The study compared four fertilizer treatments over two growing seasons: conventional chemical fertilizer, manure supplementation, and manure combined with either straw or biochar. The setting was deliberately challenging. The Yellow River Delta is characterized by high soil salinity and chronically low organic matter, conditions that limit agricultural productivity across vast areas of coastal farmland. Rather than measuring only how much carbon accumulated at the end of the experiment, the team dissected the process itself, tracking soil organic carbon, microbial community composition, enzyme activities, and the three-dimensional pore structure of the soil. That combination of chemical, biological, and physical measurements is what allowed the researchers to see that the two amendments were not simply adding carbon in parallel; they were reshaping the soil in entirely different ways.

The headline result is deceptively simple. In 2023, both the straw-plus-manure and biochar-plus-manure treatments increased soil organic carbon by approximately 19 percent compared with manure alone. For farmers and policymakers, that means either material can meaningfully improve carbon stocks in salt-affected soils. But the researchers’ deeper analysis revealed that the similarity ends at the number. Straw, it turns out, works primarily through biology, while biochar works primarily through physics. Understanding that distinction, the authors argue, is essential for designing soil management strategies that genuinely improve fertility and support carbon sequestration rather than merely inflating short-term carbon readings.

When straw was mixed with manure, it supplied a flood of readily available organic compounds that stimulated the soil’s microbial residents. Fed by this fresh substrate, microorganisms ramped up their production of carbon-cycling enzymes, accelerating the decomposition and transformation of organic matter. Crucially, this heightened activity promoted the accumulation of microbial necromass, the chemically stable remains of dead microorganisms that are increasingly recognized as a major, persistent component of soil organic matter. Compared with manure alone, the straw treatment increased total microbial necromass carbon by 10.8 percent and fungal necromass carbon by 11.2 percent. In other words, straw does not simply sit in the soil as carbon; it passes through living organisms, and much of what they leave behind becomes long-lasting soil carbon.

Biochar took the opposite route. Rather than primarily fueling microbial carbon transformation, the charcoal-like material, produced by heating biomass in low-oxygen conditions, acted on the soil’s architecture. The biochar treatment increased the proportion of large soil aggregates by 40.9 percent and improved aggregate stability by 31.9 percent relative to manure alone. Aggregates are the clumps of mineral particles and organic matter that give healthy soils their crumbly structure, and they matter enormously for carbon storage because organic material sealed inside stable aggregates is physically shielded from decomposers. Biochar also increased soil porosity, creating a more favorable physical environment in which carbon can be retained rather than rapidly mineralized and lost to the atmosphere as carbon dioxide.

Microbial community analyses added a further layer of nuance to the two pathways. The straw treatment reduced the abundance of certain microbial groups dominated by Actinobacteria, a phylum of bacteria often associated with the breakdown of complex organic compounds. Biochar, by contrast, promoted fungal groups dominated by Ascomycota, and those fungal populations were positively associated with soil carbon storage. This shift toward fungi is consistent with the physical-protection story: fungal hyphae physically bind soil particles into aggregates, so a fungal-dominated community can reinforce the very structures that biochar helps create. The two amendments, in effect, cultivate different biological neighborhoods that reinforce their respective carbon-storing strategies.

Taken together, the findings describe two complementary routes to carbon sequestration in degraded farmland. Straw drives biological transformation, converting fresh plant carbon into microbial residues that persist in the soil. Biochar drives physical protection, building the aggregate and pore structures that shelter organic carbon from decomposition. Neither pathway is inherently superior, and the study suggests that the choice between them, or the decision to use both, should depend on management goals. A farmer prioritizing rapid nutrient cycling and fertility building may favor straw, while one focused on long-term structural restoration of compacted or degraded soil may find biochar more effective. Combining the biological and physical mechanisms could, in principle, offer the benefits of both.

The research also carries a broader lesson about how carbon sequestration in agriculture should be evaluated. As corresponding author Hongyuan Zhang put it, selecting organic amendments should involve more than measuring how much carbon they add to soil; understanding how carbon is processed and protected can help guide more effective restoration of degraded agricultural land. That distinction matters because carbon that is merely added to soil can be lost again within months, whereas carbon that has been transformed into microbial necromass or locked inside stable aggregates is far more likely to persist. Carbon accounting schemes and climate mitigation programs that reward farmers for soil carbon gains could produce very different outcomes depending on whether the carbon they measure is biologically stabilized, physically protected, or simply sitting loose in the profile.

The implications extend well beyond the Yellow River Delta. Salt-affected soils occupy substantial areas of global farmland, and land degradation continues to erode the carbon storage capacity of agricultural systems worldwide. Improving carbon inputs and stabilization in these marginal lands offers a rare dual benefit: restoring soil health and productivity for the people who farm them while removing carbon dioxide from the atmosphere. The study’s demonstration that amendment choice shapes the mechanism of sequestration gives land managers a practical lever, allowing strategies to be matched to local conditions such as soil texture, salinity level, and the availability of crop residues or biochar feedstock.

The researchers are careful to note that longer-term field observations are needed to determine how these mechanisms influence carbon persistence over time. A two-year experiment can reveal pathways, but soil carbon dynamics unfold over decades, and the durability of straw-derived microbial necromass or biochar-stabilized aggregates under continued salinity stress remains an open question. Still, the study provides a clear and actionable framework: in salt-affected soils, carbon storage is not a single process but a contest between biological transformation and physical protection, and the amendments farmers choose determine which of those levers gets pulled. As agriculture faces simultaneous pressures to feed a growing population and stabilize the climate, that kind of mechanistic clarity may prove as valuable as the carbon itself.

Subject of Research: Divergent mechanisms of straw versus biochar amendment for soil organic carbon sequestration in coastal saline soils

Article Title: Two paths to healthier soils: Scientists reveal how straw and biochar store carbon differently

Article References: Two paths to healthier soils: Scientists reveal how straw and biochar store carbon differently. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: soil organic carbon, biochar, straw, saline soils, carbon sequestration, microbial necromass, soil aggregates, Yellow River Delta, soil health, manure, climate mitigation, soil microbiome

Soil is one of the planet’s largest carbon reservoirs, holding more carbon than the atmosphere and all vegetation combined. But not all soil carbon is created equal. Scientists now distinguish between two fundamentally different pools. Particulate organic carbon, or POC, consists of partially decomposed plant fragments—bits of straw, root debris, and leaf litter—that are physically visible but chemically vulnerable. Microbes can digest this material relatively easily, releasing carbon dioxide back into the atmosphere within years to decades. Mineral-associated organic carbon, or MAOC, by contrast, consists of small organic molecules that bind tightly to clay and silt particles, forming complexes that can persist in soil for centuries or even millennia. Because MAOC is the more durable reservoir, the ratio between these two fractions is a critical indicator of how stable a soil’s carbon stock really is.

