MT30 and MT76 recorded the highest mean annual cumulative fresh herb yields, at 41,776.7 and 35,149.0 kg/ha, respectively. MT30 also had the highest mean annual cumulative dry herb yield, 6,610.4 kg/ha, and the highest mean annual cumulative dry leaf yield, 3,971.1 kg/ha. The reported results indicate that this genotype combined high biomass measurements with relatively high plant height and canopy diameter. These values describe performance in the tested environment and seasons; the abstract does not establish that the same rankings would occur elsewhere.

The collection also differed in plant architecture and leaf characteristics. MT89 had the greatest measured branching capacity, averaging 18.3 branches per plant. For leaf morphology, MT72 had the highest overall mean leaf area, 23.9 cm², and leaf width, 4.9 cm. The corresponding means for MT80 were 20.5 cm² and 4.4 cm. Multivariate analyses separated the evaluated germplasm into distinct yield-oriented and morphology-oriented genotype groups, according to the abstract.

Variation among genotypes was highly significant for most agronomic and leaf traits examined. Phenotypic coefficients of variation generally exceeded genotypic coefficients, while heritability and genetic advance were high for major yield-related traits. The authors interpreted these findings as evidence of selection potential within the evaluated germplasm. Based on the two-season field trial in Adana, they identified MT30 and MT76 as candidate genotypes for high industrial biomass production, MT80 as a resource for a large-leaf ideotype and MT89 for a branching ideotype. They also proposed these genotypes as possible parental material for cultivar development and future breeding programs. The study’s conclusions are bounded by its evaluation of 90 genotypes at one location over two growing seasons, as described in the abstract.

Subject of Research: Field evaluation of 90 basil genotypes for biomass yield, plant architecture and leaf morphology in Adana

Article Title: Agronomic performance and leaf-morphological evaluation of basil (Ocimum basilicum L.) germplasm under the environmental conditions of Adana

Article References: Barut, M., & Tansi, L. S. (2026). Agronomic performance and leaf-morphological evaluation of basil (Ocimum basilicum L.) germplasm under the environmental conditions of Adana. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10010-0

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10010-0

Keywords: basil, Ocimum basilicum, germplasm evaluation, biomass yield, leaf morphology, plant branching, heritability, Mediterranean agriculture, Agronomic, performance, leaf-morphological, evaluation

Lemnos occupies a special place in the history of agriculture. Farming spread into Europe from the Fertile Crescent through Greece roughly 9,000 to 8,500 years ago, and Lemnos has been inhabited since at least the Neolithic, prized for its fertile plains and cultivable soils. Over millennia, farmers selected crops suited to local conditions, producing distinctive landraces, while wild plants co-evolved alongside the sown species to form what ecologists call agrestal communities, the wild flora of arable land. Today, arable fields still cover a substantial and relatively stable share of the island, and agriculture remains largely traditional: winter cereals grown as fodder, often in mixed intercropping systems of barley and oat, rotated with pulses and fallows, followed by grazing on stubble.

This system, which has largely disappeared elsewhere, is precisely what makes Lemnos scientifically valuable. Across most of Europe, less intensive agriculture has become rare, squeezed between abandonment on marginal land and intensification on fertile soil. Because many arable plants depend on the regular disturbance of traditional farming, both trends drive biodiversity loss. The habitat type that the study addresses, arable land managed by low-intensity methods, is listed as Endangered on the European Red List of Habitats. Understanding the species composition, land-use requirements, and environmental constraints of these communities is therefore essential for their conservation, and Lemnos offers a rare living laboratory in which rotational fallowing and stubble fields still exist.

Between 2018 and 2022, with additional sampling in May 2025, researchers recorded vegetation in 174 plots across the island: 130 in spring, during April and May, and 44 in fall, during September and October. The plots, mostly 100 square meters, lay within field interiors growing cereals such as six-rowed barley, oat, and durum wheat, pulses such as common vetch and garden pea, and in fallow and stubble fields. Fields showing signs of herbicide use or heavy fertilization were excluded. The team estimated the cover of every species using the Braun-Blanquet scale and analyzed the resulting data with non-metric multidimensional scaling, a technique that arranges plots in space according to how similar their species compositions are, together with a modified TWINSPAN clustering algorithm to classify the spring communities.

The seasonal contrast proved to be the single strongest driver of floristic variation. A permutational multivariate analysis of variance confirmed that season significantly shaped community composition, and a test of group dispersion showed the difference was driven by species identity rather than variability among plots. Spring fields belonged to early-flowering annuals such as rigid ryegrass, scarlet pimpernel, corn poppy, wild radish, and corn gromwell, plants that complete their life cycle and set seed before the May harvest. Fall plots, by contrast, were dominated by late-flowering annuals, biennials, and perennials such as stinking fleabane, European heliotrope, yellow star-thistle, and chicory, species that germinate or form rosettes in spring and flower after the harvest. Many of them share adaptations, including basal rosettes, prostrate growth, and low-attached branches, that reduce damage from mowing and grazing, allowing them to persist in the post-harvest landscape.

Within the spring fields, the clustering analysis revealed four distinct plant communities, and their distribution mapped cleanly onto the island’s geology. Volcanic rocks and tuffs cover about 30 percent of Lemnos and produce shallow, stony, acidic soils, while Eocene-Oligocene molasse sediments and Holocene alluvial deposits yield deeper, often base-rich ground. The first community, named for Anchusa hybrida and Hypecoum imberbe, occupied dry, well-drained, sandy soils derived from molasse, often on young fallows and pulse fields. The second, the Raphanus raphanistrum-Cladanthus mixtus community, preferred sandy, acidic, base-poor soils that were partly seasonally wet, indicated by species such as toad rush and corn spurrey. The third, the Glebionis segetum-Ranunculus marginatus community, grew on productive alluvial lowlands with intermediate to seasonally wet moisture, and the fourth, the Hypericum triquetrifolium-Leontice leontopetalum community, was tied to loamy, stony, base-rich soils, where it hosted striking geophytes including the pink-flowered Gladiolus italicus.

Ecological indicator values for Europe, which assign each plant species numerical scores for its preferences regarding soil reaction, moisture, nutrients, light, and temperature, allowed the researchers to quantify these relationships. Fitting the community-weighted indicator means into a three-dimensional ordination showed that the primary gradient, the first ordination axis, was strongly correlated with soil reaction, with a coefficient of determination of 0.777 and a p-value of 0.001, cleanly separating the acidic-soil communities from the base-rich ones. A second axis was marginally correlated with temperature and moisture, distinguishing the drier communities from the wetter ones. Light and nutrients were not significant. A chi-squared test further confirmed that the underlying geological substrates differed significantly among the communities, with alluvial deposits underlying 73 percent of the Glebionis segetum-Ranunculus marginatus fields and molasse and tuffs dominating the base-rich community.

