Assessing Indices for Predicting Potential Nitrogen Mineralization in Soils under Different Management Systems

Abstract

A reliable laboratory index of N availability would be useful for making N recommendations, but no single approach has received broad acceptance across a wide range of soils. We compared several indices over a range of soil conditions to test the possibility of combining indices for predicting potentially mineralizable N (N 0 ). Soils (0-5 and 5-15 cm) from nine tillage studies across the southern USA were used in the evaluations. Long-term incubation data were fit to a fi rst-order exponential

Incubation methods for assessing mineralizable nitrogen in soils under sugarcane

“…Positive correlations between STN and biological incubation parameters in the surface layer (0-20 cm) were also obtained by Rhoden et al (2006), Schomberg et al (2009) andDessureault-Rompré et al (2010). These results confirm that STN is a more reliable index than SOC for predicting net N mineralization rates, as previously reported by Yagi et al (2009) in a study of 22 soils from the São Paulo State, Brazil.…”

“…The estimate resulting from this particular method represents the amount of N that is likely to be released in mineral form from soil organic reserves to a solution in a 32-week period. Most studies provide results of aerobic incubation for the calibration of chemical methods used to estimate the N supply from SOM mineralization (Gianello & Bremner, 1986;Sharifi et al, 2007;Schomberg et al, 2009). Although long-term aerobic incubation is widely recognized as the standard reference methodology, it is expensive, timeconsuming and impractical for routine use (Curtin & Campbell, 2007;Sharifi et al, 2007).…”

Soil‐Test Biological Activity with the Flush of CO2: I. C and N Characteristics of Soils in Corn Production

“…Among 13 methods evaluated (including total soil C and N,particulate organic C and N, , hot , hydrolyzable N, NaOH and BO 7 P distillable N, anaerobic and aerobic N mineralization, flush of CO 2 , and Ca(ClO) 2 oxidation), net N mineralization during 24 d of aerobic incubation had the greatest correlation with potentially mineralizable N during 41 wk of incubation (Schomberg et al, 2009). In multiple regression, the flush of CO 2 following rewetting of dried soil combined with total soil N was considered a robust predictor of potentially mineralizable N among 11 sites in the southern United States (total of 44 management conditions-soil depths) (Schomberg et al, 2009). Total soil N is a widely determined soil property that sets a limit on N availability and the flush of CO 2 is a simple and rapid test of potential C mineralization and soil microbial activity.…”

“…Alternative approaches have since been proposed to obtain reliable indicators of potentially mineralizable N, or at least to significantly shorten analysis time (Griffin, 2008). Among 13 methods evaluated (including total soil C and N,particulate organic C and N, , hot , hydrolyzable N, NaOH and BO 7 P distillable N, anaerobic and aerobic N mineralization, flush of CO 2 , and Ca(ClO) 2 oxidation), net N mineralization during 24 d of aerobic incubation had the greatest correlation with potentially mineralizable N during 41 wk of incubation (Schomberg et al, 2009). In multiple regression, the flush of CO 2 following rewetting of dried soil combined with total soil N was considered a robust predictor of potentially mineralizable N among 11 sites in the southern United States (total of 44 management conditions-soil depths) (Schomberg et al, 2009).…”

Mineralização de nitrogênio em latossolos adubados com resíduos orgânicos

“…As taxas e quantidades de N mineralizadas em solos são dependentes, entre outros fatores, do grau de fertilidade, da textura do solo, do grau de acidez, dos teores de C e N e do balanço dos processos de perda e de ganhos de N mineral do sistema solo-planta (Cabrera et al, 2005;Khalil et al, 2005;Schomberg et al, 2009 Espindola et al, 2006;Alcântara et al, 2007); contudo, os trabalhos publicados no Brasil, até o momento, concentraram-se em aspectos relacionados à mineralização de N de restos culturais. Pouco se sabe sobre a dinâmica de mineralização de N para os resíduos de origem animal e agroindustrial.…”