DOI: 10.5281/zenodo.17826823
title: Carbon Sequestration Potential in Arable Soils of the Czech Republic – Values Aggregated at the District Level

description: The dataset presents the results of simulations assessing the carbon sequestration potential of arable soils in the Czech Republic, utilising the EPIC-IIASA CZ simulation platform. It consists of outputs derived from the modelling of various agronomic scenarios at the district level (LAU1), incorporating three climate scenarios: RCP 2.6, 4.5, and 8.5. The data reflect the effects of four model cropping systems, differing levels of nitrogen and manure fertilisation intensity, residue management, and irrigation on the principal parameter—namely, the change in average carbon content within soil organic matter in the top 30 cm of soil during the periods 2040–2060 (or 2080–2100), compared to the reference average for 2000–2020. This parameter is expressed as tonnes of carbon per hectare (t C ha⁻¹). For a given cropping system and its variants, the values indicate the potential for carbon sequestration over 40- and 80-year timescales.

Structure of the database:






Column name



Meaning and description of values (categories)



Values Example





scenario



Climate scenario identifier 



rcp26 / rcp45 / rcp85





timescale



Length of the period for which the value is calculated (years)



40 / 80





system



Code of the model cropping system (see detailed description)



CpCm1 / ApCm1 / CpRg1 / ApRg1





irrigation



Irrigation regime (rainfed, irrigated)



rf / irr





nfert



Nitrogen fertilisation level (Nn = none / Nl = low / Nm = moderate / Nh = high). Level Nh means that for each crop, the annual dose is set to the maximum N application limit according to the Nitrate Directive. Nm = 60% Nh, Nl = 30% Nh, Nn = 0% Nh.



Nn / Nl / Nm / Nh





fmfert



Share of total N dose applied in the form of manure (fm0 = 0 % / fm60 = 60 % / fm100 = 100 %).



fm0 / fm60 / fm100





baler



Post-harvest residue management (R0 = straw removed / R30 = 30 % remains in field / R60 = 60 % / R100 = 100 %)



R0 / R30 / R60 / R100





poly_id



Unique geographical code of the region (LAU 1 code).



CZ0100 





value



Numeric value of the metric. Average increase (+) or decrease (-) of organic C content in the top 30 cm of soil (t ha-1)



4.989584358158098





The dataset contains 59,136 records.
description: Description of the Modelling Approach

Introduction

One of the main sources of knowledge about the dynamics of organically bound carbon in soil (SOC) is experimental research through field trials or soil monitoring. Complex soil processes can also be translated into mathematical form. Mathematical models can facilitate understanding of SOC equilibrium across a wide range of soil-climate and agronomic conditions where experimental research is not feasible due to time, complexity, or cost constraints.

SOC models (e.g., RothC, Century/DayCent, DNDC) translate theoretical assumptions into a simplified image of the soil ecosystem using equations and schemes. The accuracy of these assumptions can be verified by comparing simulations with real data. Once a model is validated, it can be used for prediction—such as forecasting the effects of climate change or land use changes on SOC dynamics. SOC models can be integrated into more complex crop or ecosystem models.

Many simulation models can realistically mimic the impacts of agronomic interventions and climate changes (e.g., DSSAT, APSIM, WOFOST, EPIC). These models allow for the prediction of not only crop yields for a given location but also various soil and environmental characteristics.

The next step in the use of process-based models is their connection to regional databases and other sources of information. This creates comprehensive tools for research and inventory of natural resources, including soil and its functions, which can be used for predictions at various scales.

To calculate estimates of the sequestration potential of arable soils in the Czech Republic, we used the regional crop model EPIC-IIASA and its modification for the Czech Republic, named EPIC-IIASA CZ. The creation of this national agro-environmental simulation platform was motivated by the research need of the Ministry of Agriculture to quantify the potential for carbon sequestration in arable soil under various management conditions and climate change scenarios.

