Natural succession of grassland on the Loess Plateau of China affects multifractal characteristics of soil particle-size distribution and soil nutrients.

Knowledge of the changes of soil properties and soil particle-size distribution (PSD) is important for quantifying soil quality and dynamics during natural succession. We applied multifractal theory to characterize the PSDs in five soil layers of nine croplands abandoned for less than 1 year, 2, 5, 7, 10, 15, 20, 30 and 35 years and evaluated the changes of soil organic carbon (SOC), total nitrogen (total N), total phosphorus (total P), soil texture and multifractal parameters [capacity dimension ( D ), entropy dimension ( D ), correlation dimension ( D ) and Hölder exponent of order zero ( α )] during natural succession on the Loess Plateau of China. Rényi spectra ( D ) and singularity spectra f( α) characterized the PSDs well and sensitively reflected the changes of heterogeneity of the surface soil (0-20 cm) during natural succession. SOC, total N and clay contents and the multifractal parameters increased significantly by the late stage of succession, mostly in the topsoil (0-10 cm). Natural succession thus effectively improved the soil physicochemical properties on the Loess Plateau of China, even though it was time-consuming. SOC and total N contents decreased with depth throughout the natural succession, but the multifractal parameters were higher in the topsoil only in the late stage. D and D were strongly and positively correlated with SOC and total N contents in the surface layers and with fine particles in all layers, suggesting that D and D may be sensitive and practical indices for quantifying changes in soil properties and erosion. [ABSTRACT FROM AUTHOR]