On-Farm Adaptation to Climate Change: Assessment of Effects of Groundwater-Based Deficit and Supplementary Irrigation on Soil Quality Under Semi-Arid Ecosystems

Abstract

Agriculture is one of the sectors most affected by climate change, especially through the reduction in the number of rainy days in semi-arid areas, which require deficit supplementary irrigation (DSI) to minimise crop failures. Few studies have utilised soil quality indices (SQIs) to evaluate the quality changes of soils under DSI practices in semi-arid agricultural ecosystems. This paper examines the effects of DSI activities on soil quality in the Ingawa area of Nigeria’s semi-arid region. Plots subjected to different years of DSI (3, 5, 6, 8, 10, 11, 14 and 15 years) practices were chosen to serve as the controls. Soil samples were collected from each of the nine sites at depths ranging from 0 cm to 20 cm and 25 cm to 40 cm. The collected samples were analysed for physico-chemical properties. Soil quality change was estimated by computing percentage equivalence values that define the extent to which mean values of soils under DSI vary from those of the control. The results obtained show that the practices have caused significant negative changes in the levels of most of the properties considered, with significant deleterious effects on the selected physical and chemical indicators of soil quality to extents that might preclude sustainable agriculture on the soils. Potassium, organic carbon, organic matter, and some other essential nutrients needed for plant growth and soil stability have dropped a lot in irrigated farms compared to control farms, but salinization hasn't happened much. It was suggested that the right steps be taken to prevent the loss of important nutrients that crops need to grow well.