Soil organic matter depletion is a significant concern in agricultural soils, impacting crucial aspects of ecosystem health, especially soil properties such as fertility and soil moisture retention. Adopting sustainable soil management practices, such as cover crops, can mitigate this issue. In this study, we analyzed the soil organic carbon (SOC) content and quality in vineyards using two distinct management methods: permanent spontaneous cover crops and conventional tillage. Dissolved organic carbon (DOC) was quantified and chemically characterized using UV–visible spectroscopy. Our results showed an increase of 4.7 Mg C/ha in the carbon stock (50 cm depth) after 10 years of implementing vegetation covers compared with tilled soil. Additionally, cover crop management increased less humified soluble carbon in surface soil layers, while tillage transformed the solubilized carbon. This finding is important because tilled soil becomes more accessible to microbial degradation and leaching, which, in the long term, leads to a SOM content decrease. In conclusion, an increase in carbon stock was observed when using cover crops due to the incorporation of fresh organic matter, whereas tilled soils showed a depletion of carbon stock, including the mobilization of more stable carbon.

Lithofacies belonging to mud-flat and palustrine deposits (lake margin) in the Miocene of the Madrid Basin (Spain) have been studied. Four lithofacies corresponding to mud flat (1 and 3) and palustrine (2 and 4) deposits have been differentiated. Units 1 and 3 consist mainly of mudstones and carbonates (calcretes and diolocretes). The clay fraction is dominated by trioctahedral smectite (up to 79%) with illite and kaolinite as minor components. The d(060) spacing value shows reflections at 1.52 and 1.50 Å indicating also the presence of dioctahedral phyllosilicates. Unit 2 consists predominantly of lutites (claystones), locally with carbonate and chert nodules. The clay fraction is dominated by sepiolite (up to 96%) with variable contents of smectite and subordinate illite. The d(060) spacing value shows reflections at 1.51 and 1.52 Å indicating trioctahedral clay minerals. Unit 4 consists mostly of carbonates (limestones) with mudstone and lutite inserts. The clay fraction shows different contents of sepiolite, palygorskite and dioctahedral smectite. The analysis of a selection of trace elements (Cr, Co, Th, La, Sc) has allowed us to determine the characteristics of the source area as dioritic, somewhat different from those of the nearby materials from the Batallones sector. Sepiolite shows FWHM values ranging between 0.68 and 1.10 (2θ), indicating “low crystallinity sepiolite”. Differences in the conditions of formation of magnesian smectite and palygorskite have been observed in the mud-flat and palustrine deposits. The formation of sepiolite mainly by neoformation in palustrine deposits with different hydrochemistry is remarkable, leading to differences in fibre size and crystallinity of the fibrous clay mineral. Authigenic transformation processes from previous Al-rich phases would be responsible for the formation of saponite and palygorskite in mud flat and palustrine environments, with different pH conditions.

The Madrid Basin contains large and well developed deposits of Mg-clays of Miocene age. These were developed in an environment controlled by a lacustrine saline-alkaline environment with an arid or semi-arid climate, leading to large deposits of Mg-clays. This paper summarizes the study about the formation of Mg-clay minerals in the transition from mudflat lithofacies made-up of Mg-smectite to palustrine lithofacies where sepiolite is predominant. The samples collected in the field were characterized by XRD (X-Ray Diffaction) (bulk sample and clay fraction), examined using SEM (Scanning Electron Microscopy) and analyzed by XRF (X-Ray Fluorescence) and FTIR (Fourier Transform Infrared Spectroscopy). The results suggest that during the formation of these materials dissolution-precipitation, direct precipitation and recrystallization mechanisms intervened. The type of water present (runoff, lake and/or groundwater) is a key factor for the development of the different mineral phases. In the case of the study, the analyzed series goes from mudflat conditions with influence of runoff water to a palustrine environment. During this evolution, the influence of groundwater increases with time. This is reflected in the affinity between the samples analyzed and the presence of certain elements that could serve as indicators of changes between different media.

