植被恢复对高寒沙区土壤性质的影响

[目的]明确高寒沙区不同植被类型对土壤性质改良效果的差异,探讨各植被区沙地土壤恢复过程的异质性和人工林木的可开发利用潜力。[方法]以沙珠玉治沙试验林场内不同生长年限的人工植被为研究对象,分析高寒沙区6种植被类型区(乌柳、青杨、赖草、柠条、沙棘、柽柳)以及3个对照区(农田、流动沙丘、丘间沙地)土壤的机械组成、p H值、有机质及全N、全P、全K等理化性质指标。[结果](1)植被恢复生长51年后,从黏粒和粉砂粒增加的比例角度分析,土壤质地改良顺序为沙棘(206.3%)柠条(108.5%)青杨(70.5%)乌柳(56.8%)赖草(54.1%)柽柳(42.3%);从全N、全P和全K增加的比例角度分析,土壤养分改良顺序为青杨(198.2%)柠条(166.7%)沙棘(155.3%)乌柳(82.6%)赖草(75.4%)柽柳(53.9%),土壤全P含量偏低,平均0.42 g·kg-1;(2)植被恢复生长51年后,柠条、沙棘、青杨、赖草、乌柳和柽柳林下0 30 cm土壤有机质含量依次为20.19、18.25、30.81、23.57、22.13和10.62 g·kg-1,比流动沙丘或丘间沙地相应的提高了766.7%、702.4%、689.8%、517.4%、491.5%和343.9%。[结论]随着植被恢复年限的增加,土壤质地和养分状况得到显著改善,但土壤p H值的变异系数较小;各样地土层间有机质含量差距不断扩大,表聚性越来越明显,并且随深度增加各土层恢复效果存在滞后性。柠条和沙棘适宜在共和盆地推广种植,建议实施适当地抚育管理措施,以促进高寒沙区林场实现可持续经营发展。

Influence of Soil Heterogeneity Based on Vegetation Recovery in Alpine Sandy Land

[Objective] To determine the different effects of various vegetation types on soil improvement on alpine sandy land, and to discuss the heterogeneity of soil improvement and the potential of different artificial forest trees. [Method] Based on vegetation restoration of long term monitoring experiments at sandy field forest in Shazhuyu, a village of Alpine Sandy Land. 6 vegetation plots (Salix cheilophila, Populus cathayana, Leymus secalinus, Caragana korshinskii, Hippphae rhamnoides, Tamarix chinensis) and three control plots(farmland, flowing sand land, slacks dune) were selected to analyze the soil texture, pH value, soil organic matter and total N, total P and total K properties. [Result] (1) After 51 years of vegetation restoration, from the viewpoint of increased proportion of clay and silt, the soil texture improvement order was Hippophae rhamnoides(206.3%)>Caragana korshinskii(108.5%)>Populus cathayana(70.5%)>Salix cheilophila(56.8%)>Leymus secalinus(54.1%)>Tamarisk chinensis (42.3%). From the viewpoint of increased proportion of total N, total P and total K, the soil nutrient improvement order was Populus cathayana(198.2%)>Caragana korshinskii(166.7%)>Hippophae rhamnoides(155.3%)>Salix cheilophila(82.6%)>Leymus secalinus(75.4%)>Tamarisk chinensis(53.9%).The soil total P contents was low, the average was only 0.42 g·kg^-1. (2)After 51 years of vegetation restoration, the 030 cm soil organic matter contents of understory Caragana korshinskii, Populus cathayana, Hippophae rhamnoides, Leymus secalinus, Salix cheilophila, Tamarix chinensis were 20.19,18.25,30.81,23.57,22.13 and 10.62 g·kg^-1, which increased order by 766.7%, 702.4%, 689.8%, 517.4%, 491.5% and 343.9% compared with the mobile sand dunes or interdune sandy corresponding. [Conclusion] With the increase of vegetation restoration time, the soil texture had been greatly improved, the soil nutrients content increased significantly, but the variability of surface soil pH was very little. With the increase of the recovery time, the difference in organic matter content of each soil layers difference was increasing, the accumulation of organic substance was becoming more and more obvious, and there was a time lag in the soil improvement effect with depth increasing. Caragana korshinskii and Hippophae rhamnoides was more suitable on planting in Alpine Sandy Land, and could take appropriately forestry management measures to achieve sustainable development in this area.