Crop type and management also left their fingerprints. Barley was the most common crop overall and dominated the base-rich community, while mixed maslins of barley and oat appeared in at least 21 percent of fields in every spring community and reached 42 percent in the alluvial community. Pulse fields were concentrated in the Anchusa hybrida-Hypecoum imberbe community, and wheats were most frequent in the acidic-soil community. The base-rich and alluvial communities contained the island’s most productive fields, rich in nutrient-demanding species and in speirochorous plants such as corncockle and darnel ryegrass, which are sown inadvertently with farm-saved crop seed, a hallmark of traditional seed use. Species richness averaged 26.6 taxa per plot in spring against 15.6 in fall, and the base-rich community was the richest of all, with a median above 30 species per plot and a maximum of 62.

Perhaps the most consequential result concerns the obligate agrestal species, plants that in Greece occur almost exclusively in arable fields. The surveys recorded 33 such species, including several classified as threatened on the national Red List: darnel ryegrass and Leontice leontopetalum as Vulnerable, and corncockle, rough poppy, and Anagallis foemina as Near Threatened or Vulnerable. Rarer still were Adonis annua, Allium cyrilli, Bupleurum subovatum, Glaucium corniculatum, Vaccaria hispanica, and others, each found in only one to four plots, and most of them concentrated in the base-rich Hypericum triquetrifolium-Leontice leontopetalum community. The mean number of obligate species per plot was highest in that community, confirming that the least productive-looking loamy fields are in fact the island’s most important refuges for specialized arable flora.

The study’s authors place their communities within the broader syntaxonomic framework of Eurasian arable vegetation, finding affinities with alliances described from the western Mediterranean while noting that some diagnostic species of those western alliances are rare or absent in the east, and that Leontice leontopetalum appears to characterize the eastern Mediterranean branch of the base-rich alliance. Beyond classification, the message is ecological and urgent. Arable plants sustain pollinators and farmland birds, and the succession of early- and late-flowering species on Lemnos provides continuous floral resources throughout the growing season. As agricultural intensification proceeds across Europe, initiatives such as the Terra Lemnia project, which supports the island’s traditional practices, landraces, and farmland biodiversity, demonstrate that low-intensity farming and conservation are not opposing goals. Lemnos, the authors conclude, stands as a rare in situ refuge for segetal biodiversity and a reference system for restoring biodiversity-rich agricultural landscapes elsewhere.

Subject of Research: Agrestal plant communities and their soil and seasonal drivers in less intensively managed farmland on the Greek island of Lemnos

Article Title: Soil and season shape less intensively managed agro-ecosystems of a Mediterranean island—Insights from Lemnos (Greece)

Article References: Rinne, L., Meyer, S., & Bergmeier, E. (2025). Soil and season shape less intensively managed agro-ecosystems of a Mediterranean island—Insights from Lemnos (Greece). Vegetation Classification and Survey, 6, 253-271. https://doi.org/10.3897/vcs.164437

Image Credits: AI Generated

DOI: 10.3897/VCS.164437

Keywords: agro-ecosystems, arable plants, Lemnos, Greece, Mediterranean agriculture, plant communities, soil gradients, seasonality, biodiversity conservation, vegetation classification, traditional farming, threatened species

The hybrid W9 was born from a breeding program launched in the early 2000s at the INRAE research center in San Giuliano, Corsica, crossing Fortune mandarin, used as the female parent, with Ellendale tangor, a mandarin-sweet orange hybrid prized for flavor and late maturity around April. Fortune was chosen because it reliably produces a high proportion of triploid offspring, while Ellendale contributed organoleptic quality and lateness. Triploid plants carry three sets of chromosomes instead of the usual two, a configuration that makes them almost entirely seedless, a trait consumers strongly prefer. The W9 selection was picked by scientific experts and producers through sensory and pomological evaluation, grafted onto the widely used C35 citrange rootstock, and planted in a commercial-style orchard to see how it would perform under real growing conditions rather than in a greenhouse.

Polyploidy, the possession of extra chromosome sets, is a common phenomenon in plants and has become a deliberate tool in fruit breeding. Polyploid plants often show thicker leaves, altered stomatal density, improved water-use efficiency, and better management of reactive oxygen species, the chemically reactive molecules such as hydrogen peroxide that accumulate when photosynthesis is stressed. Tetraploid rootstocks have been studied extensively for drought, salinity, and even disease resistance, but triploidy applied at the scion level, the fruiting top of the grafted tree, remains poorly documented. Previous work on W9’s siblings showed enhanced tolerance to natural chilling and a greater capacity to recover from water deficit, hinting that the triploid condition itself might confer physiological advantages. The new study set out to test whether those laboratory and nursery findings would hold up across a full year of open-field weather.

The researchers monitored three eight-year-old varieties in an orchard at Aléria, all grafted onto the same diploid C35 citrange rootstock: the diploid clementine, the diploid ‘Star Ruby’ grapefruit (the pomelo of Corsican production), and the triploid W9. Sampling took place on sunny days in four seasons, from July 2023 through April 2025, with mean temperatures ranging from 25.1 degrees Celsius in summer to just 9.3 degrees in winter. On each date, the team measured gas exchange parameters including net photosynthetic rate, stomatal conductance, transpiration, and intrinsic water-use efficiency, along with chlorophyll fluorescence, which reveals the efficiency of the photosystem II machinery. Leaves were then flash-frozen in liquid nitrogen for biochemical analysis of oxidative stress markers, ascorbate pools, and the activities of four key antioxidant enzymes.

The results painted a picture dominated first by season and only second by genotype. A principal component analysis showed that the first two components explained 56.74 percent of total variance, with warm-period samples clustering on the side of high photosynthetic performance and cold-period samples on the side of activated ascorbate metabolism. All three varieties saw their photosynthetic rates, stomatal conductance, and transpiration drop significantly between the warm summer-autumn period and the cold winter-spring period, and their maximum quantum efficiency of photosystem II fell below 0.75, a classic sign of cold-induced photoinhibition. Pomelo maintained the highest photosynthetic values across nearly all seasons, peaking at 13.28 micromoles of carbon dioxide per square meter per second in autumn, while clementine and W9 tracked each other closely, with W9 edging ahead in gas exchange during spring.

The striking differences emerged in the redox data. During spring, its harvest window, W9 consistently maintained the lowest levels of hydrogen peroxide and malondialdehyde, the latter a breakdown product of lipid peroxidation that serves as a fingerprint of oxidative damage to cell membranes. In the multivariate analysis, W9’s spring samples grouped near reduced ascorbate, the active antioxidant form of vitamin C, while clementine’s spring samples clustered with dehydroascorbate, the oxidized form, reflecting an inability to keep pace with oxidative pressure. Quantitatively, W9 reached 6.43 micromoles of reduced ascorbate per gram of fresh weight in spring, the highest of any variety in any season, and its ascorbate-to-dehydroascorbate ratio stood at 1.86 in spring, compared with just 0.65 for clementine.

