氮肥类型对东南景天生长及重金属积累的影响

【目的】研究氮肥类型对东南景天套种玉米模式下生长特性及重金属锌、镉积累的影响，为植物修复实践过程中合理使用氮肥、减少修复成本和环境污染奠定基础。【方法】通过大田试验，在重金属污染的矿区采用东南景天套种玉米模式，施用同氮素水平下有机肥（鸡粪）、硫酸铵和尿素3种类型氮肥，测定土壤pH、有机质含量、重金属有效态、东南景天和玉米地上部生物量及重金属锌、镉含量的变化。【结果】施用有机肥增加土壤有机质含量，提高土壤镉的生物有效性，对土壤pH和锌的生物有效性则无影响；施用硫酸铵和尿素均降低土壤pH和土壤镉的生物有效性，提高了土壤有机质含量和土壤锌的生物有效性。氮肥类型对东南景天中锌、镉以及玉米镉积累影响不显著，但两种化学氮肥均显著增加了玉米锌的累积量；不同类型氮肥对东南景天和玉米生长均有显著促进作用，有机肥处理两种作物的地上部生物量均显著高于其他处理（P〈0．05）。【结论】有机肥对东南景天修复土壤重金属污染效率的促进作用优于硫酸铵和尿素。

Effect of different N fertilizers on the growth of Sedum and heavy metal accumulation

Objective]Effect of different N fertilizers on the growth and heavy metal accumulation of Sedum alfredii inter- cropping with maize were studied to provide references for rational N fertilizer application in phytoremediation, phytoremedia- tion cost reduction and environmental pollution management. Method]In a field of mine area seriously polluted by heavy metal, soil pH,organic content,effective state of heavy metal, aboveground biomass, and Zn and Cd content of S. al~redii and maize were measured, which were treated by organic manure, ammonium sulfate and urea. Result]Organic manure increased the content of soil organic content and improved bio-availability of cadmium, but it did not affect soil pH or bio-availability of zinc. Ammonium sulfate and urea both brought down soil pH and bio-availability of cadmium, but they boosted soil organic content and bio-availability of zinc. The type of N fertilizer did not significantly influenle zinc and cadmium accumulation of S. alfredii and cadmium accumulation of maize, but both kinds of N fertilizers significantly increased zinc accumulation in maize. N fertil- izer, regardless of either type, greatly promoted the growth of S. alfredii and maize. In general, the effect of organic manure sur- passed that of ammonium sulfate and urea. Conclusion]Compared with ammonium sulfate and urea, organic manure could bet- ter promote the efficiency of reducing heavy metal pollution in soil by S. alfredii.