RothC simulation of carbon accumulation in soil after repeated application of widely different organic amendments Clément Peltre a , Bent T. Christensen b , Sophie Dragon c , Christian Icard c , Thomas Kätterer d , Sabine Houot a, * a INRA, UMR 1091 Environment and Arable Crops, INRA-AgroParisTech, F-78850 Thiverval-Grignon, France b Department of Agroecology, Aarhus University, AU Foulum, P.O.Box 50, DK-8830 Tjele, Denmark c Ctifl/SERAIL Experimental Station, 123 chemin du Finday, F-69126 Brindas, France d Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, 750 07 Uppsala, Sweden article info Article history: Received 1 February 2012 Received in revised form 14 March 2012 Accepted 19 March 2012 Available online 21 April 2012 Keywords: Animal manure Organic amendments Composts C storage Analytical characterization RothC model Long-term experiment abstract Multi-compartment soil carbon (C) simulation models such as RothC are widely used for predicting changes in C stocks of arable soils. However, rigorous routines for establishing entry pools that account for the diversity of exogenous organic matter (EOM) applied to croplands are still lacking. We obtained data on changes in soil C stocks after repeated applications of EOM from four long-term experiments (LTEs): Askov K2 (Denmark, 31 yrs), Qualiagro (France, 11 yrs), SERAIL (France, 14 yrs) and Ultuna (Sweden, 52 yrs). The adjustment of the partition coefficients of total organic C in EOM (EOM-TOC) into the labile, resistant and humified entry pools of RothC (f DPM , f RPM , f HUM , respectively) provided a successful fit to the accumulation of EOM-derived C in the LTE soils. Equations estimating the EOM partition coefficients in the RothC model were based on an indicator (I ROC ) of the EOM-TOC potentially retained in soil. I ROC was derived from the C found in the soluble, lignin þ cutin-like and cellulose-like Van Soest fractions and the proportion of EOM-TOC mineralized during 3 days of incubation. Using the EOM partition coefficients derived from these laboratory analyses resulted in RothC simulations with only slightly larger errors than simulations based on partition coefficients fitted from LTE soil data, except for EOMs that caused very large accumulations of C in soil (e.g. peat) possibly due to factors not accounted for in the RothC model, such as change in soil pH. The proposed partitioning of EOM-TOC allows the potential soil C storage after EOM applications to be predicted regardless of field location and specific composition of EOMs. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Loss of soil organic C (SOC) may lead to reduced soil fertility and increased soil erosion (Matson et al., 1997; Ciais et al., 2010). The loss of SOC has been identified as a major threat towards the soil resource (European Commission, 2006), and small but consistent increases in SOC could mitigate climate change effects by storing atmospheric CO 2 eC(Lal et al., 2007). Annual application of exogenous organic matter (EOM) to culti- vated land may lead to long continued accumulation of SOC (Marmo et al., 2004). We define EOM as crop residues, animal manures, and organic wastes from urban areas, forestry and industry as these materials are subject to similar transformations in soil and to similar management methods (Marmo et al., 2004). In Europe, recycling of biodegradable wastes is expected to increase in the future (European Commission, 2010). Different EOMs differ in their potential contribution to SOC, depending on their origin and degree of transformation before being added to soil (Christensen and Johnston, 1997; Gerzabek et al., 1997; Bipfubusa et al., 2008). Since C stocks change slowly, long-term field experiments are needed to evaluate the effects of repeated applications of EOM (IPCC, 1997). Multi-compartment models of C turnover in soil (Jenkinson and Rayner, 1977; Parton et al., 1987; Andren and Kätterer, 1997; Bruun et al., 2003) accurately simulate SOC dynamics in long-term field experiments under different climatic conditions and soil types (Smith et al., 1997b). RothC is one of the most widely used model that simulates SOC dynamic based on relatively few parameters and input data. In RothC, total organic C in EOM (EOM-TOC) is distributed into pools of labile (DPM), resistant (RPM) and humified * Corresponding author. Tel.: þ33 1 30 81 54 01; fax: þ33 1 30 81 53 96. E-mail addresses: cpeltre@sas.upenn.edu (C. Peltre), Bent.T.Christensen@ agrsci.dk (B.T. Christensen), icard.ctifl@wanadoo.fr (C. Icard), Thomas.Katterer@ slu.se (T. Kätterer), Sabine.Houot@grignon.inra.fr, houot@grignon.inra.fr (S. Houot). Contents lists available at SciVerse ScienceDirect Soil Biology & Biochemistry journal homepage: www.elsevier.com/locate/soilbio 0038-0717/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.soilbio.2012.03.023 Soil Biology & Biochemistry 52 (2012) 49e60