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ARS Home » Southeast Area » Mississippi State, Mississippi » Crop Science Research Laboratory » Genetics and Sustainable Agriculture Research » Research » Publications at this Location » Publication #327498

Title: Soil characteristics of the vadose zone in the flood plain of the Tarim River

item Feng, Gary

Submitted to: Catena
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary: Analyses of the particle size distribution at five locations along the Tarim River indicated that soil texture ranges from sand, loamy sand, sandy loam, loam, silt loam, to silt in the vadose zone. The corresponding SOM content ranged from 1.57 to 5.80 g kg-1. All sites had low clay content (2 to 10%) and high sand content (35 to 90%) in the vadose zone. Sand content increased with soil depth, but clay, silt and SOM content decreased with depth. Soil organic matter content was positively related to clay and clay plus silt content. Saturated hydraulic conductivity estimated by pedotransfer functions was high throughout the vadose zone due to the high sand content. The Ks has implications for high infiltration of flood water and restoring groundwater resources that support vegetation along the lower reaches of the river.

Technical Abstract: Overflow from rivers plays an important role in ecological conservation. The desert-oasis ecotone in the Tarim River Basin of Northwest China, for example, relies upon overflow from the river to support a diversity of soil, vegetation, and wildlife. There is, however, limited information on soil texture and organic matter (SOM) content of the vadose zone in the Tarim River Basin. The objective of this study was to assess soil texture and SOM of the vadose zone and estimate the saturation hydraulic conductivity (Ks) at three replicated sites per five locations along the length of the Tarim River. Soil particle size analysis revealed all sites had low clay and high sand content with soil textures ranging from sand to silt in the soil profile. The surface layer of the profile was characterized by finer-textured soil while deeper layers had coarser-textured soil. Soil organic matter ranged from 1.57 to 5.80 g kg-1, with a mean of 3.21 g kg-1 (SE of 0.08 g kg-1) across all replicated sites and depths. Soil organic matter content decreased with depth and was positively related to silt and clay content and negatively related to sand content. Pedotransfer functions, which related Ks to soil texture and SOM, indicated an increase in Ks with depth. This suggests the soil surface regulates infiltration of overflow in the region. Nevertheless, the relatively high Ks throughout the soil profile provides for rapid infiltration and percolation of floodwater, which is important for recharging the local alluvial aquifers in arid environments.