The Network of Measurement Stations for Physical Parameters of the Soils of Catalonia (XMS-Cat) is a project initiated in 2015 by the ICGC. It began in the Conca de Tremp, replacing manual stations with automatic stations with continuous recording of humidity and soil temperature. Initially located in soils dedicated to vineyard cultivation, the network has been expanding towards other vineyard fields in the Pyrenees. Since 2023, they have also begun to be installed in other areas of the territory, maintaining the focus on soils dedicated to the same type of cultivation, specifically the rainfed vineyard, since its management allows characterizing the natural environment with minimal anthropic interference. The data generated are aligned with the international monitoring standards promoted by the International Soil Moisture Network (Dorigo et al., 2021; ISMN, 2023).

The aim of the XMS-Cat viewer is to generate and provide continuous soil temperature and humidity data at different depths and in different areas of the Catalan territory, with a special focus on wine-growing areas. These data, combined with the measurement of environmental parameters, allow several studies to be carried out such as:

• the determination of soil climatic diets according to Soil Taxonomy (Soil Survey Staff, 1999). 
• environmental studies on climate change, using these parameters as indicators of the resilience and resistance of ecosystems (Bradford et al., 2019). 
• hydrological studies, such as the calculation of the water balance for the recharge of aquifers, among others (Robinson et al., 2003; SSSA, 2017).

The main users of this viewer are:

• Farmers and crop managers: to optimize irrigation and agricultural practices based on accurate soil moisture and temperature data (pest prediction, irrigation optimization, etc.). 
• Researchers and scientists: to study the characteristics and behavior of soils in different environmental conditions. 
• Public administrations: to plan and implement policies related to agriculture and land management.

Viewer ICGC XMS-Cat

In the viewer provided by ICGC it is possible to consult the data of the physical parameters of the soils of the active stations that make up the network, their geographical location and the pedological information. It is possible to load the layers of the Geoindex-Soils referring to their classifications and climate regimes at scale 1:250.000.

The search for the physical parameters of the soils is carried out according to the date (day / month / year and time) and can be visualized graphically and / or downloaded in csv format. The data that can be consulted are:

• Soil moisture (m³/m³) and relative air humidity (%H₂O).
• Soil moisture (m³/m³) and total rainfall (l/m²).
• Soil temperature (ºC) and air temperature (ºC).

Visor a finestra sencera: https://visors.icgc.cat/mesurasols 

Use of the collected data

Soil moisture is the water stored in the most superficial layer of our planet, being an indispensable variable in a large number of processes and applications such as:

• flood forecasting.
• availability and retention of water.
• assessing agricultural drought.
• fire prevention.
• water resources management.

Soil temperature is important to know:

• the type, productivity and wilting of plants.
• the speed of the nutrient cycle.
• soil microfauna activities.

Both parameters also serve us to:

• classify soils (taxonomy) through climate regimes.
• to analyze the feasibility and requirements of sensors in development of small Earth observation satellites.
• geotechnics (soil mechanics), those are fundamental parameters for landslide control and slope stability.

Operation of XMS-Cat stations and technologies used
 

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Figura 1. Scheme of a station for measuring physical soil parameters.

The stations that make up the network are formed by 4 multi-parametric soil sensors at 5, 20, 50 and 100 cm depth, capacitive sensors such as those described by Bogena et al. (2007) and Rosenbaum et al. (2010), which measure soil temperature and moisture.

The installation of the multi-parametric sensors and the interpretation of the data are progressively adapted to the methodological criteria established by the Soil Science Society of America for the physical analysis of soils (SSSA, 2017), guaranteeing the quality and comparability of the results obtained.

A series of environmental sensors are also available: rain gauge, pyranometer and a probe for temperature and relative humidity of the air, which are installed in a 3 m high steel turret.

A data acquisition system, a power supply system and a data communication system are located inside the cabinet.

The perimeter of the station is marked with a fence that also serves as protection (Figure 1).

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Figura 2. Conceptual diagram of the XMS-Cat.