To determine which pool different farming practices actually build, the research team ran a seven-year field experiment comparing straw incorporation, plastic film mulching, and nitrogen fertilization, alone and in combination, against conventional tillage. What makes the study unusual is its forensic approach to carbon sources. Rather than simply measuring total soil organic carbon, the researchers deployed three molecular biomarkers, each tracing a different pathway of carbon entry. Phospholipid fatty acids, or PLFAs, revealed the size and composition of living microbial communities. Amino sugars served as fingerprints of microbial necromass—the accumulated remains of dead bacteria and fungi. And lignin phenols, compounds that plants produce in their cell walls but microbes do not, marked carbon that arrived directly from crop residues.

The yield results were striking. Nitrogen fertilization proved the most powerful productivity lever, increasing annual wheat grain yield by 45 percent. Straw incorporation raised yields by 23 percent per year, while plastic film mulching delivered a 14 percent boost. These numbers alone would encourage any farmer to adopt all three practices simultaneously. All three treatments also increased soil organic carbon contents relative to conventional tillage, seemingly confirming the widely held assumption that intensive management simultaneously improves productivity and sequesters carbon. But when the researchers decomposed that carbon into its particulate and mineral-associated fractions, a more complicated picture emerged.

Straw incorporation emerged as the most carbon-friendly of the three practices. By returning crop residues to the soil, it substantially increased plant carbon inputs and stimulated the proliferation of bacteria and saprotrophic fungi—the decomposer organisms that break down organic matter. This microbial surge was accompanied by higher enzyme activities, and the combined effect raised the accumulation of both lignin phenols and microbial necromass carbon in the soil. As a result, particulate organic carbon contents increased by 1.5-fold compared with conventional tillage, and total soil organic carbon rose by 17 percent. Crucially, straw incorporation enriched both the POC and MAOC fractions with plant-derived and microbial-derived carbon, meaning it fed both the fast and slow carbon pools at once.

Plastic film mulching told a different story. The practice, which involves covering soil with thin polyethylene sheets to conserve moisture and warm the seedbed, did increase both POC and total SOC contents. Yet beneath the surface, the mineral-associated fraction was being eroded. Mulched soils showed reduced contents of amino sugars and lignin phenols within the MAOC fraction, along with lower concentrations of microbial PLFAs there—evidence that the living microbial community and its necromass contributions to the stable carbon pool had declined. Consequently, MAOC content itself decreased under mulching. The film appears to alter the soil microclimate in ways that shift carbon cycling away from the microbial pathways that build durable, mineral-bound carbon, even as it boosts the total stock through particulate accumulation.

Nitrogen fertilization produced perhaps the most consequential trade-off of all. While it increased POC content, it decreased MAOC content and reduced the contribution of mineral-associated carbon to total SOC under both straw incorporation and film mulching. The mechanism, according to the biomarker evidence, runs through the microbial community: nitrogen addition reduced amino sugar content and microbial PLFA concentration, weakening the microbial carbon pump that converts plant carbon into necromass and ultimately into mineral-stabilized forms. In other words, the fertilizer that delivers the biggest yield gains also suppresses the very organisms and biochemical processes responsible for locking carbon into soil’s most stable reservoir.

The broader implication is that the two most celebrated pathways for building soil carbon—straw incorporation and film mulching—achieve their gains primarily through POC accumulation while simultaneously weakening the mineral-associated stabilization pathways that make carbon persistence possible. Nitrogen fertilization amplifies this effect. Particulate carbon is not worthless; it feeds soil food webs, improves aggregation, and can eventually be processed into more stable forms. But it is inherently transient, vulnerable to changes in temperature, moisture, and tillage. Recent global research has underscored this vulnerability, with studies showing that mineral-associated organic carbon across the world’s drylands is itself sensitive to climate warming—raising the stakes for management decisions that determine how much carbon sits in each pool.

For the rapidly expanding practice of agricultural carbon crediting, the findings carry a warning. Many carbon markets and national inventories currently reward measured increases in total soil organic carbon without distinguishing between its fractions. A field that gains carbon through straw incorporation and mulching may look like a sequestration success on paper, while the added carbon sits in a labile pool that could be released within a decade. The study’s authors suggest that quantifying the contributions of POC and MAOC to SOC—ideally with the biomarker toolkit they employed—reduces uncertainty in predicting how soil carbon will respond to management and should inform which practices are genuinely climate-positive. As wheat systems across China’s Loess Plateau and similar dryland regions worldwide face intensifying pressure to raise yields while storing carbon, this seven-year experiment makes clear that the two goals can pull in opposite directions, and that the stability of soil carbon, not just its quantity, must become the yardstick of success.

Subject of Research: Effects of nitrogen fertilization, straw incorporation, and plastic film mulching on wheat yield and the stability of soil organic carbon fractions

Article Title: Nitrogen fertilization, straw incorporation, and plastic film mulching increase wheat yield and soil organic carbon but reveal trade-offs in carbon stability

Article References: Zhao, Q., Abdo, A. I., Zhang, K., Li, H., Zhou, C., Chen, J., Wang, L., & Kuzyakov, Y. (2026). Nitrogen fertilization, straw incorporation, and plastic film mulching increase wheat yield and soil organic carbon but reveal trade-offs in carbon stability. Plant and Soil. https://doi.org/10.1007/s11104-026-09044-y

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09044-y

Keywords: soil organic carbon, wheat yield, nitrogen fertilization, straw incorporation, plastic film mulching, particulate organic carbon, mineral-associated organic carbon, microbial necromass, lignin phenols, phospholipid fatty acids, carbon sequestration, soil microbiology

The research, led by Tengteng Li of the South China Botanical Garden and the German Centre for Integrative Biodiversity Research (iDiv), together with Olga Ferlian, Panpan Wu, Zhanfeng Liu, and senior author Nico Eisenhauer, took advantage of a unique experimental site known as MyDiv. There, trees were planted in plots containing either one, two, or four species, and the researchers deliberately manipulated the mycorrhizal composition of the plots: some contained only arbuscular mycorrhizal (AM) trees, some only ectomycorrhizal (ECM) trees, and some a mixture of both types. Mycorrhizal fungi are symbionts that colonize tree roots, trading soil nutrients such as nitrogen and phosphorus for plant-derived carbon. The two major types differ profoundly in their biology — AM fungi penetrate root cells and are relatively fast-cycling, while ECM fungi form sheaths around roots, build persistent hyphal networks, and are often associated with slower, more fungal-dominated decomposition pathways.

