生态风险分析在农田肥力评价中的应用

生态风险分析属于生态学研究的热点问题之一。本文探讨了生态风险的内涵，定义了生态系统的风险：生态系统的风险是其生态因子所导致的不良事件发生的概率及其后果的严重程度。研究了农田生态系统产生的生态风险——土壤肥力退化风险，将生态风险的理论引进农田生态系统的风险评价中．建立了风险评价指标体系．构建了土壤肥力风险评价的实用数学模型，给出了一种度量土壤肥力风险的简单、合理的科学方法．并就具体实例进行了分析研究。计算结果表明，在评价地区所选的24个样区中，生态风险很大者占样区总数的12．5％，生态风险较大的占33．3％．生态风险一般的占37．5％．风险较小的占16．7％。其中风险很大和较大的一些样区，应是所论样区中土壤改良治理的重点样区。就各样区不同土壤肥力因子存在的风险也给出了定量结果。以上风险分析结果，为土壤肥力风险评价和土壤改良治理提供了定量依据。

Application of ecological risk analysis on soil fertility evaluation in farmlands

Ecological risk analysis is one of the hot topics in ecological study.This paper discusses the content of ecological risk and gives a definition to it:ecological risk is the probability of bad happenings caused by the ecological factors and the degrees of the outcomes.This paper tries to work out a simple and useful assessment method to single risk source,i.e.soil degradation risk in agroecosystem,based on the theory and basic properties of ecological risk.Some useful mathematic models are established to evaluate the risk of soil fertility degradation.A case study shows how to calculate the ecological risk.The results are as follows:among the 24 sample sites chosen in the research region,areas of highest soil degradation risk is 12.5%,of high risk,33.3%,of average risk,37.5% and of lowest risk,16.7%.The first two kinds are those area needing meliorating at first.The risks of every soil fertility index are also calculated in sample areas.The results can be used as a quantitative basis in evaluation soil fertility and resolving the soil degradation risk in the region.