(4) Physiological adaptations. Physiological adaptations 

 include any features of the metabolic processes of plants 

 that make them particularly fitted for life in saturated 

 soil conditions. NOTE: It is impossible to detect the 

 presence of physiological adaptations in plant species 

 during onsite visits. Physiological adaptations known for 

 hydrophytic species and species known to exhibit these 

 adaptations are listed and discussed in Appendix C, 

 Section 3. 



(5) Reproductive adaptations. Some plant species have repro- 

 ductive features that enable them to become established 

 and grow in saturated soil conditions. Reproductive adap- 

 tations known for hydrophytic species are presented in 

 Appendix C, Section 3. 



Hydric Soils 



Definition 



36. A hydric soil is a soil that is saturated, flooded, or ponded long 

 enough during the growing season to develop anaerobic conditions that favor 

 the growth and regeneration of hydrophytic vegetation (US Department of 

 Agriculture (USDA) Soil Conservation Service (SCS) 1985, as amended by the 

 National Technical Committee for Hydric Soils (NTCHS) in December 1986). 

 Criteria for hydric soils 



37. Based on the above definition, the NTCHS developed the following 

 criteria for hydric soils: 



a. "All Histosols* except Folists; 



b. Soils in Aquic suborders, Aquic subgroups, Albolls suborder, 

 Salorthids great group, or Pell great groups of Vertisols that 

 are : 



(1) Somewhat poorly drained and have a water table less than 

 0.5 ft** from the surface for a significant period 

 (usually a week or more) during the growing season, or 



(2) Poorly drained or very poorly drained and have either: 



(a) A water table at less than 1.0 ft from the surface 

 for a significant period (usually a week or more) 

 during the growing season if permeability is equal to 

 or greater than 6.0 in/hr in all layers within 

 20 inches; or 



* Soil nomenclature follows USDA-SCS (1975). 

 ** A table of factors for converting non-SI units of measurement to SI 

 (metric) units is presented on page 4. 



26 



^ 