The enzymatic machinery behind this stability tells a coherent mechanistic story. W9 showed higher catalase activity than clementine in winter and spring, and in spring its ascorbate peroxidase activity reached 0.35 units per milligram of protein, above both references. Most telling was dehydroascorbate reductase, the enzyme that recycles oxidized ascorbate back into its reduced, radical-scavenging form. DHAR activity declined in pomelo and clementine during winter but remained elevated in W9 through winter and spring. The authors conclude that W9 does not simply manufacture more ascorbate through the Smirnoff-Wheeler biosynthetic pathway; it recycles the existing pool more efficiently, keeping the antioxidant arsenal charged precisely when cold nights and rising spring light create the most dangerous conditions for photoinhibition and reactive oxygen formation. Notably, proline, an osmoprotectant often implicated in stress tolerance, did not differ among varieties in spring, indicating that W9’s advantage rests on enzymatic and redox pathways rather than osmotic adjustment.

Why would three chromosome sets produce this effect? The researchers point to a possible gene dosage effect, in which extra copies of antioxidant genes amplify the expression of catalase, ascorbate peroxidase, and DHAR, along with larger cell compartments and more efficient compartmentalization of redox reactions observed in earlier anatomical studies of related triploid hybrids. Genetic parentage likely matters too: Fortune mandarin is known to be cold-tolerant, and chilling tolerance in citrus is consistently linked to strong reactive oxygen scavenging, whereas the Ellendale tangor parent is cold-sensitive and prone to excess electron leakage during cold periods. The authors also caution that scion-rootstock interactions cannot be ruled out, since even with all trees on the same C35 citrange rootstock, bidirectional signaling between root and shoot, including hormone transport, may differ depending on the scion’s ploidy. Testing W9 on a broader range of rootstocks would establish whether its redox superiority is a constitutive triploid trait or a product of this particular grafting combination.

The practical implications reach beyond plant physiology. Because W9 ripens late, its harvest coincides exactly with the production gap that currently forces Corsican retailers to rely on imports, and its ability to hold redox homeostasis during fruit maturation, when the developing crop acts as a heavy metabolic sink that induces systemic oxidative stress, promises more stable yields and fruit quality in that window. The study also delivers the first seasonal antioxidant profile of ‘Star Ruby’ grapefruit under natural Corsican conditions, confirming its effective acclimation through robust photosynthesis. Combining clementine, pomelo, and W9 in island orchards could build a continuous production calendar from winter into late spring, reinforce the value of geographical indications, and reduce the climate-related widening of the off-season gap. For a sector built on quality rather than volume, a seedless, late-ripening, cold-resilient mandarin may prove to be exactly the missing piece.

Subject of Research: Seasonal physiological and antioxidant responses of a new late-ripening triploid mandarin hybrid in Mediterranean field conditions

Article Title: Physiological and redox status properties of a new late-ripening triploid hybrid mandarin: a seasonal field evaluation

Article References: Allegrini, B., Venturini, L.-M., Oustric, J., Julhia, L., Froelicher, Y., Berti, L., Lourkisti, R., & Santini, J. (2026). Physiological and redox status properties of a new late-ripening triploid hybrid mandarin: a seasonal field evaluation. Frontiers in Plant Physiology, 4, Article 1896981. https://doi.org/10.3389/fphgy.2026.1896981

Image Credits: AI Generated

DOI: 10.3389/fphgy.2026.1896981

Keywords: triploid citrus, mandarin hybrid, redox homeostasis, chilling tolerance, antioxidant enzymes, ascorbate, photosynthesis, Corsica, late ripening, polyploidy, oxidative stress, Mediterranean agriculture

Xylella fastidiosa is an insect-borne bacterium that colonizes the water-conducting vessels of plants, eventually blocking the flow of water and nutrients until trees dry out and die. First detected in Spain in 2016, its arrival alarmed the farming community, since the pathogen is more commonly associated with olive trees but also inflicts heavy losses on almond crops. Since 2017, the Alicante region has experienced a high incidence of the disease in almond orchards, where infections reduce harvests and kill trees, translating into major economic losses for growers in one of Spain’s most important almond-producing areas.

Until now, most research on the pathogen had concentrated on detecting infections and exploring biological control options, and the principal management response has been the eradication of infected trees. Crucially, those earlier studies focused solely on the crop itself, in this case almond trees, without considering the surrounding environment. A team led by the ERSAF research group at the University of Córdoba set out to change that perspective, widening the lens to the landscape scale and examining the ecological interactions that unfold across entire ecosystems rather than within single orchards.

The aim of the work, according to Ricardo Hernández, lead author of the study, was to assess how infection by Xylella fastidiosa, environmental factors, and adjacent vegetation jointly influenced the impact of the pathogen on almond crops. Rather than treating the bacterium as the sole driver of disease, the researchers designed their investigation to capture the combined influence of climate, water availability, and the composition of plant communities surrounding affected farms, an approach that reflects how epidemics actually unfold in real agricultural landscapes.

To do this, the team gathered information on the plant health status of almond trees across 19 plots located in an area of Alicante at the center of a major Xylella outbreak. Beyond the orchards themselves, the researchers sampled the natural surroundings, recording the type and condition of the surrounding shrubs as well as the climatic factors prevailing in the area. This landscape-scale design made it possible to identify environmental and biological relationships between the different elements of the landscape and to determine how those relationships shaped the impact of the disease.

The results revealed that the disease is driven by a combination of factors rather than by the effect of the pathogen alone. Among the most striking discoveries was the role of wild shrub species that act as reservoirs of the bacterium. The researchers observed that a greater presence of rockrose, gorse, and buckthorn, shrub species carrying high pathogen loads, was linked to a greater impact of infection on the almond trees. This finding directly contradicts the common belief that the natural environment acts as a buffer against the effects of pathogens on crops. In these landscapes, adjacent wild vegetation appears to serve instead as a source of inoculum, sustaining the bacterium and intensifying pressure on nearby orchards.

Even more consequential was the role of water. According to the study, the single most important factor aggravating the impact of the disease was water stress. Temperature and the lack of water influenced the severity of infection in both the almond trees and the adjacent shrubland, demonstrating the decisive importance of climate in mediating how badly the pathogen strikes. The connection is biologically plausible: Xylella fastidiosa occupies the very vessels that carry water through the plant, so trees already strained by drought have less capacity to tolerate the additional hydraulic disruption the bacterium causes. In drought-prone Mediterranean settings, that interaction can turn a manageable infection into a lethal one.

The study was the result of a collaboration between the University of Córdoba’s ERSAF and Agricultural Entomology groups, the Institute for Sustainable Agriculture (IAS-CSIC), and the Doñana Biological Station, bringing together expertise in landscape ecology, plant pathology, and entomology. By integrating these perspectives, the team was able to connect patterns of plant health decline across an active invasion with the environmental drivers that shape them, producing one of the most comprehensive field-based assessments of how landscape context modulates Xylella impacts in Mediterranean agroecosystems.

The practical implications are significant. In light of these findings, the researchers argue that management and surveillance efforts should prioritize orchards located in high-risk settings, particularly those in fragmented, drought-prone landscapes featuring extensive cover of pathogen-hosting shrubs in the adjacent vegetation. In other words, not all orchards face the same risk, and resources for monitoring and control could be targeted far more efficiently by mapping where susceptible crops, reservoir shrubs, and stressful climates overlap. Selective control of the reservoir shrubland and supplementary irrigation to counter drought are identified as possible control strategies warranting further study, offering growers potential tools that go beyond the costly and often controversial eradication of infected trees.

