The study, published in Frontiers in Microbiomes, addressed a pressing waste problem. China generates roughly 4 billion tons of poultry and livestock manure annually, alongside about 870 million tons of crop straw. Improper disposal, such as piling straw in fields or burning it, pollutes air and soil and squanders valuable organic matter. Cattle manure in particular contains abundant nutrients but also harmful substances including antibiotics, parasite eggs, and pathogenic bacteria. Aerobic composting is a promising recycling route, but it is a complex, microbially driven process that unfolds in four temperature-defined phases: a mesophilic heating stage, a thermophilic stage above 50 degrees Celsius, a cooling stage, and a maturation stage. Each phase is dominated by different microbial communities with different metabolic specialties, which is precisely why a one-size-fits-all inoculant added at the start often falls short.

The research team, led by Huanyao Li with Weimin Zeng and Jin Huang as corresponding authors, took a different approach. They first ran a preliminary composting experiment using cow manure from a farm in Anhua County, Hunan Province, mixed with chopped rice straw in cylindrical 50-liter fermentation tanks equipped with temperature probes, sampling ports, mechanical stirrers, and forced aeration at 0.45 liters per minute per kilogram. From samples collected on days 0, 2, 7, 14, 21, and 30, they isolated and purified 44 pure-culture strains with decomposition activity, matching the dominant taxa identified at each composting phase. During the mesophilic phase, dominant bacteria included Providencia stuartii, Klebsiella, and Brevundimonas strains; the thermophilic phase yielded Halomonas and multiple Bacillus subtilis strains; the cooling phase produced Halomonas, Alcanivorax, Rhodococcus rhodochrous, and Bacillus velezensis; and the maturation phase was characterized by Luteibacter anthropi and Halomonas strains. Additional functionally important strains were obtained from the China General Microbiological Culture Collection Center and the China Center of Industrial Culture Collection, and strains were blended at a 1:1 ratio to build phase-specific consortia.

The main experiment compared four treatments over a 30-day composting period: an uninoculated control (W), a staged commercial effective microorganisms (EM) inoculant containing Bacillus, Saccharomyces, Rhodopseudomonas, Acetobacter, Lactobacillus, Streptomyces, and Trichoderma, a single-dose composite inoculant (TF) containing all the same strains pre-mixed and added only at the start, and the staged targeted consortia (YF) added on days 0, 5, 14, and 22 to match the mesophilic, thermophilic, cooling, and maturation phases. The EM inoculant was applied at 0.4 percent by weight according to the manufacturer’s instructions, while the phase-specific and composite inoculants were applied at 0.9 percent to achieve comparable viable cell loads. Corn-cob powder, rich in cellulose and hemicellulose with a particle size of 100 to 200 mesh, was added to the control at corresponding phases to equalize carrier inputs.

The results were striking. The YF treatment achieved the longest thermophilic phase at 11 days, with a peak temperature of 62.87 degrees Celsius, exceeding the 10 days in the EM group and 8 days in the TF group, and comfortably meeting the Chinese industry standard NY/T 3442-2019 for pathogen inactivation. All inoculated treatments reached above 50 degrees Celsius by day 3, while the control took 4 days. Moisture content dropped furthest in the YF group, ending at 46.21 percent, reflecting the higher and longer heat output. By day 30, pH values in all groups ranged between 8.1 and 8.5, meeting the Chinese sanitary treatment standard GB/T36195-2018, and electrical conductivity in all treatments remained below 4 millisiemens per centimeter, indicating low salt hazard risk.

