THEORETICAL ANALYSES OF CARBON AND NUTRIENT DYNAMICS IN SOIL PROFILES

The study of C, N, P, and S profiles in soils can tell us about the ra tes and pathways within and interactions between the cycles of the fou r elements in the whole ecosystem. We now add a spatial dimension to t he continuous quality theory such that it can describe the distributio n of the four elements along the vertical direction in the soil. This extension requires the introduction of a new function describing the v elocity with which the organic matter moves along the soil profile. Th e theory is used to calculate properties of storage and mineralisation rates of C, N, P and S in soil profiles; for example, how is the posi tion of the maximum of the density profiles determined by the rate of decomposition relative to the rate of transport. Predictions of the th eory agree well with empirical information from agricultural and fores t soils. A refined analysis would require better knowledge of the velo city of transport and its explicit dependence on quality and abiotic f actors. Copyright (C) 1996 Elsevier Science Ltd