苕溪流域茶园不同种植模式下地表径流氮磷流失特征

为探讨苕溪流域不同种植模式下茶园地表径流氮磷养分流失特征,于2010年5-10月对等高种植和顺坡种植2种种植模式下茶园地表径流水样进行取样测定,分析径流水样中的氮磷元素各指标的含量、形态特征及其随时间的变化规律。结果表明:无论是顺坡种植还是等高种植,茶园径流中氮素各指标含量的峰值均出现在6月底或7月初,茶园径流中磷素各指标含量的峰值出现在6月底、7月初或9月初。在整个监测时期内,等高种植茶园径流中总氮、硝氮、铵氮含量分别比顺坡种植茶园低8.54%～43.01%,4.05%～46.70%,5.92%～33.19%,但2种种植模式间不存在显著差异;等高种植茶园径流水中总磷、可溶态总磷、颗粒态磷的含量分别比顺坡种植低8.51%～31.07%,0.39%～17.91%,8.45%～36.86%,2种种植模式之间径流水中总磷、颗粒态磷含量存在极显著差异,可溶态磷含量不存在显著差异。无论是顺坡种植还是等高种植,硝态氮均为茶园氮素地表径流流失的主要形态,颗粒态磷则是茶园磷素地表径流流失的主要形态。总的来说,等高种植模式能有效地截留茶园氮磷营养元素,防止其随地表径流流失。

Characteristics of Nitrogen and Phosphorus Losses with Surface Runoff in Tea Field of Tiaoxi Watershed Under Different Planting Patterns

In order to explore the characteristics of nitrogen and phosphorus losses with surface runoff in tea field of Tiaoxi watershed under different planting patterns,the runoff water samples from contour planting and straight row planting tea field respectively in May to October of 2010 were sampled and determined.The contents,form and temporal changing law of nitrogen and phosphorus were analyzed.The results showed that,for either contour planting or straight row planting tea field,the peak value of each form of nitrogen in runoff water appeared at the end of June or early July.However,the peaks of phosphorus appeared at the end of June or early July,and early September.In the total monitoring period,the total nitrogen(TN),nitrate nitrogen(NO-3-N) and ammonia nitrogen(NH+4-N) contents in runoff water samples from contour planting tea field were 8.54%~43.01%,4.05%~46.70%,5.92%~33.19% lower than that from straight row planting tea field,respectively.But there were no significant differences between the two planting patterns.The total phosphorus(TP),total dissolvable phosphorus(TDP),particulate phosphorus(PP) contents in runoff water samples from contour planting tea field were 8.51%~31.07%,0.39%~17.91%,8.45%~36.86% lower than that from straight row planting tea field,respectively.There were extremely significant differences between the two planting patterns for TP and PP,but not for TDP.For either contour planting or straight row planting tea field,NO-3-N was the main form of nitrogen and PP was the main form of phosphorus existing in runoff water samples.Generally speaking,the contour planting pattern could prevent the nitrogen and phosphorus losses with surface runoff in tea field effectively.