崇明岛典型果园氮素渗漏流失研究

为研究崇明岛柑橘园氮素渗漏淋失特征,采用田间原位小型土壤渗漏计法,分析土壤中氮素含量与渗漏水中氮素含量之间的关系。结果表明:随着土壤深度的增加,土壤中NH4+-N和NO3--N含量显著下降,渗漏水中NO3--N、NH4+-N含量逐步降低。0～20 cm和21～40 cm渗漏水中NH4+-N和NO3--N含量随时间延长呈现出由低到高再降低的变化特征。浅层渗漏水中氮素渗漏流失以水溶性总氮为主,NO3--N含量占水溶性总氮的比例超过90%。果园渗漏水中氮素含量与土壤中氮素含量之间相关性极显著,表明果园施肥量与渗漏水中氮素含量之间存在联系。

Nitrogen leaching losses in typical orchard of Chongming island

In order to investigate the nitrogen leaching losses in the orchid of Chongming island,the nitrogen contents in soil and in leakage was detected by soil solution extractor.As the depth of soil increased,the contents of ammonium nitrogen and nitrate nitrogen in soil significantly drop,and those in soil leakage gradually declined.The contents of ammonium nitrogen and nitrate nitrogen in soil leakage at depths of 0-20 cm and 20-40 cm presented the character of "low-high-low".The major pattern of nitrogen leaching loss was water-soluble total nitrogen,over 90% of which was nitrate nitrogen.The nitrogen accumulations in soil showed a significantly positive correlation with that in leakage,indicating a positive connection between orchard fertilization level and nitrogen concentration in soil leakage.