investigating relationships between the energy of consumed inputs and yields of tomato, cucumber and melon under plastic cover cultivation in iroozabad of fars province

abstract intensive and inefficient use of energy leads to degradation of natural resources and environmental problems. this study evaluated the relationship between the energy of consumed inputs and yield of tomato, cucumber and melon using the cobb–douglas production function. the data were collected from 90 farmers in firoozabad using a questionnaire. the farmers were chosen by simple random sampling method. econometric estimation results showed that energy inputs of human forces, machinery and irrigation water have significant and positive effects on yields of tomato and cucumber. while energy inputs of working force, chemical substances and irrigation water contributed significantly and positively to the yield of melon, the effect of fertilizer on the yield of this crop was negative. the impact of human labour energy was found the highest among the other energy inputs in tomato and melon production, but in cucumber production the highest share was related to the irrigation water. the results also indicated that the impact of indirect energy was higher than the impact of direct energy and the contribution of non-renewable energy was higher than renewable energy on yield of the studied crops.