Energy inputs and crop yield relationship in potato production in Hamadan province of Iran

The aim of this study was to determine energy consumption and the relationship between energy input and yield for potato production in Kaboud Rahang region of Hamadan state. The data used in this study are collected by questionnaire. The results revealed that nitrogen fertilizer (39%), diesel (21%), seed (14.9%), water (7.5%) and manure (6.4%) consumed the bulk of energy. In the surveyed farms, average yield and energy consumption were calculated as around 28613.7 kg/ha, 92296.3 MJ/ha, respectively. The results also showed that energy ratio, specific energy and energy productivity were 1.1, 3.2 MJ/kg and 0.3 kg/MJ, respectively. An econometric model was developed to estimate the impact of energy inputs on yield by using parametric methods. For this purpose, potato yield, an endogenous variable was assumed to be a function of energy inputs: fertilizer manure, chemical, machinery, human, water for irrigation, diesel and seed. The empirical results indicated that variables: fertilizer, chemical, seed and human were found statistically significant and contributed to yield. Among statistically significant exogenous variables, seed, water for irrigation, chemical, human and fertilizer were ranked in terms of elasticities.

► Nitrogen fertilizer (39%), diesel (21%), seed (14.9%), water of irrigation (7.5%) and phosphorus (6.1%), were the major contributors of total energy use in potato production.
► The share of machinery, potassium, human and chemical energy were found 2.4, 1.5, 0.6, and 0.6% respectively.
► The results showed that average yield in potato was 28613.7 kg/ha and potato production consumed a total of 92296.3 MJ/ha input energy.
► Energy output–input ratio was1.1 and specific energy and energy productivity were 3.2 MJ/kg, 0.3 kg/MJ
► According to parametric estimation results, seed energy was the most significant input that influences on yield. Results also showed that chemicals, diesel and machinery were other important inputs significantly contribute to yield.