喀斯特山地典型植被恢复过程中的土壤水分生态效应

Changes of Soil Moisture Ecoeffects During Process of Typical Ecosystem Restoration in Karst Mountain

研究了喀斯特山区耕地、1年弃耕地、灌草地、15年疏林地、25年次生林（侧柏）地植被演替过程中土壤水分生态效应的变化。结果表明,土壤物理性质并不是简单的＂改善＂过程：表层粘粒含量由流失逐渐转为积累;容重先升高后降低,弃耕地和灌草地较耕地增加了6.6%和11.57%,疏林地和林地较耕地减少了5.0%和10.0%;总孔隙度变化趋势与容重刚好相反;土壤有效水含量以灌草地最低;各恢复阶段表层〉0.25 mm水稳性团聚体含量较耕地的增幅为5.1%-12.5%,疏林地最高;团聚体破坏率随演替的进行依次降低,较耕地降幅为34.0%-64.7%,且与有机质呈显著负相关;土壤持水能力以林地和弃耕地最好,灌草地最差,耕地接近于疏林地,土壤供水能力强弱依次为耕地〉疏林地〉林地〉灌草地〉弃耕地,土壤持水和供水能力并不一致,但都与粘粒含量、孔隙状况和团聚体稳定性等土壤结构指标密切相关。

Five types of vegetation（farmland,1-year dropped farmland,bush-grass land,15-year scattered woodland and 25-year woodland） were selected to investigate the changes of soil moisture ecoeffects in the typical restoration process of ecosystem in karst mountain.Results showed that the improving process of soil was a complicated one.The clay granule in surface gradually turned into accumulation from loss.Bulk density in surface had the tendency of decreasing first and then decreasing soon,while the trend of total porosity was perfectly opposite to that of bulk of density.The amount of 〉0.25 mm water-stable aggregate in the last four stages were apparently higher than farmland,increasing by 5.1%-12.5%,while small water-aggregates were dominant in farmland and dropped-farmland.Percentage of aggregate destruction in the last four stages declined by 34.0%-64.7% by comparison with farmland respectively,and had significant negative correlation with the organic matter content.The soil water-holding or water-supplying capability were not reconcile with each other all the time,but they were both significantly influenced by the indicators of soil structure especially such as clay granule,total porosity and aggregate stability in the soil.