Effect of different land use types on nutrient distribution across soil depth in the Busega wetland

Abstract

This study was conducted to evaluate the effect of different land use types on nutrient distribution across soil depth in Busega wetland. The sites where this study was conducted had been under annual and perennial cropping systems for more than 10 years. Three samples were collected from annual cropping system, perennial cropping system and undisturbed cropping system at varying depth of 0-10cm, 10-20cm and 20-30cm from each block that was selected and subjected to routine laboratory analysis in Makerere university soil science laboratory. Soil samples were analyzed for physical properties like texture; chemical properties included N, P, exchangeable bases like K, and Ca, and pH; and biochemical properties like soil organic matter (SOM). All the soils were found to be moderately acidic, with pH within a favorable range for availability of nutrients like P that is 5.5 – 6.5 probably due to the moderate to high exchangeable bases observed. For all land use types, there was larger sand content at the top which ranged (57.7- 78.) % compared to either clay (10-22.7) % and silt (11-29.7) % regardless of the cropping system. Within the cropping system, SOM were higher under perennial cropping (38.8) % than annual cropping (34.0) %, and undisturbed implying that the soils under annual cropping were less protected against loss of finer particles for example through soil erosion. The soil of Busega wetland was observed to be moderately deficient in N and severely deficient in P (grand mean of 0.16%N and 4 kg kg-1 P as compared with the criticals of 0.2% and 15 mg kg-1 P) respectively with annual cropping having significantly lower values than perennial cropping and undisturbed. Perennial cropping and agroforestry systems that improve soil protection as well as application of N and P fertilizers are urgently needed.