Herbicide use dynamics on cassava-based farming systems in yewa division of Ogun state, Nigeria: Economic, environmental and health perspectives

Weed reduces cassava crop yields by competing for essential nutrients, leading to yield loss above 70 per cent of the yield potentials. Manual weeding has often been the predominant weed control practice to smallholder farmers, claiming about 50-70 per cent of their total labor time. Chemical weed control provides economically viable alternatives to hand weeding, with its attendant disruption of soil ecology, and health hazards to the farmer. This study assesses the dynamics of herbicide use on cassava-based farming systems in Yewa communities of Ogun State, Nigeria. Primary data were obtained from 128 cassava farmers, using multi-stage sampling technique. Data were analysed using descriptive statistics, and logit/covariance model estimations. Descriptively, herbicide adopters (74 per cent) were of mean age 52 years, average farm size (2 hectares); and average household size (6 persons). The environmental effect of herbicide use was 61.06 per cent on cultivated crops; 12.63 per cent on soil micro-organisms; and 26.31 per cent on the farmer/his livestock. To all respondents, herbicide use helped to boost soil organic regeneration. Barely 52 per cent of the perceived health hazards of herbicide use was on farmer's sensitive organs (eye, nose and skin), followed by body weakness (28.42 per cent) and vomiting (8.42 per cent). Empirically, sex (0.466; p<0.01), education (0.008; p<0.05), farm plot consolidation (0.138; p<0.05), and large-scale farming (0.120; p<0.05) significantly influenced farmers’ decision to use herbicides, while age (-0.005; p<0.1) and high cost (-0.051; p<0.01) reduced it. Herbicides use intensity (HUI) increased with weeding frequency and farmland segregation; but decreased with high application costs. Training of farmers to embrace herbicidal options was recommended to boost cassava production in the study area.