Carbon and nitrogen dynamics told a similar story. Total organic carbon decreased most in the YF and EM groups, with YF showing a 24.10 percent reduction compared to 16.23 percent in the control, indicating that staged inoculation promoted organic matter mineralization. Total nitrogen at the end of composting was highest in the YF treatment at 19.20 grams per kilogram, suggesting that the staged strategy reduced nitrogen loss through volatilization as ammonia. Humic substances reached 122.02 grams per kilogram in YF, a significant 24.72 percent increase over the control, while humic acid climbed to 92.32 grams per kilogram, a 35.81 percent increase. Fulvic acid, which is more active but less stable, was progressively converted into humic acid as composting proceeded, and the YF group showed the strongest fluorescence intensity for the humic acid-associated peak in three-dimensional excitation-emission matrix spectra of dissolved organic matter. Humification parameters including the humification ratio, humification index, and degree of polymerization were all significantly elevated in YF, and the seed germination index reached 90.63 percent, well above the 80 percent threshold generally considered to indicate harmless maturity. The control group, at 76.03 percent, failed to meet the standard.

High-throughput sequencing of the 16S rRNA gene V3-V4 region and the fungal ITS region revealed how the staged inoculation reshaped community succession. Bacterial Shannon diversity in the YF treatment decreased over time, which the authors attribute to targeted interventions producing a more specialized community rather than a diverse generalist one. Non-metric multidimensional scaling based on Bray-Curtis dissimilarity showed that bacterial community structures in the W, TF, and EM treatments followed similar trajectories, clustering together after the thermophilic phase, whereas the YF treatment exhibited significant shifts across time points with samples from different phases dispersed across the ordination space. At the phylum level, Firmicutes and Proteobacteria dominated, with Firmicutes enrichment in the inoculated treatments reflecting their thermotolerance and organic matter degradation capacity. At the genus level, the YF treatment showed distinct dominant taxa at each phase: Bacillus, Luteimonas, Cronobacter, and Providencia in the mesophilic phase; Bacillus, Planctomicrobium, Thermobacillus, and Vulgatibacter in the thermophilic phase; Bacillus, Planctomicrobium, Thermobacillus, and Paenibacillus in the cooling phase; and Flavobacterium and Luteimonas in the maturation phase, closely matching the taxa targeted for addition at those stages. Bacillus and Thermobacillus are renowned for thermotolerance and enzymatic machinery for degrading cellulose and hemicellulose, which contributed to the prolonged thermophilic phase, while Pseudomonas and Flavobacterium provided metabolic versatility for decomposing proteins, lipids, and simple sugars, generating precursors for humus synthesis.

Fungal communities were equally responsive. Ascomycota and Basidiomycota collectively accounted for more than 90 percent of relative abundance, with Basidiomycota more prominent in the early days and Ascomycota increasing in the middle and late stages. In the control group, the fungal community was relatively simple, dominated by Wallemia and Chaetomium, whereas no single genus exceeded 80 percent relative abundance in the TF and YF treatments, indicating a more complex fungal structure. In the YF treatment, Wallemia and Chaetomium were enriched initially, alongside the appearance of Thermomyces and Saccharomyces corresponding to the fungi added at that stage. Saccharomyces became dominant during the cooling and maturation phases, likely promoting stable microbial coexistence through metabolic exchange relationships. Redundancy analysis showed that pH was the primary explanatory factor for both bacterial and fungal community variance, followed by moisture content, humic substances, total organic carbon, electrical conductivity, temperature, and total nitrogen in descending order of influence for bacteria, and by total organic carbon, moisture content, total nitrogen, electrical conductivity, temperature, and humic substances for fungi.

The real test came in pot experiments. Four organic fertilizers derived from the respective compost treatments were applied at 3 percent by weight to 2.5 kilograms of soil per pot, with pakchoi grown under controlled conditions of 4000 lux light intensity, a 12-hour photoperiod, 60 to 80 percent relative humidity, and 20 to 30 degrees Celsius. On day 45, the YF-derived fertilizer treatment (YFP) achieved available nitrogen of 161.29 milligrams per kilogram, 98.3 percent higher than the unfertilized control and 19.8 percent higher than the EM-derived fertilizer. Available phosphorus reached 254.97 milligrams per kilogram, 118.2 percent above the control, and available potassium reached 184.40 milligrams per kilogram, 190.2 percent above the control. Plant height in YFP reached 20.83 centimeters, 261.1 percent higher than the control, and root length matched this figure exactly. Chlorophyll content climbed to 1.54 milligrams per gram, 126.5 percent above the control, while superoxide dismutase activity dropped to 305.17 units per gram, 30.2 percent below the control, indicating reduced oxidative stress and healthier plant growth. Electrical conductivity in the YFP soil decreased continuously over the 45-day period, reaching 272.19 microsiemens per centimeter, well below the 1000 microsiemens per centimeter threshold generally associated with salinization risk.

