Management of Symbionts in Calliandra (Calliandra calothyrsus Meisn., Leguminosae) Based Agroforestry Systems to Improve Growth, Productivity, Quality of Fodder, and Biological N₂ Fixation

In eastern Africa, continuous land use, due to the shortage of land and the lack of resources to use chemical fertilisers, has induced a decline in small-scale farm productivity. Therefore, as part of an INCO-DEV project (Contract No. SAFSYS Project No. ICA4-2000-20037), the long-term goal is to find low-input ways of sustainably improving tree establishment, growth, and fodder production, which are likely to be widely adopted by the resource-poor small-scale farmers in eastern Africa. Calliandra calothyrsus (calliandra), an N₂-fixing agroforestry tree, is being used because of its increasing socio-economic and environmental importance for the resource-poor smallscale farmers in the region. In common with many other tree species, mycorrhizal and rhizobial inoculation is beneficial to its growth, but participatory research with tree nurseries, farmers, and other stakeholders is necessary to develop appropriate inoculation methods and improve uptake pathways. We have undertaken a multidisciplinary approach and utilised effective strains of rhizobia and arbuscular mycorrhizal (AM) inoculants to study the persistence of inoculants and evaluate their effects on growth, productivity, and quality of calliandra fodder in field conditions.