水保所知识产出(1956---)知识库

Determining the soil moisture content (SMC) distribution is indispensable for field management, especially in
arid and semiarid regions. Effective parameters can contribute to the optimization of SMC models for accurate
SMC prediction. Therefore, in this study, the relationships between the SMC and multifractal parameters (D 2 , D v ,
D s , A v , and F v denote the correlation dimension, property of small probability and large probability, spectrum
width, and symmetry of spectrum shape, respectively) of the soil particle size distribution (PSD) were explored in
the hilly loess region of China. A grid method was adopted (20 m × 20 m, total = 384 points) to sample the SMC
in the 0–40 cm and 40–80 cm soil layers on the second, eighth, and twelfth days after the first rainfall, which
were defined as the early sampling (ES), medium sampling (MS), and late sampling (LS), respectively. We found
that the variation in the SMC explained by the multifractal parameters increased as SMC decreased, where they
accounted for 40.07% and 75.75% of the SMC in the 0–40 cm and 40–80 cm soil layers in LS, respectively. The
variation in the SMC in the 0–40 cm explained by the multifractal parameters was lower than that in the 40–80
cm soil layer in all sampling stages. The equations fitted for the whole soil layer were significant in all sampling
stages (P < 0.01). A v (31.95%) and D v (13.59%) had negative correlations with SMC, and their relative
importance values with respect to SMC were high in all sampling stages (P < 0.05). SMC at higher values had a
positive correlation with F v , whereas SMC at lower values had a significant positive correlation with D 2 and
negative correlation with D s , and these two parameters in the MS and LS stages explained more than 75% of the
variation in the SMC in the 40–80 cm soil layer. These results suggest that the characteristics of the soil PSD can
be described in detail by the multifractal parameters, which can directly reflect the SMC. Thus, we conclude that
SMC is closely related to the multifractal parameters of the PSD (A v , D v , D s , D 2 , and F v ) and it can be applied to
optimize SMC models.