پژوهشهای حبوبات ایران (Feb 2024)
Evaluation of Energy Efficiency of a Common Pea Dry Land Farming System through Application of Complementary Irrigation
Abstract
IntroductionCommon pea is an annual crop of the legominosae family with the capability of biological nitrogen fixation, and as such it has an important role in increasing productivity of field soil and is commonly used in crop rotation programs. This crop has high nutritional value due to high concentrations of the essential amino acids lysine and tryptophan. Sustainability, in terms of obtaining maximum crop productivity from a system while maintaining conservation of its resources, is one of the most important components of an agricultural system. There is a close relationship between agriculture and energy, so that energy has a direct effect on the efficiency of crop production. Agricultural systems need to be evaluated in terms of input and output energy, so that based on that, the amount of energy consumed for product production per unit area can be determined. In essence, assessing the sustainability of production in agricultural systems involves considering the balance between energy input and output. Consequently, the identification and effective management of input energy become pivotal factors in enhancing the overall energy efficiency of a production system. The current research was carried out to evaluate energy consumption and production in a common pea dry land farming system to reach the best possible improvement of energy balance. Materials and MethodsEvaluation of the energy balance of a common pea dry land farming system and the effect of a complementary irrigation on total energy efficiency was determined from values for energy inputs and outputs including seed, pesticide (liquid herbicide), human labor (men and women), machinery, diesel fuel and grain yield per unit area. Energy inputs were determined from questionnaires completed by farmers. Farmers were asked to provide the information on their cultivation system including technical specifications for type of machinery used, including motor capacity, total land area, planting and harvesting method, crop yield per unit area, number of workers, amount of seed, amounts of fertilizer and pesticides. Energy efficiency of the system was evaluated by calculating the energy ratio and net output energy. Results and DiscussionResults showed that the highest energy input belonged to diesel fuel, followed by seed. Distances between the input of diesel fuel and other inputs were high, where 87% (12724 MJ.ha-1) of total consumed energy was allocated to diesel fuel. Grain yield of the common pea production system with and without complementary irrigation were 863 Kg.ha-1 and 645 Kg.ha-1, produced by consuming 14488 MJ.ha-1 and 14679 MJ.ha-1, respectively. In other words, complementary irrigation resulted in more input energy and grain yield. In the current research, complementary irrigation caused a considerable improvement in grain yield that resulted in higher output energy. Complementary irrigation increased input energy from 14589 MJ.ha-1 to 14679 MJ.ha-1 (60 MJ.ha-1was added) (Figure 2), but evaluations of energy ratio and net output energy revealed the positive effect of complementary irrigation on energy efficiency. ConclusionsThe dry land farming system for common peas exhibited low energy efficiency, primarily attributed to diminished grain production. Notably, diesel fuel consumption represented the highest energy input. While some essential production activities inevitably lead to increased input energy, it is recognized that managing inputs may not always guarantee improved energy efficiency. However, the experiment demonstrated that introducing complementary irrigation during the flowering stage of common peas resulted in an enhanced energy efficiency for the system.
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