Integrated mechanical and chemical control of wild rice (Oryza Longistaminata) and its impact on rice yield in upper east region, Ghana

Abstract

Wild rice (Oryza longistaminata) is a pervasive weed in rice fields in the Upper East Region, significantly reducing rice yields and threatening food security. The study aimed to evaluate the efficacy of integrated mechanical and chemical control methods in Garu and Tempane Districts. The experiment was laid out in a split-plot design with three replications. The districts were assigned to the main plots and the weed control methods to the subplots. Land preparation was done manually, and Glyphosate was applied one week after, at a rate of 100 ml per 15 litres of water. One week later, Jasmine rice was planted. Data were collected on the wild rice population and rice yield parameters. The data were analyzed using GenStat 12 Edition; a two-way ANOVA was used to determine treatment differences. Means were separated using Lsd at a 5% level of significance. Results showed that glyphosate-based treatments effectively suppressed weeds. Plough + Glyphosate achieved the highest grain yields of 3.87 t/ha in Garu and 3.53 t/ha in Tempane. The weed control method was significant (p < 0.001) and reduced wild rice population by 2.7-fold.  Uncontrolled wild rice infestation reduced rice yields by approximately 56%. Combined Plough + Glyphosate application is recommended for managing O. longistaminata, with Glyphosate application only where resources are limited. Awareness of the weed's rhizomatous regeneration capacity is essential for farmers to understand the control methods. Further research should examine the cost-benefit analysis of the control methods and socio-economic factors that could influence adoption.