Biological Nitrogen Fixation with the Soybean and Common Bean Crops in the Tropics

Abstract

The majority of rural farmers produce maize in mono-cropping systems. Despite the relatively high rainfall, problems with acidity, low soil fertility, erosion, and poor management hamper crop production. Cost-effective strategies are required to improve the yields of resource-poor farming communities. A Participatory Research and Development approach was followed in the projects at Mlondozi, Bergville, Lusikisiki, Bizana, Qunu, and Thohoyandou. Information regarding the agricultural and socioeconomic status of communities was gathered using Rural Appraisals. The aim was to determine the needs, problems, fears, and aspirations of the people living in a community. The tribal authority and community were informed of the results, after which a planning session was held with representatives in the community on agricultural intervention options. Leader farmers were selected and trained in conservation agriculture. The technologies included reduced tillage, retention of crop residues, increased crop diversification, and integrated soil fertility management as well as plant pest and disease management. 'Best practice' manuals were compiled in the specific language of an area and translation was done during training sessions. Due to the incidence of illiteracy, the use of pictograms and clear associations clarified concepts, such as the process of nitrogen fixation, inoculation, and nodulation. Capacity building is an important aspect in agricultural development, and we have found that project sustainability largely depends upon the success of farmer-to-farmer training and the interest of the second-generation farmers. The process, benefits, and factors that influence biological nitrogen fixation (BNF) are well studied, but its significance needs to be conveyed to farmers continually. Since 1999, BNF was promoted in the crop diversification strategy of the Landcare. Traditional and alternative production methods were compared in researcher-and farmer-managed demonstration trials. The versatility of legumes in farming systems was emphasized as a protein-rich food source and/or animal feed, while improving soil fertility. Crop rotation, intercropping, and multiple cropping were evaluated, using cowpeas, soybeans, dry beans, lablab, and through Sustainable Agriculture.