Quantification of intra- and inter-row weed competition in maize

Abstract

Maize is sown in wider rows (60cm) and has slow initial growth making the crop sensitive to weed competition. The information on contribution of weeds in intra- and inter-row spaces on maize grain yield would help in designing effective weed management strategies. The competitive effect of intra and inter-row weeds on maize grain yield was investigated in a field study conducted at two locations under different agroecological zones in 2018. Four treatments (weedy check, weed free check, weed free in intra-rows (20 cm wide), weed free in inter-rows (40 cm wide) were evaluated in a randomized complete block design. The experimental fields had dominance of grass and sedge weeds. Weedy check plots recorded significantly higher density and dry biomass of weeds than
all weed control treatments. Weed free in inter-row had significantly lower total weeds density and biomass than weed free in intra-row. Season long weed competition reduced maize grain yield by 31-40%. Weed free check recorded the highest maize grain yield (6.9-7.3 t ha ^-1) which was significantly higher than all weed control treatments. Weed competition in intra-row and in inter-row reduced grain yield by 10-14% and 14-15%, respectively, in comparison with weed free check. The study concluded that effective control of weeds in inter-row as well as in intra-row was important and broadcast application of herbicide was desirable. Alternatively, integrated use of band application of herbicide in intra-row and mechanical weeding in inter-row could be adopted for reducing herbicide load in maize.