土壤管理措施对坡耕地侵蚀退化耕层的恢复作用

【目的】紫色土坡耕地土壤侵蚀严重,研究土壤管理措施对不同侵蚀程度坡耕地耕层侵蚀恢复作用,为紫色土坡耕地耕层质量调控和坡耕地持续利用提供理论及实践依据。【方法】采用单因素方差分析（One-way ANOVA）检验各指标的差异显著性,研究不施肥（CK）、施化肥（F）、施生物炭+化肥（BF）3种土壤管理措施对侵蚀0 cm（S_-0）、侵蚀5 cm（S_-5）、侵蚀10 cm（S_-10）、侵蚀15 cm（S_-15）、侵蚀20 cm（S_-20） 5个不同侵蚀程度坡耕地耕层土壤属性的恢复作用。【结果】（1）随侵蚀程度增加,土壤砂粒含量由38.1%—42.4%逐渐增至44.2%—46.4%,土壤黏粒含量由12.6%—14.8%逐渐减少至9.6%—11.0%;与S_-0、S_-5、S_-10相比,S_-15、S_-20土壤容重显著增大;S_-10侵蚀程度下,土壤抗剪强度最大,在8.71—9.56 kg·cm^-2之间;F、BF处理下S_-15侵蚀程度的土壤稳定入渗率、平均入渗率降幅均最大。（2）不同管理措施下坡耕地耕层土壤属性差异显著,BF处理下土壤砂粒含量小、黏粒含量最大,0—10 cm、10—20 cm土层土壤容重显著低于CK（P<0.05）,土壤总孔隙度、毛管孔隙度均显著高于CK、F处理;BF处理下土壤初始入渗率、稳定入渗率、平均入渗率均最大,CK处理最小;与CK处理相比,BF处理土壤抗剪强度显著增大。（3）随侵蚀程度增加,土壤可蚀性K值显著下降,与S_-0相比,S_-20侵蚀程度下土壤可蚀性K值下降0.1960%—0.2192%;BF处理下土壤可蚀性K值最大,F处理次之,CK最小;S_-10侵蚀程度下F、BF处理的K值均较CK增加幅度最大,分别增加0.0684%、0.1404%。【结论】施加生物炭+化肥在改善土壤物质组成、结构特征、提高土壤蓄渗性能等方面较单施化肥效果更为显著,可有效减轻紫色土坡耕地耕层土壤侵蚀,对侵蚀10 cm条件下的坡耕地耕作层（0—20 cm）土壤的改良效果最佳。

Effects of Different Fertilization Methods on Restoration of Eroded and Degraded Cultivated-Layer in Slope Farmland

【Objective】The soil erosion of purple soil slope farmland is serious. The study on the effects of soil management measures on the restoration of soil erosion of different erosion degree of cultivated-layer in slope farmland could provide a theoretical and practical basis for the quality control and sustainable utilization of purple soil slope farmland. 【Method】One way ANOVA was used to test the significance of the differences of each index, and the effects of soil management measures on the restoration of soil properties in the cultivated-layer of slope farmland with five degrees of erosion was studied. 【Result】(1) With the increase of erosion degree, the content of sand increased from 38.1%-42.4% to 44.2%-46.4%, while the content of clay decreased from 12.6%-14.8% to 9.6%-11.0%. Compared with S_-0, S_-5 and S_-10, soil bulk density of S_-15 and S_-20 increased significantly. Under the S_-10 erosion degree, the total porosity and capillary porosity decreased the most, and the shear strength of soil was the largest, between 8.71 and 9.56 kg·cm^-2. Under the treatments of F and BF, the stable infiltration rate and average infiltration rate of S_-15 erosion degree soil decreased the most. (2) There was significant difference in soil properties of cultivated-layer under different management measures. The soil bulk density of 0-10 cm and 10-20 cm soil layers under fertilization treatments was significantly lower than that under CK (P<0.05), and the soil total porosity and capillary porosity were significantly higher than that under CK and F. Under BF treatment, the initial infiltration rate, stable infiltration rate and average infiltration rate were the largest, while those under CK treatment are the smallest. Compared with CK treatment, the shear strength of BF treatment increased significantly. (3) With the increase of erosion degree, K value of soil erodibility decreased significantly. Compared with S_-0, K value of soil erodibility was decreased by 0.1960%-0.2192% under S_-20 erosion degree. Under BF treatment, K value of soil erodibility was the highest, followed by F treatment, and CK was the lowest. Compared with CK, the increase of F and BF in S_-10 was the largest, with an increase of 0.0684% and 0.1404%, respectively. 【Conclusion】The application of biochar and chemical fertilizer was more effective than that of chemical fertilizer alone in improving soil material composition, structural characteristics and soil water storage and permeability. Applying biochar and chemical fertilizer could effectively reduce the soil erosion in the cultivated-layer of purple soil slope farmland, and the effects of soil improvement in the cultivated-layer (0-20 cm) of 10 cm slope was the best.