Spatio-temporal Variability of Soil Water at Three Seasonal Floodplain Sites： A Case Study in Tarim Basin, Northwest China

• Published in: Chinese geographical science Vol. 24; no. 6; pp. 647 - 657
• Main Authors: Grashey-Jansen, Sven, Kuba, Martin, Cyffka, Bernd, Halik, Ümüt, Aishan, Tayierjiang
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer-Verlag 01-12-2014; Science Press; Springer Nature B.V
• Subjects: anthropogenic activities; Basins; Capillary water; Case studies; cotton; Earth and Environmental Science; ecosystems; Floodplains; Geography; groundwater; Groundwater levels; irrigated farming; irrigation; Moisture content; Plant communities; River banks; river water; Rivers; root systems; Soil analysis; soil matric potential; Soil moisture; Soil properties; Soil texture; Soil water; Soils; Spatial distribution; spatial variation; Statistical analysis; temporal variation; Vegetation; Water; Water availability; Water supply; water table; Zonation; 中国西北; 土壤水分; 塔里木河流域; 塔里木盆地; 季节性; 时空变异; 植被退化; 河漫滩; China; soil texture; soil water tensions; soil moisture; water retention; Tarim River
• ISSN: 1002-0063; 1993-064X
• DOI: 10.1007/s11769-014-0717-y

The floodplain vegetation of the Tarim River in Northwest China is strongly influenced by irrigated agriculture. The abstraction of river water disturbs the natural dynamics of the floodplain ecosystem. The human impact on the hydrological system by bank dams and the irrigation of cotton plantings have caused adverse changes of the Tarim River and its floodplains, so the current stocks of the typical Tugai vegetation show significant signs of degradation. Field studies of soils and statistical analysis of soil moisture data have shown that the vitality of the Tugai vegetation is primarily determined by its position to the riverbank and the groundwater. There exist complex interactions between soil hydrological conditions and the vitality of the vegetation. But the availability of water is not only influenced by the groundwater level and seasonal flood events. The spatial distribution of stocks at different states of vitality seems also to be decisively influenced by physical soil properties. Our results show that the water supply of plant communities is strongly influenced by the soil texture. Spatial differences of soil moisture and corresponding soil water tensions may be the decisive factors for the zonation of vegetation. Physical soil properties control the water retention and rising of capillary water from deeper soil layers and the phreatic zone and may supply the root systems of the phreatophytic vegetation with water.