Progress and outlook of agricultural ecological footprints

As an effective metrology tool to assess the sustainable development of agriculture, the agricultural ecological footprint has been widely adopted by scholars worldwide due to the model's high operability and result comparability. In the process of its development, the combination of the agricultural ecological footprint with other measurement methods, such as the energy theory, life cycle theory, input-output method, scenario simulation, etc., has provided an effective approach for sustainable agricultural development. In recent years, the contribution of agriculture to the GDP in China has been declining. Sustainable agricultural development and management are very important aspects for China to solve the "Three Rural Issues", which have already become extremely worthy of attention and research. Agriculture has its peculiarities. On the one hand, agricultural activities consume raw materials and energy resources. On the other hand, agriculture also yields products in addition to agricultural wastes and pollutants. Therefore, the agricultural ecological footprints are different from the ecological footprints of other industries. Based on the concept of agricultural ecological footprints, this article reviewed the domestic and international researches on the algorithm for agricultural ecological footprints, parameter adjustments, and application of agricultural ecological footprints for assessing sustainable agricultural development. In terms of the algorithm, this paper summed up four perspectives:1) only considering the agricultural consumption of biological resources, 2) simultaneously considering the agricultural consumption of both biological resources and energy, 3) considering agricultural waste and pollutants, and 4) combining other measurement methods. We also summarized the general methods for adjusting the parameters of agricultural ecological footprints. The paper also discussed the general methods for adjusting the parameters of agricultural ecological footprints, including the general methods for the adjustment of the yield (YF) and equivalence factors (EQF). In addition, this paper reviewed the impact of different agricultural technologies and modes of agricultural production on agricultural ecological footprints, as well as the application of agricultural ecological footprints for the sustainable development of agriculture. This research showed that scholars worldwide had made a series of empirical explorations in the fields related to agricultural ecological footprints, thus making significant progress. In terms of the algorithm, researchers had begun to improve the original algorithm from the traditional model of agricultural ecological footprints. In terms of parameter adjustments, scholars had constantly adjusted the YF and EQF to make the results closer to the reality of local agricultural development. In terms of the application, scholars had taken agroecology as the main line and combined social, economic, and technological dimensions to comprehensively study agricultural sustainable development.