| Agricultural research is an investment which has to compete for resources. While different studies have evaluated the performance of agricultural research systems in many counties, studies from Africa are very limited and in Tanzania, no study has attempted to quantify returns from investments in agricultural research. This study assessed the effect of expenditures on agricultural research on the productivity of crop production in Tanzania. The study also tested for technical change.; The study employed two measures of productivity. First, several partial productivity indicators were computed. These include the value of crop output per unit area, farm machinery per unit area, the quantity of fertilizer, improved seed and agricultural chemicals per unit area and the cultivated area per unit of farm labor. Second, an econometric model involving time series data from 1971 to 1992 was developed. In this model, the total factor productivity for fifteen selected crops was regressed against real expenditures on agricultural research and extension, the literacy rate, annual rainfall and real export earnings.; Results from the study show that, over the period of the study, biological technical change due to increasing use of fertilizer, improved seed and agricultural chemicals accounted for significant gains in agricultural productivity in Tanzania. However such gains and the potential for mechanical technical change were limited by adverse economic conditions, macro-economic policies that were not favorable to the agricultural sector and frequent policy changes.; Nevertheless, the study established that investments in agricultural research have contributed to agricultural productivity which has demonstrated a mild but erratic upward trend. A marginal internal rate-of-return of 33.2% for agricultural research was computed. However, expenditures on agricultural extension, a complement to agricultural research, were found to have a very low rate-of-return. Results from this study provide a bench-mark against which the performance of future investment in agricultural research and extension can be compared. |
