柠条林径流聚集工程的土壤水分研究

黄土高原半干旱地区降水少是植被生长的主要限制因子之一,采取径流调控工程发展径流林业是提高降水 资源利用率、增加局地供水的有效途径;所以对甘肃省定西市荒山造林实施的隔坡水平阶径流调控工程,在最大与 最小降雨年份对土壤水分、植被生长的影响进行调查分析。结果表明:在长期干旱条件下,隔坡水平阶与对照区、 隔坡与水平阶不同部位的土壤含水率呈现出规律变化,对照区略高于隔坡水平阶,水平阶区域均高于隔坡区域,但 均未达到显著差异水平。在持续受旱的情况下,柠条林及对照区土壤水分处于低位运行,土壤含水率平均只有5% 左右。今后还需再加大径流调控工程设计的聚流比,加强径流调控工程的养护。 

Variation of soil water in Caragana microphylla woodlands with runoff-gathering project,Gansu of northwestern China

Low precipitation is the major constraint for plant growth in the semi-arid region of Loess plateau in China. Runoff regulation has been proved to be a promising approach to increase the utilization of precipitation and local water supply. The objective of this study was to investigate the soil water and plant growth conditions in Dingxi semi-arid area 14 years after applying runoff regulation project on slope- separated flat terraces (SSFT) in the years with maximum or minimum rainfall. The results showed that in the long-term drought conditions, there were regular changes for the soil moisture content in the different areas of the SSFT, control area, slope-separated and flat terraces, soil moisture higher in control area than in slope-separated flat area, and higher in flat area than in slope-separated area, however the differences were insignificant. Under the condition of continuous drought, soil water in both of Caragana microphylla woodland and control area was in lower level with average soil moisture only 5%. It is true that runoff regulation project could effectively control soil and water loss, increase soil water in C. microphylla woodland, improve water supply to the grass and wood growth. However, the C. microrphylla suffered from the low and insufficient soil water supply under the long-term dry climatic condition in this region. In the future there is a need to increase the water-gathering percentage in designing runoff regulation project and enhance the maintenance of the engineering practices.