Integrating life cycle assessment (LCA) with boundary line analysis (BLA) to reduce agro-environmental risk of crop production: a case study of soybean production in Northern Iran

Increasing the yield of oilseeds is considered an important plan and strategy in different countries such as Iran. With limited available arable land, boosting the cultivation of oilseeds should involve increasing per unit area. Therefore, narrowing the yield gap (YG) and optimizing agricultural practices/inputs can be the efficient strategies for improving food security and mitigating the environmental impacts of agriculture. For this purpose, the boundary line analysis (BLA) was integrated with the life cycle assessment (LCA) in this study to survey 301 soybean farms. BLA analysis calculated attainable yield and YG as 4437 and 1972 kg ha(-1), respectively. According to the results, the BLA improved the efficient use of resources and attenuated environmental hazards by exploring the causes of YG and optimizing farm practices, something which was confirmed by the LCA and the ReCiPe2016 model. For instance, optimization of nitrogen, phosphorus, potassium, and sulfur fertilizers resulted in reduction rates of 44%, 45%, 87%, and 56% the in global warming potential, respectively. As a result of the BLA-optimized tillage operations, the impacts of mineral resource scarcity and freshwater eutrophication were reduced by 15% and 16%, respectively. In addition, a reduction rate of 52% was also observed in the water use impact category due to the optimal irrigation frequencies, i.e., 1-3 times. Moreover, diesel fuel and fertilizers are the primary sources of environmental damage. Eventually, tillage optimization and fertilization should be first taken into account in order to produce larger amounts of healthier food by bridging the YG.

Automated summary

Increasing the yield of oilseeds is an important strategy in countries like Iran. Narrowing the yield gap and optimizing agricultural practices can improve food security and mitigate environmental impacts. Boundary line analysis integrated with life cycle assessment was used to survey soybean farms, showing improved resource use efficiency and reduced environmental hazards.