SPATIAL VARIABILITY OF SOIL PARTICLE-SIZE DISTRIBUTION HETEROGENEITY IN FARMLAND

The objective of this research was to reveal the spatial variability of soil particle-size distribution heterogeneity. The farmland (48 m x 48 m) used in this study is located in the black soil region of northeast China and was divided into sixty-four 6 m x 6 m squares for sampling. The soil particle-size distribution was measured with a Mastersizer 2000. Soil particle-size distribution heterogeneity, the spatial variability of soil particle-size distribution heterogeneity, and the relationships between soil particle-size distribution heterogeneity and the clay, silt, and sand contents were studied by applying multifractal, geostatistical, and joint multifractal methods, respectively. The soil particle-size distribution had multifractal characteristics. Local information causing soil particle-size distribution heterogeneities were mainly low values of soil particle-size distribution; heterogeneities from the low-value side of the particle-size distribution were larger than those from the high-value side of the particle-size distribution. In the different soil layers, the degree of variation in soil particle-size distribution heterogeneities was moderate, with spatial correlation ranges of 37.82 m and moderate spatial dependences. At the single scale and multi-scale, the impacts of the clay, silt, and sand contents on the soil particle-size distribution heterogeneity changed with soil layer depth. The clay, silt, and sand contents had different degrees of influence on the spatial variability of soil particle-size distribution heterogeneity at the single scale and multi-scale. Multi-scale analysis could better reveal the degrees of influence of the above soil properties on the spatial variability of soil particle-size distribution heterogeneity. The results of this study enrich the knowledge of the spatial variability of soil properties and provide a reference and additional information for the quantitative characterization of soil particle-size distribution heterogeneity and soil management in this research area.