Subsystems, level variable feedback loops structural analysis method to generate system development strategies -- An example of modern agriculture area construction in Yinhe Eucommia economic and ecological systems.

System feedback loop structure analysis is an effective way to generate strategies for promoting the development of the system. For the lack of standardized methods for feedback loop construction and its operating rules analysis, a method named subsystems' level variable feedback loops structural analysis was provided. The process of the method is as follows: firstly, to construct the system's stock and flow diagram via rate variable fundamental in-tree modeling approach; then to calculate all feedback loops of the system by using the in-tree branch vector determinant calculation method; subsequently, to determine the subsystems according to the research question and management strategic objectives, to identify the level variables and feedback loops each subsystem involved and embed them, respectively; to analyze the feedback loop structure of each subsystem to reveal key variables, adjustable variables and adjustable causal chain of the loops, to obtain the policy leverage points for solving practical problems; classification analysis of all adjustable variables, establish a general system development strategy principle feedback loop diagram; finally, based on the policy leverage points and the general strategies generating principle, determine the system development strategies. As the application and demonstration of our method, an actual example of the modern agriculture area construction in Yinhe Eucommia economic and ecological systems was presented, where four management strategies were determined and implemented. [ABSTRACT FROM AUTHOR]