New classes: fragipan layer, fragipan layer depth

[celineaubert]

fragipan layer

• subclassOf soil layer in ENVO
• definition An altered subsurface soil layer that restricts water flow and root penetration. The required characteristics of a fragipan are: 15-cm or more thickness; evidence of pedogenesis within the horizon or, at a minimum, on the faces of structural units; and a very coarse prismatic, columnar, or blocky structure of any grade, has weak structure of any size, or is massive. Separations between structural units that allow roots to enter have an average spacing of 10 cm or more on the horizontal dimensions; and air-dry fragments of the natural soil fabric, 5 to 10 cm in diameter, from more than 50 percent of the layer slake when they are submerged in water; and the layer has, in 60 percent or more of the volume, a firm or firmer rupture-resistance class, a brittle manner of failure at or near field capacity, and virtually no roots; and the layer is not effervescent in dilute HCl. https://en.wikipedia.org/wiki/Fragipan

fragipan layer depth

• subclassOf depth http://purl.obolibrary.org/obo/PATO_0001595
• subclassOf inheres in fragipan layer
• definition A depth quality inhering in fragipan layer by virtue of the fragipan layer's downward dimenision in soil