Predicting potentially mineralizable nitrogen based on organic carbon

María Teresa Varnero M.1; Carlos Benavides Z.1, José Miguel Reyes P.2 y Manuel Casanova P.1

The effect of residue management and surface thermal «regimen» on soil nitrogen mineralization «capacity» and soil organic matter content was studied. Fifteen soils from cold mesophyle regions (average temperatures less than 15 ºC during 60% of the year) and fifteen soils from warm mesophyle regions (average temperatures greater than 20 ºC during 60% of the year) were used on this study. Organic carbon content was determined by three methods: Walkley and Black, Anne and Calcination. Potentially «mineralizable» nitrogen (N0) was determined by the method of Stanford and Smith (1972), by incubation at 35 ºC for 18 weeks. Values for No were stimated by two kinetic models: simple and double exponential. The different management systems produced changes in organic carbon content and an increase in levels of N0. The relationship between No and organic carbon content is promisory as long as data come from homogeneous conditions in terms of thermal, textural and drainage factors.

Keywords: organic carbon, potentially mineralizable nitrogen, soil organic matter, surface temperature
1 Departamento de Ingeniería y Suelos, Facultad de Ciencias Agrarias y Forestales, Universidad de Chile, Casilla 1004, Santiago, Chile.
2 Tesista.