Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 4/25/2011
Publication Date: 10/16/2011
Citation: Castellano, M., Kaye, J., Lin, H., Schmidt, J.P. 2011. Incorporating carbon saturation concepts and nitrogen retention theory[abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts. Paper No. 352-6. Interpretive Summary: An interpretive summary is not required.
Technical 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 a soil texture gradient to test hypotheses that link C saturation with soil 15N retention and nitrification. At our site, increasing concentrations of organic N in the silt + clay mineral particle fraction were negatively correlated with 15N-ammonium-N transfer to silt + clay-associated organic matter during a 3d in situ incubation (R = -0.67), but positively correlated with in situ gross nitrification (R = 0.70). Moreover, 15N-ammonium -N transfer to the silt + clay-associated insoluble organic matter fraction was negatively correlated with in situ gross nitrification (R = -0.66). By demonstrating that the capacity for silt + clay to stabilize mineral ammonium-N inputs is similar to the capacity for silt + clay to stabilize organic C inputs, we extend soil C saturation theory to mineral N and link it with N retention and saturation theories. Incorporating the organic matter retention capacity of fine mineral particles into N saturation theory will improve predictions of N saturation rates and resolve inconsistent relationships between soil organic matter, texture, N mineralization, and N retention.