Utilization of allelopathy and planting geometry for weed management and dry matter production of maize.

Undesirable impact of herbicides on environment had led to the efforts to search for alternative of herbicides. Allelopathy and planting geometry are possible alternatives for achieving sustainable weed management and dry matter production. The objective of this study was to evaluate the response of maize to allelopathy and planting geometry. Maize was planted in 75, 85 and 95 cm apart rows at New Developmental Farm, NWFP Agricultural University, Peshawar during 2006. Three allelopathic crops, sorghum (Sorghum bicolor L.), sunflower (Helianthus annuus L.) and mungbean (Vigna radiate Wilczek) were intercropped in maize rows alongwith sole maize with no weeding (control) and sole maize with hand weed control. Row spacing and allelopathic crops significantly affected plant height, weeds density and weeds biomass. Maize row spacing of 75 cm produced taller plants height (161.0 cm) and maximum stalk (7093.7 kg ha -1 ), whereas in allelopathic crop treatments, maximum plant height (170.9 cm) and stalk yield (8854.1 kg ha -1 ) were produced by hand weed control treatment. Sorghum intercropped with maize suppressed weeds density and resulted in low biomass of deela (Cyprus rotundus L.), field bind weed (Convolvulus arvensis L.) and itsit (Trianthema portulacastrum L.) compared with other treatments. It may be inferred from this study that weeds were better suppressed by 75 cm row spacing and sorghum intercropped plots.