Compost is a widely used organic amendment to improve soil health and increase crop yield. However, the contamination of compost with microplastics (MPs) has emerged as a growing concern for the sustainability of agroecosystems. Despite concerns, the fate of compost bound MPs largely remained unclear. This review critically assessed the sources, characteristics and fate of MPs in the compost. The findings clarified that contaminated organic waste feedstocks were the main contributor of MPs to compost, with fibers, fragments, and films being the most observed shapes. The abundance of polypropylene (PP), Polyethylene (PE), and Polyethylene terephthalate (PET) polymers in compost reflected their widespread use in the production of everyday plastic products. The review further investigated the effect of MPs on the soil system and found that the severity of impact mainly depends on MP morphology. The results also highlighted that partial degradation of bioplastics could persist as non-point source of MPs in the compost. However, addition of biochar, strict monitoring of composting conditions, and introduction of specific microbial strains during the composting process could be possible solutions to increase the degradation of MPs.

Plant growth-promoting rhizobacteria (PGPR) inoculants are eco-friendly microbial formulations that offer sustainable alternatives to chemical fertilizers and pesticides, playing an increasingly important role in modern agriculture. However, the success of solid inoculants depends on the choice of carrier material, with peat traditionally dominant, facing limitations due to its non-renewable nature. This review examines alternative carriers that can enhance microbial viability, functionality, and field performance. Publications from 2000 to 2025 (with emphasis on 2020–2025) were reviewed across mineral substrates, decayed organic materials, biochar, agro-industrial residues, biopolymers and nano-enabled carriers, focusing on how these materials influence microbial survival, shelf life, crop response, and stress tolerance in both controlled and field studies. Mineral-based carriers such as talc, kaolin, and vermiculite demonstrated improved storage stability, while organic residues, including lignite, mill mud, and composted manures, supported long-term survival and biological nitrogen fixation. Biochar emerged as a versatile carrier with high porosity and water-holding capacity, consistently enhancing root colonization and nodulation. Biopolymers such as alginate and starch improved microbial encapsulation and gradual release in soil environments. More recently, nanomaterials, including polymer nanoshells, silica, and metal organic frameworks, have shown promise for protecting PGPR against abiotic stress and improving delivery efficiency, though their scalability remains limited. Alternative carriers offer viable, sustainable options to replace peat, with biochar and biopolymers demonstrating strong immediate potential and nanocarriers representing a promising frontier. Future research should focus on optimizing these carriers for cost-effectiveness, ecological safety, and large-scale agricultural applications.

Hydrochar from agricultural residues is a promising bio-based fertilizer product. We optimized rice-straw hydrochar slow-release fertilizers (SRFs) by varying hydrothermal temperature (200-280 degrees C) and postoxidation (0-8 h), then compared them with a pyrochar SRF and a conventional fertilizer. The optimized hydrochar (H-240 and its oxidized H-6h derivative) showed high nutrient loading at 30.74 wt% of N and rich oxygenated surface groups favorable for nutrient binding. In water, the conventional fertilizer released up to 95 % of N within 1 h, whereas hydrochar SRFs cut the initial burst to 35 % (H-240) and 22 % (H-6h) and sustained release over 5-7 days; in sandy soil, they delayed 80-85 % cumulative N release from day 2 (conventional) to day 4-5. Pot experiments revealed that these optimized hydrochar-based fertilizers increased soil total N and organic matter by up to 63 % and 12 %, respectively, and enhanced nitrate retention by 26 %. Maize plants treated with H-240 and H-6h achieved 23-28 % higher shoot biomass, 21 % thicker stems, and up to 42 % greater root surface area relative to the chemical fertilizer control. Partial least squares structural equation modeling demonsrated that mesoporosity and surface oxidation enhanced nutrient loading, which strongly promoted soil fertility and nutrient retention capacity, and further plant nutrient uptake and growth. These results deliver design rules at 240 degrees C and 6 h oxidation to convert rice-straw waste into effective, circular SRF products that improve soil fertility and early crop growth.

