Agriculture Reference
In-Depth Information
discussed by Sanchez
et al.
(1979) have significantly higher overall organic reserves
than the alfisols and ultisols In temperate
regions, mollisols were found to have higher C reserves than alfisols (5.0) and ultisols (3.8).
In addition to the above, large differences exist among soils, even within small areas,
depending on variation in the local soil forming factors. At the regional scale of tropical
northeastern Queensland, rainforested soils derived from basaltic materials have sub-
stantially greater organic matter levels than those formed from granitic or acid-volcanic
parent materials (Spain, 1990). In the same study, both carbon and nitrogen concentrations
(Figure I.50) were negatively correlated with temperature and precipitation; topography
was also shown to be of importance through its control of drainage and soil depth.
