Soil properties and nutrient availability in furrow irrigated plots of Mubuku irrigation scheme in Kasese District

Abstract

Irrigation and application of mineral fertilizers are some of the strategies being undertaken in the irrigation schemes to boost crop yields amidst climate change and soil fertility decline. However, there is limited information on the interaction between water and nutrient movement in the rizosphere. This study therefore assessed the effect of furrow irrigation on nutrient variability across the gentle distance from tertiary canals of Mubuku irrigation scheme in Kasese district. Thirty six soil samples were collected using random sampling method at a depth of 0-15cm and 15-30cm from three points: near the tertiary canal, in the midpoint away from the canal and at the end of the plot where the excess irrigation water is drained. Samples were collected in two replicates from each of the plots under three treatments of UREA (0, 50 and 100 kg N ha-1arranged in a randomized complete block design. Soil sample analysis was done in the soil, water and plant analytical laboratory, School of Agricultural Sciences, Makerere University. Each of the soil samples was air dried, ground using mortar and sieved through a 2 mm sieve and analyzed for pH, OM, EC, available P, total N, exchangeable cations (K and Na) and soil texture following standard laboratory procedures. Data subjected to analysis using the GenStat 14th Edition Statistical software using (LSD) at 5% probability level. There was no significant (P>0.05) effect of urea application on N content at the end of the cropping season across two sampling depths (0-15cm and 15-30cm) and distance away from the tertiary canal. Likewise other selected soil properties (pH, SOM, available P, K, Na and texture) did not significant vary with sampling depth and distance from the tertiary canal (source of water furrow irrigation).Based on absolute values, there was slight surface movement of nitrogen, phosphorous and soil organic matter and accumulation at the end of the plots probably due to runoff during irrigation. Therefore, here is need for timely application of irrigation water in correct amounts so as to optimize water and nutrient use efficiency. Future studies could also focus on assessing soil biological properties as affected by irrigation and nutrient management. Additionally, there is need to track changes in soil properties before, during and after irrigation to have a temporal perspective during the cropping season. Soil and water conservation practices should be done to reduce on soil and nutrient loss in runoff to the bottom end of the field