Soil management requirements for banana production on the heavy soils around Lake Victoria in Uganda.

摘要

Production of bananas, the basic staple for 75% of the population, has declined in Uganda. This decrease has been attributed to many factors among which soil fertility is paramount. A long term study was carried out during 1990-95 to investigate thesoil management options that would sustain banana production in the Lake Victoria region of Uganda. The study involved three experiments, the first being a study on the effect of different mulches on banana yields and soil conditions. The mulches included maize stover, soyabean residues, tall swamp grass and mucuna live mulch. The second experiment studied the effect of potassium fertilizer on banana yields and soil conditions after application of 25, 50, 100 and 200 kg K ha-1. The third experiment investigated the effect of four application techniques viz. 100% surface, 50% surface plus 50% incorporated, a third (48 t) surface and a third (48 t) incorporated and 100% incorporation of 144 ton ha-1 of coffee husks, on soil fertility, banana root systemand bunch yield. Banana root biomass, soil water infiltration rates, soil macrofauna, and banana yields were recorded. Maize stover mulch increased banana yields more than any other mulch, while the control had reduced yields every subsequent year. Thismeans that mulches that are easily degraded to release nutrients, increase banana yields enormously. Application of 200 kg K ha-1 more than doubled the yield, which showed that potassium deficiency in farmers fields could be one of the factors responsible for banana production decline in the country. Coffee husk application more than doubled banana yield in comparison to the control plots where coffee husks were not applied. However, the best technique of application was half-incorporated and half on the surface. This was attributed to soil betterment that led to improved root biomass and yield. It was concluded that sustainable banana production in the Lake Victoria region of Uganda, which has relatively heavy soils, requires improved soil physical,chemical and biological properties. This could be done through mulching with easily degradable materials, improved organic management and where possible potassium fertilizer should be applied to meet the high plant demand for this nutrient.