Non-living soil organic matter: what do we know about it?

Non-living soil organic matter is a small but critical component of soils c ontributing to soil structure, fertility and a range of other chemical, phy sical and biological functions. Although considerable work has contributed to our knowledge of its distribution, chemical structure, mineral associati ons and turnover, there is still little information on which fractions or p ools of non-living soil organic matter are implicated in various soil funct ions and to what extent. This review paper summarises some of what is known about the distribution, chemistry, mineral associations and soil structure , turnover and the measurement of non-living soil organic matter, with part icular emphasis on Australia. It also discusses some of the difficulties in using current methods for describing the function of this material in soil .