Wetland reclamation is one of the most globally widespread land-use transformations and strongly affects belowground biogeochemical processes. Even so, we still do not fully understand how the soil micro-food webs re-organized and regulate ecosystem multifunctionality (EMF) following the conversion of wetland to paddy field and soybean field. A natural experimental system of the Sanjiang Plain was created in this study using natural wetland (NW) as well as paddy (PF) and soybean (SB) fields. Through the integration of high-throughput sequencing, energy-flow analysis, and structural equation modeling, we systematically examined community assembly, interaction networks, and functional dynamics across multiple trophic levels. The findings revealed that the bacterial and fungal communities in paddy fields were mostly driven by strong deterministic processes while in soybean fields stochastic processes were dominant. In contrast, paddy fields selected protistan communities mainly by stochastic processes; soybean fields underwent a transition to deterministic selection. The co-occurrence network of micro-food web in paddy fields shrank and was characterized by a marked increase in positive correlations (64.44%) while soybean fields showed a marked increase in negative correlations. In agricultural systems, the overall state of the micro-food web changed from the wetland “structured” state to a “enrichment-driven” state. The main drivers of ecosystem multifunctionality also changed, transitioning from an “endogenous carbon limitation” pattern in wetlands to an “exogenous nutrient-driven” mechanism in farmland. Several key taxa, including the bacterium Romboutsia and the nematode Pseudacrobeles, showed strong predictive power for ecosystem multifunctionality. Structural equation modeling further revealed that positive network cohesion, rather than species diversity, acts as the primary driver promoting EMF. Overall, this study reveals the key mechanisms underlying the coordinated evolution of belowground micro-food web structure and ecosystem multifunctionality during wetland reclamation from a multi-trophic interaction perspective, providing a new theoretical framework for understanding how land-use change regulates ecosystem multifunctionality.

Boreal forests play a crucial role in global carbon regulation but are increasingly exposed to logging and fire disturbances. However, how belowground microbial-dissolved organic matter (DOM) interactions shape EMF during post-disturbance recovery remains unclear. Using absolute quantitative high-throughput sequencing and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), we investigated microbe–DOM coupling (co-occurrence) in post-logging and post-fire boreal forests. The study included eight treatments with three independent replicate plots per treatment, resulting in 24 plots in total. These treatments comprised four post-logging forests representing undisturbed control and 20–32 years of natural recovery after clear-cutting or selective cutting, and four wildfire treatments representing unburned reference and light, moderate, and severe fire after 21 years of post-fire recovery. Post-logging forests exhibited incomplete recovery of soil nutrients and enzyme activity, accompanied by a shift toward K-strategist microbial communities and reduced proportions of recalcitrant-like DOM compounds. In contrast, high-severity fire was associated with the accumulation of thermodynamically constrained, recalcitrant-like DOM pools within the PPL-extractable and negative-ion-detectable DOM fraction; here, recalcitrance is interpreted as an operational inference based on molecular indices rather than direct biodegradability measurements. Despite recovery in DOM α-diversity, the complexity of microbe-DOM coupling networks remained lower than in undisturbed forests. Threshold analysis further showed that EMF responses were disturbance-dependent, with lower coupling thresholds in post-logging forests but higher minimum threshold (Tmin) values for microbe-DOM interactions following fire. In post-logging forests, the minimum EMF thresholds for bacterial-DOM coupling were relatively low, including 0.25 for all bacteria, 0.42 for core bacteria, and 0.26 for satellite bacteria, whereas the threshold for all bacterial species-DOM coupling was higher in post-fire forests (Tmin = 0.71). Moreover, EMF drivers differed between disturbance types, being primarily associated with soil nutrients in post-logging forests and litter quality in post-fire forests. These findings suggest that logging and fire reshape boreal carbon turnover through coordinated shifts in microbial life-history strategies, DOM molecular composition, and interaction network structure.

Solar radiation aging significantly enhances the environmental functionality of hydrochar (HC) by modifying its physicochemical properties and dissolved organic matter (DOM) composition, thereby improving its efficacy in soil remediation. In this study, hydrochars derived from pig manure and mandarin peels were prepared at 180 °C and 260 °C and subjected to simulated solar aging. Comprehensive characterization via FTIR, XPS, 3D-EEM, and ESI-FT-ICR MS revealed that high-temperature HC (260 °C) exhibited a higher specific surface area and more heterogeneous surface morphology. Solar aging further promoted the development of micropores and facilitated the transformation of oxygen-containing functional groups (e.g., C = O and C–O) through photochemical reactions. Although aging reduced the total DOM content, it markedly increased molecular diversity, particularly enhancing the proportion of low-molecular-weight, bioavailable organic compounds such as protein-like substances (+ 1.2

