不同造林模式对铁尾矿地土壤性质的影响

Impacts of Different Forestation Pattern on Soil Properties of Iron Tailings

为了了解不同造林模式对尾矿地物种多样性的影响以及对土壤物理、化学和生物性质的影响,采用空间替代时间的研究方式,分别调查未造林尾矿地、紫穗槐纯林、沙棘纯林以及沙棘—紫穗槐—桑树人工混交林下土壤的物理、化学及生物性质。结果表明:(1)与裸尾矿相比,紫穗槐纯林、沙棘纯林以及混交林林下土壤容重、田间持水量、毛管持水量以及毛管孔隙度均有不同程度的下降,土壤饱和持水量、总孔隙度及非毛管孔隙度有所上升,且混交林林下土壤物理性质的变化最大,土壤容重、田间持水量、毛管持水量与毛管孔隙度较裸尾矿分别下降了12.07%,3.49%,4.66%,3.67%,土壤饱和持水量、总孔隙度及非毛管孔隙度分别增加了6.44%,9.29%,12.96%;(2)与裸尾矿相比,紫穗槐纯林、沙棘纯林以及混交林林下土壤有机质含量及各种养分元素含量明显增加,土壤pH值下降,尤以混交林的变化最为明显;(3)造林后土壤主要微生物类群的数量及主要酶活性均有所上升,且以混交林上升最明显。由此可以看出,在尾矿地进行人工造林可以在一定程度上改善尾矿土壤的性质,且营造混交林模式对尾矿土壤的改良效果最佳。

In order to understand the impacts of different forestation patterns on biodiversity and soil properties of iron tailings,the method of spatial sequence instead of time successional sequence was adopted to investigate the physical,chemical and biological properties of soils in iron tailings without plantation,and with Amorpha fruticosa Linn.pure plantation,Hippophae rhamnoides Linn.pure plantation and Hippophae rhamnoides Linn.-Amorpha fruticosa Linn.-Morus alba Linn.mixed plantation.The results showed that：（1）In iron tailing area,2types of pure plantation（Amorpha fruticosa Linn.and Hippophae rhamnoides Linn.）and the mixed plantation all showed lower level of soil bulk density,field capacity,soil capillary water holding capacity and capillary porosity,while higher level of soil saturated water holding capacity,total porosity and non-capillary porosity,than those in control area（iron tailings without plantation）.The most significant differences in soil physical properties were observed between iron tailings without plantation and with the mixed plantation.Compared to soil properties in control area（iron tailings without plantation）,soil bulk density,field capacity,capillary holding water capacity and capillary porosity in under mixed plantation reduced by 12.07%,3.49%,4.66%and 3.67%,respectively,while soil saturated water holding capacity,total porosity and non-capillary porosity increased by 6.44%,9.29% and 12.96%,respectively.（2）All forestation patterns increased the contents of soil organic matter and nutrients,while decreased the pH value of soil,and the mixed plantation showed the most significant effects.（3）After forestation,the quantity of major groups of soil microorganisms and soil enzyme activities were all increased,especially under the mixed plantation.The results indicated that forestation in iron tailings could improve soil properties to some extent,and mixed plantation showed the best improvement effects among different forestation patterns.