The authors conclude that phase-synchronized microbial management using autochthonous consortia represents a novel and practical framework for improving composting efficiency and product quality. While single-dose inoculation accelerated temperature rise, the high-temperature period was shorter than with staged addition, and the commercial EM inoculant had a weaker promoting effect on humification. By matching dominant microorganisms to each composting stage, the staged strategy enhanced cellulose and lignin degradation, drove the conversion of organic matter into stable humus, and reduced nitrogen loss. The study provides what the authors describe as the first empirical framework for phase-synchronized microbial management via indigenous consortia, revealing that temporal precision in community augmentation is critical for maximizing composting performance. For a livestock sector drowning in manure and a straw surplus that is too often burned, the message is clear: the right microbes at the right time can turn an environmental liability into a genuine agronomic asset.

Subject of Research: Environmental microbiology

Article Title: Enhancing cow manure composting via staged inoculation of functional microbial consortia

Article References: Li, H., Zeng, W., Huang, J., & Tan, S. (2026). Enhancing cow manure composting via staged inoculation of functional microbial consortia. Frontiers in Microbiomes, 5, Article 1855343. https://doi.org/10.3389/frmbi.2026.1855343

Image Credits: AI Generated

DOI: 10.3389/frmbi.2026.1855343

Keywords: aerobic composting, cow manure, microbial consortia, humification, staged inoculation, organic fertilizer, pakchoi, soil nutrients, Enhancing, manure, composting, staged

The study, published in the journal Discover Sustainability, tracked the effects of farmyard manure and nitrogen fertilization across 56 years in an irrigated pearl millet-wheat cropping system. Researchers led by Pooja Rani and Sarvendra Kumar of the ICAR-Indian Agricultural Research Institute in New Delhi, working with colleagues at CCS Haryana Agricultural University and several other Indian institutions, examined four manure rates—0, 10, 20, and 30 megagrams per hectare—each split equally between the rabi and kharif growing seasons, and combined them with three nitrogen fertilization levels of 0, 60, and 120 kilograms per hectare.

The results, drawn from yield records spanning 2000 to 2023, revealed that plots receiving 20 megagrams of manure per hectare produced average pearl millet yields of 2.45 megagrams per hectare and wheat yields of 4.77 megagrams per hectare. Those figures were statistically comparable to the yields from plots receiving the heaviest manure dose of 30 megagrams per hectare, yet they represented gains of 25 percent for pearl millet and 43 percent for wheat relative to unfertilized control plots. The finding suggests that farmers may not need the maximum manure input to achieve near-maximum productivity, a conclusion with significant implications for the scalability of organic nutrient management.

Equally important was what happened when nitrogen fertilization was omitted. The researchers found that removing nitrogen from the system significantly diminished yield potential regardless of manure rate, emphasizing that organic inputs alone cannot substitute for this essential macronutrient in crop production. Manure and mineral nitrogen, the study indicates, work best in tandem: the organic fraction builds soil structure, carbon, and microbial life over decades, while mineral nitrogen supplies the readily available nutrient that crops need in the short term.

Beneath the yield statistics lies a deeper story about soil transformation. Continuous application of the heaviest manure dose increased soil organic carbon by 143 percent in surface soils and 183 percent in subsurface soils compared with control plots. Available phosphorus rose 4.1-fold in surface soils and 6.2-fold in subsurface soils, while available potassium increased 1.7-fold and 2.7-fold respectively. These are not marginal adjustments; they represent a fundamental reconstitution of the soil’s chemical and biological capacity to support plant life in a region where fertility has been declining for decades.