The objective of the result is to provide spatial information on the magnitude of carbon sequestration potential in arable soil for model cropping systems, its variability, and regional differences.

Description of the simulation platform EPIC-IIASA CZ

The basis for simulating the sequestration potential of arable soils in the Czech Republic is the regional crop model EPIC-IIASA, which was developed to simulate the growth and production of agricultural crops at global, continental, and subcontinental scales (see Fig. 1). This simulation platform utilizes the already existing and extensively validated process-based crop model EPIC.

 Fig. 1 EPIC-IIASA Platform – elements, structure, and functionality

 

 The dynamics of crop growth during the growing season are simulated by the EPIC-IIASA model on a daily basis simultaneously for a large number of separate, spatially localized sites, usually over a time horizon of several years to decades. EPIC-IIASA produces output data on the temporal and spatial changes in crop production in response to recorded (historical) or projected (future, alternative) factors that influence crop production, such as weather, topography, soil and its management, agronomic practices, the crop itself, and its cultivar characteristics.

The core of the platform is the EPIC model, which includes modules for simulating crop growth, soil water balance, and nutrient balance (cycling and transformation of C, N, and P in soil and plants). The EPIC model incorporates the validated and widely used CENTURY model of soil organic matter dynamics. The model is further supplemented by a wide range of agronomic management options. The second component is the geospatial data infrastructure, which provides spatially represented inputs for the EPIC model (weather, location, geomorphology, soil, crop, nutrient inputs, and soil management), either in the form of a grid or spatial simulation units (SimU). The third component consists of scenarios, which represent the formulation of specific research questions regarding the intended purpose. Scenarios affect the choice of outputs and are usually defined using alternative input data on climate (historical climate, climate projections) and land management (adaptation and mitigation measures, such as carbon farming).

The EPIC-IIASA model has been validated as a tool for assessing the impacts of climate change, both independently and as part of model ensembles. Its reliability as part of integrated modeling systems has also been demonstrated.

Thanks to the highly scalable process-based EPIC model, the project task was to modify the EPIC-IIASA platform for regional studies of agroecosystems in the Czech Republic, mainly to assess carbon sequestration potential and to propose and test the effectiveness of model carbon sequestration systems in agricultural soil.

For the needs of regional simulations of agricultural systems in the Czech Republic, a national geospatial data infrastructure, EPIC-IIASA CZ, was created and implemented in a LINUX environment. It consists of 977 spatial SimU, created by dividing districts according to climate region and prevailing soil properties (depth, soil type, and humus content class). Each SimU was assigned a typical soil profile and daily weather data from 1989–2019 from a 10 × 10 km grid, as well as estimated sowing and harvest dates of main crops based on the respective production area. The design allows for aggregation of outputs at the LAU1 (district) and NUTS2 (region) levels, which corresponds to the state administration's requirements for the level of quantification and interpretation of results.

 Table I Elements and Measures Incorporated in the EPIC-IIASA CZ Platform






Crops



annual/perennial, forage crops, root crops, etc., including cultivar characteristics (e.g., earliness)





Crop rotation



monoculture / crop rotation





Mineral fertilizers



application rate of N (5 levels), method of application (specific timing / application based on crop need)





Manure and organic fertilizers



quantity and type according to composition and origin (cattle manure, sewage sludge, compost, etc.)





Irrigation



rainfed / additional irrigation, possibility to limit maximum daily and total annual irrigation volume





Soil tillage



depth and type (plough, discs, harrows, etc.), conventional / reduced / no-till





Cover crops



without / with cover crop (N-fixing / non-N-fixing)





Post-harvest residue management



residues completely / partially removed from the field (4 levels implemented)





For the purposes of the reserach, the soil sequestration potential is defined as the quantification of the soil's ability to increase the content of soil organic matter in the top layer when a certain model type of management is introduced. In the simulations, we only considered selected agronomically meaningful methods of arable land use, ranging from intensive practices that are less suitable or unsuitable for C storage, through sustainable and carbon farming-recommended practices such as reduced tillage, greater incorporation of post-harvest residues, use of cover crops, crop diversification, application of organic fertilizers, and irrigation.

