黑土坡面垄侧少耕措施的土壤侵蚀特征分析

为探究黑土区坡耕地垄侧少耕措施对土壤侵蚀特征的影响,在5°和7°坡面开展人工模拟降雨试验,降雨强度为75,100 mm/h,横垄处理方式包括全松（土壤容重均为1.00 g/cm³）、上松下实（土壤容重分别为1.00,1.20 g/cm³）、上实下松（土壤容重分别为1.20,1.00 g/cm³）及全实（土壤容重均为1.20 g/cm³）4种。结果表明：垄侧少耕措施有助于延缓横垄溢流时间,具有明显的调控土壤侵蚀作用。土壤侵蚀量大小总体表现为全松>上松下实>全实>上实下松。除75 mm/h降雨强度下的5°坡面外,与全松处理相比,上实下松和全实处理的径流量分别减少16.1%~19.4%和6.6%~11.4%,土壤侵蚀量分别减少25.0%~52.5%和17.9%~31.6%,且上实下松和全实处理的径流率和土壤侵蚀速率随降雨历时的变化相对比较平稳。可见,垄侧少耕措施在调控总径流量和土壤侵蚀量的同时,也具有较好地调控径流侵蚀过程的作用。因此,建议根据黑土区坡耕地具体降雨特征和地形坡度等因素科学选用垄侧少耕措施。

Analysis of Soil Erosion Characteristics of Half-ridge Less Tillage Measure on the Black Soil Hillslope

To reveal effects of the half-ridge less tillage measure on soil erosion characteristics at sloping farmlands of the Chinese black soil region, the artificial simulated rainfall experiments were carried out on 5° and 7° slopes with 75 mm/h and 100 mm/h rainfall intensities. The cross ridge treatments included all looseness (the soil bulk density was 1.00 g/cm³), upper looseness+lower compaction (the soil bulk densities was 1.00 and 1.20 g/cm³, respectively), upper compaction+ lower looseness (the soil bulk densities was 1.20 and 1.00 g/cm³, respectively) and all compaction (the soil bulk density was 1.20 g/cm³). The results showed that the half-ridge less tillage measuredelayed the overflow time of crossridge, and obviously regulated soil erosion. The soil erosion amounts decreased in the order of all looseness>upper looseness+lower compaction>all compaction>upper compaction+lower looseness. Except for the 5° slope with 75 mm/h rainfall intensity, compared with the all looseness treatment, the total runoff amounts of the upper compaction+lower looseness and all compaction treatments decreased by 16.1% to 19.4% and 6.6% to 11.4%, respectively, the soil erosion amounts decreased by 25.0% to 52.5% and 17.9% to 31.6%, respectively. Furthermore, the changes of both runoff rate and soil erosion rate of the upper compaction+ lower looseness and all compaction treatments with rainfall duration were relatively stable. Therefore, the half-ridge less tillage measure not only controlled the total runoff and soil erosion amounts but also regulated the runoff and soil erosion processes. In conclusion, the half-ridge less tillage measure should be selected scientifically according to the specific rainfall characteristics and topographic slope gradients of farmlands in the black soil region.