For a pathogen with no known cure once a tree is infected, prevention and landscape management may prove to be the most powerful weapons available. By showing that drought and reservoir vegetation jointly amplify the toll of Xylella fastidiosa on almond trees, the Córdoba team has reframed the fight against the bacterium as an ecological problem as much as an agricultural one. As climate change brings hotter, drier conditions to the Mediterranean, the interaction between water stress and pathogen reservoirs is likely to become even more pronounced, making landscape-scale planning an increasingly urgent priority for protecting almond orchards and the farming communities that depend on them.

Subject of Research: Landscape and environmental drivers of Xylella fastidiosa impact on almond trees in Mediterranean agroecosystems

Article Title: Drought shapes the impact of Xylella fastidiosa on almond trees

Article References: Drought shapes the impact of Xylella fastidiosa on almond trees. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Xylella fastidiosa, almond trees, drought, water stress, plant pathology, landscape ecology, Mediterranean agriculture, Alicante, reservoir shrubs, crop disease management, University of Córdoba, NeoBiota

The starting point is a technical innovation in how water itself is measured. Rather than relying on irrigation quotas or rainfall records, the researchers quantify effective crop water using actual evapotranspiration, or ETa, derived from the FAO’s WaPOR satellite database. Evapotranspiration captures the water a crop genuinely consumes—the sum of evaporation from soil and transpiration through leaves—making it a far more honest accounting unit than the water that is nominally delivered. Dekadal ETa values are summed to seasonal totals, converted into volumes using intersected administrative and crop-mask areas, and screened with quality flags so that low-confidence satellite pixels are masked rather than imputed. Every governorate-crop-year cell in the resulting panel carries provenance and quality-control documentation, a level of transparency that the authors treat as essential for any policy-facing conclusion.

But measuring water is only half the problem. The other half is causal: how much extra yield does an additional unit of effective crop water actually produce? Simply correlating water use with yields would be misleading, because farmers who irrigate more may differ systematically from those who do not—in soil quality, capital, or institutional access. To solve this, the researchers assembled a governorate-by-crop-by-year panel spanning 2010 to 2024 and identified yield responses using instruments that plausibly shift water availability without directly affecting yields: lagged rainfall anomalies aggregated over upstream basins, with pixels inside the target governorate excluded, and reservoir filling ratios matched to downstream irrigated perimeters through an assignment matrix built from scheme geography and operator records. The logic is elegant. Rain falling upstream of a governorate, and water stored in dams feeding its canals, change how much water crops can consume, but they do not directly change the agronomic or economic conditions inside the governorate itself.

On top of this causal backbone sits the study’s most distinctive component: a fuzzy inference layer that captures the state dependence of water’s marginal value. The idea is grounded in agronomic reality. The same proportional increase in effective crop water does not produce the same yield gain everywhere. Where irrigation delivery is already adequate and technology is efficient, an extra cubic metre buys relatively little; where water stress is high and a binding constraint exists, the same increment can be transformative. To formalise this, the authors built a fuzzy system with three antecedents—water stress, irrigation adequacy, and technology efficiency—each expressed through trapezoidal membership functions that allow a range of values to be unambiguously high or low rather than a single sharp threshold. Three linguistic terms per antecedent generate twenty-seven rules, each encoding an economically and agronomically plausible statement about when marginal returns to water should be larger or smaller. The full rule base, calibrated membership-function parameters, and alternative rule structures are published in the paper’s appendices, an unusually complete disclosure for a component that might otherwise be dismissed as researcher discretion.

The results upend the conventional ranking of where water should go. Average water productivity—the yield per unit of water that dominates most irrigation planning—would direct scarce water toward the regions and crops that already use it most efficiently. But when the state-dependent, causal marginal value of water is estimated instead, the ranking changes. A proportional increase in effective crop water yields different gains across Tunisia’s governorates, and accounting for this heterogeneity reverses some of the priorities implied by average productivity. In practical terms, the water that looks most productive on paper may not be the water that generates the most value at the margin, because productivity averages conceal the local hydrologic and technological states that determine what one more cubic metre is actually worth.

The framework’s second pillar connects agricultural water to human wellbeing. The authors construct governorate-level multidimensional deprivation indicators using household survey and regional accounts data from Tunisia’s National Institute of Statistics, drawing on a fuzzy measurement tradition in poverty analysis that Belhadj has developed in earlier work. They then compare water allocation scenarios against three criteria simultaneously: efficiency, in the total value generated; distribution, in how deprivation changes across territories; and institutional feasibility, scored by a second fuzzy system over five criteria including the metered delivery headroom that existing infrastructure can absorb. This triple test is what elevates the paper from an econometric exercise to a statement about territorial quality of life. Water allocation, the authors argue, should be treated as an environmental-social determinant of wellbeing—one link in a chain that runs from the canal to the household.

The headline finding concerns the trade-off between efficiency and equity. In the scenario accounting, a Rawlsian maximin allocation—one that prioritises the worst-off territories, in the spirit of philosopher John Rawls’s difference principle—retains 90.9 percent of the total value gain that a purely utilitarian allocation would achieve. When the comparison is restricted to crop groups whose elasticity estimates pass over-identification tests, the maximin allocation retains 97.0 percent of the utilitarian gain, while producing a larger reduction in mean deprivation. In other words, the equity-efficiency trade-off that policy makers usually assume to be painful may be remarkably mild: choosing the fairer allocation sacrifices almost nothing in total value while delivering substantially greater reductions in territorial deprivation. For water-stressed Mediterranean governments wrestling with allocation politics, that is a strikingly hopeful result.

The authors are notably careful about what their evidence can and cannot support. The Hansen over-identification test rejects for vegetables and high-value annuals at p equals 0.007, meaning the two instrument families do not identify a common effect for that group; the corresponding coefficient is therefore reported as a diagnostic rather than a validated causal estimate, and the Nabeul citrus value, which uses the same coefficient as a proxy, inherits that limitation. The transmission step from agricultural value added to deprivation is explicitly framed as accounting rather than causal inference: the income-deprivation gradient used to convert value gains into deprivation changes is an estimated cross-sectional association from a single household survey, applied uniformly across governorates because cell sizes do not support separate estimation. The paper claims only the productive and distributional stages of the water-to-wellbeing pathway, not wellbeing outcomes themselves—a restraint that strengthens rather than weakens its credibility.

The robustness apparatus is equally thorough. Sensitivity analyses vary the fuzzy specification, testing triangular and Gaussian membership functions against the trapezoidal baseline and alternative rule structures, and re-estimate the central results without the fuzzy layer entirely, showing that the substantive conclusions survive even when the discretionary component is removed. Leave-one-reservoir-out reconstructions test the storage instrument, alternative SPEI drought horizons test the climate inputs, and cells failing satellite coverage thresholds are masked rather than imputed so that data uncertainty remains traceable and separate from sampling uncertainty. Scenario capacities are checked against one-season metered delivery headroom records held by Tunisia’s regional agricultural development commissariats and agricultural development groups, with each pilot module capped at the minimum of a conservative 200,000 cubic metre ceiling and the actual infrastructure headroom—an upper bound on what existing systems could absorb without new construction.

