鄱阳湖沙化地区不同下垫面土壤水分动态

土壤水分状况是沙化防治,固沙植物选育,退化生态系统修复与重建的重要参考指标。基于野外实测数据对鄱阳湖典型沙化地区不同下垫面类型(7年生湿地松、4年生湿地松、草地、裸沙地)土壤水分(0—80cm)的动态变化进行了分析。结果表明:(1)不同下垫面土壤平均体积含水量大小顺序依次为:4年生湿地松(5.22%)草地(4.88%)7年生湿地松(4.01%)裸沙地(2.95%)。(2)不同下垫面不同深度的土壤水分年内均表现为中等变异程度。其中,4年生湿地松变异程度最高,裸沙地最低。(3)不同时期,4种下垫面土壤水分在垂直方向上的变异程度存在差异,变异系数在8月份最大,10—12月份次之,3—6月份最小;相对于裸沙地,除8和10月份外,有植被覆盖的土壤水分在垂直方向上的变异程度较低。

Soil Moisture Dynamics Under Different Underlying Surfaces in Sandy Land of Poyang Lake

Soil moisture is an important refereed index for controlling desertification, breeding sand fixing plants, restoring and reconstructing degraded ecosystem. Soil moisture dynamics(0-80 cm) under different underlying surfaces(7-year-old Pinus elliotii, 4-year-old Pinus elliotii, grassland and bare sandy land) in the sandy land of the Poyang Lake were measured and analyzed. Results are as follows: (1) The underlying surfaces, in order of decreasing average soil moisture content, were 4-year-old Pinus elliotii(5.22%), grassland(4.88%), 7-year-old Pinus elliotii(4.01%) and bare sandy land(2.95%). (2) All of the annual soil moisture contents at different depths under different underlying surfaces showed moderate variation. The variation coefficient under the 4-year-old Pinus ellioti was the highest, while that under the bare sandy land was the lowest. (3) There were seasonal changes in the vertical variation coefficients of soil moisture content under different underlying surfaces. The variation coefficients in August were the highest, followed by those from October to December. The smallest variation coefficients were observed from Match to June. Apart from August and October, the vertical variation coefficients for the underlying surfaces with vegetation coverage were lower than those of the bare sandy land.