What makes the new study unusual is its vertical ambition. Rather than sampling only the top few centimeters of soil, the team quantified total carbon, total nitrogen, and microbial necromass along a full one-meter soil profile, tracking how these pools changed over the first ten years of stand development. Microbial necromass was estimated using amino sugar biomarkers — molecular fingerprints that allow researchers to distinguish fungal residues from bacterial residues in soil. This matters because a growing body of research indicates that microbial residues, not just dead plant litter, constitute a major and often dominant fraction of stable soil organic matter. If biodiversity influences how much microbial necromass accumulates, it may ultimately shape how much carbon soils can lock away for decades or centuries.

The headline finding is one of decoupling. Over the decade, total soil carbon declined by roughly 3 percent across the profile, total nitrogen by about 17 percent, and microbial necromass by around 14 percent. Soil depth was the single strongest driver of overall variation, which is perhaps unsurprising given that organic matter concentrates near the surface. But the temporal trajectories of the three pools diverged in revealing ways. Nitrogen declined first in the upper 40 centimeters during the initial five years, then its losses extended deeper even as the topsoil began to recover. Total carbon declined later, mainly at intermediate depths between 5 and 40 centimeters. Microbial necromass, meanwhile, decreased later still, but across the entire one-meter profile. These staggered patterns suggest that the early years of afforestation are not a uniform period of soil building; instead, different pools respond on different clocks and at different depths.

The most striking result, however, concerns biodiversity. Effects of tree species richness and mycorrhizal type were detected only for microbial necromass — not for bulk carbon or nitrogen — and those effects varied with mycorrhizal identity, soil depth, and time. Fungal necromass dominated the dynamics of total microbial necromass and showed the strongest biodiversity responses of any measured pool. In mixed AM-plus-ECM communities, fungal necromass in the topsoil initially increased by 21 to 27 percent. In pure ECM communities, a similar magnitude of increase — around 24 percent — emerged only after a full decade. In other words, the composition of the below-ground symbiotic community determined both the timing and the magnitude of the fungal necromass response.

Why should mixed mycorrhizal communities act early while ECM-dominated communities act late? The authors’ findings are consistent with a mechanistic picture in which complementary mycorrhizal strategies accelerate the early build-up of fungal biomass and its subsequent turnover. Mixing AM and ECM trees may broaden the range of nutrient acquisition strategies operating in a plot, stimulating overall productivity and, with it, the flux of plant carbon into fungal tissue. When that tissue dies, its chitin-rich cell walls become necromass, a chemically stabilized precursor to soil organic matter. ECM-dominated systems, by contrast, may require longer for their slower-cycling hyphal networks to accumulate enough standing biomass and turnover to register as a detectable necromass signal. The decade-long delay in the ECM response fits this slower tempo.

The study’s implications reach well beyond soil ecology’s internal debates. Global assessments consistently identify forest restoration as one of the most promising nature-based strategies for carbon removal, and recent work has shown that tree diversity can enhance decadal soil carbon and nitrogen accrual in forests. But if biodiversity effects on the stable, microbial-derived fraction of soil organic matter appear in necromass years before they appear in bulk carbon pools, then standard soil carbon monitoring may systematically undercount the early benefits of diverse plantings. A restoration project could be quietly building long-term carbon storage capacity through fungal pathways while its measured soil carbon stock remains essentially flat, potentially leading managers and policymakers to undervalue mixed-species, mixed-mycorrhizal designs.

The depth-resolved design also carries a caution for how soil carbon is accounted for. Because the temporal trajectories of carbon, nitrogen, and necromass diverge across the one-meter profile — with nitrogen losses penetrating deeper even as topsoil recovers, and carbon losses concentrated at intermediate depths — shallow sampling alone could paint a misleading picture of whether a young forest is gaining or losing soil fertility. The finding echoes a broader concern in the literature that deep soil organic carbon responds to global change in ways that topsoil-focused studies miss, and that afforestation effects on soil carbon and nitrogen depend strongly on initial soil conditions and profile position.

For the growing community of researchers working on microbial necromass, the study adds an important temporal dimension. Much of the existing work has established that microbial residues contribute substantially to stabilized soil organic carbon and that necromass formation depends on microbial death pathways and clay-organic matter interactions. What this experiment demonstrates is that the necromass pool is not merely a passive integrator of past microbial activity; it is an early, biodiversity-sensitive responder that can move independently of the bulk pools it will eventually feed. That decoupling — fungal necromass shifting by 20 percent or more while total carbon barely budges — is precisely the kind of signal that could serve as a leading indicator of future soil carbon change.

The authors conclude that biodiversity effects during afforestation emerge through fungal-mediated pathways before becoming detectable in bulk soil carbon pools. If that sequence holds in other systems and over longer timescales, it suggests a reframing of how restoration success should be judged. The trees are the visible half of the story; the fungi that partner with their roots, live, die, and leave their walls in the soil are the other half — and on the evidence of this decade-long experiment, the fungal half speaks first. For anyone betting on forests to draw down carbon, listening to that early signal, at depth and over time, may prove essential.

Subject of Research: Effects of tree diversity and mycorrhizal type on fungal necromass, soil carbon and nitrogen across the soil profile during a decade of afforestation

Article Title: Tree diversity and mycorrhizal type induce stronger shifts in fungal necromass than in soil carbon and nitrogen across the soil profile over a decade of afforestation

Article References: Li, T., Ferlian, O., Wu, P., Liu, Z., & Eisenhauer, N. (2026). Tree diversity and mycorrhizal type induce stronger shifts in fungal necromass than in soil carbon and nitrogen across the soil profile over a decade of afforestation. Plant and Soil. https://doi.org/10.1007/s11104-026-09082-6

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09082-6

Keywords: tree diversity, mycorrhiza, fungal necromass, microbial necromass, soil carbon, soil nitrogen, afforestation, soil profile, amino sugar biomarkers, ectomycorrhiza, arbuscular mycorrhiza, soil organic matter

The review, which synthesizes literature from Web of Science, Scopus, and Google Scholar up to December 2025, assembles evidence for a suite of mechanisms by which biochar might stabilize root-exudate carbon. The most straightforward is physicochemical sorption. Biochar’s highly porous structure, enormous surface area, and functional surface groups can adsorb dissolved organic compounds as they diffuse away from root tips, physically sheltering them from the extracellular enzymes that microbes deploy to break them down. Because root exudates concentrate in narrow, microbially hyperactive hotspots around roots, any material that intercepts compounds within these zones could, in principle, dramatically slow their mineralization before it begins.

