Influence of Seasons on Selected Water Quality Parameters within the Aquatic Ecosystem in South Nyanza Sugarcane Zone

Abstract

Sugarcane farming is the main agricultural activity done on a large scale in South Nyanza zone of Western Kenya. Farmers apply high rates of nitrogenous fertilizers for maximum yields. High rates of fertilizer application impact negatively on water physicochemical parameters within such ecosystems. However, such an impact seems to be region specific depending on land topology, soil type and rainfall patterns. In this work, we demonstrate the influence of seasonal variation on various physicochemical parameters within South Nyanza sugarcane belt. The parameters monitored include temperature, pH, turbidity, conductivity, biological oxygen demand, Cl-, F-, Fe2+, Zn2+, and Cu2+. The concentration of these parameters was monitored both in the dry and wet seasons. The experiment was laid down in a two factor completely randomized design with site as the main treatment and season as a sub factor. Analysis of variance was used to analyze the differences between trends within seasons at P ≤ 0.05. Mean seasonal results for wet season was 23 oC, 6, 135 NTU, 155 uS/cm, 65 ppm, 354 ppb, 100 ppb, 12 μg/L, 7 μg/L, and 6 μg/L respectively. While dry season was 26 oC, 7, 51 NTU, 106 uS/cm, 45 ppm, 168 ppb, 19 ppb, 2 μg/L, 1 μg/L, and 1 μg/L respectively. Seasonal variation greatly influenced the concentrations of physicochemical parameters within the sugarcane zone. The wet season is characterized with high fertilizer rate application and therefore it could be responsible for such like changes.