GEOGRAPHICAL RESEARCH ›› 2014, Vol. 33 ›› Issue (11): 2125-2134.doi: 10.11821/dlyj201411012

• Orginal Article • Previous Articles     Next Articles

Determining key factors for soil stratification: A case study in the farmland of Xinxiang

Yalu SONG1,3(), Suxia LIU1(), Ying MA1, Chao HU2, Xingguo MO1   

  1. 1. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
    2. Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang 453003, Henan, China
    3. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2014-04-11 Revised:2014-09-21 Online:2014-11-10 Published:2015-03-13

Abstract:

Multi-layered soil is a ubiquitous soil structure in the soil profile. The key factors to divide multi-layered soil were discovered, which is of great significance to simply and accurately determine layered soil stratification. In this paper, a measured profile was dug in Xinxiang city, Henan province, whose depth was 160 cm. Meanwhile, lots of field observation and laboratory analyses were done on the soil samples collected in the profile. Then we obtained a number of soil hydraulic and physical parameters, including soil texture, soil bulk density, saturated soil moisture, saturated hydraulic conductivity, residual moisture and non-capillary porosity. By using correlation analysis, systematic cluster analysis and principal component analysis of the factors obtained in the profile, it is indicated that the soil profile (0-160 cm) can be divided into four layers: 0-50 cm, 50-80 cm, 80-120 cm and 120-160 cm. The importance order of the factors to divide the layered soil is: residual moisture > saturated water content > saturated hydraulic conductivity > soil bulk density> non-capillary porosity. In the discussion, the method of soil layer classification is robust. Therefore, the results obtained in this paper would provide scientific guideline for the numerical model of multi-layered soil moisture equation.

Key words: layered soil, soil hydraulic parameters, principal component analysis, systematic cluster analysis