川中紫色土旱坡地磷素的输出特征研究

在中国科学院盐亭农业生态站进行了为期1年(2002 4～2003 4)的定期监测研究,探讨了磷素的农业非点源输出规律。研究表明紫色土旱坡地磷素输出以颗粒吸附态为主,全磷输出量不高,但水溶性磷素和磷酸盐的输出浓度对环境的影响应值得重视。全磷的输出随不同的耕作方式不同而不同,短期降雨:顺坡>平作>垄作;垄作种植,在长期降雨条件下,水溶性磷的径流输出将会增大,从而使全磷的输出量相应增加,即长期阴雨天气下,全磷的输出量:顺坡种植、垄作>平作。通过分析还发现磷素地下渗漏与降雨量之间也存在类似的关系,即磷素下渗浓度存在极值,它与降雨量之间不是单调递增关系,而是开口向下的抛物线,其相关系数为R2=0 9232。

Study of Phosphorus Load from Purple Soil Cropland in Mid-Sichuan

P load from cropland mostly is in the form of PP (Particulate P). The amount of TP (total Phosphorus) isn't high, but the concentration of DP and ortho-phosphrous should be noticed. Because the bimestrial rain from June to July in 2002, all forms of P of the sample gotten in the 4th, July 2002 are head and shoulders above other samples. After comparing the three different cultivates manner sections, we find some laws: the load of TP in runoff is diverse by cultivate manner sections. In instant rain, the amount of TP load with runoff is FT (Flat tillage)>DT (Down slope tillage) > RT (Ridge tillage): while in continuous rain is DT, RT>FT. On the other hand, there is the resemble relation between leakage P and rainfall, the correlative coefficient R~2=0.9232. In conclusion, the amount of total P load from agricultural system by NPS isn't high, but the environmental effects caused by DP should be paid attention to. The NPS P has less influence on ground water than surface water. The NPS P influences on surface water are potential, which will break out in the moderate conditions.