INTEGRATED WATER AND NUTRIENT MANAGEMENT IN IRRIGATED KANO PLAIN’S PADDY FIELDS, KENYA

Abstract

Water shortage and paddy field nutrient (nitrogen) depletion are major constrains to sustaining and increasing rice (Oryza sativa L.) production in Kano plains, Kenya. Scarcity of water resources and increasing cost of conveying to paddy field calls for proper in situ water management towards reducing volume used per unit rice field. On the other hand high cost of commercial fertilizer makes rice farming expensive to many peasant rice farmers. As a response, an experiment was initiated with an objective to study effect of local inputs (rice straw, Azolla and fish culture- droppings) on some soil physico-chemical properties, nitrogen uptake, rice growth, yields and paddy field water requirement, when the inputs were used as nitrogen supplement to farmers’ practice (58kgN-Urea/ha).The experiment was conducted in West Kano Irrigation Scheme Kisumu County, consisting of three treatments and a control (farmer’s practice), laid out in a Randomized Complete Block Design (RCBD), replicated three times. Sample collection and characterization were done using standard procedures. Data was managed using Microsoft Excel software. Analysis of variance between treatments on the mentioned soil and rice attributes was carried out using General Statistical (GENSTAT) computer software and means separated with LSD (p≤ 0.05). Significant difference in nitrogen uptake (p≤ 0.05) were obtained in treatments; Azolla>fish-culture>farmers’ practice> rice straw. This was reflected in rice biomass accumulation and yield of 4.3, 3.8, 3.6 and 3.0 ton /ha respectively. Effective hydraulic conductivity induced by change in soil bulk densities was significantly different (p≤ 0.05) in the treatments; rice straw>Azolla>fish-culture>farmers’ practice, that of straw being exceptionally higher translating to treatment with the highest paddy-field water requirement (20.3 Megalitres/ha). The paddy field water requirements of Azolla and Fish-culture were significantly lower due to other factors that affected paddy- field water balance. Azolla and fish-culture treatments were considered to have potential to increase paddy rice production in Kano plains.