Fluvic material (WRB)
Fluvic material is one of the diagnostic materials used, in the WRB system, to discriminate some soils from others.
Contents
Description
Fluvic material (from Latin fluvius, river) refers to fluviatile, marine and lacustrine sediments that receive fresh material at regular intervals or have received it in the recent past[1].
Diagnostic criteria
Fluvic material is of fluviatile, marine or lacustrine origin that shows stratification in at least 25 percent of the soil volume over a specified depth ; stratification may also be evident from an organic carbon content decreasing irregularly with depth, or remaining above 0.2 percent to a depth of 100 cm from the mineral soil surface. Thin strata of sand may have less organic carbon if the finer sediments below meet the latter requirement.
Field identification
Stratification, taking such forms as alternating darker coloured soil layers, reflects an irregular decrease in organic carbon content with depth. Fluvic material is always associated with organized water bodies and should be distinguished from colluvial deposits (sheet colluvia, splays and colluvial cones), even though they look very much the same.
RSG in which fluvic material can be observed
See also
- The FAO reference text, (2007 version)
Notes
- ↑ Recent past covers the period during which the soil has been protected from flooding, e.g. by empoldering, embanking, canalization or artificial drainage, and during which time soil formation has not resulted in the development of any diagnostic subsurface horizon apart from a salic or thionic horizon.
