Insights into ECOSSE modelling of soil organic carbon at site scale from Irish grassland sites and a French grazed experimental plot
Authors: Premrov Alina , Zimmermann Jesko , Dondini Marta , Decau Marie-Laure , Green Stuart , Fealy Reamonn , Fealy Rowan , Saunders Matthew 
Published: March 2021

&lt;p&gt;ABSTRACT&lt;/p&gt;&lt;p&gt;The work provides insights into soil organic carbon (SOC) modelling procedures associated with different management practices for Irish grassland sites selected from two large soil databases (LUCAS-2009 &lt;sub&gt;[1] &lt;/sub&gt;and Teagasc-SIS &lt;sub&gt;[2]&lt;/sub&gt;) and a single treatment-plot&amp;#160; from France &amp;#160;(paddock of a long- term grassland-experiment) &lt;sub&gt;[3]&lt;/sub&gt;. Modelling of SOC was done at site scale using &amp;#8220;Model to Estimate Carbon in Organic Soils -Sequestration and Emissions&amp;#8221; (ECOSSE) 6.2b version of the model in site-specific mode &lt;sub&gt;[4]&lt;/sub&gt;. The selection of Irish sites and the Irish model input-parameters followed procedures explained in Premrov et al. (2020) &lt;sub&gt;[5]&lt;/sub&gt;. As explained in Premrov et al. (2020) &lt;sub&gt;[5]&lt;/sub&gt;, special attention was given to model SOC-input data because the preliminary findings showed high sensitivity of model predictions to the initial SOC-inputs &lt;sub&gt;[5]&lt;/sub&gt;. Initial SOC-inputs for Irish sites were extracted from the Irish soil NSDB-database &lt;sub&gt;[8] &lt;/sub&gt;because of lack of data at that time. The preliminary SOC modelling results from Irish sites [RMSE &gt;36%; 84 sites (out of total 95 pre-selected LUCAS and SIS sites after excluding 11 potential outliers &lt;sub&gt;[7]&lt;/sub&gt;)]&lt;sub&gt;&lt;/sub&gt;indicated that further work is needed on obtaining initial SOC-input data. The new LUCAS-2015 &lt;sub&gt;[6]&lt;/sub&gt; soil-point data in combination with older LUCAS-2009 &lt;sub&gt;[1]&lt;/sub&gt; data provide opportunities to resolve this issue, which is currently work in progress. Considering that Irish sites were selected from large soil-databases that lacked detailed site-specific information (i.e. stocking rates and fertilisation-data could be obtained only in general form), the treatment-plot from France &lt;sub&gt;[3]&lt;/sub&gt; was also simulated to gain further insights into the ECOSSE SOC modelling at site/point-scale. This work confirmed the importance of using appropriate conversion-factor when applying stocking rates as a proxy for the manure-inputs (as an alternative for grazing &lt;sub&gt;[7]&lt;/sub&gt;). Further insights included the importance of assessing the modelled SOC &amp;#8216;trends&amp;#8217; over time, and its comparison with observed ones &lt;sub&gt;[7]&lt;/sub&gt;.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Acknowledgements&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;SOLUM project is funded under the Irish EPA Research programme 2014-2020. Thanks go to Dr Jo Smith (University of Aberdeen, Scotland) for ECOSSE-model and to all who provided data or advice/support, among others, Teagasc-SIS, Ireland; &amp;#160;French national-observatory SOERE ACBB, a part of ANAEE-F French national infrastructure, and Dr Katja Klumpp (INRAe, France).&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Literature&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;[1] JRC (2018). LUCAS-2009, ESDAC. JRC. EC.&lt;/p&gt;&lt;p&gt;[2] Teagasc, (2018) Irish Soil Information System (SIS). Teagasc, EPA, Ireland.&lt;/p&gt;&lt;p&gt;[3] SOERE ACBB (2020) http://www.soere-acbb.com/&lt;/p&gt;&lt;p&gt;[4] Smith, J., et al. (2010). ECOSSE. User Manual.&lt;/p&gt;&lt;p&gt;[5] Premrov, A., et al. (2020). Insights into modelling of soil organic carbon from Irish grassland sites using ECOSSE model. EGU2020-8090. doi.org/10.5194/egusphere-egu2020-18940; (CC-BY-4).&lt;/p&gt;&lt;p&gt;[6] JRC (2020). LUCAS 2015, ESDAC. JRC. EC.&lt;/p&gt;&lt;p&gt;[7] Saunders, M. et al. (draft-report 2020) SOLUM. EPA Research Report. 2016-CCRP-MS.40.&lt;/p&gt;&lt;p&gt;[8] EPA (2007). National Soils Database (NSDB). Environmental Protection Agency, Ireland.&lt;/p&gt;