Comparison of Principles for Allocating Emergy to Recycled Materials in Natural and Managed Ecosystems

Emergy Algebra rules may not allow for appropriate accounting of recycled material emergy. The loss of emergy is not permitted using Emergy Algebra rules, but is necessary to address recycling material. It has been proposed to use Dynamic Emergy Accounting so that emergy loss can be factored in when allocating emergy to material recycle pathways. However, systems are often evaluated at steady-state (and when stationary or slowly transient) following Emergy Algebra rules. By studying these natural and managed systems, indices that address recycling of materials and the most appropriate allocation of their emergy will be developed to improve emergy methodology regarding emergy cycling. Three production systems in Maryland and the District of Columbia will be evaluated for emergy inputs and outputs. Each system will be evaluated on a per hectare basis. First, a hectare of Maryland forest will be evaluated. The primary emergy inputs to the natural forest are from environmental sources. Two agricultural systems will also be evaluated: a traditional farm and an organic CSA farm. The traditional farm is a small, family-owned and -operated farm on Maryland’s Eastern Shore that employs traditional farming techniques such as conservation tillage, herbicide application, manure and rock phosphate fertilization, and center pivot sprinkler irrigation. The Community Supported Agriculture (CSA) farm, located in suburban Columbia, MD, reduces fossil fuel requirements by using cover crops and reduced tillage, smaller farm equipment, and more human labor. The CSA farm also rotates crops and adds organic amendments to promote soil biological and physical health, maintained pollinators, and attracted wildlife while irrigating and fertilizing conservatively. Material recycle in both agricultural systems is roughly equal to that in the forest, but from this study, it appears emergy associated with that recycle is much greater in the forest. Current methodology does not explicitly address emergy tied to material recycling pathways in both natural and managed systems, the aim of this study is to improve methods of allocating emergy to material recycle pathways.