investigation of renovation effect of combine harvesters on wheat losses decrease in iran

in this research, the effects of combine renovation as a mechanic harvest evaluation index of wheat were studied. results show that this renovation has decreased wheat losses by 1368 thousand tons which worth 2462400 million rials. two scenarios were investigated. first, under real condition with earmark of government subsidies for purchasing machines, was studied at both guaranteed and world prices. internal rate of return in these cases were 96.92 and 88.43 percent, respectively. in the second scenario, in which government subsidies were considered, these rates were 18.58 and 15.98 percent, respectively. results suggest that renovating old combines is acceptable in all scenarios and with proper rate of return, and even with eliminating governmental subsidies and world prices, it has economic justification.