江苏省沿海地区耕地系统能值分析及高效持续利用评价

Study on the Emergy Analysis and Efficiency and Sustainability Evaluation of the Coastal Region Cultivated Land System in Jiangsu Province

采用能值分析法,在对耕地资源高效持续利用内涵及评价指标界定的基础上,对江苏省沿海区域2000—2008年耕地生态经济系统的高效持续性水平进行了评价。研究结果表明:①2000—2008年江苏沿海地区耕地生态经济系统资源环境负载指数(A1)呈上升趋势,由2000年的0.9上升至2008年的1.573。在时间序列上,系统生产要素投入能值具有较强的稳定性,而初级生产力稳定性较弱。②研究区域耕地生态经济系统具有经济效益,集约化水平不断提高。但生产要素投入结构不合理,存在集约不经济现象,且生产要素投入结构差异性呈上升趋势。2008年土地集约度(B1)为1.85×1016sej/hm2,不可更新资源与不可更新工业辅助能值投入比例达61.13%,比2000年均有明显增长。而产出投入能效指数(B2)则呈现下降趋势,2008年为1.036 4,比2000年降低了15.90%。③2000—2008年农民人均能值占有量保持逐年增长,2008年已达1.08×1016sej/人,比2000年增长了92.81%,这说明农民生活水平(C1)越来越高。但从历年环比增长率分析,存在一定的不稳定性。2000—2008年间,研究区域耕地生态经济系统能值产出密度较不稳定,总体呈现倒V字型,2005年以来研究区域耕地生态经济系统能值产出密度呈缓慢下降趋势并趋稳发展,粮食安全压力较大。

Based on the connotation defining of the efficiency and sustainability of cultivated lands, the author built an index system for efficient and sustainable cultivated land use evaluation, gave a system analysis evaluation of the cultivated land eco-economic system in the coastal region of Jiangsu Province using the theory of emergy analysis provided by H. T. Odum. The results showed that： 1 ） Emergy-based resource and environmental loading index of cultivated lands （A1 ）was on the rise from 0.9 to 1. 573 in 9 years（2000 -2008）. In the temporal sequence, the stability of the input subsystem was strong, but that of the output subsystem was weak. 2） Cultivated land eco-economic system of the coastal region in Jiangsu Province was cost-efficient, the degree of land use intensity（ B1 ）was increasing every year. But the input emergy structure of productive factors was unreasonable, and the input of productive factors was intensive but not economical. What＇s more, the difference index of the input emergy structure became increasingly great. It presented that the degree of land use intensity（B1）was 1.85 × 1016 sej/hm2 and the proportion of both non-renewable resources and non-renewable industrial assistant emergy in the input emergy structure accounted for 61.13% in 2008, which had significantly increased compared with 2000. But the outputinput ratio based on emergy（B2） was 1. 0364 in 2008, fell by 15.90% compared with 2000, which presented a declining trend. 3 ） The emergy per farmer was increas- ing year by year from 2000 to 2008. In 2008, the emergy per farmer had reached 1.08 × 10^16 sej, increased by 92. 81%, nearly doubled from 2000 to 2008. This indicated that the living index of farmer（ C1） had greatly improved. But the growth rate of the emergy per farmer year on year was unstable. The output of emergy density of the coastal region in Jiangsu Province presented an inverted ＂V＂ shape on the whole from 2000 to 2008. There was slowly declining trend obviously since 2005, which means that the problem of grain security is very serious.