JOURNAL OF NATURAL RESOURCES ›› 2018, Vol. 33 ›› Issue (4): 634-643.doi: 10.11849/zrzyxb.20170477

• Resource Evaluation • Previous Articles     Next Articles

Methods of Sampling Soil Organic Carbon in Farmlands with Different Landform Types on the Loess Plateau

ZHANG Sheng-min1, XU Ming-xiang1,2, ZHANG Zhi-Xia2, LI Bin-bin1   

  1. 1.College of Forestry, Northwest A & F University, Yangling 712100, China;
    2. State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation, CAS and Ministry of Water Resources, Yangling 712100, China
  • Received:2017-05-17 Revised:2017-11-17 Online:2018-04-10 Published:2018-04-10
  • Supported by:
    Science and Technology Basic Work, No. 2014FY210100;National Key R & D Program of China, No. 2017YFC0506503.

Abstract: Sampling design is a critical issue in soil organic carbon research. In this paper, the purpose was to find out the most appropriate sampling method among various sampling designs in farmlands with different landform types. We used the sample representative evaluation in classical statistics to compare the efficiency of most commonly used sampling methods, including random distribution, grid sampling design and joint unit method. The representative samples of soil organic carbon in farmlands with different landform types on the Loess Plateau were evaluated. The results demonstrated that: 1) A reasonable sampling method for Ning County in the upland area of Loess Plateau was grid sampling design with a suggested grid interval of 4 km. The efficiency of grid sampling design was 64.3% and 31.8% higher than the efficiency of random distribution method and joint unit method, respectively. 2) A reasonable sampling method for Wugong County in the plain area of the Loess Plateau was also grid sampling design with a suggested sampling interval of 2 km. The efficiency of grid sampling method was 64.8% and 128.8% higher than the efficiency of random distribution method and joint unit method, respectively. 3) The reasonable sampling method was joint unit layout method in the hilly and gully region of the Loess Plateau, such as in Zhuanglang County. The suggested density of the joint unit layout method in this area was 1 unit/1 314 hm2, and the efficiency of joint unit distribution was 205.8% and 294.2% higher than the efficiency of random distribution and grid distribution, respectively.

Key words: representative of samples, sampling design, sampling efficiency, soil organic carbon

CLC Number: 

  • S153.6