The biological dimension proved just as consequential. Manure-treated plots showed significantly higher microbial functions and enzyme activity, indicators of a living soil community actively cycling nutrients and supporting plant growth. Soil microbes and their enzymes mediate the decomposition of organic matter, the release of nitrogen and phosphorus, and the formation of stable soil aggregates—all processes that determine whether a soil can sustain productivity through drought years and climate variability.

To untangle which factors mattered most for crop yields, the team employed partial least squares path modeling, a statistical technique capable of quantifying the relative influence of multiple interacting variables. The analysis revealed that macronutrients were the principal drivers of crop yield, with a path coefficient of 1.18 and a p-value below 0.001. Macronutrients alone accounted for 72 percent of yield variability, highlighting the critical interplay between biotic factors such as microbial activity and abiotic factors such as nutrient availability in determining agricultural outcomes.

The researchers conclude that integrating 20 megagrams of farmyard manure per hectare with optimum nitrogen fertilization may provide a scalable, climate-resilient solution for sustaining yields, restoring degraded soils, and strengthening food security in semiarid regions and comparable soil types. The moderate manure rate, statistically indistinguishable in productivity from the highest rate, offers a practical compromise that avoids the logistical and economic burdens of applying excessive organic material while still delivering the long-term soil benefits that underpin resilience.

For a world grappling with soil degradation, climate volatility, and rising food demand, the study’s message is both simple and profound: patience pays. Five decades of steady organic inputs transformed exhausted semiarid soils into productive, carbon-rich, biologically active farmland. The experiment demonstrates that sustainable intensification is not a contradiction but an achievable reality, provided farmers and policymakers commit to nutrient cycling practices whose benefits compound over generations rather than seasons.

The 56-year experiment behind these findings belongs to a rare class of field trials. Long-term agricultural experiments spanning multiple decades are uncommon worldwide, and those conducted under uniform management in semiarid environments are rarer still. Their value lies in the ability to separate slow-acting processes—such as the gradual accumulation of soil organic matter and the slow build-up of nutrient reserves—from the year-to-year noise of weather and management. Because the manure treatments were split equally between the kharif (monsoon) and rabi (winter) seasons, the study captured how organic inputs behave across both of the contrasting growing windows that define cropping in much of semiarid South Asia.

The choice of cropping system matters as much as the duration. Pearl millet and wheat together form a staple rotation across large parts of the Indian subcontinent, with pearl millet grown during the hot, rain-fed-influenced monsoon season and wheat cultivated under irrigation in the cooler months. Yields averaging 2.45 megagrams per hectare for pearl millet and 4.77 megagrams per hectare for wheat in the moderately manured plots represent substantial productivity for semiarid conditions, where heat stress, erratic rainfall, and inherently low soil organic matter typically constrain output. The fact that these yields were achieved with manure as the primary nutrient foundation suggests that organic matter accumulation can buffer crops against the environmental stresses characteristic of dryland agriculture.

The differential response of surface and subsurface soils offers a window into how manure reshapes the soil profile over time. The larger relative gains in subsurface layers—183 percent for organic carbon, 6.2-fold for phosphorus, and 2.7-fold for potassium—indicate that decades of organic additions have moved nutrients and carbon below the topsoil. This matters because subsurface reserves influence root development, water-holding capacity, and the ability of crops to access moisture during dry spells. Surface enrichment alone can be washed away or volatilized; deep accumulation suggests a durable restructuring of the soil’s fertility architecture.

The statistical finding that the 20 megagram rate matched the 30 megagram rate carries practical weight for resource-constrained farming systems. Farmyard manure is bulky, labor-intensive to transport and apply, and often in limited supply at the farm scale. Halving the required dose without sacrificing yield means more farmers can adopt the practice, and more land can be covered with the same quantity of available manure. It also reduces the risk of nutrient oversaturation, which can occur when heavy organic applications exceed crop uptake capacity over many years.