Data recordings are every 30 minutes. The acquisition systems are equipped with a telemetry system (modem with a SIM card) powered by a 30 W photovoltaic panel, which allows the data to be sent automatically to the ICGC server.

The data are uploaded and organized in the spatial database management system NetMon© (ICGC measurement and control station monitoring system) from which and through a web service they can be consulted, analyzed and downloaded.

These data are public and accessible through the ICGC-Network of Physical Parameters Stations for Soil Measurement (XMS-Cat) Viewer, in which the edaphological information of each station can also be accessed (Figure 2).

Installation of the stations

The installation of the station is carried out in two phases:

• In a first phase, excavations are made for the foundations of the tower and for the installation of the buried sensors. A description of the soil is also carried out in which the different horizons are identified and analyzed in the laboratory, since this edaphic knowledge will be basic to understand the data obtained by the sensors at different depths.
• In the second phase, the tower is installed with the environmental sensors, the solar panel and the cabinet with the power supply, data capture and sending system, where all the sensors are connected. These stations are installed on the edge of the plot, outside the cultivation area.

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Installation process of the Llívia station (Cerdanya)

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Sensor installation process at 5, 20, 50 and 100 cm

Implementation status (November 2023)

The project began in 2013 in the Conca de Tremp with manual sensors in vineyard fields associated with an initiative on high-altitude wines. These sensors had limitations (manual unloading, feeding problems, damage due to agricultural work), which did not guarantee the continuity of the data. For this reason, in 2016 they began to be replaced by automatic stations with remote transmission.

Currently, the network has 17 stations spread across several regions of the Pyrenees: Alt Empordà, Alt Urgell, Cerdanya, Noguera, Osona, Pallars Jussà, Pallars Sobirà and Solsonès.

Finally, the integration of XMS-Cat data into the International Soil Moisture Network (ISMN) portal (https://ismn.earth/en/dataviewer/) expands the scope of these data for international research, offering points of comparison and cross-validation with other soil networks on a global scale (Dorigo et al., 2021).

Station table

References

• Dorigo, W. A., Gruber, A., Scanlon, T., Ford, T. W., Hahn, S., & Van der Schalie, R. (2021). The International Soil Moisture Network: Serving Earth system science for over a decade. Earth System Science Data, 13(4), 2345–2364. https://doi.org/10.5194/essd-13-2345-2021
• ICGC (2014). Estimació dels règims climàtics de Catalunya segons la classificació de la Soil taxonomy (SSS, 1999). Informes tècnics de l’Institut Cartogràfic i Geològic de Catalunya, ED-0005/14, 40 p., Generalitat de Catalunya. 
• ICGC i DARP (2019). Mapa de sòls de Catalunya 1:250.000 (MSC250M). Institut Cartogràfic i Geològic de Catalunya i Departament  d'Agricultura, Ramaderia, Pesca i Alimentació. Barcelona. ISBN: 978-84-393-9821-9 (imprés), 978-84-393-9836-3 (GeoPDF).
• International Soil Moisture Network (ISMN). (2023). Data viewer. https://ismn.earth/en/dataviewer/
• Robinson, D. A., Jones, S. B., Wraith, J. M., Or, D., & Friedman, S. P. (2003). A review of advances in dielectric and electrical conductivity measurement in soils using time domain reflectometry. Vadose Zone Journal, 2(4), 444–475. https://doi.org/10.2113/2.4.444
• Rosenbaum, U., Huisman, J. A., Weuthen, A., Vereecken, H., & Bogena, H. R. (2010). Sensor-to-sensor variability of the ECH2O EC-5, TE, and 5TE sensors in dielectric liquids. Vadose Zone Journal, 9(1), 181–186. https://doi.org/10.2136/vzj2009.0036
• Soil Science Society of America (SSSA). (2017). Methods of soil analysis: Physical methods (SSSA Book Series No. 5). Madison, WI: SSSA.
• Soil Survey Staff. (1999). Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys (2nd ed.). USDA Agriculture Handbook No. 436.