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Integrated Emergy and Economic Evaluation of Lotus-Root Production Systems on Reclaimed Wetlands Surrounding the Pearl River Estuary, China
Citation:
Lu, H., Y. Tan, W. Zhang, Y. Qiao, Daniel E. Campbell, L. Zhong, AND H. Ren. Integrated Emergy and Economic Evaluation of Lotus-Root Production Systems on Reclaimed Wetlands Surrounding the Pearl River Estuary, China. JOURNAL OF CLEANER PRODUCTION. Elsevier Science Ltd, New York, NY, 158:367-379, (2017).
Impact/Purpose:
This study provides some major new insights about agriculture and its potential environmental impacts. Lotus production in China is characterized using several different methods of estimating the load on the environment. Under one method (Lu et al. 2014) agriculture is characterized as the matching between emergy inputs that characterize environmental load and those that enhance environmental processing capacity. The implication of the analysis is that often agriculture may be a much less intense activity that formerly thought. This new view has implications for land use planning and for the comparative analysis of agricultural production systems, in this case lotus production in China. Emergy is the only common denominator for evaluating environment, economy, and society is energy or more specifically available energy, which has the potential to do work. Furthermore, available energy alone is not sufficient to provide an accurate evaluation, because energies of different kinds have different potentials to do work. A simple example of quality differences in work can be seen in human labor, where a brain surgeon and a ditch digger expend the same joule of metabolic work with very different outcomes, that is the quality of the work done is different based on the knowledge and experience of the human performing the labor. This same principle applies to all actions performed in a system and can be generalized through accounting for actions in terms of the emergy required to perform them. For, business, government, and institutions, emergy accounting provides a new perspective on value that can be used in decision-making. It goes beyond economic value and its extension as ecosystems services, which are subjective in nature, to provide a comprehensive objective measure of worth for the comparison of alternatives.
Description:
Lotus (Neumbo nucifera, Gaertn) is the most important aquatic vegetable in China, with a cultivation history of over 3000 years. The emergy, energy, material, and money flows of three lotus root cultivation modes in Wanqingsha, Nansha District, Guangzhou, China were examined using Energy Systems Language models and emergy evaluation to better understand their ecological and economic characteristics on multiple spatial and temporal scales. The natural resource foundations, economic characteristics and sustainability of these modes were evaluated and compared. The results showed that although all three modes were highly dependent on purchased emergy inputs, their potential impacts as measured by the local (ELRL) and global (ELRW) environmental loading ratios were less than 1.2 and 0.7, respectively. The lotus-fish mode was the most sustainable with its emergy index of sustainable development (EISD) 2.09 and 2.13 times that of the pure lotus and lotus-shrimp modes, respectively. All three lotus-root production modes had superior economic viability, since their Output/Input ratio ranged from 2.56 to 4.95. The results indicated that agricultural systems may have different environmental impacts and sustainability characteristics at different spatial and temporal scales, and that these impacts and characteristics can be simultaneously explored using integrated emergy and economic evaluations.