The interdependence between manure and mineral nitrogen deserves emphasis. The finding that omitting nitrogen fertilization significantly diminished yield potential, regardless of manure rate, aligns with a broader principle in soil science: organic amendments release nutrients gradually as microbes decompose them, and this slow mineralization frequently cannot match the rapid nutrient demand of cereal crops during critical growth stages. Integrated nutrient management—combining organic matter building with judicious mineral fertilization—has emerged as a central strategy for reconciling productivity with soil conservation, and this experiment provides multi-decadal empirical support for that approach in a semiarid context.

The path modeling results add a quantitative dimension to understanding what drives yield in these systems. A path coefficient of 1.18 for macronutrients, with 72 percent of yield variability explained, indicates that while microbial activity and enzyme dynamics are essential mediators of nutrient cycling, the ultimate constraint on productivity remains the supply of essential plant nutrients. This does not diminish the biological story; rather, it clarifies the causal chain. Manure feeds the microbial community, microbes decompose organic matter and release nutrients, and those nutrients—nitrogen, phosphorus, potassium—directly fuel crop growth. The biotic and abiotic components are not competing explanations but sequential links in the same process.

Soil organic carbon itself deserves attention beyond its role in fertility. Carbon stored in agricultural soils represents one of the few widely available mechanisms for removing atmospheric carbon dioxide while simultaneously improving food production. The 143 percent surface and 183 percent subsurface increases observed here, achieved through a practice already familiar to farmers, suggest that semiarid croplands—often dismissed as having limited carbon sequestration potential—can accumulate substantial carbon when managed with sustained organic inputs over long horizons. The magnitude of these gains, accumulated over 56 years, also illustrates the patience required: carbon accrual in soils is slow, and short-term trials frequently underestimate the eventual benefits.

The enzyme activity and microbial function findings round out the picture of a soil transformed from a largely mineral substrate into a functioning biological system. Enzymes involved in carbon, nitrogen, phosphorus, and sulfur cycling serve as sensitive indicators of soil health, responding to management changes faster than bulk organic matter measurements. Their elevation in manure-treated plots confirms that the added organic material is not merely accumulating inertly but is being actively processed by soil organisms, sustaining the nutrient flows on which crop productivity depends.

Taken together, the study offers a template for dryland agriculture facing intensifying climate pressure. It demonstrates that the combination of moderate organic inputs and balanced mineral fertilization, maintained consistently over decades, can simultaneously address food production, soil restoration, and climate resilience in environments where these goals have often been treated as competing priorities.

Subject of Research: Long term manure driven nutrient cycling enhances productivity resilience and food security in semiarid agroecosystems

Article Title: Long term manure driven nutrient cycling enhances productivity resilience and food security in semiarid agroecosystems

Article References: Rani, P., Kumar, S., Raj, D., Purakayastha, T. J., Sinha, N. K., Mandal, D., Rosin, K. G., Govindasamy, V., Sharma, A., Sinha, S. K., Vishwanath, Jangir, A., Chowdhuri, A., & Kumar, A. (2026). Long term manure driven nutrient cycling enhances productivity resilience and food security in semiarid agroecosystems. Discover Sustainability. https://doi.org/10.1007/s43621-026-03974-4

Image Credits: AI Generated

DOI: 10.1007/s43621-026-03974-4

Keywords: Long, term, manure, driven, nutrient, cycling, enhances, productivity, resilience, food, security, semiarid

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

The scale of the transformation the dataset documents is striking. In the early 1960s, at the dawn of the Green Revolution, synthetic fertilizer delivered roughly 11 teragrams of nitrogen to the world’s croplands each year. By 2023, that figure had climbed past 100 teragrams per year, nearly a tenfold increase in six decades. Manure nitrogen, the older and more diffuse pathway of nutrient delivery, rose more modestly but still substantially, from about 14 to 23 teragrams per year over the same period. Together, these two streams now represent one of the largest deliberate alterations of the global nitrogen cycle in Earth history, and their consequences ripple through greenhouse gas inventories, water quality assessments, and climate models alike.

