Due primarily to parent material. Salinization occurs when water evaporates leaving behind sodium and chloride that can reach toxic levels. Man often created dirty dirt through dumping materials like oil and solvents into landfills and from leaking underground tanks, this can contaminate groundwater. Cleaning up dirt can be costly, includes landfilling, bio-venting, soil roasting and even soil washing. Found in tropics have poor fertility, linked to destruction caused by loss of the rain forest.
Soil organisms interact with climate and vegetation.
Low pH, leaching of nutrients, few worms. Higher pH, more OM, nutrients and worms. Observe existence of soil horizons. The taste test and the clay roll . A cylindrical soil core is extracted.