荒漠草原人工柠条林对土壤物理稳定性的影响

Effect of Artificial Caragana intermedia Shrubs on Soil Physical Stability in Desert Steppe

采用时空互代方法,通过测定荒漠草原植被恢复过程中不同林龄人工柠条林（9a,17a,27a）0-40cm土层土壤颗粒组成、土壤有机碳（SOC）含量,研究人工柠条对土壤物理稳定性的影响。结果表明,人工柠条林建植过程中,各林龄土壤的颗粒组成均以细沙粒（0.05∽0.25mm）为主,其在柠条灌丛不同部位所占百分比为内部大于外部,不同种植年限柠条土壤粘粉粒百分比均随土层深度增加而逐渐降低,粘粉粒（〈0.05mm）含量的增加和中粗沙（〉0.25mm）含量的减少,共同导致柠条林下土壤质地细粒化;不同林龄柠条灌丛各部位SOC含量在垂直剖面上随着深度的增加逐渐降低,且呈现显著差异（P〈0.01）;不同林龄柠条灌丛不同部位SOC含量为灌丛内部大于外部;各林龄柠条灌丛土壤物理稳定性在各年限的内外部整体上呈现极显著性差异（P〈0.01）,各年限内、外部随土壤深度的增加土壤的物理稳定性表现为先增大后减小的趋势,在0-5cm和20-40cm土层,各年限的土壤物理稳定性整体上是内部大于外部;在5-20cm土层,各年限土壤物理稳定性整体上是外部大于内部,局部有波动。

Using spatiotemporal substitution method, soil particle-size distribution and soil organic carbon content（SOC）were measured in-shrub and out-shrub of 0--40 cm soil layers under different planting yeas （9 a, 17 a, 27 a） of Caragana intermedia shrubs in the desert steppe in Ningxia, and then soil physical sta- bility was researched. The results showed that：With the increase of the planting years of Caragana interme- dia shrubs, in the particle composition, the particle-size was mainly ranging from 0.05 mm to 0.25 mm in each shrubs, and the percentage of fine sand in-shrub was bigger than out-shrub, especially, the percentage of fine sand decreased gradually with increasing soil layer in planted years of 9 a, 17 a and 27 a. With the in- crease of planted years, the top soil （0--40 cm） gradually changed from coarse graining （0.25 mm） into sandy loam effectivelly. The content of SOC decreased gradually with increasing soil layer in planted years of 9 a, 17 a and 27 a, and there were showing a significant difference （P〈0.01） among 9 a, 17 a and 27 a. The content of SOC in-shrub was bigger than out-shrub with soil layers increasing. The physical stability of desert soil changed significantly （P〈0.01） at each planted years and each sites, the physical stability of the soil showed a decreasing trend after the first increased with the increase of the soil depth at every years and every sites. The physical stability of the soil inside the artificial Caragana intermedia shrubs was bigger than out- shrub in 0--5 cm and 20--40 cm, while in 5--20 cm showed a contrary trend.