Thaw depth thaw line than clays. Yet another factors are the vegetation and the percentage of the soil organic matter, which influence the bulk density of the soil, and hence thermal conductivity. Thaw depth In soil science, the thaw depth or thaw line is the instantaneous level down to which the soil has warmed to zero degrees celcius. The active layer thickness is the maximum thaw depth over a period of two years. The layer of soil over the thaw depth is called the active layer, while the soil below is called permafrost. The term frost front refers to the varying position
Night soil Night soil Night soil is a historically used euphemism for human excreta collected from cesspools, privies, pail closets, pit latrines, privy middens, septic tanks, etc. This material was removed from the immediate area, usually at night, by workers employed in this trade. Sometimes it could be transported out of towns and sold on as a fertilizer. Another definition is "untreated excreta transported without water (e.g. via containers or buckets)". The term "night soil" is largely an archaic word, used in historical contexts. The modern term is "fecal sludge"; fecal sludge management is an ongoing challenge, particularly in developing countries. Night