SOIL SURVEY

-174-Field capacity - The percentage of water remaining in the soil 2 or 3 days after th esoil has been saturated, and free drainage has practically ceased .Fine earth - The fraction of mineral soil consisting . of particles less than 2 mm i ndiameter .Fine texture - Consisting of or containing large quantities of the fine fractions ,particularly of silt and clay . Includes all clay loams, and clays; clay loam ,sandy clay loam, silty clay loam, sandy clay, silty clay, and clay textura lclasses . It is sometimes subdivided into clayey texture and moderately fin etexture . See soil texture .Firm - See consistence, soil .Floodplain - The land bordering a stream, built up of sediments from overflow ofthe stream and subject to inundation when the stream is in flood stage .Fluvial deposits - All sediments, past and present, deposited by flowing water,including glaciofluvial deposits . Wave worked deposits and deposits resultingfrom sheet erosion and mass wasting are not included .Forb - A herbaceous plant which is not a grass, sedge or rush .Formation (stratigraphy) - Any assembly of rocks that have some characteristic i ncommon, whether of origin, age or composition . See glossary of geology(Gary et al . 1972) .Friable - Soil aggregates that are soft and easily crushed between thumb and fore -finger (see consistence, soil) .Frost-free period - The period or season of the year between the last frost of sprin gand the first frost of autumn .Frost heave - The raising of a surface caused by the growth of ice lenses or masse sin the underlying soil .Genesis, soil - The mode of origin of the soil especially the processes or soil formin gfactors responsible for the development of the solum, the true soil, fro munconsolidated parent material .Geomorphology - That branch of both physiography and geology that deals with th eform of the earth, the general configuration of its surface, and the change sthat take place in the evolution of landforms .Glacial drift - All rock material transported by glacier ice and glacial meltwate ror rafted by icebergs . This term includes till, stratified drift, and scatteredrock fragments .