Introduction: Wheat is the most important agricultural product in Sistan, which, depending on the availability of water, provides a substantial portion of the region's farmers with a living. Consequently, farmers attempt to expand their cultivated area. But any progress towards increasing production will be valuable if it continues for an extended period of time, particularly the continuation of the production of this product, which is of great importance in terms of meeting a portion of families' food needs and generating income for its producers. Proper management of the production system, environment, and natural resources is required to ensure the long-term sustainability of this crop. In order to determine whether this production system will continue to exist in the future, it is necessary to examine the production stability of these systems by analyzing the total input and the effect of these inputs on the substrate and the surrounding environment. Consequently, it was decided to evaluate the sustainability of wheat production in the Sistan region by employing the emergy analysis technique and determining the contribution of each input and their impact on the production system and the surrounding ecosystems using this method's indicators. The emergy exchange ratio was used to assess the sustainability of wheat systems in this article.
Materials and Methods: In 2020, wheat fields in Sistan (including Zabol, Zahak, Hamoun, Nimrouz, and Hirmand) were surveyed for this study. Each category was further subdivided into renewable and nonrenewable categories. Regional meteorological stations recorded renewable environmental inputs. The USLE model was used to calculate soil erosion, and wheat fields were measured for organic matter changes. The amount of economic inputs was determined by interviewing wheat farmers, and the amount of machinery was based on its lifespan. The ISO1928 method defines energy output in calories. Multiplying the total input current by the transformities yielded solar emjoules (sej). In addition to inputs, emergy indices, a function of environmental and purchased flows, must be calculated to evaluate wheat production sustainability. The desired indicators for this study are transfomity (Tr), specific emergy (SpE), emergy renewability percentage (R%), emergy yield ratio (EYR), environmental load ratios (ELR and ELR*), environmental sustainability indices (ESI and ESI*), emergy investment ratios (EIR and EIR*), and emergy exchange ratio (EER).
Results and Discussion: It was important that environmental inputs contributed 5.35E+16 sej ha^-1 yr^-1to the total inputs that the production system required. Both EYR and EIR have favourable values, as a result of the strong impact that environmental inputs have on the production process. Considering that all methods of production include the use of natural resources, it is inevitable that there would be negative effects on the surrounding ecosystem. As a result of the significance of this matter, an index that has been given the name environmental loading ratio has been established in order to provide an approximation of the amount of pressure that this system puts on the environment. The determined value of this index is 3.85, which suggests that the manufacturing system only puts a moderate amount of stress on the environment. However, taking into account the fact that this system was sustained by 34% renewable resources, the revised environmental load ratio index caused the production system to behave more flexibly with the ecosystems that were located in its immediate vicinity.
Conclusion: The normal operation of a production system requires the interaction of natural and purchased inputs, and the absence of one of these inputs causes more of the other type to be introduced. The substantial contribution of natural resources to the production process, relative to purchased inputs, demonstrated that wheat production in the Sistan region is traditional. This traditional production method has had the greatest impact on wheat production in the region due to soil erosion. Therefore, management practices that preserve plant residues within the field can have a positive effect on the region's wheat production.