Peat is the most widely used commercial carrier for rhizobial inoculants, but it is non-renewable and increasingly scarce. We aimed to formulate pinewood biochar (PWBC) carrier blended at defined ratios with a biopolymer (xanthan gum), a superabsorbent polymer (polyacrylamide), and waste-derived organics (eggshell, mulch hay) to improve moisture buffering and rhizobial persistence, nodulation and nitrogen (N) fixation. Shelf-life and survival rate were first determined across six carriers peat; PWBC; PWBC + xanthan (PWBC-X); PWBC + xanthan + polyacrylamide (PWBC-XP); PWBC + xanthan + polyacrylamide + eggshell (PWBC-XPE); PWBC + xanthan + polyacrylamide + eggshell + mulch hay (PWBC-XPEM) for 120 days, stored at 28 ℃. The foremost carrier PWBC-XPEM was then selected for glasshouse evaluation against uninoculated control, peat, and PWBC. Soybean (Glycine max L.) was grown under three watering regimes (D0: 55

Accurate estimation of soil organic carbon (SOC) is vital for soil monitoring and carbon accounting, yet conventional laboratory analyses are destructive and labour-intensive. Hyperspectral imaging (HSI) offers a rapid, non-destructive alternative by simultaneously capturing spectral profiles and surface spatial heterogeneity. In this study, we investigated SOC estimation from fused visible-near-infrared (VNIR) and shortwave-infrared (SWIR) hyperspectral imagery using 555 tropical soil samples represented by 1,656 image cubes spanning 268 contiguous spectral bands. Four predictive modelling paradigms were benchmarked: partial least squares regression (PLSR), a one-dimensional convolutional neural network (1D-CNN), a dual-branch Fusion-ResNet (FResNet), and the proposed Spatial-Spectral Transformer Regression (SSTR) model. Under a strict sample-code grouped evaluation across 10 independent splits, SSTR yielded the highest mean predictive performance among the evaluated models. In the 8:2 split, SSTR reached R² = 0.8198 ± 0.0361, Pearson r = 0.9258 ± 0.0079, RMSE = 0.7396 ± 0.1043%, and RPD = 2.4040 ± 0.2493, compared with PLSR (R² = 0.5568 ± 0.0566). Furthermore, SSTR used 2.57 M parameters compared with 43.30 M for FResNet (a 94.1% reduction), and maintained higher mean performance under constrained training data (20% training ratio: R² = 0.6329 ± 0.0365, RPD = 1.6583 ± 0.0810). These findings support the use of joint spatial-spectral representation learning for proximal SOC sensing and provide a methodological basis for future evaluation with imaging spectroscopy.

Abstract Hydrothermal carbonization (HTC) transforms wet or dry biomass into hydrochar, generating a nutrient-rich process water, hereafter termed HTC-PW, which is often overlooked as waste. This review synthesizes current knowledge on HTC-PW composition, including varied pH (3.5–9.2), high organic content (TOC 4,000–31,700 mg L−1), and nutrients such as NH₄⁺–N (up to 4,400 mg L−1) and potassium (5,870–6,330 mg L−1), derived from feedstocks such as sewage sludge and food waste. Process controls such as temperature and residence time tune HTC-PW properties for agronomic use, enabling enhanced partitioning of elements between solid and liquid phases. Pathways include direct fertigation, co-application with biogas slurry, and conditioned recovery, such as struvite precipitation yielding 92–99% P and 43–88% N. Performance metrics demonstrate yield increases of 6.7–29.2% and improved nutrient use efficiency of 15–30% in crops such as rice, alongside microbiome shifts favoring bacterial communities for better nutrients cycling. Beyond fertilization, valorization routes encompass anaerobic digestion for biogas (250–350 mL CH4 g−1 COD, with 70–85% COD removal) and catalytic reforming for H₂. Risks such as salinity (EC 5–24 mS cm− 1) and context-dependent N2O responses (suppression under inhibitory organics versus pulses under high NH4⁺ loading) necessitate bioassays and regulatory compliance, while techno-economic analysis and life-cycle assessment indicate scenario-dependent benefits, including economic savings where avoided wastewater-treatment credits apply and 20–50% reductions in global warming potential when mineral fertilizer substitution is credited. Gaps in long-term trials and scalability are identified, with future directions emphasizing machine learning for predictive optimization of HTC-PW properties and applications. Overall, current evidence supports HTC-PW primarily as a nutrient-rich liquid amendment (fertilizer-like input) that alters soil DOM and microbial processes, while direct evidence for consistent improvements in soil physical structure remains limited and warrants targeted measurement in future field trials. Graphical Abstract