Beyond simple adsorption, the review outlines several more intricate pathways. Biochar is redox-active: its surfaces can shuttle electrons and mediate abiotic reactions that transform labile organic molecules into less available forms. Biochar particles can also participate in organo-mineral complexation, in which dissolved carbon binds to clay minerals and iron or aluminum oxides, often with biochar acting as a scaffold or co-sorbent. In addition, biochar can promote the formation of stable soil aggregates, the microscopic clumps of mineral and organic matter that physically protect carbon from decomposers. Finally, biochar modulates the microbial community itself, potentially shifting the balance from carbon respiration toward carbon assimilation into microbial biomass, which after cell death can become microbial necromass, one of the most persistent reservoirs of soil organic carbon.

This last mechanism reflects a major shift in how soil scientists think about carbon persistence. Rather than assuming that only recalcitrant plant compounds form stable soil organic matter, the microbial efficiency-matrix stabilization framework holds that even labile inputs can become durable carbon if microbes convert them efficiently into biomass that then associates with soil minerals. The review argues that biochar may enhance exactly this route: by improving microbial carbon use efficiency, biochar could redirect exudate carbon away from immediate respiration and into necromass and mineral-associated organic matter, the two pools most responsible for long-term carbon storage in soils.

The strongest direct support comes from a landmark decade-long field study published in Nature Climate Change, which found that biochar built soil carbon over ten years by stabilizing rhizodeposits, the full suite of carbon deposited by roots. Complementary work on Ferralsol soils showed that the accumulation of rhizodeposit-derived carbon in organo-mineral fractions promoted biochar-induced negative priming, meaning biochar suppressed rather than stimulated the decomposition of native soil organic carbon. Other studies have reported that biochar amendment increases microbial carbon use efficiency and reduces the mineralization of both native and added organic carbon, and that biochar outperforms crop straw amendments in promoting carbon sequestration. Shorter-term and analogous investigations, including studies of dissolved organic matter and litter, lend further, though indirect, support.

However, the review is emphatic that the evidence base remains thin where it matters most. Direct evidence that biochar specifically stabilizes root-exudate compounds, as opposed to total rhizodeposits or other organic matter pools, is limited, and much of it traces back to that single long-term field study. Most experiments use surrogate compounds such as glucose rather than the complex, shifting exudate mixtures that real roots release, and few have tracked exudate carbon at the compound-specific level with the isotopic tracers needed to follow it into stable pools. The review classifies the available evidence as direct, indirect, or analogous, and finds that the direct category is by far the sparsest, a candid admission that distinguishes this analysis from more promotional treatments of biochar.

Efficacy, moreover, is strongly context-dependent. The outcome hinges on biochar properties such as feedstock, pyrolysis temperature, and surface chemistry; on soil mineralogy, since clay-rich soils offer far more mineral protection than sandy ones; on plant traits that govern how much and what kind of carbon roots exude; on management practices; and critically on the spatial contact between exudate diffusion zones and biochar particles. If biochar sits centimeters away from active root tips, it may never encounter the exudates it is supposed to capture. Recent work showing that biochar shifts the balance between hydrophilic and lipophilic molecules in root exudates adds another layer of complexity, suggesting biochar does not merely capture exudates passively but may alter what plants exude in the first place.

The review also catalogs competing processes that could erode or reverse any stabilization benefit. Positive priming, in which labile inputs or biochar itself stimulate the decomposition of existing soil organic carbon, has been documented in multiple studies, though its direction varies with soil pH and texture. Sorbed compounds can desorb back into solution, microbes can directly utilize compounds attached to biochar surfaces, dissolved organic carbon can leach downward, and biochar can impose nutrient trade-offs, for example by reducing nitrogen availability in ways that constrain microbial growth. Any credible accounting of biochar’s climate benefit must weigh these losses against the gains, which is precisely why the author calls for rigorous life-cycle assessment alongside field measurement.

The stakes are considerable. Soils hold vast reserves of organic carbon, and cropland sequestration is widely promoted as a negative emissions strategy, yet the durability of that carbon is often the weak link. If biochar can reliably convert a transient carbon flux, the exudates that would otherwise become carbon dioxide within days, into mineral-associated and necromass carbon persisting for decades, it would address that weak link directly while potentially improving soil fertility, water retention, and crop productivity at the same time. The review frames this synergy between root exudates and biochar as a plausible avenue for climate-smart agriculture, one that could be integrated with regenerative practices such as cover cropping and reduced tillage that naturally boost root carbon inputs.

Still, the bottom line is deliberately cautious: biochar-mediated stabilization of root-exudate carbon is a plausible but incompletely tested mechanism, not a demonstrated scalable strategy. The review lays out a research agenda to change that, including advanced isotopic tracing to follow individual exudate compounds into stable pools, mechanistic studies of how context determines outcomes, integration of these processes into soil carbon models, life-cycle assessment of the full climate impact, and, above all, long-term field validation across diverse soils and cropping systems. Until those studies are done, the idea that charcoal can catch the carbon leaking from living roots and keep it out of the atmosphere remains one of soil science’s most tantalizing unproven hypotheses, a reminder that even the most promising climate solutions demand decades of patient verification before they can be deployed at scale.

Subject of Research: Whether biochar can stabilize labile root-exudate carbon into long-term soil organic carbon pools

Article Title: Does biochar stabilize root-exudate carbon? A hypothesis-driven critical review

Article References: Etesami, H. (2026). Does biochar stabilize root-exudate carbon? A hypothesis-driven critical review. Plant and Soil. https://doi.org/10.1007/s11104-026-09117-y

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09117-y

Keywords: biochar, root exudates, rhizodeposition, soil organic carbon, carbon sequestration, priming effect, microbial necromass, mineral-associated organic matter, organo-mineral complexes, climate change mitigation, soil health, rhizosphere

For much of the history of soil science, researchers assumed that the slow decay of tough plant compounds such as lignin was the main route by which organic matter accumulated in soils. That view has been overturned in the past decade. Today, a growing body of evidence indicates that a large share of stable soil organic carbon is not plant material at all, but the residues of dead microorganisms, often called microbial necromass or microbial residue carbon. Microbes consume plant litter, build their own biomass, and when they die, their cell walls and other structural molecules bind to soil minerals and persist far longer than most raw plant debris. This pathway, sometimes described as the microbial carbon pump, effectively converts labile plant carbon into a more durable form. Understanding what controls the pump has become a central question for scientists trying to predict how soils will respond to climate change and shifting vegetation.