What emerges is a template that extends well beyond Tunisia. The Mediterranean basin is among the world’s most water-stressed regions, and allocation decisions there are increasingly made under conditions of genuine scarcity, where every cubic metre redirected is a cubic metre taken from someone. By combining satellite-derived water accounting, credible causal identification, transparent state-dependent modelling, and multidimensional deprivation measurement, the framework offers a way to make those decisions with evidence about their distributional consequences rather than averages that hide them. The finding that a fairness-first allocation can retain nearly all of the efficiency gains—while cutting deprivation more deeply—suggests that the hardest choices in Mediterranean water policy may be less agonising than feared, provided the value of water is measured where it actually lands, in the states and places where crops and communities actually live.

Subject of Research: Causal, state-dependent estimation of the marginal value of irrigation water and its distributional effects on territorial quality of life in Tunisia

Article Title: From Crop Water Productivity to Territorial Quality of Life: A Causal, State-Dependent ETa Framework for Water Allocation in Mediterranean Agriculture

Article References: Belhadj, B., & Fridhi, B. (2026). From Crop Water Productivity to Territorial Quality of Life: A Causal, State-Dependent ETa Framework for Water Allocation in Mediterranean Agriculture. Social Indicators Research, 185(1), Article 5. https://doi.org/10.1007/s11205-026-03949-y

Image Credits: AI Generated

DOI: 10.1007/s11205-026-03949-y

Keywords: water allocation, evapotranspiration, Tunisia, Mediterranean agriculture, causal inference, instrumental variables, fuzzy logic, multidimensional deprivation, water productivity, quality of life, irrigation policy, satellite data

The stakes could hardly be higher. Soil organic carbon is a cornerstone of the global carbon cycle, and schemes that pay farmers to sequester carbon in their fields—from voluntary carbon markets to emerging European certification frameworks—depend on trustworthy numbers. If models and measurements disagree, the entire architecture of agricultural carbon credits wobbles. The new study, led by Francisco Contreras of CEBAS-CSIC in Murcia, is one of the rare long-term experiments designed to test exactly that agreement, and its findings expose weaknesses on both sides of the ledger.

The experiment ran from 2013 to 2024 in a certified organic grove sitting 423 metres above sea level in a cold semiarid Mediterranean climate, where average annual rainfall is a meagre 263 millimetres. The soil is a sandy loam Haplic Calcisol with an alkaline pH and modest starting organic carbon content of 1.30 percent. The team set up a randomized complete block design with twelve plots and four treatments: compost produced on-farm from two-phase olive mill waste, pruning residues and sheep manure; biochar; a mixture of 90 percent compost and 10 percent biochar; and an unamended control. Amendments were applied five times over the trial at a rate of 20 megagrams of dry matter per hectare, spread along the drip lines of the trees and manually incorporated into the soil.

Seventeen sampling campaigns tracked carbon in the top 20 centimetres of soil, with outliers filtered using a robust median absolute deviation method that removed just over 10 percent of observations. By the end of the experiment, every treatment had gained carbon, even the control, with final concentrations of 1.80, 2.56, 2.84 and 3.01 grams per 100 grams of soil for control, compost, mixture and biochar respectively. Both the field data and the model agreed on the headline ranking: biochar was the most effective amendment for carbon accumulation, followed by the mixture and then compost. But when the researchers converted those concentrations into sequestration rates, the two approaches parted ways dramatically.

Field measurements pointed to soil carbon sequestration rates of 1.67 to 2.66 megagrams of carbon per hectare per year across the amended treatments. The RothC model, a multi-compartment carbon turnover model developed at Rothamsted Research and used worldwide, simulated rates of 2.98 to 5.34 megagrams—roughly double the field-based figures. The model systematically overestimated soil organic carbon stocks, and the size of the error depended on what had been added to the soil. Compost and the compost-biochar mixture showed the closest agreement between simulation and reality, with coefficients of determination of 0.43 and 0.39. Biochar, by contrast, was the worst performer, with an R² of just 0.10 and a root mean square error of 19.44 megagrams of carbon per hectare, the highest of any treatment.

Getting the model to work at all in this environment required serious technical surgery. Standard RothC struggles in semiarid regions, where it demands unrealistically high carbon inputs to match observations, so the team adopted a modified soil moisture function that allows soils to dry out thoroughly and slows decomposition accordingly. They also used a version of RothC adapted for amended soils, which adds three extra pools for exogenous organic matter—decomposable, resistant and humified—each with its own size and decay rate. Compost parameters were calibrated by inverse modelling against carbon dioxide fluxes measured in laboratory incubations of similar composts in three Mediterranean soils. Biochar could not be calibrated this way because its mineralisation emissions were simply too low, so the researchers instead derived pool parameters from the char’s thermal stability and hydrogen-to-carbon molar ratio, following a method proposed by Leifeld and colleagues in 2024.

The model’s initialization proved equally consequential. Because the grove had been converted from low-intensity agriculture to olives in 1997 and had received compost before the trial began, the soil was not at equilibrium. The team ran a historical spin-up, simulating a thousand years of equilibrium under the previous land use and then transitioning through the olive orchard phase, so that carbon pool sizes carried forward realistically. Even so, the model failed to reproduce the carbon accumulation observed in the unamended control plots, where field measurements showed a steady rise of about 0.04 grams of carbon per 100 grams per year. The researchers attribute this partly to the shredding and incorporation of olive pruning residues—inputs that are notoriously difficult to quantify—and to the growing biomass of the maturing trees, which their remote-sensing-based above-ground biomass model captured only imperfectly.

Biochar emerged as the study’s most provocative character. On paper, and in the model, it is a carbon storage champion: the simulations estimated that 98.1 percent of the added biochar carbon remained in the soil at the end of the experiment, and projected a permanence fraction of 97.9 percent after a century—figures consistent with the upper range of published estimates and with IPCC guidance. Yet in the field, biochar-derived carbon appeared far less abundant than expected, with only 49.3 percent of added carbon apparently remaining. The likely culprit is not decomposition but detection. Biochar persists as discrete, lightweight, highly concentrated particles rather than blending homogeneously into the soil matrix like compost, so a spade sample either hits a particle-rich pocket or misses it entirely. This fine-scale horizontal variability inflates uncertainty, and the outlier filtering procedure flagged some of the highest soil carbon values in the entire experiment within the biochar plots—values whose exclusion may have depressed the final estimate.

