Suffix[edit] -al. of or pertaining to; adjectival suffix appended to various words, often nouns, to make an adjective form. Often added to words of Latin origin, but used with other words also.
Remember: there is a difference between soil and dirt. Dirt is what you get on your clothes and hands while working in the soil. Soil is made up of elements that have been decomposing since the earth was created. Soil is composed of bedrock and mountain stones broken down over eons by wind and rain.
Silt has larger particles than clay and are mainly inorganic in nature. The particle size is less than 0.075mm and exhibits slightly plastic or non plastic behaviour. Loam is a mixture of sand, silt and clay in different proportions. Humus is soil consisting of dead and decaying organic matter. It is mainly organic in content but some inorganic particles may be mixed in it. The top soil in a tropical forest may be considered as humus.