黄淮海平原农业生态系统演替及其可持续性的能值评估

该文利用能值模型对黄淮海平原17 a农业生态系统演替及可持续性进行评估.结果表明,随着外界输入系统能值的增加,渔业子系统和家畜子系统能值产出趋向增加,但总能值产出呈下降趋势,各类能值效率也是如此.系统能值指标讨论表明系统的发展正趋向于依靠石化能源和经济资源的投入,系统能值投资率不断提高;能值产出率有所下降,但均大于1,高于中国的平均水平(0.27),其中2000年总能值产出高达1.856×1024sej,相当于3.640×1011EMS,高于区域农业产值6.410×1010地;环境负荷牢趋向增加,2000年(3.79)与中等发达国家水平相当,也高于全国平均水平(2.8);可持续性指数趋于下降.最后建议增加有机肥的投入,提倡动植物多样性培育,以优化区域农业生态系统功能,提高系统的可持续性.

Emergy assessment on succession and sustainability of the agro-ecosystem in Huang-Huai-Hai Plain, China

Based on the emergy models, the authors assess the succession and sustainability of the agro-ecosystem of Huang-Huai-Hai plain in China during the past 17 years. Results show that the emergy production of the fishy subsystem and the livestock subsystem are growing subsystem while two producing subsystems and total emergy production of the systems will decline with the emergy inputs increasing. Likewise all kinds of emergy efficiency will decrease. The discussion of emergy indicators indicates as follows: the development of the system tends to the dependence on fossil-energy and economy resource gradually, the investment ratio (EIR) tends to increase; the emergy yield ratio remains to decrease but is higher than 1 and the Chinese Average (0.75), thereby the total emergy production of the system reaches 1.856×1024Sej in 2000 with being equivalent to 3.640×1011EM$ and overtopping total value of agriculture production 6.410×1010$; Environmental loading ratio remains increased, and reaches 3.79 in 2000, which equals to the level of the moderately developed countries and is higher than the Chinese Average (2.8); Environmental sustainability index gradually declines. At last, the suggestion is put forward to optimize agro-ecosystem function and improve the sustainability of the system by increasing the application of organic fertilizer and cultivating the diversity of the animal and plant.