Climate variability and effect of management practices on soil properties among banana farmers in Mbarara district, Uganda.

A dissertation submitted to the Directorate of Research and Graduate Training in partial fulfillment of the requirements for the award of the Degree of Master of Science in Environment and Natural Resources of Makerere University.

Climate variability is a significant challenge facing perennial crop farmers in Mbarara district Uganda. East African Highland Bananas (Musa AAA-EAHB) are vulnerable because production systems are built on highly weathered soils, the crop has a large water requirement and a shallow rooting system. With the loss of sustainability due to declining soil organic matter levels and increasing pest pressure widely reported, climate variability is thus likely to exacerbate the situation. Small-scale farmers of Mbarara district rely on this crop for food, sale in urban centers such as Kampala for income to meet basic needs. The aim of this study was to assess farmer’s perception on climate variability and effects of management practices on soil chemical and physical properties. Data was collected from three sub-counties Nyakayojo, Biharwe and Bubaare of Mbarara district, and 36 banana farmers were randomly selected from each sub-county for interview. Projected data were obtained from the Rossby Center regional atmospheric model (RCA) while historical data from NASA. A total of 108 soil samples were collected from the 3 sub-counties. Soil samples were taken at three depths; 0–30 cm, 30–60 cm and 60–90 cm. Soil samples were analyzed from Soil and plant analytical laboratory at Makerere University. Results show that for the period of (1981–2019), the long-term annual rainfall trend was significantly decreasing (P-value = 0.002). Projected rainfall is expected to slightly increase throughout the future period. In the near future rainfall is expected to increase slightly by 115.3mm (RCP4.5) and 89.1mm (RCP8.5), mid-century by 68.4mm (RCP4.5) and 89.1mm (RCP8.5), end-century by 100.1mm (RCP4.5) and 171.1mm (RCP8.5) per annum. Projected temperature both minimum and maximum may decrease thought the future period except maximum temperature under RCP 8.5 in both mid-century and end-century. Farmers in the sub-counties had fair knowledge on climatic variability with only 67% reporting changes in seasons. Soil nitrogen (N), organic matter (OM) content and cation exchange capacity (CEC) were below critical levels for satisfactory banana growth in Bubare and Nyakayojo implying that the management practices were not having a big impact on soil parameters. There was a significant difference in the Cation Exchange Capacity (CEC) between Biharwe and Bubare (P < 0.001); Biharwe and Nyakayojo (P-value = 0.03). Farmers should therefore focus on climate adaptation measures to counter the impacts of climatic variability. There is also a need to raise knowledge or education levels of the farmers on climate variability on banana farming. In order to increase the soil nutrients such as cation exchange capacity, soil nitrogen and organic matter, farmers should be advised to manage and apply more farmyard manure, compost and mulch the banana plantations.

GMES AND AFRICAN –ICPAC PROJECT