The implications ripple directly into carbon markets. Voluntary carbon market methodologies such as those of Verra and Gold Standard increasingly require both measured and modelled estimates of soil carbon change, with explicit uncertainty assessments, and recent European certification rules acknowledge that some amendments, biochar chief among them, resist accurate quantification by field sampling alone. The study suggests that compost-amended soils are comparatively predictable and verifiable, while biochar-based interventions carry a double uncertainty: field sampling struggles with its particulate heterogeneity, and models may overstate its persistence because parameters derived from thermal stability do not fully capture ageing, fragmentation and interactions with the soil environment. Allocating carbon credits to biochar projects, the authors argue, demands a cautious approach that integrates field measurements, adapted modelling and thorough upstream characterisation of the material itself.

Ultimately, the researchers are not asking anyone to abandon either tool. Modelling remains a fast, cheap and scalable way to project soil carbon dynamics across landscapes and decades, and it correctly captured the direction and relative ranking of treatment effects over eleven years. Field sampling remains indispensable for validating those trends against reality. What the Jumilla experiment makes unmistakably clear is that the two approaches are not interchangeable, and that neither is equally reliable for every kind of organic amendment. As governments and corporations pour money into soil carbon as a climate solution, this decade-long reality check from a Spanish olive grove delivers an uncomfortable but necessary message: the numbers on which carbon credits rest are only as good as the sampling designs, model calibrations and honest uncertainty estimates behind them.

Subject of Research: Soil organic carbon modelling and measurement in an amended organic olive grove

Article Title: Challenges in soil carbon modelling and measurement: a decade of experimental data vs. RothC simulations in an organic olive grove

Article References: Contreras, F., Cayuela, M. L., Sánchez-García, M., Ronchin, E., Mondini, C., & Sánchez-Monedero, M. A. (2026). Challenges in soil carbon modelling and measurement: a decade of experimental data vs. RothC simulations in an organic olive grove. SOIL, 12(2), 773-790. https://doi.org/10.5194/soil-12-773-2026

Image Credits: AI Generated

DOI: 10.5194/soil-12-773-2026

Keywords: soil organic carbon, RothC model, biochar, compost, carbon sequestration, olive grove, carbon accounting, voluntary carbon market, soil sampling, Mediterranean agriculture, organic amendments, climate mitigation

Researchers from the Instituto Valenciano de Investigaciones Agrarias (IVIA) in Moncada, Valencia, led by corresponding author Isabel Rodríguez-Carretero, spent two consecutive growing seasons testing composts in a commercial orchard of adult Tango mandarins grafted onto a hybrid rootstock and irrigated by traditional surface flooding. The team compared two industrially produced composts: one made from pruning residues and sewage sludge at a 1:3 fresh-weight ratio, the facility’s usual recipe, and a second made from rice straw and sewage sludge at a 1:8 ratio, using the rice straw as a locally available bulking agent. Composts were surface-applied each June within the tree canopy projection at two rates, 10 and 20 tonnes per hectare, alongside unfertilised-with-compost control plots, in a randomized complete block design with three replicates.

The chemical characterisation of the two composts revealed a striking difference. The rice straw–sewage sludge compost contained significantly higher total nitrogen, largely as organic nitrogen, and a lower carbon-to-nitrogen ratio of 10.3 compared with 13.8 for the pruning-residue version. Most notably, its phosphorus content, expressed as P2O5, was more than double that of the conventional compost and exceeded average values typically reported for livestock manures. The researchers suggest this makes the rice straw compost a promising phosphorus-rich organic fertiliser, a significant finding at a time when phosphate rock reserves are finite and Europe depends heavily on imported fertiliser raw materials.

Both composts met Spanish legal requirements for fertilising products, including minimum organic matter thresholds and maximum carbon-to-nitrogen ratios. One caveat emerged: the rice straw compost slightly exceeded the 500 milligrams per kilogram zinc limit for Class B classification under the older RD 506/2013 regulation, though it complied with the stricter thresholds of the more recent RD 1051/2022, which governs sustainable soil nutrition. The compost’s slightly acidic pH of 6.71, unusual for sewage sludge-based products, may actually be an advantage in the alkaline, carbonate-rich soils of eastern Spain, where it can enhance the solubility and availability of nutrients that are otherwise locked up by calcium carbonates.

In the field, the effects on soil chemistry unfolded over time. Soil organic matter and organic nitrogen rose significantly in the first season at both application rates, and in the second season at the double dose. Available phosphorus increased significantly in both seasons regardless of dose, pushing soil levels from normal or high into the high to very high categories used in citrus nutritional diagnostics. Available potassium rose significantly only at the double rate, by 17 percent in the first season and 29 percent in the second. Interestingly, exchangeable sodium decreased in composted plots in the second season, while soil pH dropped significantly under the double dose, a cumulative effect the authors attribute to repeated organic matter inputs and the release of organic acids during decomposition.

Salinity was the one indicator demanding caution. Electrical conductivity rose by 21 percent in the first season and 105 percent in the second under the double application rate, reflecting the salt load carried by successive compost additions. The values nonetheless remained below both the 4 dS per metre threshold that defines a saline soil and the 1.7 dS per metre level at which citrus yields begin to decline. The authors recommend that long-term management might involve reduced annual rates or biennial applications, combined with irrigation practices that promote salt leaching through the improved soil permeability that organic matter confers.

Soil biology responded quickly but transiently. In the first season, microbial biomass carbon jumped 65 percent under the double compost dose, and dehydrogenase activity, a standard proxy for overall microbial metabolic activity, increased under both rates. By the second season, however, no significant differences among treatments remained. The researchers suggest the first-year compost, richer in readily oxidisable organic carbon, offered microorganisms a more accessible substrate, and note that biological indicators are highly sensitive to soil moisture, temperature, and sampling timing. They call for future studies with multiple sampling dates across crop phenological stages to disentangle these dynamics.

Heavy metal concentrations in the soil, including copper, zinc, nickel, lead, cadmium, and chromium, stayed within permissible limits under both older and current Spanish regulations throughout the trial, although the double compost dose raised total soil zinc by roughly 17 to 18 percent in both seasons. Foliar nutrient analysis told a similarly reassuring story: macronutrient concentrations remained within optimal ranges in all treatments, with the sole exception of potassium in the second season. Compost significantly increased leaf zinc only in the first season. Encouragingly, because soil and foliar phosphorus were already elevated after the first compost application, the team cut mineral phosphorus fertilisation by 10 percent in the second season, and leaf phosphorus stayed optimal, evidence that compost-derived phosphorus can partially replace mineral P inputs under comparable conditions.

Perhaps the most commercially significant result is what did not change. Yield, fruit weight, diameter, peel thickness, colour index, total soluble solids, titratable acidity, and maturity index showed no agronomically relevant differences between composted and control trees in either season. All fruit met EU marketing standards for mandarins, with diameters above 45 millimetres, juice content above 33 percent, and maturity indices exceeding 7.5. Because mineral fertilisation met crop requirements across all plots, the soil fertility gains from composting simply had no yield gap to fill. The authors caution that their findings come from a flood-irrigated orchard, a system still used on roughly 13 percent of Spanish citrus acreage, and that responses under modern drip irrigation may differ. Still, the study demonstrates that industrial-scale composting of rice straw and sewage sludge is a technically viable, regulation-compliant route to closing nutrient loops in Mediterranean agriculture, turning two disposal headaches into a soil-building resource while keeping the region’s mandarins just as sweet.

