Strategic Priority Research Program of Chinese Academy of Sciences（No. XDA20040202）
砾石（>2 mm）是土壤组成部分之一，其含量对侵蚀产沙有重要影响。在土壤可蚀性因子（K）计算中充分考虑砾石含量的影响，计算所得土壤可蚀性因子会更加准确。利用30弧秒分辨率土壤砾石含量和土壤质地等级等数据，利用文献报道的砾石含量与土壤渗透性和土壤侵蚀关系估算方法，在全球范围内分析估算砾石含量对土壤可蚀性因子的影响。结果表明，（1）土壤剖面中砾石的存在，通过降低土壤入渗速率（土壤渗透性等级增加5.68%）、增加地表径流而使土壤侵蚀增加，进而使全球土壤可蚀性因子增加4.43%；砾石覆盖通过保护土壤免遭雨滴打击和径流冲刷减少侵蚀，在山地、荒漠（沙漠和戈壁）地区，这一影响会使土壤可蚀性值减小约18.7%。考虑土壤剖面砾石含量和表面砾石覆盖综合影响时，土壤可蚀性因子降低5.52%。（2）以砾石影响为主的地区，占全球62.7%，土壤可蚀性因子可降低0.0091（t·hm2·h）·（hm-2·MJ-1·mm-1）；以剖面砾石影响为主的地区，占全球的31.1%，土壤可蚀性因子增加0.0019（t·hm2·h） （hm-2·MJ-1·mm-1）。（3）剖面和表面砾石共同作用使6个样区土壤流失速率减少约11.8%。因此，剖面砾石的存在会增加土壤可蚀性，而表面砾石覆盖会减少土壤可蚀性，综合影响使土壤侵蚀降低。在区域土壤可蚀性制图研究中，应考虑这两个方面的影响，进而提高土壤可蚀性因子的制图精度。
[Objective] Rock fragments (>2mm diameter)are an important component of soil, and its presence has a significant impact on soil erosion and sediment yield. So it is essential to take into full account content of the rock fragments for accurate calculation of soil erodibility factor (K). [Method] In this paper, based on the data available of the content of rock fragments and classes of soil texture with a resolution of 30 arc-second, influence of the content of rock fragments, including rock fragments in the soil profile (RFP) and gravels on the surface of the soil (SC), on K was assessed at a global scale, using the equation (Brakensiek, 1986) of the relationship between saturated hydraulic conductivity and grade of soil permeability, and the equation (Poesen) of soil erodibility attenuation under a rock fragment cover. [Result] Results show: (1) The existence of rock fragments in the soil increased K by 4.43% and soil permeability by 5.68% on average in grade and lowering soil saturated hydraulic conductivity by 11.57% by reducing water infiltration rate of the soil and increasing surface runoff. The gravels on the surface of the mountain land and desert/gobi reduced K by 18.7% by protecting the soil from splashing of rain drops and scrubbing of runoff; so once the content of rock fragments in the soil profile and gravels on the surface of the land are taken into account in calculation, soil K may be 5.52% lower; (2) In the areas dominated with the effect of rock fragments, about 62.7% of the global land area, soil K decreased by 0.0091(t·hm2·h)·(hm-2·MJ-1·mm-1)on average, while in the area affected mainly by rock fragments in profile, about 31.1% of the global land area, soil K increased by 0.0019(t·hm2·h) (hm-2·MJ-1·mm-1); and (3) The joint effect of rock fragments in profile and gravels on the surface reduced the soil erosion rate by 11.8% in the 6 sample areas. [Conclusion] The presence of RFP increases soil K while the presence of SC does reversely. The joint effect of the two leads to decrease in soil erosion. In plotting regional soil erosion maps, it is essential to take both of the two into account so as to improve accuracy of the mapping.
杨苗苗,杨勤科,张科利,李玉茹,王春梅,庞国伟.砾石含量对土壤可蚀性因子估算的影响研究[J].土壤学报,2021,58(5):1157-1167. DOI:10.11766/trxb202004200185 YANG Miaomiao, YANG Qinke, ZHANG Keli, LI Yuru, WANG Chunmei, PANG Guowei. Effects of Content of Soil Rock Fragments on Calculating of Soil Erodibility[J]. Acta Pedologica Sinica,2021,58(5):1157-1167.复制