What makes HaNi-Crop different from earlier attempts to map fertilizer use is its combination of four dimensions of detail that previous datasets handled only separately. It is crop-specific, distinguishing nitrogen applied to wheat from nitrogen applied to maize, rice, soybeans, and eighteen other crop groups. It is spatially explicit, resolved at a grid cell size of 0.1 degrees by 0.1 degrees, fine enough to capture variation between neighboring agricultural counties. It is temporally deep, spanning more than sixty years of annual estimates. And it is chemically differentiated, separating ammonium-based nitrogen inputs from nitrate-based ones, a distinction that matters enormously because the two forms behave differently in soil, emit different amounts of nitrous oxide, and leach into waterways at different rates.

The technical architecture behind the dataset builds on the History of Anthropogenic Nitrogen Inputs, or HaNi, data infrastructure established by Tian and colleagues in 2022. To construct the crop-level product, the team fused national and sub-national statistics on fertilizer consumption and manure production with high-resolution crop harvested-area maps, information on the specific fertilizer products used in different countries and eras, and a set of spatial allocation procedures that distribute reported totals across the landscapes where each crop actually grows. The result is an annual, gridded estimate of nitrogen application rates for every crop group, differentiated by chemical form, that can be dropped directly into ecosystem and Earth system models.

Among the dataset’s headline findings is the enduring dominance of the three great cereal crops. Wheat, maize, and rice together consistently absorbed approximately half of all synthetic fertilizer nitrogen applied globally throughout the entire 1961 to 2023 record. This concentration reflects both the sheer acreage these staples occupy and the intensive management they receive, particularly in the irrigated rice paddies of Asia and the maize belts of North America and China. It also means that any serious attempt to reduce the environmental footprint of nitrogen must grapple with cereal production systems, which feed the majority of humanity but operate at some of the lowest nitrogen use efficiencies in global agriculture.

The chemical split documented in the dataset tells its own story. Ammonium-based nitrogen, the form delivered by urea, ammonium sulfate, and anhydrous ammonia, surged from 8 teragrams per year in the early 1960s to nearly 90 teragrams per year by 2023. Nitrate-based fertilizers, by contrast, grew from only about 3 to roughly 12 teragrams per year. The divergence reflects decades of industrial chemistry favoring ammonium and urea products, which are cheaper to produce and transport. But it carries environmental weight: ammonium inputs undergo nitrification in soils, a microbial process that releases nitrous oxide, a greenhouse gas nearly 300 times more potent than carbon dioxide, and produces nitrate that is prone to leaching into groundwater and coastal waters.

Why does crop-specific resolution matter so much? Crops differ profoundly in how much nitrogen they demand, how efficiently they take it up, and what happens to the surplus. Rice paddies, flooded for much of the growing season, lose nitrogen through different pathways than rain-fed wheat fields. Perennial forage crops recycle nutrients differently than annual vegetables. When models lump all cropland together with a single average fertilizer rate, they systematically misestimate nitrous oxide emissions, nitrate leaching, and soil carbon dynamics. HaNi-Crop gives modelers, for the first time at global scale and across six decades, the crop-by-crop, form-by-form inputs needed to close those gaps, sharpening everything from national greenhouse gas inventories reported under the Paris Agreement to regional assessments of coastal hypoxia.

The dataset’s applications extend well beyond emissions accounting. Nitrogen budget analyses, which compare inputs against crop removal to calculate the surplus that escapes into the environment, depend critically on knowing which crops received which nutrients where. Agrifood-system resilience studies, increasingly urgent in an era of fertilizer price shocks and export restrictions, can use the record to identify regions dangerously dependent on synthetic inputs and to evaluate where manure recycling could substitute for manufactured fertilizer. Climate mitigation strategies, from nitrification inhibitors to precision application technologies, can now be evaluated against a realistic baseline of what was actually applied, to which crop, and in what chemical form, rather than against coarse national averages.