Subject of Research: Effects of rice straw–sewage sludge compost on soil fertility, tree nutrition, and fruit quality in Mediterranean citrus orchards

Article Title: Field application of rice straw–sewage sludge compost in Mediterranean citrus orchards: effects on soil properties, nutrient status and fruit quality

Article References: Rodríguez-Carretero, I., Canet, R., Pérez-Piqueres, A., & Quiñones, A. (2026). Field application of rice straw–sewage sludge compost in Mediterranean citrus orchards: effects on soil properties, nutrient status and fruit quality. SOIL, 12(2), 841-853. https://doi.org/10.5194/soil-12-841-2026

Image Credits: AI Generated

DOI: 10.5194/soil-12-841-2026

Keywords: compost, rice straw, sewage sludge, citrus, soil fertility, circular economy, phosphorus, soil organic matter, microbial biomass, Mediterranean agriculture, mandarin, organic fertiliser

The factsheet, published by Pensoft Publishers on behalf of the three consortia, opens with a headline that captures the shared ambition of all three projects: technology-driven early detection of biotic stressors threatening European plant health. It is more than a summary document. By presenting each project’s core objective side by side, and by highlighting the thematic lines, technological solutions and methodological approaches the projects have in common, the factsheet offers policymakers, researchers and stakeholders a concise map of where Europe’s digital plant-protection effort stands and where it is heading. The shared vision uniting the three initiatives is that artificial intelligence, remote sensing and citizen engagement can transform how Europe identifies and responds to pest outbreaks.

Each project brings a distinct focus to the partnership. FORSAID concentrates on Europe’s forests, developing a comprehensive framework for the detection, monitoring and management of ten EU-regulated biotic stressor species. The four-year project brings together seventeen partner organisations from ten countries, and it places artificial intelligence and digital technologies at the core of its strategy for mapping the future of forest pest control. Forest ecosystems are particularly vulnerable to regulated pests because once an invasive organism establishes itself in a woodland landscape, eradication is often technically impossible and containment becomes the only realistic option. Early detection is therefore the difference between a manageable incursion and a landscape-scale catastrophe.

CERBERUS addresses the other side of the European agricultural spectrum: Mediterranean crops. The project is building a multi-layer early detection and monitoring system that integrates remote and proximal sensing, ground-based automation and artificial intelligence. Its data streams come from three distinct sources — space, the field and the public — and they feed into the management of both quarantine pests and commonly managed pests across vineyards, olive groves and citrus orchards. The system’s outputs include AI-driven risk maps and spraying recommendations, a combination designed to reduce pesticide use while maintaining effective crop protection. That dual goal reflects a broader pressure on European agriculture, where regulatory targets for pesticide reduction must be reconciled with the economic realities of farming in regions already stressed by climate change.

STELLA completes the triad with a holistic digital platform known as the STELLA Pest Surveillance System, or PSS. The system is designed to support the early warning and early detection of regulated pests, drawing on AI-supported innovations in satellite and UAV-based sensing, in-situ sensor technologies and crowdsourcing. What distinguishes STELLA’s approach is the pairing of detection capability with a response strategy: the project explicitly aims to help stop outbreaks before they can spread, rather than simply documenting them after the fact. In plant health, that distinction matters enormously, because the window between the arrival of a pest and its irreversible establishment can be measured in weeks.

Although FORSAID concentrates on forest pest control while CERBERUS and STELLA focus on agricultural crops, the factsheet demonstrates that the three projects have far more in common than a shared funding call. All three are tackling comparable challenges with overlapping tools. AI-driven risk modelling, remote sensing from satellites and drones, and citizen science monitoring appear in all three portfolios, adapted to different crops and ecosystems. This convergence is not accidental. The Horizon Europe call that funded the projects was designed to build a portfolio of complementary capabilities, and the factsheet makes visible how those capabilities interlock — from the algorithms that interpret sensor data to the networks of observers who report suspicious symptoms in the field.

The collaboration is not confined to documents. The common ground between the projects has already brought their younger generation of researchers together. In June 2025, PhD students and postdoctoral researchers from all three consortia met for a first joint Young Scientist Meeting, where they discussed forming dedicated working groups on citizen science, communication, remote sensing and pest surveillance. For early-career researchers, whose careers often unfold within the boundaries of a single project, such cross-consortia meetings create the professional networks and shared methodological vocabulary that outlast any individual grant. The working groups under discussion signal an intent to institutionalise that exchange rather than leave it to chance encounters at conferences.

Since that meeting, the partnership between FORSAID and STELLA has moved from discussion into the field. In May 2026, the two projects carried out joint fieldwork on the Greek island of Euboea, deploying drone-based remote sensing to evaluate tree health in forests affected by canker stain disease. The campaign illustrates the practical value of the sister-project model: STELLA’s expertise in UAV-based sensing and FORSAID’s forest-focused analytical framework could be combined on a single site, testing how detection pipelines developed for different regulated pests perform when applied to a shared, real-world outbreak. Euboea’s canker-stain-affected forests provided exactly that test case, and the results are expected to inform both projects’ ongoing methodological development.

The technological core shared by all three projects deserves a closer look, because it represents a genuine shift in how plant health surveillance is conceived. Traditional pest monitoring relies heavily on physical inspection by trained surveyors, a labour-intensive process that inevitably leaves vast areas unsurveyed between visits. The approach championed by FORSAID, CERBERUS and STELLA layers multiple observation systems on top of one another. Satellites provide broad, repeated coverage of vegetation condition across entire regions. Drones and UAVs add high-resolution imagery over specific sites flagged by the satellite layer. Ground sensors and automated field platforms capture micro-level signals that aerial systems cannot resolve. Finally, crowdsourcing and citizen science enlist farmers, foresters and the general public as distributed observers, extending the human sensing network far beyond what any institutional survey programme could staff. Artificial intelligence sits at the centre of this stack, fusing heterogeneous data streams into risk maps and alerts that decision-makers can act on.

As all three projects move deeper into their implementation phases, this spirit of collaboration is expected to grow further. The joint factsheet serves both as an introduction to the combined work of FORSAID, CERBERUS and STELLA and as an invitation to explore what a united, technology-driven plant health protection response can achieve across Europe. For a continent whose forests and farms are under increasing pressure from invasive pests and pathogens, the message of the factsheet is straightforward: no single project, technology or institution can provide the early detection Europe needs, but a coordinated portfolio of AI, remote sensing and citizen engagement — spanning forests and farmland alike — can build a surveillance fabric dense enough to catch outbreaks while they are still small enough to stop.

