in the preparation of catalytic materials and in material applications (e.g. plastic reinforcement and construction materials). Humins can also be subjected to thermal treatments in order to form interesting solid materials, such as lightweight and porous humin foams. Overall, humins appear to improve the final properties of the materials although research is mainly at the proof-of-principle stage (early). See also Organic matter Soil organic matter Humus Humic substance References Further reading Singer, Michael J., and Donald N. Munns (2005). Soils: An Introduction (6th Edition). Upper Saddle River: Prentice Hall. . Plant nutrition Soil science