Amino acids are the organic molecules and are known as the building units of proteins and play a crucial role in biological processes. Amino acid fertilizers are produced from hydrolysis or through enzymatic purification of animal or plant proteins. . ....

Extant parts of organic matters which have been consumed and transformed by a large number of soil organisms is called " Humus ".

Humic acids are produced from the complete decomposition of organic remnants and contain long chains of molecules which beside their heavy weigh, have dark brown color.