Soil fertility management in banana plantations using grass mulches and manures in South Western Uganda

Abstract

Uganda’s soils were once believed to be the most fertile in Africa, but soil nutrient mining and soil erosion have led to soil degradation and declining agricultural productivity. Lack of environmental awareness among farmers, traditional agricultural practices, minimal inorganic fertilizer use, and little to no use of improved crop varieties all contribute to continued soil degradation. East Africa Highland banana yields on smallholder farms in the Great Lakes region are small Uganda inclusive. The major causes of poor yields are declining soil fertility and soil moisture stress. In order to improve production, knowledge on highland banana response to fertilization is important, to establish the effect on soil and hence the crop yield. The objective of this study was to determine the effect of mulching and manuring on chemical and physical properties of soils in banana plantations in Bushenyi district. The study was conducted in Kyeizooba sub-county, Bushenyi district in southwestern Uganda. Ten soil samples were taken from mulched and ten from unmulched, five from top soil and five from subsoil for each treatment were analyzed at Makerere university soil science laboratory for pH, total nitrogen, available phosphorus, exchangeable potassium, soil organic Carbon and texture. For top soils, the pH was significantly higher in mulched (7.25) than in unmulched (6.34). For sub soils the same trend was observed mulched (5.93) and unmulched (4.78). However for both mulched and unmulched plantations, the pH of sub soils and top soils were not significant (p>0.05). Nitrogen content in top soils of mulched and manured plantations was significantly (p<0.05) higher than that in sub soils. Also under both treatments, the N content of top soils was higher than that in sub soils. P content in top soils of mulched and manured plantations was significantly (p<0.05) higher than that in sub soils. In both treatments, the P content of top soils was higher than that in sub soils. The K content in top soils of mulched and manured plantations was significantly (p<0.05) higher than that in sub soils. Also the K content of top soils was higher than that in sub soils under both treatments. SOC content in top soils of mulched plantations was significantly (p<0.05) higher than that in sub soils. Also under both treatments the SOC content of top soils was higher than that in sub soils. The clay content in top soils was significantly (p<0.05) higher in mulched than in unmulched plantations. For both soil levels, sand content was significantly (p<0.05) higher in unmulched plantations than in mulched, for both mulched and unmulched sand content was higher in topsoil than in subsoil. Silt content was similar in the top soils of both treatments. For sub soils, silt content was higher (p<0.05) in unmulched than in the mulched. For mulched silt content was higher in top soil than in subsoil and in unmulched, no significant difference was observed.