title: Integrating plant litter quality, soil organic matter stabilization, and the carbon saturation concept.
abstract: Labile, 'high-quality', plant litters are hypothesized to promote soil organic matter (SOM) stabilization in mineral soil fractions that are physicochemically protected from rapid mineralization. However, the effect of litter quality on SOM stabilization is inconsistent. High-quality litters, characterized by high N concentrations, low C/N ratios, and low phenol/lignin concentrations, are not consistently stabilized in SOM with greater efficiency than 'low-quality' litters characterized by low N concentrations, high C/N ratios, and high phenol/lignin concentrations. Here, we attempt to resolve these inconsistent results by developing a new conceptual model that links litter quality to the soil C saturation concept. Our model builds on the Microbial Efficiency-Matrix Stabilization framework (Cotrufo et al., 2013) by suggesting the effect of litter quality on SOM stabilization is modulated by the extent of soil C saturation such that high-quality litters are not always stabilized in SOM with greater efficiency than low-quality litters.
authors.affiliation: Department of Agronomy, Iowa State University, Ames, IA, 50011, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Castellano
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Rangeland Resources Research Unit, Ft. Collins, CO, 80526, USA.
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Mueller
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, National Laboratory for Agriculture and the Environment, Ames, IA, 50011, USA.
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Olk
authors.affiliation: Department of Agronomy, Iowa State University, Ames, IA, 50011, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Sawyer
authors.affiliation: Department of Environmental Systems Science, Swiss Federal Institute of Technology, ETH-Zurich, Zurich, CH 8092, Switzerland.
authors.forename: Johan
authors.initials: J
authors.lastname: Six
mesh_terms: D057486:Carbon Cycle; D017753:Ecosystem; D008954:Models, Biological; D009930:Organic Chemicals / Q000737:chemistry*; D018521:Plant Physiological Phenomena; D012987:Soil / Q000737:chemistry*
chemical_list: D009930:Organic Chemicals; D012987:Soil
keywords: decomposition; litter; mineralization; nitrogen; residue