Distribution of the soil salinity in northwest China
2001
Saito, M. (Forestry and Forest Products Research Inst., Sapporo (Japan). Hokkaido Research Center) | Tanimoto, T. | Zhang, L.Y. | Li, Z.W.
Soil size composition and salt accumulation were investigated in the Taklimakan Desert and the Hexi Corridor, arid area in the northwest of China. The soil was including large gravels over 10mm in the size, in the upper parts of alluvial fan, pediment and wadi, and the soil in the lower pediment mainly consisted of the sand about 0.2mm in the size. On the electric conductivity (EC) and NaCl content, salt accumulation have been occurred lightly on some soil samples from the middle to low part of the pediment. The upper-edge of the Tamarix cone has high saline concentration, it decreases as going down, and on the center and bottom of it the salinity is very little. Though in surface soils under the young coppice forests of Populus puruinosa and P. euphratica, EC and NaCl content were shown over 20 mS/cm and over 1.5%, these values dropped as it to the lower layer. EC value was 0.2 mS/cm in the midle of soil profile under the P.pruinosa forest, while it was 2 to 5 mS/cm in same layer under the P.euphratica forest. This difference of the soil salinity seems to reflect the difference of salt tolerance between the two Populous species. The results of survey on the mixed forest of these poplars on a flood plain, also supported difference of the salt torelance between both species. The degree of salt accumulation on the soil was evaluated on 8 land-forms by EC and NaCl content. In most of samples from sand-dune and pediment, the salt accumulation had not been caused, however, in few ones were shown lightly salt accumulation by the salt except for NaCl. In the flood plain, there were two types of salt accumulation, by NaCl or other kinds of salt, while in the salt accumulation area the accumulated salt was mainly NaCl.
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