Agronomic and economic impact of legume inoculant use in Zambia, 1985-1992.

Abstract

The global economic impact of BNF technology is enormous, estimated at $85 billion annually. But donor and government policy makers do not have access to meaningful and accurate data with which to make effective decisions on national investments in BNF technology. It is infrequent that a BNF development component of a research project is viewed under the microscope and analysed for economic impact eight years after start-up. In May 1993, a team made up of USAID, NifTAL and Zambian BNF specialists pursued a unique opportunity to accurately measure the various impacts resulting from the introduction of BNF technology. Prior to NifTAL’s participation in the establishment of the inoculant production unit at Mt. Makulu in 1984, there was minimal inoculant production and the soyabean industry was just emerging. This situation provided a clear database. Other complimentary factors include the single crop — single inoculant — single user situation that exists in Zambia which facilitated data collection and narrowed the focus enabling the team to produce meaningful and accurate conclusions. High quality inoculant production was effectively maintained at Mt. Makulu up to the 1989-90 production season; in 1990, peat processing and inoculant production was transferred to the Balmoral Veterinary Research Institute. Although soyabean is not the predominant legume crop, its production level is increasing at a fast rate with a production growth rate of 27% and an increase in area under production from 5 300 ha in 1982 to 35 000 ha in 1990 (an increase of 660%). It is also the only commercial legume crop where inoculant is applied, thus making it the focus of this study. The total economic benefit derived from inoculants over the 1984-92 period which is attributed to soyabean yield increase is about $17 874 000. It is estimated that soyabean inoculation practices reduce national urea fertiliser consumption by about 14% annually (7 000 mt). For the eight year period concerned in this study, inoculation benefits (in terms of derived N) equalled about 6% of total urea consumed for that period or about 30 000 mt (1984 to 1992). Economical and environmental impacts are significant.