耕作侵蚀对紫色土坡耕地土壤容重和有机质二维分布的影响

Effect of Tillage Erosion on the Two Dimensional Distribution of Soil Bulk Density and Organic Matter on a Steep Hillslope

为了研究耕作侵蚀对坡耕地土壤容重、有机质以及两者相互关系的影响,选择四川盆地中部的简阳县的坡耕地作为研究对象,采用模拟耕作的方法,通过对比模拟耕作前与5次、20次模拟耕作之后的土壤容重、有机质的水平以及垂直变化与分布规律,并探讨耕作侵蚀对两者关系变化的影响规律。研究结果表明:由于耕作侵蚀的搬运作用,5次和20次耕作之后坡顶位置的表层土壤被不断搬运至下坡位置,从而导致坡顶表层土壤容重增加;并且耕作过程中锄头的翻转作用改变了土壤容重在垂直方向的分布。耕作前土壤有机质在各坡面位置的垂直分布可用对数方程描述,然而5次和20次耕作之后其两者之间没有显示任何关系。耕作前土壤有机质含量与土壤容重呈现显著的负相关关系,5次和20次耕作之后,土壤有机质和土壤容重之间无相关关系。因此,耕作侵蚀改变土壤有机质和容重在水平和垂直方向的分布并且改变有机质和容重之间的关系。

In order to ascertain the effect of tillage erosion on the distribution of soil bulk density, soil organic matter （SOM） and their relationship on steep hillslope, this research selected a slope farmland in Jianyang County of the eastern part of Sichuan Basin as farmland to explore the effect of experimental site, Then the simulated tillage tillage was conducted 5 and 20 times on the erosion on the relationship between soil bulk density and SOM by comparing their distribution before and after simulated tillage. The results showed that the topsoil was translocated from the summit to the lower slope position after tillage for 5 and 20 times, , which leads to the increase in soil bulk density at the top of slope compared with pre-tillage. What＇s more, the hoeing tillage changed the vertical distribution of soil bulk density. Before simulated tillage, the vertical distribution pattern of SOM was described by a logarithmic equation and SOM concentration had a negative relationship with soil bulk density. However, these relationships did not be found after 5 and 20 times tillage. Our research showed that tillage erosion not only changed the horizontal and vertical distribution of SOM and soil bulk density, but also changed the relationship between SOM and soil bulk density.