Improved Common Bean (Phaseolus vulgaris L.) Production Systems in Masaka, Uganda.

Common bean (Phaseolus vulgaris L.) is an important food source to Ugandans, supplying 15% of their dietary protein. Unfortunately, bean production in Uganda has a yield gap of about 75%. To narrow this yield gap, we conducted a field study in Masaka District, Uganda to determine whether improved bean management systems could significantly increase yield and profitability. The experimental design was a RCB in a split-plot configuration. The whole plot factor was three bean management systems and subplots were four bean cultivars. Management systems were conventional farmer low-input (LI), moderate inputs (MI), and high inputs (HI). The study was conducted at two locations varying for soil type: black soil Hapludoll and red soil Eutrudox. Both soils were sandy clay loam texture. Specific nutrient additions and rates differed between sites. Farmers avoid planting bean on red soil if black soil is available.

On black soil, the HI yielded 1808 kg ha^-1, 896 kg ha^-1 more than LI. Beans grown on red soil under MI or HI had mean yield of 1213 kg ha^-1, 795 kg ha^-1 more than LI. The NABE 4 and NABE 14 bean varieties frequently produced significantly greater yields than the other bean varieties under MI and HI. For the first rainy season on black soil, bean grown in MI and HI had greater net profit than bean managed with LI. Conversely, on the red soil greatest net profit was obtained with bean under LI. Beans grown with MI and HI on the red soil provided net losses due to the need for expensive limestone to ameliorate soil acidity. The experiment is being continued for a second rainy season on both sites to determine residual effects of management system and bean variety.