The timing of the release is notable. Global nitrogen flows have crossed several proposed planetary boundaries, and the United Nations and national governments have repeatedly called for improved nutrient management. Yet until now, the scientific community has lacked a single reference dataset that simultaneously covered crop specificity, fine spatial resolution, long temporal depth, and fertilizer form differentiation. Studies that needed such detail had to stitch together multiple products with incompatible assumptions, introducing uncertainties that propagated through policy-relevant conclusions. By harmonizing these dimensions in one openly available resource, published under a Creative Commons license and hosted on Zenodo, the HaNi-Crop team has removed a persistent bottleneck in sustainability science.

As with any dataset built from statistics and spatial allocation, HaNi-Crop carries uncertainties inherited from its inputs, and the preprint remains under peer review, with the discussion open to the community. But the six-decade record it assembles already offers an unflinching portrait of humanity’s nitrogen habit: a tenfold expansion of synthetic inputs concentrated on three cereal crops, increasingly dominated by ammonium chemistry, and spread across a map that now reveals, cell by cell, where the surplus nitrogen that fuels dead zones, smog, and warming will come from. Turning that portrait into policy, the authors suggest, is the next step, and for the first time the world has the data resolution to attempt it.

Subject of Research: A global gridded dataset of crop-specific nitrogen inputs from synthetic fertilizer and manure, 1961–2023

Article Title: HaNi-Crop: A Harmonized and Gridded Global Dataset of Crop-Specific Nitrogen Inputs from Nitrogen Fertilizer and Manure

Article References: Hao, W., Tian, H., Shi, H., Yu, X., Pan, N., Pan, S., Tubiello, F. N., Adalibieke, W., Bernoux, M., Ciais, P., Maggi, F., Nishina, K., Uwizeye, A., & Zhou, F. (2026). HaNi-Crop: A Harmonized and Gridded Global Dataset of Crop-Specific Nitrogen Inputs from Nitrogen Fertilizer and Manure. https://doi.org/10.5194/essd-2026-595

Image Credits: AI Generated

DOI: 10.5194/essd-2026-595

Keywords: nitrogen, fertilizer, manure, crops, HaNi-Crop, dataset, greenhouse gas emissions, nitrogen use efficiency, Earth system modeling, food security, agriculture, climate mitigation

The study was designed to address a persistent gap in soil ecology. Although many investigations have examined how fertilization affects individual groups of soil organisms, comparatively few have traced the consequences across the entire food web, spanning microbes at the base to earthworms near the top, and fewer still have done so over a time frame long enough to capture the slow, cumulative changes that define soil health. To fill that gap, a team of researchers led by first and corresponding author Professor Yunfeng Chen of the Hubei Academy of Agricultural Sciences compared four long-term treatments: chemical fertilizer supplying nitrogen, phosphorus and potassium, known as NPK; organic manure alone; a combined treatment of manure plus NPK; and an unfertilized control plot that served as the experimental baseline.

The measurement strategy was deliberately broad. Rather than tracking a single indicator organism, the team quantified biomass or abundance across key taxonomic and functional groups, including microorganisms, protozoa, nematodes, mites, collembolans, enchytraeids and earthworms. They also calculated nematode ecological indices, a set of established metrics that soil ecologists use to infer the structure and maturity of soil food webs. Together, these measurements allowed the researchers to evaluate the relative strength of two competing regulatory forces: bottom-up control, in which the availability of resources such as organic carbon and nutrients determines how many organisms higher trophic levels can support, and top-down control, in which predators and higher consumers suppress or structure the populations below them.

The headline finding was unambiguous. Long-term fertilization increased the inputs of resources entering the soil, and that surge in resources enhanced most of the functional groups the team measured. Fertilized plots supported larger and more complex communities than the unfertilized control, confirming that sustained nutrient management is a powerful lever for shaping the living architecture of agricultural soils. But the differences among fertilization strategies proved just as consequential, and here the organic treatments stood out clearly.

