南方稀土矿区植物根际与非根际土壤碳氮含量与pH值变化

目的]揭示南方稀土矿区根际与非根际养分含量变化,为南方稀土矿区的生态恢复和侵蚀退化区的水土保持提供科学依据。方法]以福建省长汀县稀土矿治理区为研究对象,采用野外调查与室内分析相结合的方法,选取3个稀土矿开采区进行植物样方调查及土壤取样,对研究区的主要水土保持植物(芒萁、枫香)根际与非根际土壤碳氮含量、pH值变化以及根际与非根际间土壤碳氮含量、pH值的差异性进行研究分析。结果](1)随着治理年限的增加,芒萁根际土壤的有机碳、全氮含量逐渐升高,硝态氮含量逐渐减少,pH值先增加后减少,铵态氮含量无显著性差异;枫香根际土壤的硝态氮随着治理年限的增加而减少,而有机碳、全氮、铵态氮含量和pH值均无显著性差异。(2)随着治理年限的增加,芒萁非根际土壤的有机碳、全氮、铵态氮、硝态氮均无显著性差异,pH值先增加后减少;枫香非根际土壤的有机碳、全氮、铵态氮、硝态氮、pH值均无显著性差异。(3)芒萁根际土壤的有机碳含量显著高于非根际土壤的有机碳含量,全氮、铵态氮、硝态氮和pH值均无显著性差异;而枫香根际与非根际土壤养分含量均无显著性差异。结论]植被能够改善土壤,但土壤肥力恢复却是一个长期的过程。

Variations of Carbon, Nitrogen and pH Value in Rhizosphere and Non Rhizosphere Soil in Rare Earth Mining Area in Southern China

Objective] To reveal the variations of nutrients in rhizosphere and non-rhizosphere soil in rare earth mining area in Southern China, and to provide scientific basis and data support for local ecological restoration and soil and water conservation in erosive area.Methods] Sample survey of rare mine in Changting County of Fujian Province was conducted and soil samples were assayed indoor to obtain carbon and nitrogen contents, pH values of two main soil and water conservation plants (Dicranopteris dichotoma and Liquidambar formosana) in three mines with different rehabilitation ages, and their values in the rhizosphere and the non-rhizosphere were compared among the three mines.Results] (1) With the prolongation of mine harness, nutrients in D. dichotoma rhizosphere soil exhibited different changes:the contents of organic carbon and total nitrogen both increased, nitrate nitrogen content gradually reduced, pH value increased first and then decreased, ammonium nitrogen had no obvious change. In Liquidambar rhizosphere, the nitrate nitrogen content decreased, organic carbon, total nitrogen, ammonium nitrogen, pH value had no significant differences. (2) With the prolongation of harness, items of organic carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen in D. dichotoma non-rhizosphere soil all had no significant difference; pH value increased first and then decreased. In L. formosana non rhizosphere soil, no significant differences of organic carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen, pH value among the three mines were observed. (3) The organic carbon content of D. dichotoma rhizosphere soil was significantly higher than that of non-rhizosphere soil. The contents of total nitrogen and ammonium nitrogen, nitrate nitrogen and pH value all had no significant differences; the soil nutrient content had no significant difference between L. formosana rhizosphere and non-rhizosphere.Conclusions] Vegetation can improve soil, but the soil fertility restoration is a long-term process.