Using sorghum to suppress weeds in autumn planted maize

Weeds reduce the yield of maize (Zea mays L.) by utilizing the available resources such as water, nutrient and space. The phenomenon of allelopathy offers pragmatic option to suppress weeds in cereals including maize. This study was conducted to evaluate the weed suppression potential of sorghum in maize sown on beds or flat fields in post-sorghum and fallow plots. Sorghum-based weed management treatments included: i) control, ii) sorghum mulch (SM) at 8 t ha⁻¹, iii) sorghum water extract (SWE) at 18 L ha⁻¹, and iv) SM + SWE. The post-sorghum planted maize had significantly lower density (23.1%) and biomass (23.6%) of weeds than post-fallow planted maize. Weed density and dry biomass was 17.2% and 18.1% less in bed-sown maize than the flat-sown maize, respectively. Application of sorghum based treatments significantly reduced weed infestation in both maize cropping systems, however, combined application of SM and SWE in post sorghum bed-sown maize was the most effective treatment. Bed-sown maize planted in post-sorghum plots produced higher grain yield than post-fallow bed-sown maize or post-sorghum/post-fallow flat-sown maize. The treatment SM + SWE produced the taller plants and had more number of grains per cob, higher seed weight, grain and biological yields, and harvest index in post sorghum bed-sown wheat than other sorghum based treatments. In conclusion, the combined application of SM + SWE in bed-sown maize in post-sorghum fields provided fair control of weeds and increased maize grain yield.