A system dynamics model for analyzing the eco-agriculture system with policy recommendations

Ecological agriculture (eco-agriculture) is an approach to agriculture that seeks a balance between ecological and economic benefits to promote the sustainable development of both. This paper proposes a scientific method for analyzing the environmental and economic effects of eco-agriculture and simulating their long-term trend. Here, we focus on the eco-agriculture system of Kongtong District, Pingliang City, Gansu Province, China, and we build a system dynamics model named “AEP-SD” to evaluate the integrated effects of the system from 2009 to 2050. Under business as usual conditions, simulation results ystem dynamics model cological agriculture ustainable development ystem improvement ongtong District show rapid improvement until a peak is reached in 2027, after which the system will decline gradually. The model identifies some defects and disadvantages of the current agriculture system, such as the excessive increase of cattle slaughter, unstable production of methane, slow development of organic agriculture, and unsustainable energy structure. System improvement policies are offered and then proven by the model that they can indeed reduce the negative effects and eliminate the potential risks of system hina decline. . Introduction As the scale of human economic activity increases its presence n the globe, an ecological economic approach has arisen to account or these interactions (Gale, 2000; Ropke, 2005). As one economic ctivity, agriculture has the most direct and close interaction with he environment. Agricultural development is not only the basis of uman survival, but also directly affects the global environment. mproving agricultural development, establishing eco-agriculture ystems, and achieving good ecological and economic benefits are rucial to human development. In recent years, eco-agriculture has been widely studied Kleinman et al., 1995). Some studies have revealed the implicaion and prospect of eco-agriculture from a theoretical point of iew (Altieri and Anderson, 1986; Yunlong and Smit, 1994), and ome research has used case studies to demonstrate advantageous evelopment policies of eco-agriculture (Larsson and Granstedt, 010; Maurer, 1989; Schroll, 1994). More and more studies have aken the ecological effects into account besides economic benefits n agriculture development, and many indicators have been develped to provide decision makers with useful information, such as ∗ Corresponding author at: Room 1505, Institute of Geographic Sciences and Natral Resources Research, Chinese Academy of Sciences, 11A, Datun Road, Chaoyang istrict, Beijing 100101, China. Tel.: +86 13716210163/86 10 6488 9093; ax: +86 10 6485 4230. E-mail address: [email protected] (F.J. Li). 304-3800/$ – see front matter © 2011 Elsevier B.V. All rights reserved. oi:10.1016/j.ecolmodel.2011.12.005 © 2011 Elsevier B.V. All rights reserved. nitrogen use efficiency and cumulative energy (Granovskii et al., 2007; Hau and Bakshi, 2004; Hoang and Alauddin, 2011; Libralato et al., 2006; Sciubba, 2003), to assess the environmental and ecological performance of agricultural production at many scales from farms and industries to nations and the global biosphere (Hezri and Dovers, 2006; Hoang, 2011; Niemeijer, 2002; Piorr, 2003; Smith et al., 1999). It is now evident that ecological agriculture is a complex system involving ecology, economics, industry, human behavior, policy and many other factors. A systems perspective can be used to analyze comprehensively each relevant factor of eco-agricultural development (Chen et al., 2009). However, often eco-agriculture studies focus more on the analysis of some external influencing factors (such as the income change and the soil fertility, etc.) (Shi and Gill, 2005), and less on the industrial chain and the material-energy flow in the eco-agriculture system. The core of an eco-agriculture system is the process of material-energy production and consumption, which generates all ecological and economic effects caused by the processes. If the material-energy production and consumption cannot continuously develop, then the eco-agriculture system will decline. Therefore, to fundamentally enhance the sustainable development capacity of an eco-agriculture system, the integrated simulation and analysis of the material-energy flow processes and the trends of the ecological and economic positive-negative effects should be addressed. Therefore, taking the case of Kongtong District, Pingliang City, Gansu Province, China, we build a system dynamics model of the eco-agriculture system named “AEP-SD” F.J. Li et al. / Ecological Mode