Campus Units
Agronomy
Document Type
Article
Publication Date
2012
Journal or Book Title
Ecosystems
Volume
15
Issue
2
First Page
175
Last Page
187
DOI
10.1007/s10021-011-9501-3
Abstract
Recent advances in soil C saturation concepts have increased our understanding of soil C storage and mineralization without explicit links to N retention and saturation theories. Here, we exploit soil texture and organic matter (OM) gradients in a Maryland, USA hardwood forest to test hypotheses that link soil organic C saturation with soil 15N retention and nitrification. At our site, mineral-associated OM (MAOM) N concentrations in the silt + clay particle fraction (g MAOM-N g silt + clay−1) were negatively correlated with the fraction of NH4-N transferred to MAOM during a 3-day in situ incubation (R = −0.85), but positively correlated with potential net nitrification (R = 0.76). Moreover, the fraction of NH4-N transferred to MAOM was negatively correlated with potential net nitrification (R = −0.76). Due to physico-chemical stabilization mechanisms, MAOM is considered to be resistant to mineralization. Carbon saturation theory suggests that the proportion of new C inputs that can be stabilized in MAOM decreases in proportion to the amount of C already present in the fraction; C inputs not stabilized in MAOM are susceptible to rapid mineralization. We demonstrate that NH4-N stabilization in MAOM is similar to C stabilization in MAOM and associated with nitrification, thereby extending soil C saturation theory to mineral N and linking it with N retention and saturation theories. These data and concepts complement N saturation models that emphasize vegetation type, N input levels, and microbial turnover. Incorporating the OM retention capacity of fine mineral particles into N saturation theory can improve predictions of N saturation rates and resolve inconsistent relationships between soil organic matter, texture, N mineralization, and N retention.
Rights
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
Language
en
File Format
application/pdf
Recommended Citation
Castellano, Michael J.; Kaye, Jason P.; Lin, Henry; and Schmidt, John P., "Linking soil carbon saturation concepts to nitrogen retention and saturation" (2012). Agronomy Publications. 195.
https://lib.dr.iastate.edu/agron_pubs/195
Comments
This article is published as Castellano MJ, Kaye JP, Lin H, Schmidt JP. 2012. Linking soil carbon saturation concepts to nitrogen retention and saturation. Ecosystems doi: 10.1007/s10021-011-9501-3. Posted with permission.