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Item type:Publication, Access status: without files , Exploring the Relation Between Soil Salinity on Soil Organic Carbon Dynamics in Global Terrestrial Ecosystems(2024-05); ; Soil Organic Carbon (SOC) is a fundamental component of terrestrial ecosystems, connected to climate regulation, nutrient cycling, and soil health. The influence of soil salinity - referring to the concentration of soluble salts in the soil solution - on SOC content is acknowledged (1,2), but there is limited understanding regarding the precise direction and extent of SOC’s response to varying levels of soil salinity in real field conditions. This study explores the relationship between soil salinity and SOC content, necessary for understanding carbon sequestration processes, climate change mitigation, and terrestrial carbon stock stability. Using the SOC of 60,392 soil samples collected globally since 1950, we developed a statistical model (General Additive Model) and analyzed soil salinity’s relation with SOC dynamics while controlling the role of other environmental parameters. According to the results of the statistical analysis, we estimate that an increase in soil salinity from 1 to 5 dS m-1 would be correlated with a decrease in SOC, equivalent to dropping from 0.92 g kg-1 above the mean predicted SOC (31.77 g kg-1) to 6.34 g kg-1 below the mean predicted SOC (-700%), while considering other influencing environmental factors such as precipitation and temperature. Our results show the minor contribution of salinity to SOC while other factors such as climate, vegetation, and land management practices exert more substantial effects on SOC content. Key covariates in relation with SOC include soil nitrogen, anthropogenic phosphorous input, and soil pH. Additionally, our study estimates the effects of one standard deviation increases in soil salinity of the analyzed soil samples on topsoil (0 – 20 cm) SOC content, showing a 6.98% decrease in SOC. These findings highlight the importance of considering diverse factors in understanding SOC dynamics, providing insights into mitigating the impacts of soil salinity and climate change on terrestrial ecosystems.Publicationtype: Conference Paper24 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Integrating LUCAS data with AI-driven models for predicting soil Salinization across the EUSoil salinization influences vegetation, biodiversity, crop production, land-atmosphere interactions, soil health and ecosystem functioning. Quantifying soil salinity is essential to mitigate its determinantal effects (Hassani et al., 2020; 2021). This study utilizes an AI-driven approach for the quantification of soil salinity in EU using a wide range of environmental covariates including soil properties, terrain attributes, climate, and remotely sensed variables. Soil salinity point data from the LUCAS survey (2015 and 2018) were used for the training and validation of the models. Different algorithms were employed in our analysis including Random Forest, LightGBM, and XGBoost, with XGBoost demonstrating superior accuracy in predicting soil salinity across EU. The predictive model output is a gridded dataset illustrating the spatial and temporal variations of soil salinity, with corresponding uncertainty maps. This work represents one of the first attempts to integrate LUCAS data with AI models, aiming to generate soil salinization maps specifically designed for EU soils. The outcome will contribute substantially toward devising necessary action plans for protection of EU soils against salinization and degradation which is at the heart of the European Green Deal, Paris Agreement, and the United Nations Sustainable Development Goals especially UN SDG15.Publicationtype: Conference Paper60 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , How does surface salt crystallization influence saline water evaporation from porous media in the presence of a water table?Saline water evaporation from soil is ubiquitous in many environmental and hydrological processes such as soil water evaporation, vegetation and crop production. It plays an important role on soil salinity influencing soil health and ecosystem functioning. When the salt concentration in soil substantially exceeds its solubility limit as a result of water evaporation, salt crystallization occurs (1). Although how different parameters such as type of salt, soil texture, angularity of the grains, presence of a water table and atmospheric condition influence the formation (1-6), patterns and dynamics of crystallization is relatively well understood, how exactly the presence of crystalized salt influence the evaporation dynamics is poorly understood with the majority of the previous investigations offering qualitative description. We thus aimed at quantifying the effect of crystallized salt on dynamics of saline water evaporation from porous media under controlled laboratory conditions. To do so, three sets of experiments were conducted using NaCl solutions of 10%, 15%, and 20% (mass basis) in a climate chamber with constant air temperature and relative humidity of 30 °C and 30%, respectively. Sandy soil with particle sizes ranging from 0.4 to 0.8 mm and density of 2.65 gr/cm3 was used as the model porous medium packed in cylindrical glass columns (20 cm height - 8 cm diameter). The columns were supplied from Marriott’s flasks to keep the columns fully saturated during the evaporation experiments. Mass loss from sand samples was measured digitally while crystallization dynamics and their corresponding thermal signatures were monitored with a high resolution optical camera and a thermal imager, respectively. This setup enables us to quantify the contribution of crystalized salt on evaporation. Our preliminary results highlight the key role of salt crystallization on changing evaporation dynamics from sand columns relative to the reference sample supplied with freshwater. Despite the impact of salinity in reducing saturated vapor pressure, we observed enhanced evaporation rates from samples with crystalized salt at the surface by a factor of 4 to 12 (depending on the salt concentration). Furthermore, highly resolved surface temperature dynamics recorded by the thermal camera enabled us to investigate the correlations between the intermittent temperature fluctuations of salt crystals and the evaporative flux from the surface. Our findings provide new insights regarding how the presence of crystalized salt at the surface influences the soil evaporation dynamics.Publicationtype: Conference Paper107