Research evaluation and impact analysis of biological nitrogen fixation

Although viable Rhizobium inoculation technology for cultivated legumes has long been available, there has been little sustained adoption of this technology in tropical regions. Reasons contributing to this include inadequate demonstration of the technology, presence of adequate native rhizobia, high soil mineral nitrogen levels which suppress nitrogen fixation, inadequate quality control of Rhizobium inoculum and difficulties of inoculating under tropical conditions. In order to ensure a better adoption rate of existing or emerging biological nitrogen fixation (BNF) technologies, it is proposed that future research and development efforts better focus on the research-adoption-impact continuum. The salient features of this approach are described in this paper, using the example of recently developed nodulation variants in chickpea as a potential means of increasing BNF in this crop. It is suggested that previous experience with Rhizobium inoculation technology is amenable to ex-post impact analysis to analyze bottlenecks, and that ex-ante impact analysis should be built into on-going or planned BNF research, to better ensure that technology adoption occurs.