The research team set out to answer that question by comparing three types of forest stands: broadleaved forests, coniferous forests, and mixed forests. In each, they measured the chemical quality of the leaf litter, the total soil organic carbon content and its various fractions, and two powerful molecular fingerprints of carbon origin. Amino sugars served as markers for microbial residues, allowing the researchers to distinguish carbon left behind by bacteria from carbon left behind by fungi. Lignin phenols, meanwhile, acted as tracers of plant-derived carbon and revealed how far the lignin in the litter had been degraded. To probe the nutritional state of the microbial communities, the team applied an ecological stoichiometric approach, which evaluates whether microbes are limited more by carbon, nitrogen, or phosphorus based on the balance of these elements in their environment.

The results revealed a striking pattern. Broadleaved forest litter contained the lowest lignin content and the least carbon lability, meaning its carbon was less readily decomposable, but it boasted the highest levels of nitrogen, phosphorus, and cellulose, as well as the highest ratio of nitrogen to lignin. These stands also showed the greatest microbial nitrogen limitation, the highest total soil organic carbon, and, crucially, the largest accumulations of microbial residue carbon, including both bacterial residue carbon and fungal residue carbon. Lignin phenol concentrations and the degree of lignin degradation were likewise highest under broadleaved trees. In other words, the forests with the most nitrogen-rich, easily digestible litter were the ones where microbes were working hardest, dying in greatest numbers, and leaving the most residue behind.

Across all three stand types, the researchers observed that microbial residue carbon and plant residue carbon accumulated in step with total soil organic carbon, suggesting that both sources contribute synchronously to the growing carbon pool rather than one simply replacing the other. To identify which factors mattered most, the team used random forest analysis, a machine learning technique that ranks the influence of many variables simultaneously. The verdict was unambiguous: litter nitrogen emerged as the primary driver of microbial residue carbon accumulation, outweighing other litter characteristics such as lignin content or carbon lability.

But correlation alone does not establish mechanism, so the researchers turned to structural equation modeling, a statistical framework that allows scientists to test hypothesized chains of cause and effect. The model supported a compelling sequence. Higher litter nitrogen intensified the microbial nitrogen limitation, and that intensified limitation in turn promoted the accumulation of microbial residue carbon. This may seem counterintuitive at first glance: why would nitrogen limitation stimulate carbon storage? The likely explanation lies in microbial physiology. When nitrogen-rich litter raises the nitrogen supply relative to microbial demand, it spurs microbial growth and activity, and microbes constrained by nitrogen must invest more effort in acquiring it, processing more carbon in the process and building more biomass that eventually becomes residue. The nitrogen limitation detected by the stoichiometric analysis thus reflects a dynamic, growth-driven system in which abundant nitrogen fuels the microbial engine that converts plant carbon into persistent soil carbon.

The study also traced the consequences of this microbial activity for the composition and stability of the soil carbon pool. The accumulation of microbial residue carbon, and particularly bacterial residue carbon, increased the content of recalcitrant organic carbon, the fraction of soil organic carbon that resists decomposition. At the same time, this shift reduced the overall carbon lability of the soil, meaning a smaller proportion of the carbon pool was readily available for microbes to respire back into the atmosphere as carbon dioxide. In practical terms, nitrogen-rich broadleaved litter did not just add more carbon to the soil; it changed the character of that carbon, steering it toward a more stable, longer-lived form. This is a critical distinction, because the climate value of soil carbon depends not only on how much is stored but on how long it stays stored.

The implications extend well beyond forest ecology. As governments and land managers around the world pursue afforestation and reclamation programs to sequester carbon, the choice of tree species is often made on the basis of growth rates and timber value. This study suggests that litter chemistry deserves equal attention. Planting or encouraging nitrogen-rich broadleaved species could enhance the microbial carbon pump, boosting both the quantity and the stability of soil organic carbon. Conversely, stands dominated by conifers, whose litter is lignin-rich and nitrogen-poor, may build soil carbon more slowly and in a less stable form. In mixed forests, the researchers found intermediate patterns, hinting that species composition within a stand can be tuned to manage below-ground carbon dynamics. Such insights could inform everything from carbon credit accounting to the restoration of degraded soils.

The work also adds nuance to a long-running scientific debate about the role of nitrogen in decomposition. Nitrogen limitation of decay has been documented in many ecosystems, and some researchers have argued that it slows the breakdown of organic matter, potentially preserving soil carbon. The new findings suggest a more intricate picture: nitrogen availability shapes not only how fast litter decomposes but how effectively the products of decomposition are funneled into microbial biomass and, ultimately, into stable necromass. The microbial carbon pump, in this view, is throttled by the nitrogen supply in the litter, and managing that supply is a lever for managing soil carbon. As the authors conclude, shifts in stand type alter litter nitrogen, which primarily regulates soil organic carbon sequestration through this microbial pathway.

There remain open questions. The study was conducted across forest stands of different types, and future work will need to test whether the same relationships hold across climates, soil types, and timescales, and how disturbances such as fire, harvesting, or warming might disrupt the nitrogen-microbe-carbon chain. Data from the study will be made available on request, and the research was supported by funding from Chinese national and provincial science programs. For now, the message is clear and quietly profound: the fate of carbon in forest soils rests substantially on the shoulders of microscopic organisms, and what those organisms accomplish depends on the chemistry of the leaves that fall above them. A forest’s legacy in the soil, it turns out, is written as much in the nitrogen of its litter as in the wood of its trees.

