人为改造措施对六盘山两种典型林分土壤物理性质及其水文功能的影响

Effects of Improvement of Typical Forests on Soil Physical Properties and Hydrological Functions in Liupan Mountains

以空间代替时间的方法，在同--／b流域选择华北落叶松＋灌木复层林和稀植乔木天然灌丛作为调整后的目标林分，并以与此相邻的华北落叶松单层人工纯林和天然灌丛作对照，分析两种现有林分经过调整后对其土壤水分物理性质及水文功能的影响。结果表明：（1）与对照样地相比，华北落叶松＋灌木复层林0～100cm土壤各层次的土壤容重降低5．52％～12．07％，土壤孔隙度提高4．82％～38．45％；而稀植乔木天然灌丛0—60cm剖面的容重降低10．Og％～18．10％，土壤孔隙度提高5．02％～74．33％。（2）稀植乔木天然灌丛的土壤最大持水量、田间持水量和毛管持水量在0～60cm土层上分别比对照样地提高32．00％，26．31％，23．49％；而华北落叶松＋灌木复层林与单层纯林相比，各指标分别提高38．45％，1．22％，0．17％；土壤蓄水性能表现为华北落叶松＋灌木复层林（3063t／hm2）〉华北落叶松人工单层纯林（2590t／hm2），稀植乔木天然灌丛（3287t／hm2）〉天然灌丛（2937t／hm2）。（3）除10-20cm土层外，稀植乔木天然灌丛各层的土壤稳渗速率均与对照样地呈显著性差异（P〈O．05）；华北落叶松人工纯林经过改造后，不同土层的稳渗速率分别提高50．86％，14．90％，6．25％和34％。（4）各种林分类型的土壤稳渗速率与其孔隙度呈极显著地正线性关系（P〈0．01）。以上结果说明，通过采取稀植乔木和单层纯林复层改造等措施可以明显地改善天然灌丛和华北落叶松人工单层纯林的土壤生态水文功能。

The mixed shrubs with sparse arbor trees （treatment plot）, natural shrubs （control）, the mixed forest of Larfx prfncfpfs-rupprechtii （mixed Larix forest, treatment plot） and pure Larix forest （control） in the same watershed were chosen to study the effects of adjusted forests on soil physical properties and hydrological functions. The results showed that. （1）Compared with the control plots, the bulk density of mixed Larix forest in the soil layer of 0--100 cm and mixed shrubs in the soil layer of 0--60 cm reduced by 5.52%~12.07% and 10.09%~18.10% respectively, the porosity of mixed Larix forest in the soil layer of 0--100 cm and mixed shrubs in the soil layer of 0--60 cm increased by 4.82%-38. 45% and 5. 02% ~ 74.33%, respectively. （2）The maximum moisture capacity, field capacity and capillary capacity of mixed shrubs in the soil layer of 0--60 cm increased by 32.00%, 26.31% and 23. 490/00, respectively compared with the control. And compared with pure Larix forest, the parameters increased by 38. 450/oo 1. 22%0.17% rest）ective/v in rnipure Larix forest（2 590 t/hm2）, mixed shrubs（3 287 t/hm2） 〉natural shrubs（2 937 t/hm2）. （3） Besides the depth of 10--20 cm, the soil stable infiltration rate at the other soil depths in the mixed shrubs was significantly different from the natural shrubs（P〈0.05）, the soil stable infiltration rate of mixed Larix forest increased by 50.86%, 14.90%, 6.25% and 34% respectively at the different depth. （4）There were extremely significant positive correlations（P〈0.01） between soil stable infiltration rate and soil porosity. O- verall, the practices of sparse planting trees in the natural shrub and planting shrub under pure Larix planta- tion could improve the soil eco-hydrological function of natural shrubs and pure Larix forests obviously.