Distribution and properties of soft weathered bedrock at ≤ 1 m depth in the contiguous United States
Distribution and properties of soft weathered bedrock at ≤ 1 m depth in the contiguous United States
复制标题
美国本土 ≤ 1 m 深度软风化基岩的分布和性质
DOI：
10.1002/esp.3343
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发表时间：
2013
影响因子：
3.3
通讯作者：
Phillip J. Schoeneberger
中科院分区：
文献类型：
--
作者：
J. Wald;R. Graham;Phillip J. Schoeneberger
风化基岩带越来越被认为是生态和水文系统的重要组成部分，但其分布在美国本土知之甚少。我们使用来自美国农业部（USDA）-自然资源保护局的空间和实验室表征数据来评估美国48个相邻地区内软风化基岩（腐岩和腐岩）的分布和土壤性质。由于美国农业部土壤库存一般不延伸到2米以下，并且由于上面1米明显涉及生态系统功能和渗流区水文，因此我们将调查限制在地表1米以内的软风化基岩。地表1米范围内的软风化基岩在美国本土广泛分布，至少占陆地面积的6%。对三个州的深入分析表明，加州、怀俄明州和北卡罗来纳州总土地面积的22%、33%和18%的地下为≤ 1 m深度的软风化基岩。软风化基岩承载成土活动，如数据库中的土壤描述中记录的根、粘土膜和铁（Fe）-/锰（Mn）-氧化物结核等形态特征所示。软风化基岩的物理和化学性质通常与上覆土壤的物理和化学性质相似，这表明软风化基岩在许多方面表现得像土壤。它为植物提供水分和养分，植物的根渗透到它里面，它调节通流径流到溪流。为了更全面地了解软风化基岩，需要系统的数据，其厚度在景观和一致的术语，其各种形式需要通过和广泛使用。版权所有© 2012约翰威利父子有限公司.
The weathered bedrock zone is increasingly recognized as an important part of ecological and hydrologic systems, but its distribution is poorly known in the contiguous United States. We used spatial and laboratory characterization data from the US Department of Agriculture (USDA)‐Natural Resources Conservation Service to assess the distribution and soil‐like properties of soft weathered bedrock (saprock and saprolite) within the 48 contiguous United States. Because USDA soil inventories generally do not extend below 2 m, and because the upper 1 m is clearly involved in ecosystem function and vadose zone hydrology, we restricted our inquiry to soft weathered bedrock within 1 m of the land surface. Soft weathered bedrock within 1 m of the land surface is widespread throughout the contiguous United States, underlying at least 6% of the land area. In‐depth analysis of three states showed that soft weathered bedrock at the ≤ 1‐m depth underlies 22% of the total land area in California, 33% in Wyoming, and 18% in North Carolina. Soft weathered bedrock hosts pedogenic activity, as indicated by morphological features such as roots, clay films, and iron (Fe)‐/manganese (Mn)‐oxide concretions recorded in pedon descriptions in the database. The physical and chemical properties of soft weathered bedrock are often similar to those of the overlying soil, suggesting that in many respects soft weathered bedrock behaves like soil. It supplies water and nutrients to plants whose roots penetrate into it and it modulates throughflow runoff to streams. For a more complete understanding of soft weathered bedrock, systematic data are needed on its thickness across landscapes and a consistent terminology for its various forms needs to be adopted and widely used. Copyright © 2012 John Wiley & Sons, Ltd.