A susceptibility model for post wildfire soil erosion in a temperate oceanic mountain area of Spain
A susceptibility model for post wildfire soil erosion in a temperate oceanic mountain area of Spain
复制标题
西班牙温带海洋山区野火后土壤侵蚀的敏感性模型
DOI：
10.1016/j.catena.2005.03.006
复制
发表时间：
2005
期刊：
影响因子：
6.2
通讯作者：
R. Duarte
中科院分区：
文献类型：
--
作者：
S. Fernández;J. Marquínez;R. Duarte
在坎塔布里亚山脉西北部（西班牙北部），气候是海洋性的，植被覆盖是连续的。在畜牧业盛行的地区，野火很常见，尽管规模不大，但野火的反复发生使这一现象对土壤保护至关重要。在这项研究中，我们提出，土壤的结构稳定性，与结构团聚体的类型和大小，可能是一个有用的指标，以评估烧蚀土壤的侵蚀敏感性。我们选择了一个面积约为485平方公里的石英岩岩性，其中野火的高复发率已被注意到，并显示出几种形式的侵蚀：冲沟，沟流和侵蚀的漫流。我们已经测量了质地，百分比和程度的结构性团聚体的稳定性和渗透率在土壤中已被烧毁了3次，在过去的20年，也在未燃烧的土壤。所获得的结果使我们能够建立野火，土壤恶化和宏观团聚体稳定性之间的联系。我们使用的稳定性的大团聚体作为一个指标，阐述了一个大面积的10,600平方公里的急剧起伏和大西洋气候的土壤侵蚀敏感性模型。该模型综合考虑了土壤结构稳定性、火灾强度和地形起伏三个主要因素。与土壤结构稳定性和碱性阳离子存在相关的变量来自岩性（%粘土和%粉土+细砂）。腐殖化有机物质的可用性也被考虑作为形成稳定大团聚体的一个额外变量。根据可燃物的数量和不同植被类型的结构计算了预期的火灾强度。最后，考虑边坡陡度的影响，分析了地形起伏对边坡稳定性的影响。由此产生的制图模型提出了五种类型的野火后土壤侵蚀的敏感性。那些风险最高的地区对应于石英岩岩性地区，长而陡峭的山坡上覆盖着石南。风险最低的区域是有缓坡和草本植被的石灰岩基岩区。模型的精度取决于原始专题图的比例尺：1：25000，数字地形模型的单元尺寸为50×50 m。
In the North-West of the Cantabrian Range (North of Spain) the climate is oceanic and vegetation cover is continuous. In those areas where livestock farming prevails, wildfires are common, although small in size, their recurrence makes the phenomenon critical for the conservation of soils. In this study we propose that the structural stability of soil, associated with the type and size of the structural aggregates, may be a useful indicator to assess erosion susceptibility in burnt soils. We have chosen an area of approximately 485 km2over quartzitic lithologies where a high recurrence of wildfires has been noted and which displays several forms of erosion: gullying, rilling and erosion by overland flow. We have measured texture, percentage and degree of structural aggregate stability and the rate of infiltration in soils that have been burnt up to 3 times over the last 20 years and also in unburnt soils. The results obtained enable us to establish connections between wildfires, soil deterioration and macro-aggregate stability. We have used the stability of macro-aggregates as an indicator to elaborate a soil erosion susceptibility model for a large area of 10,600 km2with sharp relief and Atlantic climate. The model was constructed by combining three main factors: soil structural stability, fire intensity and relief. Variables related to soil structural stability and presence of basic cations have been derived from lithology (% Clay and % Silt+Fine Sand). The availability of humified organic material has also been taken into account as an additional variable in the formation of stable macro-aggregates. The expected fire intensity was calculated from the amount of inflammable material and the structure of the different vegetation types. Finally, the influence of relief was analyzed by considering the slope steepness. The resultant cartographic model presents five types of post wildfire soil erosion susceptibility. Those areas with the highest risk correspond to quartzite lithology regions, with long, steep hillsides covered with heaths. Those with the lowest risk correspond to limestone bedrock areas with gentle slopes and herbaceous vegetation. The accuracy of the model is determined by the scale of the original thematic cartography: 1:25000, and the cell size of the Digital Terrain Model is 50×50 m.