紫色土坡地土壤性质对耕作侵蚀的影响

目的]揭示土壤性质对耕作侵蚀土壤的敏感性,为紫色土区域采取适宜的耕作措施提供依据。方法]利用磁性示踪技术定量旋耕机上下耕作和等高耕作的土壤耕作位移和土壤位移量,选取土壤容重、土壤含水量、土壤有机质、土壤全氮、土壤有效磷、土壤抗剪强度和土壤紧实度等土壤理化性质和力学性质指标,研究土壤性质对旋耕机上下耕作和等高耕作的耕作侵蚀的影响特征。结果]旋耕机上下耕作和等高耕作的土壤净位移和净位移量不仅受坡度影响,也受土壤性质的影响。土壤力学性质和土壤物理性质对旋耕机耕作侵蚀有显著影响,对于上下耕作的土壤抗剪强度、土壤紧实度和土壤容重与土壤净位移量呈显著正相关。对于等高耕作措施的土壤抗剪强度、土壤紧实度、土壤容重和土壤含水量与土壤净位移量呈显著正相关,其他指标关系不显著。结论]土壤抗剪强度、土壤紧实度和土壤容重可以作为评价耕作侵蚀的土壤可蚀性指标。

Effects of Soil Properties on Tillage Erosion on Hillslopes of Purple Soil

Objective] Soil property is one of the important factors that influence the tillage erosion intensity. Revealing soil erosion susceptibility by tillage operations under different soil conditions was expected to provide basis for the adoption of appropriate tillage measures on steep land. Methods] Magnetic tracer was used to measure the soil translocation and soil flux under up and down slope tillage and contour tillage by rotary cultivator. The effect of variations in soil properties on net soil displacement and the associated tillage erosion was investigated for the two tillage practices in purple soil under two different soil conditions is consolidated soil(conventional tillage about half a year ago) and loosened soil(consecutive tillage for 20 times tillage operations). Seven soil physical, chemical and mechanical properties were selected as indices, including soil bulk density, soil water content, soil organic matter, total nitrogen, available phosphorus, soil shear strength and soil compactness. Results] The results showed that net soil displacement distance and soil flux were not only influenced by slope gradient but also by soil properties irrespective of tillage practices. Soil mechanical and physical properties had significant impacts on tillage erosion. For the up and down slope tillage, net soil translocation rate was significantly positively correlated with the indices of soil shear strength, soil compactness, and soil bulk density. For the contour tillage, net soil translocation rate was significantly positively correlated with the indices of soil shear strength, soil compactness, soil bulk density and soil water content. No significant correlations were found between net soil translocation rate and soil chemical properties index for the two practices. Conclusion] It is suggested that soil shear strength, soil compactness and soil bulk density could be taken as indicators in evaluating soil erodibility for tillage erosion.