Legumes play important roles in the cereal-based systems of southern Africa to contributing to family nutrition, income and building fertile soils for a sustainable future. Legume diversification is central to farming system productivity, and using limited supplies of manure and fertilizer in an effective manner. Through biological nitrogen fixation legumes are major source of N, and there is growing evidence that semi-perennial, deep rooted species have unique properties and mychorrhizal symbioses that build soil organic matter and solubilize soil phosphorus (P), thus are crucial to improving water relations and enhancing fertilizer efficiency. Maize yields in Malawi had remained low, partly due to low adoption of improved varieties but also due to soil nutrient loss through continuous mono-cropping. Since 2005/06 season there have been substantial improvements in maize production and food self-sufficiency following implementation of a government subsidized seed and fertilizer scheme, supporting 1.7 million vulnerable households in 2010/11. This has become increasingly expensive as fertilizer prices have risen so alternative approaches to make efficient use of more limited fertilizer inputs across the country are a priority. Since 2006 the research team has been working with farming communities in Ekwendeni and Kasungu districts of Malawi to explore, through on-farm trials, “best bet” combinations of legumes: groundnut, soya and pigeon pea planted in rotation with maize. Sustainable intensification strategies must take into account the urgent need to build resilience, and the capacity to adapt to climate change. Best bet legumes and enhanced farmer innovation are proposed as means to improve water and soil management, while diversifying crops. Legumes are key to enhancing soil organic matter, for sustained improvements in farming system productivity – in the face of erratic rainfall. In phase II of the project, the multidisciplinary team has documented adoption among farmers of ‘doubled up’ legume technologies. Farmers are now growing doubled up legumes, primarily intercrops of pigeon pea with groundnut, and trying out new combinations of legume varieties and growth types. The benefits of adoption by thousands of families need to be evaluated, in terms of impact on soil fertility, cropping system resilience and family nutrition. Moreover, farmer experimentation and adoption over a larger area needs to be promoted. Scaling out adoption and documenting ‘best bet’ legume impact (investigating consequences for farming system resilience and soil resources) is at the core of Best bets phase two. Led by University of Malawi, the project team includes support for post-graduate training, climate and crop modeling from Michigan State University. Field work is implemented with agricultural extension staff, NGOs Malawi Enterprise Zone in Kasungu, Ekwendeni Hospital and in Ntcheu with the NGO LOMADEF. The team links knowledge on role of legumes in increasing crop productivity to nutrition education provided by Ekwendeni hospital.
The project goal is to expand the knowledge base regarding how legumes impact farming system resilience, over the short term through cropping system diversity and over the long-term through improved soils, expanded market opportunities, and nutritious diets. Project results are:Improved knowledge of best bet legume influence soils and cropping system resilience in the face of climate change.Enhanced innovation and scaling out best bets to reach >40,000 farmers living in or near project sites, and extension materials developed and disseminated to support Malawi and Mozambique governments educate their citizens.Deepened impact of best bets legume diversification through expanded legume knowledge and use by the most at risk HIV-AIDS affected households.Enhanced knowledge of scientific principles of family nutrition, soil processes and legume agronomy will be widely promoted, and capacity enhanced at University of Malawi to carry out ‘science for development.
Outputs and Outcomes:
Maize planted after a groundnut/pigeon pea intercrop and fertilized with 23 kg N ha-1 produces an equivalent yield to continuous maize fertilized with 92 kg N ha-1.Farmers prefer to plant a pigeon pea/groundnut inter-crop in rotation with maize as it is labor saving and contributes to diet diversification, high levels of residual N in soil and high maize yields compared to sole crop maize and single legume/maize rotations.70% of participating farmers are expanding production of doubled up legume best bets in Ekwendeni, and 90% of farmers experimenting with pigeon pea in Kasungu are interested in growing the multipurpose legumes.Farmer to farmer exchange through visits between Ekwendeni and Kasungu sites have enhanced local knowledge of integrated soil fertility management and use of legume grains to diversify family diets through new recipes.Innovative extension underway includes nutrition education through recipe days, on-farm adaptation of legume varieties and residue management practices, and farmer-to-farmer visits.During 2011 the project established trials in Ntcheu district to introduce the potential for legume integration to additional extension partners and farming communities.One PhD and two MSc studies have been completed through the project and two further MSc projects are on-going.