Pine wilt disease (PWD) is a highly destructive disease in forest ecosystems, resulting in extensive forest decline and substantial economic losses. As soil pH plays a critical role in soil microbial activity and significantly impacts the prevalence and severity of diseases, we conducted an experiment to regulate soil pH for alleviating PWD in a black pine (Pinus thunbergii) forest. The result reveals that: (1) The pH of the soil under a P. thunbergii forest was 5.19 ± 0.40, which was significantly lower than that of soils under other vegetation types at 8.53 ± 0.44. (2) Finely ground shell powder (F-SP) was the optimal size for long-term and efficient regulation, but quicklime (QL) exhibited the strongest efficacy in raising soil pH, followed by F-SP and plant ash. The regulation effect strengthened with the dosage amount. (3) In the situ experiments, part of symptomatic black pine in F-SP or QL plots were apparently improved and converted to asymptomatic trees separately by 15.9% and 5.4%. Applying F-SP can alleviate PWD in a sustainable way. This paper presents the first investigation to assess the effects of regulating soil pH for controlling PWD. It holds significant practical value for the rational planning and the sustainable development of artificial forests in coastal regions.

The transport/detachment regimes of each particle size vary with size. Moreover, the changing transport/detachment regimes of sediments with size and their related mechanisms considerably affect sediment transport capacity (T_c). To investigate the transport/detachment regimes of each particle size and their explanation for T_c prediction, 27 simulated rainfall experiments were conducted under slope gradients of 8.7%, 17.6%, and 26.7% and rainfall intensities of 60, 90, and 120 mm h⁻¹. The experimental soil was Cumulic Anthrosols, and the duration of each rainfall was 1 h. Results showed that for rain-induced overland flow erosion, the average transport ratios (T_rs) of clay, fine silt, and coarse sand (0.25 mm, respectively) for rainfall, were greater than 1.0, and their erosion regimes were detachment-limited. The T_rs of coarse silt and fine sand (0.02–0.05 mm and 0.05–0.25 mm, respectively) were less than 1.0, and their erosion regimes were transport-limited. The transport-/detachment-limited degree of each size class of particles, except for coarse sand, increased with the slope gradient, but slightly and complexly changed with rainfall intensity. The T_rs of each size class of particles on the gentle slope (8.7%, 17.6%) increased with the T_rs of total sediments. In the case of the steep slope (27.6%), however, the T_rs of fine silt and clay increased with a decrease in the T_rs of the total sediment particles. Different prediction equations were established to simulate the T_cs of sediments with different sizes in the two slope ranges (R² > 0.823, p < 0.01). The findings will help to elucidate the selective transport mechanisms of all sizes of sediment particles and improve the prediction of T_c in the future.