Soil fertility variation in mulched and unmulched Robusta coffee fields in Namayumba sub-county, Wakiso district

Abstract

The study aimed at investigating the variation in soil physicochemical properties between mulched and un-mulched Robusta coffee fields and the contribution of different mulching materials to soil properties. Mulching materials used in this study included; dry bean trash and dry banana leaves/ pseudo stem and the control where no mulching material was used. Simple random sampling was used to obtain composite soil samples from the coffee fields at the depth of 0-30 cm. In each Robusta coffee field, four replicates were made and a total of thirty two composite soil samples were transported and analyzed in the soil Science laboratory in Makerere University for soil pH, soil Organic carbon (OC), Total Nitrogen (TN), available Phosphorus (Av.P), Potassium (K), Sodium (Na) and Calcium (Ca). Statistical analysis was done using SPSS version 27. An independent sample t-test was used to check if there was any difference between mulched and un-mulched Robusta coffee fields and a one-way ANOVA was used to check for statistical significance between the different mulching materials used in the Robusta coffee fields. Over all, the bean mulch resulted to higher SOM, TN, pH, and exchangeable bases like Ca and K. The bean mulch was followed by fields that were under dry banana mulch and the control respectively. The findings of this study conclude that mulching especially in the resource poor communities can be potentially beneficial in improving soil properties and help build the soil resource for sustainable coffee production amidst the increasing strategies to promote coffee growing and exports in Uganda. However, the observed TN was low in all the study areas, this suggests that for improved crop production, incorporation of inorganic fertilizers is encouraged to supplement on the status of soil N, P and K that are essential for yield if other production factors are enhanced and optimized for Robusta coffee production.