Contents lists available at ScienceDirect Geoderma journal homepage: www.elsevier.com/locate/geoderma Long-term modelling of soil N mineralization and N fate using STICS in a 34- year crop rotation experiment Xiaogang Yin a,b,c, ⁎ , Nicolas Beaudoin b, ⁎⁎ , Fabien Ferchaud b , Bruno Mary b , Loïc Strullu d , Florent Chlébowski b , Hugues Clivot b , Christian Herre e , Jérôme Duval b , Gaëtan Louarn c a College of Agronomy and Biotechnology, China Agricultural University and Key Laboratory of Farming system, Ministry of Agriculture and Rural Affairs of China, Beijing 100193, China b INRA, UR 1158 AgroImpact, Site de Laon, 02000 Barenton-Bugny, France c INRA, UR4 URP3F, F-86600 Lusignan, France d ASAE esplanade R. Garros, 51100 Reims, France e UMR 614, INRA, Fractionnement des Agro-Ressources et Environnement (FARE), 2 Esplanade R. Garros, 51100 Reims, France ARTICLE INFO Handling Editor: Jan Willem Van Groenigen Keywords: Grain N N uptake Drainage N leaching N surplus Catch crops ABSTRACT Net soil N mineralization is a driver for N uptake and N losses at an annual scale, but is itself dependent on long- term N surplus and C-N storage in agricultural systems. The accurate modelling of N mineralization remains challenging. Thus, the STICS research version V1610 that includes modified soil organic nitrogen (SON) mi- neralization and root biomass turnover modules was assessed in this study regarding its predictions of net N mineralization and long-term N fate in a 34-year experiment comparing crop rotations with or without catch crops (CC) and bare soil. The in situ gross balance method was used as a reference to estimate net N miner- alization based on measured N variables (i.e. N uptake, exported N and N leaching). The Index of Agreement (IA) of STICS predictions concerning crop biomass, crop yield, N uptake and exported N ranged between 0.61 and 0.76, 0.79–0.89, 0.49–0.64 and 0.47–0.58, respectively, depending on the crop rotations. STICS also enabled a good simulation of annual drainage and N leaching with IA ranges of 0.92–0.96 and 0.78–0.93, but high leaching values were not captured by the model. The STICS research version simulates the decay of deep roots (below a depth of 25 cm) but it neglects their decomposition. This simplification could cause an underestimation of N leaching. The observed N surplus ranged from 27 to 51 kg N ha -1 yr -1 in the cropped rotations depending on the crop rotations, and the N surplus was accurately simulated with an IA of 0.75–0.84. STICS produced a good prediction of changes in SON stocks under cropped rotations and bare soil, with both the rRMSE and rMBE being lower than 10%. Estimated mean annual N mineralization was 115 kg N ha -1 under cropped rotations and 42 kg N ha -1 under the bare soil treatment. STICS relatively well predicted net N mineralization regarding both differences between crop rotations and over time. Moreover, STICS correctly simulated the long-term effects of CC on drainage, N leaching, SON accumulation and net N mineralization. To conclude, STICS is a useful model to predict net N mineralization and N fate in long-term crop rotations. Moreover, this work raised new questions concerning the long-term fate of N stored in deep dead roots. Further improvements to describe the fate of these residues should enhance the prediction of N leaching by the STICS model and enable the optimization of N management in cropping systems.- 1. Introduction The nitrogen cascade is a major issue when managing cropping systems. N losses (except for NH 3 ) mainly originate from soil organic matter (SOM) turnover, which varies with pedological, climatic and management factors (Galloway et al., 2003; Billen et al., 2013). Gen- erally, soil N mineralization plays a direct role in crop N uptake and an indirect role in N partitioning between crop uptake and environmental losses. High soil mineral N levels may cause increased risks of deni- trification and N leaching if soil N mineralization is not synchronized https://doi.org/10.1016/j.geoderma.2019.113956 Received 22 March 2019; Received in revised form 29 August 2019; Accepted 2 September 2019 ⁎ Corresponding author at: College of Agronomy and Biotechnology, China Agricultural University and Key Laboratory of Farming system, Ministry of Agriculture and Rural Affairs of China, Beijing 100193, China. ⁎⁎ Correspondence to: N. Beaudoin, INRA, UR 1158 AgroImpact, Site de Laon, 02000 Barenton-Bugny, France. E-mail addresses: xiaogangyin@cau.edu.cn (X. Yin), nicolas.beaudoin@inra.fr (N. Beaudoin). Geoderma 357 (2020) 113956 0016-7061/ © 2019 Published by Elsevier B.V. T