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可利用磷(P)指标来说明农用地中非点源P的损失。为更改和改善P管理工具的有效性,有必要对P指标进行评价。实验对德克萨斯州、阿肯色州和衣阿华州P指标进行了估计。德克萨斯州和衣阿华州的实验也能合理的估计P的损失潜力,P指标值与年标准P负荷呈显著的线性相关关系(p<0.01)。总的来说,P指标值、土壤测得P和厩肥施用率与可溶性P质量分数和负荷的相关性要比与总P和颗粒P负荷的相关性好。P指标负荷估计中的主要误差源是不能捕获年土壤侵蚀变异性。用准确的侵蚀代替估计出的年均侵蚀可以大大减少误差来源。不管用何种方法,结果都能描述P指标评估相对P损失的潜力,研究抑制土壤P水平形成的诱因,寻找土壤P检验水平与接受的水体中的P水平之间联系的纽带,保证了与P指标应用相关的其它重要项目的研究。此项研究内容及方法,可为我国进行营养流失研究作参考。
Phosphorus (P) can be used to explain the loss of non-point source P in agricultural land. To change and improve the effectiveness of P management tools, it is necessary to evaluate the P indicator. The experiment estimated the P indicators for Texas, Arkansas and Iowa. Experiments in Texas and Iowa also provide a reasonable estimate of the potential for P loss, with a significant linear correlation (P <0.01) between the P indicator and the annual standard P load. In general, the correlation between P-index values, soil measured P and manure application rates and soluble P mass fraction and load was better than the total P and particulate P loads. The main source of error in P indicator load estimation is the inability to capture annual soil erosion variability. Replacing the estimated annual average erosion with accurate erosion can greatly reduce the source of error. Regardless of the method used, the results can describe the potential of the P indicator to assess the relative P loss, study the incentives that inhibit the formation of P, and find the link between the P test of soil and the P level in the receiving body of water, P indicator applications related to other important projects. The content and method of this study can be used as a reference for the study of nutrient loss in our country.