Impact of agrochemicals application on soil quality indicators and trace elements level of wetlands under different uses

Abstract

An attempt to boost agricultural production has led to increased agrochemical usage. Continuous agrochemical usage for decades has brought changes to soil properties. The study assessed the impact of agrochemicals (fertilizers and pesticides) on wetland characteristics in Abeokuta, Nigeria. Five wetlands under maize, plantain, rice, vegetable productions, and control site were studied. Profiles were dug on each wetland, and soil samples were collected from pedogenic horizons and analysed using appropriate techniques. The morphological properties like colour, texture, structure, and consistency differ across the wetlands. The particle size fraction showed that the sand content was higher than silt and clay contents. Soil chemical indicators like pH, OM, TN, and K were lower in agrochemicals applied fields than in the control site, whereas available P was increased in these fields. The total trace element contents were highly affected and their levels have almost reached the permissible limit of WHO standards for agricultural purposes. Nutrient depletion and trace element build-up were more prominent in agrochemicals applied fields as against the control field. Information gathered from this study can help the policymakers on the proper usage and management of these wetlands on a productive and sustainable basis. To reduce agrochemicals impact which majorly contributed to the differences in the soil quality indicators and trace elements level, it is our opinion that planning to shift toward organic agriculture with no or minimal use of agrochemicals are to be considered.