山体土壤水分布特征及其影响因素——以东江流域为例

Characteristics of Soil Moisture Distribution and Its Influence Factors in Mountain Area——Taking Dongjiang Basin as an Example

土壤水是流域水文及生态环境的重要因素,研究流域山体土壤水分布规律对防治土壤侵蚀、控制水土流失、恢复生态环境具有重要意义。选取广东省东江流域内具有不同覆被、地形、土壤特征的典型山体,利用TDR测定山体不同位置的土壤含水率,分析土壤水的空间分布规律及其影响因素。结果表明,山体不同坡位至上而下、所覆土壤垂向由上到下土壤粘性增加,土壤持水能力增强。地形及地表覆被变化是影响东江流域土壤水分分布的重要因素,植被覆盖稀少的山坡,土壤水分分布主要取决于山坡地形变化,呈现由山体上部向下部逐渐增加,随坡度的增加而减小;有植被覆盖的山体取决于植被覆盖程度,植被覆盖程度高的山坡表层土壤含水率大。研究成果为流域水土流失治理及生态环境保护提供重要参考依据。

Soil moisture is a key factor governing the hydrology and environment of local area. This study of soil moisture distribution and regularity plays an important role for soil erosion prevention, soil and water loss control and environment recovery in theory and practice. In our research, soil moisture contents in typical mountains in Dongjiang were measured by TDR in many locations with different land covers, land- form, soil characteristics, land surface slopes in different slope position. Their influencing factors were revealed on the basis of the observation data. The results show that water holding capacity has a significant increase tendency from the mountain higher to lower portion, from soil surface to deep, because of the decrease of sand content and the increase of soil viscidity. Landform and surface vegetation cover affects the distribution of soil moisture content acutely. Soil moisture content in surface with sparse vegetation depends on topographic change. Soil moisture is higher at the top than at the bottom, and decreases significantly in the areas with sharper slope surface. Moreover, hillside on shady slope is wetter than sunny one. Soil moisture content with better forest depends on the pattern of vegetation cover. It is greater under vegetation canopy than in the bare sites. The above achievements offer some important reference for soil and water loss control and ecological environment protection.