Application of a general relationship between soil particle density and organic matter to molisoles of Santa Fe (Argentina)

PILATTI, M.A.; GHIBERTO, P.; IMHOFF, S.

Filadelfia

Congreso; 18th World Congress of Soil Science; 2006

ASSS

The soil particle density (dp) is useful to calculate total porosity and particle size distribution of the soils. dp synthesizes the contribution of diverse minerals and organic components present in the studied material. For most of the mineral soils dp oscillates between 2.6 and 2.75 Mg m-3 due to the predominance of quartz, feldspar, micas and clay minerals. Organic matter possesses a density that varies between 0.9 and 1.3 Mg m-3. The phytoliths (2.21 Mg m-3) presence, common in the light fraction of silt of A horizons, can modify the mean value of dp of the Pampas soils in Argentina. The Pampas Loess is the origin material of a great proportion of soils in Santa Fe, where silicates and volcanic glasses prevail. For this reason, dp depends basically on these minerals and on the organic matter content. The knowledge of dp for Mollisols is very important because they are the most productive soils, occupying 57% of the province. Pedotransfer functions, generally lineal, have been elaborated to estimate dp for several soils. However, this information is not available for soils of Santa Fe. A general relationship between dp, mineral particles density and organic matter is proposed.