2006–2011 on sandy loam soil at Central Research Farm of Indian Grassland and Fodder Research Institute, Jhansi to find out the effect of weed control measures on forage productivity, quality, soil fertility status and economics of Guinea grass (Panicum maximum Jacq.)-based pasture intercropped with legumes. Intercropping of Stylosanthes seabrana B.L. Maass &’t Mannetje with Guinea grass produced significantly higher total green and dry forage yields (25.10 and 6.68 t/ha) than Clitoria ternatea vine (19.10 and 5.41 t/ha), Macroptillium atropurpureum (DC.) Urb. (20.17 and 5.60 t/ha) and Stylosanthes hamata (L.) Taub., (23.36 and 6.29 t/ha). Intercropping of Stylosanthes seabrana with Guinea grass also resulted in significantly higher total crude protein yield (582.0 kg/ha) as compared to Clitoria ternatea (457.7 kg/ha) and Macroptillium atropurpureum (474.9 kg/ha). In weed management practices, hand-weeding 35 days after sowing in first year and 25 days after onset of monsoon rain from second year onwards recorded significantly higher green forage, dry forage and crude protein yields of both Guinea grass (16.48 and 5.02 t/ha and 344.0 kg/ha) and legumes (9.05 and 2.0 t/ha and 271.8 kg/ha) than weedy check, pre-emergence application of pendimethalin @ 0.75 kg a.i./ha and weeding with weeder cum mulcher. The highest net returns (13, 733/ha) and net returns/rupee invested (1.48) were obtained by intercropping of Guinea grass with Stylosanthes seabrana. Hand-weeding 35 days after sowing in first year and 25 days after onset of monsoon rain from second year onwards also recorded maximum net returns (12, 746/ha). Intercropping of Stylosanthes seabrana with Guinea grass resulted in significant improvement in organic carbon (0.48%) and available nitrogen (228 kg/ha) than Clitoria ternatea and Macroptillium atropurpureum. Available nitrogen (226.2 kg/ha), phosphorus (9.91 kg/ha) and potassium (195.8 kg/ha) were also significantly higher in hand weeded plots than weedy check (211.3, 9.05 and 179.1 kg/ha).