Subject of Research: Technology-driven early detection and monitoring of plant pests and pathogens in European forests and Mediterranean agriculture

Article Title: Safeguarding European plant health: New joint factsheet outlines synergy between Horizon Europe projects FORSAID, CERBERUS and STELLA

Article References: Safeguarding European plant health: New joint factsheet outlines synergy between Horizon Europe projects FORSAID, CERBERUS and STELLA. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: plant health, pest detection, FORSAID, CERBERUS, STELLA, Horizon Europe, artificial intelligence, remote sensing, citizen science, forest pests, Mediterranean agriculture, early warning systems

The analysis began with the Scopus database, where an initial search for biochar literature returned more than 50,000 documents. After filtering for work connected to carbon farming and the Mediterranean basin, the researchers retained 112 publications for detailed evaluation, mapping the field’s networks with VOSviewer software and adopting a structured narrative review approach. Their central finding is both encouraging and cautionary: biochar consistently builds soil carbon stocks and generally reduces nitrous oxide emissions, but its benefits for crops appear only when it relieves a genuine limitation, such as drought, salinity, or degraded soil structure. Applied indiscriminately to healthy, non-stressed fields, it may deliver little gain, or even cause harm.

The technical foundation of biochar’s appeal lies in pyrolysis, a thermal decomposition process conducted under oxygen-limited conditions at temperatures ranging from 300 to 1000 degrees Celsius. Slow pyrolysis, fast pyrolysis, and gasification each yield materials with distinct physicochemical properties. Higher-temperature biochars, produced at or above 600 to 700 degrees Celsius, are richer in aromatic carbon, more structurally stable, and more porous, making them exceptional long-term carbon vaults. Lower-temperature biochars retain more labile compounds and oxygen-containing functional groups that boost short-term nutrient availability and cation exchange capacity. Feedstock matters too: manure-derived biochars carry higher nutrient and ash content, while lignocellulosic materials from straw and wood produce denser, more porous, more persistent carbon structures.

Unlike compost or other conventional organic amendments, which soil microbes decompose within seasons, biochar’s pyrogenic carbon resists breakdown for centuries, with estimated mean residence times ranging from several hundred years to more than a millennium. Global meta-analyses cited in the review indicate that biochar application raises soil organic carbon stocks by an average of roughly 39 percent, and Mediterranean field studies confirm consistent accumulation even under the region’s punishing wet-dry cycles. Notably, one cited study demonstrated that biochar-induced increases in soil organic matter pools were not significantly altered by simulated climate change scenarios, suggesting that the stored carbon would survive the hotter, drier Mediterranean of the coming decades. Biochar can also slow the decomposition of existing soil organic matter through negative priming, adding a second layer of protection to carbon already in the ground.

On greenhouse gases, the picture is nuanced and, in one respect, troubling. Mediterranean field experiments generally report neutral or reduced carbon dioxide emissions after biochar application, confirming that the amended carbon is not being rapidly re-released, and reductions in nitrous oxide, a greenhouse gas nearly 300 times more potent than carbon dioxide, of 30 to 70 percent have been documented. The mechanism involves adsorption of ammonium and nitrate ions, which starves nitrifying and denitrifying microbes of substrate, alongside improved soil aeration that suppresses the anaerobic microsites where denitrification thrives. Mitigation is particularly pronounced when biochar is paired with organic fertilizers or digestates, stabilizing labile carbon inputs that would otherwise fuel microbial activity.

Methane, however, is the review’s warning flag. Several long-term Mediterranean field studies recorded increased methane emissions following biochar application, especially during warm, moist autumn and winter conditions. The culprit is the formation of biologically induced anaerobic microsites within biochar’s pore network when soils become water-saturated, creating localized oxygen-free pockets that favor methanogenic archaea. Emissions rose in proportion to application rate in at least one study, exposing a stark trade-off between maximizing carbon sequestration and minimizing greenhouse gas losses. The authors conclude that moderate application rates, generally 10 to 30 megagrams per hectare, represent the sweet spot, and that net climate assessments excluding methane risk seriously overestimating biochar’s mitigation value, particularly in fine-textured or poorly drained soils.

Crop responses vary sharply by species and growing condition. Among cereals, durum wheat has benefited from biochar through improved water retention during grain filling and enhanced nitrogen and phosphorus availability, though some controlled studies found reduced early shoot growth when biochar was applied without complementary nutrients. Rice shows consistent gains when biochar is combined with sprinkler or deficit irrigation, boosting yields, photosynthesis, and water-use efficiency while easing the transition away from flooded production. Maize responds strongly in saline soils, where biochar curbs sodium uptake and preserves potassium, but medium-term trials under non-stress conditions reported negligible yield gains despite measurable soil improvements, reinforcing the principle that soil chemistry alone does not guarantee agronomic return.

Legumes and perennial woody crops emerge as the stars of the analysis. Fenugreek, faba bean, and cowpea all showed improved yields, chlorophyll content, antioxidant activity, and stress tolerance, likely because biochar enhances phosphorus availability and rhizosphere conditions that support biological nitrogen fixation. In vineyards, a single biochar application improved vine water status, stomatal conductance, and drought resilience for more than a decade, a persistence that dramatically improves cost-effectiveness. Super-intensive olive groves treated with biochar from olive residues showed higher soil moisture, net photosynthesis, water-use efficiency, and fruit yield even under deficit irrigation. Vegetables tell a more mixed story: tomato and pepper respond reliably well, melon and zucchini benefit when biochar is combined with digestate or compost, while lettuce and onion have suffered yield losses in volcanic Mediterranean soils, apparently due to nutrient imbalances and phytotoxic compounds. Peach trees showed reduced survivability despite normal yields among surviving plants, underscoring the need for species-specific testing before large-scale deployment.

The review’s authors argue that biochar should be deployed selectively, targeting degraded or coarse-textured soils, water-limited or saline fields, and long-lived perennial systems such as orchards and vineyards, rather than applied uniformly across the landscape. They call for long-term, crop-centered field experiments to validate yield persistence and net greenhouse gas balances, with particular attention to methane mitigation strategies and underexplored systems like legumes and diversified rotations. Beyond the agronomy, economics will decide adoption: feedstock collection, pyrolysis processing, transport, and field application are costly in a region marked by fragmented landownership and limited infrastructure, while carbon credit markets remain uncertain and unevenly supported across Mediterranean countries. If pricing frameworks mature and decision-support tools reach farmers, the researchers conclude, biochar could convert the Mediterranean’s agricultural waste streams into a durable bridge between food production and climate stabilization, provided the methane caveat is heeded every step of the way.

Subject of Research: The role of biochar in carbon farming and climate-smart Mediterranean agroecosystems

Article Title: Carbon farming strategies for mediterranean agriculture: the role of biochar in climate-smart agroecosystems

Article References: Borgatti, D., Radicetti, E., Mancinelli, R., Coluccia, L., Allam, M., Jamal, A., Abideen, Z., Ahsan, M., & Hassine, M. B. (2026). Carbon farming strategies for mediterranean agriculture: the role of biochar in climate-smart agroecosystems. Crop Health, 4(1), Article 19. https://doi.org/10.1007/s44297-026-00081-8

Image Credits: AI Generated

DOI: 10.1007/s44297-026-00081-8

Keywords: biochar, carbon farming, Mediterranean agriculture, carbon sequestration, greenhouse gas emissions, nitrous oxide, methane, soil health, climate-smart agriculture, crop productivity, pyrolysis, sustainable agriculture