Organic carbon in the silt + clay fraction of Tasmanian soils

Organic carbon (C) was measured in the silt + clay fraction of 78 soils from agricultural areas in Tasmania, and the relationship between C in the silt + clay fraction and the percentage by weight of particles in this fraction was compared with similar data for soils from other regions and climates. Most of the cropping soils from Tasmania followed a previously published linear relationship, which is considered an indication of the capacity of soils to store C. The soils which fell the greatest distance below this relationship were sandy soils, consistent with previous evidence that these soils in Tasmania have been degraded. Soils which showed a major positive departure from the relationship were clay loams with >60% silt + clay. Most were also pasture soils. Tasmania's cool‐temperate climate would promote plant growth and C inputs and slow C breakdown, while the high clay content would help protect C. The results for the clay loam soils are consistent with earlier observations that these soils are generally in good health.