Subject of Research: The role of litter nitrogen in regulating soil organic carbon sequestration through microbial residue carbon accumulation in forest soils

Article Title: Litter nitrogen drives soil organic carbon sequestration by promoting microbial residue carbon accumulation

Article References: Zhang, M., Li, H., Wang, Y., Cui, Y., Gao, Y., Jia, Y., Yu, H., Dong, Q., Wang, Y., & Xu, Z. (2026). Litter nitrogen drives soil organic carbon sequestration by promoting microbial residue carbon accumulation. Plant and Soil. https://doi.org/10.1007/s11104-026-09109-y

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09109-y

Keywords: soil organic carbon, microbial residue carbon, litter nitrogen, microbial carbon pump, forest soils, broadleaved forests, coniferous forests, lignin, amino sugars, ecological stoichiometry, carbon sequestration, microbial necromass

The review, led by Pengfei Xu and colleagues, analyzed more than 61,000 publications indexed in the Web of Science Core Collection between 2000 and 2025, of which 7,893 focused specifically on soil carbon sequestration. The bibliometric analysis reveals a research field that has grown explosively, with publication output accelerating sharply after the 2016 Paris Agreement. But it also exposes a striking imbalance: outcome-related keywords such as soil organic carbon and greenhouse gas emissions dominate the literature, while process-oriented terms like microbial community, priming effect and adsorption remain far less visible. The authors argue that this gap between what scientists measure and what they explain has left the field without a unified mechanistic framework.

Artificial carbon materials come in three main flavors, each forged from biomass through different thermochemical routes. Biochar, the best studied of the three, is produced by heating biomass above 300 degrees Celsius under oxygen-limited conditions, yielding a carbon-rich, aromatic material. Hydrochar is made through hydrothermal carbonization, which uses water and moderate temperatures and produces a more oxygenated, more microbially accessible substance. Artificial humic substances, the youngest class, are created through alkaline hydrothermal humification, a process that accelerates the chemistry of natural humification and yields oxygen-rich materials resembling natural soil humic acids. The review is careful to keep these classes distinct, noting that they differ profoundly in molecular composition, surface chemistry and likely behavior in soil.

The evidence that these materials raise measured soil organic carbon is generally positive but strikingly heterogeneous. In one 180-day incubation of maize cropland topsoil in Jilin, China, cotton straw-derived biochar applied at equivalent carbon inputs increased soil organic carbon concentration by 94.6 percent, compared with 64.4 percent for raw straw. In a paddy soil column experiment, hydrochar applications increased native soil organic carbon by 1.0 to 3.0 percent while shifting carbon from labile to stable pools. In black soil from Harbin, artificial humic acid raised total organic carbon by 21.4 grams per kilogram within 28 days. But the authors caution that these numbers cannot be pooled into a universal average, because responses depend on feedstock, production conditions, soil texture, mineralogy, pH, moisture, climate and experimental duration.

The most provocative part of the review concerns what a rise in soil carbon actually means for the climate. Soils globally release roughly 60 petagrams of carbon per year through decomposition, a gross flux that dwarfs annual fossil fuel emissions, though it is largely part of the natural carbon cycle. When an amendment is added, total carbon dioxide emissions may fall or rise, but a bulk flux measurement alone cannot tell scientists whether the carbon came from the amendment or from the soil’s native organic matter. The review draws a sharp evidentiary line: only isotope-based or otherwise source-resolved methods count as direct evidence of priming, the acceleration or suppression of native soil carbon decomposition. Many widely cited studies, it turns out, fall short of that standard.

Biochar studies report both positive and negative priming depending on pyrolysis conditions, soil pH and texture, substrate supply and duration. Hydrochar, with its soluble and aliphatic components, may boost short-term respiration, but the authors stress this is not proof of positive priming without source separation. Evidence for artificial humic substances remains thin, with few isotope-tracing studies. The message is blunt: no material class can be assumed to uniformly suppress native carbon loss, and short-term declines in carbon dioxide emissions may simply reflect transient microbial suppression or substrate limitation rather than genuine stabilization.

The mechanistic heart of the review organizes sequestration into three interacting pillars. The first is material persistence: pyrolysis creates condensed aromatic structures that resist decomposition, while hydrochar contains larger microbially accessible fractions, and artificial humic substances may gain persistence through association with minerals despite their chemical reactivity. Elemental ratios such as hydrogen-to-carbon and oxygen-to-carbon serve as rough screening tools, but the authors warn they cannot capture pore accessibility, mineral coatings or carbon-domain heterogeneity. Long-term isotope studies confirm that biochar contains persistent fractions while also releasing a measurable labile fraction shortly after incorporation, yet comparable multi-year field data for the other two classes are almost entirely absent.

The second pillar is physical and mineral protection. Soil aggregates restrict microbial access to carbon, and artificial carbon materials can promote aggregation through their pores, surface chemistry and interactions with clay minerals, roots, fungal hyphae and microbial glues. In grassland and rice paddy soils, biochar increased macroaggregates within the first 60 days, with microaggregates enriched in biochar-derived carbon developing later. Mineral type matters enormously: expanding 2:1 clays like montmorillonite offer far more sorption capacity than kaolinite, and iron and aluminum oxides can lock up carboxyl-rich compounds through ligand exchange and co-precipitation. Aging further reshapes these interfaces, with mineral bonding detected on biochar after roughly three months and organo-mineral coatings observed on particles recovered from field trials after up to 9.5 years.

The third pillar is microbial transformation. Artificial carbon materials modify habitat conditions, buffering water fluctuations and altering pH, nutrients and redox, while their soluble compounds feed microbes. Rather than simply sitting inert, amendment carbon can flow through microbial biomass into necromass, the dead residues that subsequently bind to minerals or become sealed inside aggregates. A 12-year field experiment found biochar increased microbial necromass carbon by 23.3 to 39.0 percent in topsoil but reduced it at depth, while a four-year paddy study reported decreases at all depths measured, a reminder that total soil carbon gains can coexist with losses in specific microbial carbon pools. Microspectroscopic work in a long-term pasture showed biochar particles sorbing root-derived carbon and accumulating mineral coatings that incorporated microbial necromass, effectively lifting the soil’s carbon ceiling.

The review’s practical upshot is that there is no universally optimal material. Alkaline biochars suit acidic soils but risk over-liming neutral ones; hydrochar fits wet wastes that need no pre-drying but carries soluble carbon whose fate varies; artificial humic substances offer reactive mineral interactions and may even promote biological carbon dioxide assimilation, though their long-term field persistence is unproven. The authors call for multi-year, multi-site trials using isotope source partitioning, standardized aging protocols, integrated mineralogical and microbial analyses, and full life-cycle assessments. As the 4 per mille initiative seeks to grow global soil carbon stocks by 0.4 percent annually, this review offers both a caution and a roadmap: engineered carbon materials can genuinely help soils fight climate change, but only if scientists and farmers track where the carbon comes from, where it goes, and how long it stays.

