Assessment of physicochemical properties of soil under different flood patterns in recession farming in the Okavango Delta, Botswana

Abstract

This study examined the physical and nutritional properties of soils in the Okavango Delta flood plains recession farming systems to understand how flood patterns affect soil qualities and agricultural productivity. A soil auger was utilized to sample soil at 30‐cm depth for physicochemical parameters. Absorption spectrophotometry was used to measure exchangeable cations, such as calcium (Ca ²⁺ ), magnesium (Mg ²⁺ ), potassium (K ⁺ ), and sodium (Na ⁺ ), and Bray‐1 to measure phosphorus (P). Soil organic matter was measured by loss on ignition. Bouyoucos hydrometers analyzed soil texture. Mean differences in soil nutrient scores, pH, and soil organic matter between flood types were compared using one‐way analysis of variance. One‐way multivariate analysis of variance was used to compare soil nutritional components across the flood types. The results showed that seasonal flood plains where flood‐recession farming is performed have soils with good nutrient status and physical qualities, making them more productive in terms of plant growth. Soils under flood‐recession farming have a high concentration of calcium and a nutritional order of Ca > Mg ≈ K > Na > P. Lake flats have very high Mg concentration and mildly acidic soils (pH 5.72). The study revealed a highly stratified nutritional environment that was dominated by Ca, with large amounts of Mg and K. P was the most important potential limiting nutrient for crop yield in these agricultural systems. Variations in the flood pattern had no substantial effect on soil organic matter, pH, or physical qualities indicating environmental resilience, a benefit to Botswana's agricultural sector. Additionally, climate change affects flooding patterns.