محاسبه نرخ بازده سرمايه گذاري در تحقيقات كشاورزي ايران

Calculating the marginal rate of return of agricultural research investment in Iran

Increasing population and deficit of production resources, draw attentions to increase productivity and optimal use of resources. Therefore, due to its specific impact, agricultural research will be important. Then, evaluating of optimal agricultural research investment is necessary. In this study, tornqvist-teil productivity index was calculated. Then, the impact of agricultural research and extension was considered on productivity by polynomial degree lag model and in next step the marginal internal rate of return calculated for agricultural research. The results showed that the productivity have had a climbing trend in agricultural sector during 1978-2002. Also, agricultural research investment affects productivity after 5 years and this effect will be left for 3 years. Long-term coefficiency of agricultural research is 0.28 and marginal internal rate of return was calculated up to 33.52 % in productivity model .