Subject of Research: Mechanisms of soil organic carbon sequestration by artificial carbon materials in agroecosystems

Article Title: Artificial carbon materials for soil organic carbon sequestration in agroecosystems: A bibliometric analysis and mechanistic review

Article References: Xu, P., Yu, H., Zhang, J., Xu, Y., & Liu, Z. (2026). Artificial carbon materials for soil organic carbon sequestration in agroecosystems: A bibliometric analysis and mechanistic review. Journal of Agriculture and Food Research, 31, Article 103343. https://doi.org/10.1016/j.jafr.2026.103343

Image Credits: AI Generated

DOI: 10.1016/j.jafr.2026.103343

Keywords: soil organic carbon, biochar, hydrochar, artificial humic substances, carbon sequestration, priming effect, soil aggregates, mineral association, microbial necromass, greenhouse gas emissions, agroecosystems, climate change mitigation

The research, led by Xiaoyu Long and Changchun Song of the Northeast Institute of Geography and Agroecology at the Chinese Academy of Sciences, together with colleagues, focused on peatlands in the Greater Khingan Mountains of northeastern China. Using a space-for-time approach—a technique in which sites representing different stages of shrub dominance are compared as a proxy for change over time—the team surveyed a gradient running from herbaceous dominance to full shrub dominance. At each site, they measured soil carbon fractions, microbial necromass, community composition, extracellular enzyme activities and microbial carbon use efficiency, building one of the most complete pictures to date of how vegetation change cascades down into the dark, cold layers of permafrost soil.

The first surprise lies in how thoroughly shrubs transform the physical and chemical environment of the peat. Where shrubs established, the team found soils with higher pH, lower moisture and eased nutrient limitations. That combination matters because peatland carbon storage has historically depended on the opposite conditions: cold, acidic, waterlogged and nutrient-poor ground that slows decomposition to a crawl. Shrubs effectively open a window for microbial activity, aerating and chemically ameliorating soils that have been preserving plant remains for millennia. In effect, the woody plants act as ecosystem engineers whose presence changes the rules of the carbon game.

Beneath the shrubs, the microbial communities reorganized in strikingly divergent ways. Bacterial communities shifted toward K-selected taxa—slower-growing, more competitive organisms that thrive in stable, resource-limited environments—while fungal communities became enriched in r-selected groups, fast-growing opportunists that rapidly exploit available resources. This split in life-history strategies, the authors report, was accompanied by increased complexity in microbial interaction networks, suggesting a denser web of ecological relationships underground. More connections among microbes can mean more efficient transfer of carbon through the food web, with consequences for how much of that carbon ends up locked in stable forms.

The enzyme data tell a parallel story. Hydrolytic enzyme activity—the chemical toolkit microbes use to break down complex organic molecules such as cellulose and chitin—was enhanced in shrub-dominated soils. At the same time, microbial carbon use efficiency, a measure of how much consumed carbon microbes convert into their own biomass rather than respiring as carbon dioxide, declined. Lower carbon use efficiency means that a larger share of the carbon flowing through the microbial community is released back to the atmosphere, while a smaller share is built into microbial cells. Together with the elevated enzyme activity, this points to accelerated decomposition in shrub-expanded peatlands.

The consequences for carbon stocks are double-edged. On one hand, the team measured lower stocks of particulate organic carbon—partially decomposed plant fragments that are physically protected but chemically vulnerable—in shrub-dominated communities. This is a warning sign: particulate organic carbon in cold regions is a dominant form of soil carbon storage, and its loss suggests that shrub expansion is accelerating net carbon release from these peatlands. On the other hand, the researchers found higher accumulation of microbial necromass—the residual cell walls and biomolecules of dead microorganisms—and a greater proportion of mineral-associated organic carbon, the fraction of soil carbon that is chemically bound to mineral surfaces and can persist for decades to centuries.

This dual outcome reframes how scientists think about carbon stabilization in a warming Arctic. For decades, soil carbon models have treated plant litter as the primary feedstock for long-term carbon storage. But a growing body of work, including the microbial efficiency–matrix stabilization framework that this study builds upon, argues that living microbes are the gatekeepers: they consume plant carbon, incorporate part of it into their biomass, and upon death leave behind necromass that binds to minerals. The new findings suggest that shrub expansion is shifting permafrost peatlands from a regime where carbon persists as intact plant debris to one where carbon persists as microbially processed, mineral-bound material. The carbon is not simply vanishing—it is changing form, and the new form may be more durable.

Why does this matter for the global climate? Permafrost peatlands contain an enormous reservoir of carbon accumulated over thousands of years, and the fate of even a small fraction of it could influence the pace of climate change. If shrub expansion accelerates the decomposition of vulnerable particulate carbon while simultaneously promoting the formation of stable necromass-derived carbon, the net climate feedback will depend on the balance between these two opposing processes—and on how quickly mineral surfaces in these organic-rich soils can actually bind the new carbon. Peatlands are typically low in mineral content, so the capacity for mineral association may be limited, a caveat the authors’ findings implicitly raise for long-term projections.

The study also highlights the power of linking microbial functional traits directly to measured carbon dynamics, rather than inferring carbon fate from vegetation cover alone. By connecting community composition, enzyme activities and carbon use efficiency to direct measurements of carbon fractions and necromass, the researchers traced a complete causal chain from plant shift to soil outcome. This trait-based approach is increasingly seen as essential for improving Earth system models, which have historically represented soil carbon as a single homogeneous pool and are now being rebuilt around physically distinct fractions with different vulnerabilities.

As shrubs continue their northward march, the underground world of permafrost peatlands is being reorganized from the bottom up. The new research indicates that the transition is not a simple story of carbon loss or carbon gain, but a transformation in the very pathways by which carbon is stabilized—away from the preservation of plant-derived particles and toward microbial necromass accumulation and mineral association. Understanding and monitoring that transformation, the authors argue, will be critical for predicting how one of the planet’s largest carbon reservoirs will respond as the climate continues to warm.

