RESUMO
Based on long-term monitoring conducted in Chang-ning county, a pilot site of the 'Grain for Green Program' (GFGP), an integrated emergy and economic method was applied to evaluate the dynamic ecological-economic performance of 3 kinds of bamboo systems planted on sloping farmland. The results confirmed the positive effects of all 3 kinds of bamboo systems on water conservation and soil erosion control. The benefits gained progressively increased during the first 8 years after conversion, going from 4639 to 16127 EMyuan/ha/yr on average. All three bamboo plantations were much more sustainable than common agricultural crops planted on sloping land (CP) on both the short and long-term scales with their Emergy Sustainability Index (ESI) and Emergy Index for Sustainable Development (EISD), respectively, being 14.07-325.71 and 80.35-265.80 times that of CP. However, all 3 bamboo plantations had a Net Economic Benefit (NEB) less than that of CP during the first 8 years after conversion. Even with the government-mandated ecological compensation applied, the annual NEBECs of the Bambusa rigida (BR) and Phyllostachys pubescense (PP) plantations were, respectively, 3922.03 and 7422.77 yuan/ha/yr lower than the NEB of CP. Emergy-based evaluation of ecosystem services provides an objective reference for applying ecological compensation in strategy-making, but it cannot wholly solve the economic viability problem faced by all bamboo plantations. Inter-planting annual herbs or edible fungus, such as Dictyophora echinovolvata, within bamboo forests, especially in young bamboo plantations, might be a direction for optimizing bamboo cultivation that would improve its economic viability.
RESUMO
Lotus (Newnbo 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.
RESUMO
The environmental effect of degraded ecosystem's vegetation restoration in low subtropical China was studied. Results indicated that the vegetation recovery on degraded lands significantly ameliorates surrounding environment, increases species diversity, improves soil structure, raises soil fertility, enhances productivity, and promotes regional agricultural production and social economic development dramatically. Through the combining engineering and biological measures, the restoration of degraded ecosystem in low subtropical area is possible and economical. The restoration experience in Xiaoliang, Wuhua and other sites are valuable for other degraded subtropical area was introduced.