Spatial Heterogeneity of Field Capacity of Chernozem Soil in Northeast of China

【Background】 The soil moisture characteristic has the obvious spatial heterogeneity, and the determination of its spatial heterogeneity is the theoretical basis for the precision management of soil water. Field capacity is an important soil moisture characteristic parameter, at present, the study on the spatial heterogeneity of field capacity is relatively few. Furthermore, the soil degradation in chernozem soil is serious, the capacity of soil moisture preservation is decreasing, and the spatial heterogeneity of field capacity in chernozem soil is a scientific problem worthy of discussing. 【Objective】 The aim of this work is to explore spatial heterogeneity mechanism of field capacity in chernozem soil. 【Method】 Spatial heterogeneity degree of field capacity and local information causing its spatial heterogeneity were analyzed with traditional statistics and multifractal methods, and multi-scale relationship between field capacity and soil physical property were studied with joint multifractal method. 【Result】 Field capacity had multifractal characteristics, and its spatial heterogeneity degree first decreased and then increased with the increase of soil layer depth. The local information that caused spatial heterogeneity of field capacity was mainly its high value information in 0~5 cm and 10~15 cm soil layers, and was mainly its low value information in 5~10 cm and 15~20 cm soil layers. At the single scale, the most obvious soil physical property that correlated with field capacity was clay content and soil bulk density in 0~5 cm soil layer, was silt content and clay content in 5~10 cm and 10~15 cm soil layers, and was soil bulk density and silt content in 15~20 cm soil layer. At the multi-scale, the most obvious soil physical property that correlated with field capacity was clay content and silt content in 0~5 cm, 5~10 cm and 10~15 cm soil layers, and was soil bulk density and silt content in 15~20 cm soil layer. 【Conclusion】 Spatial heterogeneity degree of field capacity was weak in farmland of chernozem soil. Relationship degree between field capacity and soil physical property was different at single scale and multi-scale.