Subject of Research: Microbial mechanisms of soil carbon stabilization under shrub expansion in permafrost peatlands

Article Title: Shrub expansion alters soil carbon stabilization via microbial necromass accumulation in permafrost peatlands

Article References: Long, X., Song, C., Song, Y., Wang, N., Long, S., & Sun, Z. (2026). Shrub expansion alters soil carbon stabilization via microbial necromass accumulation in permafrost peatlands. Plant and Soil. https://doi.org/10.1007/s11104-026-09132-z

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09132-z

Keywords: permafrost peatland, shrub expansion, soil organic carbon, microbial necromass, carbon use efficiency, particulate organic carbon, mineral-associated organic carbon, microbial communities, extracellular enzymes, life-history strategies, climate change, Greater Khingan Mountains

The experiment compared annual applications of biochar at a rate of 2.625 tonnes per hectare with maize stover incorporation at approximately 7.5 tonnes per hectare, alongside an untreated control plot. After ten crop seasons, researchers sampled soil at depths of 0 to 20, 20 to 40, and 40 to 60 centimeters to capture how carbon had moved and stabilized throughout the profile. Both amendments significantly increased soil organic carbon across the entire 0 to 60 centimeter depth range, confirming their value as carbon-building tools. But the similarities largely ended there. In the topsoil, the two amendments performed almost identically, with carbon gains of 49.70 percent for biochar and 48.87 percent for stover. Below the surface, however, the paths diverged dramatically.

Maize stover proved far more effective at pushing carbon into deeper soil layers. In the 20 to 40 centimeter horizon, stover increased soil organic carbon by 105.90 percent, compared with 72.81 percent for biochar. In the deepest layer measured, 40 to 60 centimeters, stover delivered a 32.35 percent gain while biochar managed only 4.74 percent. These contrasting depth patterns indicate that carbon accumulation depends on amendment-specific transport and stabilization processes rather than on the sheer quantity of carbon added. Stover-derived dissolved organic carbon showed stronger vertical movement through the soil column, carrying plant-derived compounds downward, whereas biochar contributed more stable carbon directly to the layers where it was incorporated.

To understand what was happening at the molecular level, the research team deployed an impressive analytical arsenal. Dissolved organic carbon was characterized using Fourier transform ion cyclotron resonance mass spectrometry, a technique capable of resolving thousands of individual molecular formulas in complex environmental samples. This was complemented by lignin phenol analysis to trace plant-derived carbon, amino-sugar measurements to quantify microbial necromass, soil aggregate fractionation, and statistical modeling to tie the pools together. The combination allowed the investigators to assess not just how much carbon was present, but where it came from and how vulnerable it was to decomposition.

The molecular analysis revealed that both amendments increased dissolved organic carbon concentrations, but they altered its properties in fundamentally different ways. Biochar lowered the nominal oxidation state of carbon in the dissolved fraction, a pattern associated with lower bioactivity and greater persistence in the environment. Stover, by contrast, produced dissolved organic carbon with higher bioactivity in the topsoil, consistent with a more readily metabolized carbon supply that fuels microbial activity. In essence, biochar appeared to deliver carbon in a chemically recalcitrant form destined for long-term residence, while stover fed the soil food web with labile substrates that were rapidly processed and redistributed.

The fate of carbon from each amendment also diverged at the level of microbial residues and plant-derived compounds. Biochar increased microbial necromass carbon while reducing plant-derived carbon in the 0 to 20 and 20 to 40 centimeter layers, a pattern the authors associate with enhanced decomposition of native plant carbon alongside the substantial input of stable biochar carbon. Stover increased both plant-derived carbon and microbial necromass carbon, particularly through active microbial processing of the incorporated residues. In other words, stover stimulated the biological machinery of the soil, generating microbial biomass that itself becomes a stable carbon pool, while biochar largely bypassed that machinery by depositing pre-stabilized carbon.

Soil structure played a decisive role in shaping these outcomes. Both amendments increased the proportion of small macroaggregates, the soil clumps that physically protect organic matter from decomposition, but stover exerted the stronger effect across the entire soil profile. Partial least-squares path modeling, a statistical technique for testing hypothesized causal chains, indicated that stover enhanced soil organic carbon through a coordinated pathway involving aggregates, plant-derived carbon, and microbial necromass carbon. Biochar operated primarily through direct stable-carbon input, with an indirect contribution from accumulating microbial residues. The two amendments, in effect, built soil carbon through entirely different architectural strategies.

The practical implications are significant for carbon management in agriculture. Biochar appears better suited to long-term carbon sequestration and the stabilization of persistent carbon pools, making it attractive for climate mitigation schemes that require durable offsets. Maize stover, meanwhile, supports active carbon cycling, microbial processing, and the retention of plant-derived carbon, functions that sustain soil fertility and nutrient supply. The results favor matching amendment choice to management objectives rather than assuming that any organic input will deliver the same carbon benefits. A farmer prioritizing durable carbon storage might favor biochar, while one seeking to revitalize soil biological activity might lean toward residue incorporation, or potentially combine both.

The authors are careful to note the limitations of their study. The experiment used three field replicates, and technical replicates were not performed for the mass spectrometry analysis because of high analytical costs. Initial soil properties were measured from a composite sample rather than separately by soil layer, and lignin phenols and amino sugars do not capture the entire spectrum of soil organic carbon, including highly processed organic matter and black-carbon-like materials. The proposed differences in microbial necromass turnover and dissolved organic carbon transport therefore require further direct testing. Future work should quantify the differential persistence of fungal and bacterial necromass carbon and clarify the mechanisms controlling dissolved organic matter movement into deeper soil layers, with longer-term monitoring across soils, climates, and cropping systems needed to establish how broadly these divergent carbon sequestration pathways apply.

Even with those caveats, the decade-long record provides rare empirical weight behind an increasingly important question: how agricultural soils can be managed as carbon sinks without compromising productivity. As carbon markets mature and governments seek verifiable soil-based climate solutions, understanding which amendment delivers which kind of carbon, and where in the soil profile it ends up, becomes essential information. This study demonstrates that the answer is not one-size-fits-all. Biochar and maize stover, applied to the same field under the same climate for ten years, sculpted the soil’s carbon inventory in measurably different ways, from the molecular composition of dissolved organic matter to the architecture of aggregates and the balance of plant and microbial residues. For researchers and policymakers alike, the message is clear: the route carbon takes into soil matters as much as the amount that goes in, and choosing the right route may determine whether soil carbon gains endure for years or fade within seasons.

Subject of Research: Divergent carbon sequestration pathways of biochar and maize stover in agricultural soil

Article Title: Biochar and maize stover take different routes to store carbon in soil

Article References: Biochar and maize stover take different routes to store carbon in soil. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: biochar, maize stover, soil organic carbon, dissolved organic carbon, microbial necromass, carbon sequestration, soil aggregates, lignin phenols, amino sugars, FT-ICR-MS, agricultural amendments, soil depth