Effect of different tillage methods on soil particle size distribution characteristics in dry sloping fields of Guangxi

<bold>Objective</bold> This study aimed to address the challenges of subsoil compaction，significant soil and nutrient loss，and unstable crop yields in the dry sloping of southern China.It investigated the impacts of various tillage methods on soil particle size distribution to provide a theoretical foundation for optimizing soil tillage layer structure，promote crop root development，and select efficient tillage practices to enhance crop quality and yield. <bold>Method</bold> Using the sugarcane variety “Gui Sugar 44” as the test crop，field experiments were conducted on dry slopes in Qinzhou City，Guangxi，China.Three tillage methods（Fen-long tillage，rotary tillage，and no-tillage）were implemented，with no-tillage as the control treatment.A laser particle size analyzer was used to determine the soil particle size distribution within the 0-40 cm soil layer.The effects of different tillage practices on soil particle size distribution were elucidated by analyzing soil particle size composition，soil texture，particle size parameter characteristics，and particle size frequency distribution. <bold>Result</bold> The soil in different tillage treatments was mainly composed of medium sand，fine sand and silt，accounting for 75.10%-87.59%.Soil textures were classified as sandy soil，sandy loam，and loamy sand.The overall sorting effect of soil in each soil layer is excellent，with mean particle sizes ranging from 2.66 to 4.58 mm.The skewness was strongly negative，indicating a greater proportion of coarse particles than fine ones.Kurtosis values ranged from broad-flat to moderate，with a tendency toward broad-flat as soil depth increased.Compared with rotary tillage and no-tillage，Fen-long tillage significantly increased the depth of the tillage layer，reduced the clay，silt，and fine sand content in the topsoil，thus leading to their accumulation in the subsoil.Moreover，the soil particle size distribution frequency curve shifted from a bimodal to an unimodal distribution.The peak height，peak width corresponding to particle size，and the cumulative frequency curve slope were much higher under Fen-long tillage compared with those of rotary tillage and no-tillage.This suggests that Fen-long tillage resulted in a more concentrated soil particle size distribution. <bold>Conclusion</bold> Various soil tillage methods can profoundly influence soil particle size distribution，thereby fostering the development of an optimal tillage structure and stimulating robust crop root growth.The Fen-long tillage technique is especially effective in establishing an optimal tillage structure，which leads to a notable coarsening of soil particles，thus enhancing soil heterogeneity，and improving soil structural stability.It can be further applied in the planting management of dry slope land in Guangxi to ensure the increase and stable yield of crops.