Manure alone and the combined manure-plus-NPK treatment outperformed pure chemical fertilizer across most groups. When the researchers expressed these gains as relative increases compared with the NPK treatment, the manure plots showed improvements ranging from 20.69 to 972.52 percent, with an average of 241.62 percent, while the combined plots ranged from 26.55 to 792.30 percent, averaging 189.02 percent. Those are not marginal differences; they represent order-of-magnitude shifts in the abundance of some soil organisms. The practical implication is that organic amendments, whether applied alone or alongside mineral fertilizers, deliver substantially more nourishment to the soil food web than chemical fertilizer alone.

Interestingly, the manure-only and combined treatments did not differ significantly from each other. The researchers attribute this convergence to high soil fertility: once fertility reaches a sufficiently high level, the distinction between the two organic approaches diminishes, and both support similarly rich communities. In other words, the food web appears to saturate, and beyond a certain threshold of resource abundance, adding mineral fertilizer on top of manure yields little additional biological benefit even though it may still matter for crop nutrition.

The evidence for bottom-up regulation was strong and came from multiple independent lines. Functional groups showed positive correlations with one another, a pattern consistent with resources flowing upward through the web and lifting every level together rather than predators imposing their own structure from above. The enrichment index, a nematode-based metric that signals an abundance of opportunistic, resource-responsive organisms, rose by 51.27 percent under manure and 28.49 percent under the combined treatment relative to chemical fertilizer alone. The enrichment footprint, a complementary measure that captures the cumulative enrichment signal across the food web, increased even more dramatically, by 11.80 percent under manure and 47.17 percent under the combined treatment relative to NPK.

To synthesize these patterns into a causal framework, the team employed partial least squares path modeling, a statistical technique well suited to disentangling direct and indirect pathways among correlated variables. The modeling confirmed what the correlations and indices had suggested: bottom-up forces predominantly determined both the structure and the total biomass of the soil food web. Resource availability, shaped by decades of fertilization, was the dominant driver, while top-down influences played a comparatively minor role in this system. For a rice–wheat rotation, where flooded and aerobic phases alternate and organic matter dynamics are complex, this finding provides a clear conceptual anchor for future soil management research.

The implications extend well beyond the experimental plots. Soil food webs underpin essential ecosystem services, including decomposition, nutrient mineralization, suppression of plant pathogens and the maintenance of soil structure. A food web enriched through bottom-up channels is, in effect, a soil with greater biological capacity to sustain crop productivity over time. The study suggests that sustained organic inputs, particularly when integrated with mineral fertilizers, effectively enhance both the complexity and the size of the soil food web primarily through this bottom-up regulatory mechanism. For farmers and policymakers weighing the trade-offs between organic and conventional inputs, the results add a biological argument in favor of manure-based strategies, whether used alone or in combination with chemical fertilizer.

The research also carries a cautionary note for the long term. Because the experiment spanned thirty years, it captured changes that short-term studies inevitably miss, including the slow accumulation of soil organic matter and the gradual response of larger, slower-reproducing organisms such as earthworms and enchytraeids. The authors’ conclusion is that fertilization is not merely a plant nutrition tool but a food-web engineering instrument, and that its effects compound over decades. As agriculture worldwide faces pressure to maintain yields while restoring degraded soils, this long-term evidence from a major cereal rotation offers a template: feed the base of the soil food web, and the rest of the web, along with the services it provides, is likely to follow.

Subject of Research: Long-term effects of chemical and organic fertilization on the soil food web in a rice–wheat cropping system

Article Title: Long-term fertilization enriches soil food web mainly through bottom-up regulation in a rice–wheat cropping system

Article References: Long-term fertilization enriches soil food web mainly through bottom-up regulation in a rice–wheat cropping system. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: soil food web, long-term fertilization, rice–wheat rotation, bottom-up regulation, manure, NPK fertilizer, nematodes, earthworms, soil fertility, enrichment index, agroecology, soil biodiversity