This study aimed to establish sound relationships between soil properties of agricultural land in central Spain and their spectral attributes to contribute to deriving an indicator for sustainable farm management. Sixteen plots, managed under various conditions, eight with traditional tillage and eight with other alternative managements, were selected to gather soil samples representing three predominant soil orders (Leptosols, Cambisols, and Luvisols). Soil sampling was conducted from depths ranging from 0 to 30 cm (0–50; 5–10, 10–20, and 20–30 cm), ensuring a broad spectrum of sample variability across different times and locations. The reflectance of soil 64 soil samples was measured within the range of 400 to 900 nm, and the corresponding concentrations of soil organic carbon and majoritarian minerals, calcium carbonate, quartz, phyllosilicates, K-Feldspar, and plagioclase were determined for each sample. Partial least squares analysis was employed to construct prediction models using a calibration dataset comprising 66% of randomly selected samples. The remaining 33% of samples were utilized for model validation. The prediction models for the measured soil chemical properties yielded R² values ranging from 0.14 to 0.79. Only SOC and limestone provided accurate prediction models. These findings hold promise for developing a soil health indicator tailored for site-specific crop management. However, the complex composition of soil organic carbon and calcium carbonate in certain soils underscores the importance of careful interpretation and validation of remote sensing data, as well as the need for advanced modeling approaches that can account for the interactions between multiple soil constituents.

Context: Soil degradation and water scarcity pose critical challenges for vineyard sustainability in semi-arid regions. Objectives: This study evaluates the long-term effects of spontaneous cover cropping (CC) on soil health in a rainfed vineyard in central Spain, managed without irrigation or pesticides for over two decades. Methodology: By comparing soils under CC and conventional tillage (TILL), we assessed changes in soil physical properties (porosity and water retention), nutrient content, and microbial function up to 30 cm depth. Stepwise regression analysis was used to explore management-driven relationships among CC, soil properties and nutrient dynamics. Results: Soils under CC showed significantly higher organic matter content (1.74 ± 0.37% in the topsoil with CC vs. 0.83 ± 0.24% in TILL) and porosity (51.2 ± 2.5% vs. 44.0 ± 1.8% at 10–30 cm depth). Available phosphorus tended to be higher under CC (19.13 ± 0.60 mg/kg in CC vs. 14.13 ± 4.52 mg/kg in TILL), and this trend was further supported by stepwise analysis, which identified P availability as a variable influenced by management practices. Enzymatic activities were consistently elevated under CC, particularly in the topsoil; β-glucosidase (25 ± 9 mU/g) nearly doubled the value observed under tillage. Although soil water availability showed a non-significant trend in the topsoil (10 cm), it was higher in the subsoil (30 cm) under CC (29.0 ± 0.97% vs. 25.1 ± 0.32% in TILL). The stepwise regression analysis supported a management-driven model where CC influence soil organic matter (SOM) and nutrient availability. SOM and soil moisture strongly influenced extractable phosphorus (R² = 0.790, p =0.0047) and mineral nitrogen (R² =0.907, p =0.00018), with moisture at the time of sampling emerging as the dominant driver of nitrogen dynamics. Conclusions: The analysis supports a management-driven pathway in which long-term vegetation inputs under CC enhance SOM accumulation. Soil water availability tended to increase in the subsoil under CC, while SOM together with short-term moisture conditions emerged as the main regulators of nutrient dynamics under semi-arid conditions. Implications: By aligning ecological processes with practical agronomic outcomes such as nutrient retention and soil structure, these findings offer compelling evidence to support the broader adoption of sustainable ground cover practices in Mediterranean viticulture.

In Mediterranean semi-arid regions, rainfed olive groves are increasingly being abandoned due to drought, low profitability, and rural depopulation. The long-term impact of abandonment on soil conditions is debated, as it may promote vegetation recovery or lead to degradation. In contrast, some farmers are adopting low-disturbance management practices that allow spontaneous vegetation to establish. These contrasting scenarios offer valuable opportunities for comparison. This study aims to develop a framework to assess the impact of different management regimes on soil health and to investigate (1) the impact of spontaneous vegetation cover (SVC) and tillage regimes on soil organic carbon (SOC), and (2) the long-term ecological dynamics of abandoned groves, through a combination of field surveys, remote sensing, and object detection. SOC was assessed using both ground-based and remote sensing-derived indicators. Vegetation cover was quantified via a grid point intercept method. Field data were integrated with a land-use monitoring framework that includes abandonment assessment through historical orthophotos and a deep learning model (YOLOv12) to detect active and abandoned olive groves. Results show that abandoned zones are richer in SOC than active ones. In particular, the active groves with SVC exhibit a mean SOC of 1%, which is higher than that of tilled groves, where SOC is 0.45%, with no apparent moisture loss. Abandoned groves can be reliably identified from aerial imagery, achieving a recall of 0.833 for abandoned patches. Our results demonstrate the potential of YOLOv12 as an innovative and accessible tool for detecting zones undergoing ecological regeneration or degradation. The study underscores the ecological and agronomic potential of spontaneous vegetation in olive agroecosystems.