摘要
磷指数(PI)是一个结合磷源因子和传输因子来对土地磷流失的脆弱性进行分类的风险评估工具。本文阐述了条件磷指数的结构和概念,用来作为教育和磷管理的有效工具,加以调节后可以用来对瑞典的实际环境条件进行评估。由于某一特定因子对磷流失的重要程度强烈依赖于他们同其他因子的相互影响作用,更为精确的过程描述和量化的条件规则是必不可缺的。考虑通过土壤剖面磷的流失,单独计算活性磷和惰性磷,用动态的方法来计算土壤侵蚀流失中磷的流失评价,是本文提出的教育和管理工具的一些全新的特征。通过比较计算的PI值和从一个瑞典水质监测项目中7个观测地点观测的磷年传输数据,对本文提出的方法进行测试。首次测试表明,这个方法能够成功地用于磷流失风险评估。
Phosphorus index (PI) is a risk-assessment tool that combines phosphorus (P) source factors and transport factors to rank the vulnerability of fields to P losses.Here we present the structure and concepts of conditional PI,developed as an educational and P-management tool adjusted for Swedish conditions.Because the significance of certain factors for P losses depends on their interplay with other factors,conditional rules are needed for a more accurate process description and quantification.Accounting for P losses through the soil profile,separate calculations for reactive and unreactive P and a changed approach to P loss assessment from erosion losses are some of the new features included in the tool presented here.The performance of the tool was tested by comparing the calculated PI values with measured annual P transport from seven observation fields included in a Swedish water quality monitoring program.This first test indicated that the tool could be used successfully for P loss risk assessment.
