A fragipan is a diagnostic horizon in USDA soil taxonomy. They are altered subsurface soil layers that restrict water flow and root penetration. Fragipans are similar to a duripan in how they affect land-use limitations. In soil descriptions, they are commonly denoted by a Bx or Btx symbol. They often form in loess ground. [1]

2013年5月1日 · Fragipans are dense subsurface soil layers that severely restrict water flow and root penetration. They are considered a pedogenic horizon, but their exact genesis is not well understood. In Soil Taxonomy (2010) a fragipan is defined as a layer that is at least 15 cm thick, contains a coarse structure, and is reversibly cemented. We examined ...

fragipan 定 义 干时坚硬，湿时脆碎的磐层。 应用学科 土壤学（一级学科），土壤发生、分类和制图（二级学科）

publication includes discussion of possible processes fragipan formation as well problems in field identification. Such information should help answer some questions and stimulate further research concerning soils with these morphological features. The Soil Science Society of America is pleased to have sponsored the

Solution Chemistry of Fragipans—Thermodynamic Approach to Understanding Fragipan Formation 1 (Pages: 113-139)

2023年5月1日 · In-row subsoiling therefore has potential to improve crop yields significantly on soils with a shallow fragipan. This research was performed in continuous corn and it might be possible to obtain the same results within crop rotations including soybeans or sod.

A fragipan is a compact subsurface horizon with limited root penetration, evidence of pedogenesis, and soil structure, often explained by the presence of amorphous silica, illuvial clay, iron, and aluminium compounds.

2016年1月1日 · Fragipan is recognized as a diagnostic subsurface soil horizon by the WRB and Soil Taxonomy systems of classification. World Reference Base for Soil Resources. Several hypotheses have been proposed to explain the characteristic interlocking pattern of …

“To be identified as a fragipan, a layer must have all of the following characteris- tics: 1) the layer is 15 cm or more thick; and 2) the layer shows evidence of pe- dogenesis within the horizon or, at a minimum, on the faces of structural units;

2013年5月1日 · Fragipans are firm or massive, have high bulk densities, high base saturation, and low soil organic C. There are 362 pedons with fragipans in the NRCS database and detailed 36 case studies from the USA literature. Fragipan soils are classified primarily at the great-group but also at the subgroup level. Fragipans