The end point of the gradient is a system that is strongly focused on increasing soil C content, which is a monoculture of alfalfa mulched and fertilized with farmyard manure. We believe that for most real-world farming systems used by Czech farmers, it is possible to find an analogue within the proposed model systems that corresponds to their management. The simulations did not consider variants such as land use change (conversion of arable land to permanent grassland/forest or combined cultures—e.g., agroforestry), application of biochar, etc.

Findings from long-term experiments, as well as simulations, show that the soil's sequestration capacity is limited, not only physically-chemically (C saturation) but also in terms of C balance. With a certain steady management method, equilibrium is reached over time between the input of organic matter into the soil and the mineralization of soil organic matter. After reaching this equilibrium, the SOC content no longer increases. Further increase is only possible by switching to a management system with a higher intensity of organic matter inputs or with additional measures aimed at C accumulation.

To evaluate the sequestration potential in Czech regions, we consider two basic model management systems:



-        Crop production system without livestock (Cp – crop production): excludes forage crops and does not utilize farmyard manure or organic fertilizers.

-        Crop production system with livestock (Ap – animal production): incorporates feed crops into the crop rotation, with two-thirds of the nitrogen applied in the form of farmyard manure.


Both systems are further divided into two subtypes:



-        Commercial (Cm - commercial): A crop rotation system with a smaller number of commercial crops (including bioenergy crops), generally considering the removal of post-harvest residues, deep plowing, higher fertilizer application rates, and irrigation (CpCm, ApCm).

-        Regenerative (Rg - regenerative): A higher number of crops in the rotation (including less traditional ones), inclusion of cover crops, generally considering leaving post-harvest residues in the field, reduced tillage, lower fertilizer application rates, and no irrigation (CpRg, ApRg).


A description of the basic characteristics of the model systems and the concept for creating sub-variants of these systems are shown in Figures 2 and 3.

Figure 2 Basic model sequestration systems considered in the creation of the maps.

 

Figure 3 Schematic representation of the sub-variants of model sequestration systems.

 

Initial values of SOC were derived from the digital base map “Map of Humus Stocks in Agricultural Soils of the Czech Republic” (Žížala, 2020).

Simulations were conducted for the period 2000–2100 using the regional circulation model CSC_REMO2009_MPI-ESM-LR. The considered climate scenarios were RCP 2.6 (an optimistic scenario assuming a rapid reduction in global CO2 emissions), RCP 4.5 (medium), and RCP 8.5 (pessimistic, assuming efforts to reduce CO2 emissions will not be successful).

Carbon sequestration was expressed as the difference in average SOC content in the top 30 cm soil layer during the periods 2040–2060 (or 2080–2100) compared to the average for 2000–2020 (expressed in t C/ha), based on the simulation of the same cropping system (and its variants) throughout the period. In this way, the defined sequestration potential in arable land expresses the degree of carbon retention/release in the topsoil layer over 40 or 80 years.

The information about the research is published on the web page https://www.carc.cz/agrosimulace.

License and Disclaimer

Data are available for free download and distribution. Use is strictly conditional upon the content remaining unchanged and the full source (citation) being consistently provided. We utilize the latest scientific knowledge and exercise utmost diligence in preparing our outputs. Nevertheless, due to the inherent limitations of current scientific understanding, technical constraints, and data scope, the absolute temporal and spatial accuracy of all published information cannot be guaranteed. Users assume all risk and acknowledge that neither the authors nor the cooperating organizations shall bear any liability for direct or indirect damages arising from the misinterpretation or misuse of the information provided herein.

Acknowledgment

The authors of the dataset thank Dr. Wiktor Żelazny for programming work in the implementation of the EPIC-IIASA CZ simulation infrastructure.