Extracellular polymeric substances (EPS) constitute a significant component of soil organic matter (SOM), but the processes by which EPS are transformed and further retained by soil minerals remain poorly understood. This study investigated the chemical speciation of biogenic elements and mineral-SOM associations after EPS adsorption and turnover in typical clay minerals and three soils. Synchrotron-based X-ray absorption near-edge structure (XANES) analysis revealed that incubation induced approximately twice the changes in C and S speciation compared to EPS surface adsorption alone, suggesting that stimulated microbial activity is a more important pathway for EPS to participate in SOM turnover. Incubation with EPS significantly increased carboxylic carbon by 15.9

Sustainable agriculture requires maintaining soil health, yet conventional management (CM) practices may not protect soils from stresses such as compaction. This study compared microbial resilience to compaction in two soils collected from sugarcane farms under improved management (IM: minimum tillage, cover cropping and stubble retention) and CM (conventional tillage, no cover crop and stubble retention) practices. Samples were placed in 96-well deep-well plates and compacted using a bespoke device to achieve bulk densities of 0.9 (control), 1.1 (low), and 1.2 g cm-3 (moderate). Microbial resistance was assessed 14 days after compaction, and resilience 14 days after stress relief. Under low and moderate compaction, IM soils showed 49.5 % and 45.7 % higher CO2 emission resistance indices (i.e., the ability of soil to maintain microbial respiration under compaction stress) than CM, indicating greater stability. Microbial biomass carbon and nitrogen were 56.2 % and 47.9 % higher in IM soils under low compaction, compared to CM. Soil microbial metabolic quotient (qCO2) was similar across compaction levels within each system, but was 19.5 %-36.3 % lower in IM soils than CM at equivalent compaction, indicating lower microbial stress under IM. Fourteen days after stress relief, qCO2in moderately compacted CM soil increased by 41.1 % and 25.0 % compared to control and low compaction. In contrast, IM soil under moderate compaction had 40.6 % lower qCO2than CM. The CM showed no effects of compaction on hot water extractable organic carbon content, while compaction of IM showed a 13 % decline compared to its control. Hot water extractable total nitrogen did not vary with compaction within the management systems but was 12 %-15 % higher in IM than CM under the same compaction during the resistance phase. Total mineral nitrogen was unaffected by compaction treatments under each system but was 11 %-13 % higher in IM than CM during resistance phase. These findings highlight the potential of improved management practices to sustain soil health and resilience under compaction stress.

Natural rubber (NR) is a critical industrial commodity, and its production in Southeast Asia is dominated by smallholder farmers. In the Philippines, rubber farming is a major source of income for rural communities. However, the link between field management, soil properties and rubber tree growth in the region remains poorly understood, particularly in the key production areas such as the Province of Agusan del Sur, southern Philippines. This study investigated the rubber tree growth and soil properties – including soil type, ammonium, nitrate, soil pH/EC, soil organic carbon (SOC) and total nitrogen (TN) – and evaluated how these variables are associated with two common field management systems in Agusan del Sur: rubber monoculture (RM) vs. rubber-based intercropping (RI). We collected data from 36 smallholder rubber farms growing 9–10-year-old trees. The results showed field management significantly affected rubber tree growth and soil properties. Trees under monoculture system had a larger girth (57.3 ± 11.9 (SD) cm) but with lower soil pH (pH 5.38 ± 0.67), compared to those under intercropping (51.4 ± 8.8 cm; pH 5.81 ± 0.73). Results showed that the monoculture systems were associated with higher tree girth, due to the higher TN and NH4⁺ availability in the soil, and enhanced leaf N uptake. These findings highlight that improving ammonium availability while managing soil acidification may be critical to optimizing productivity and sustainability in smallholder rubber farming systems.

Soil cadmium (Cd) contamination is a persistent global threat due to its high mobility and bioaccumulation. While biochar is a common remediation tool, empirical results remain inconsistent. This global hierarchical meta-analysis synthesized 5437 observations from 239 studies to quantify biochar's efficacy in reducing soil Cd and identify key regulatory drivers. The study confirms that biochar application significantly reduces soil Cd levels, though results vary by context. Feedstock type and pyrolysis temperature emerged as primary regulators. Specifically, biochars derived from wood, organic waste, and lignocellulosic materials were most effective. Interestingly, the response exhibited a non-linear pattern, with both low and high pyrolysis temperatures outperforming intermediate ranges. The model further identified 605.85 t ha-1 as a statistical inflection point for soil Cd response, beyond which the marginal reduction effect weakened; however, this threshold far exceeds conventional field application rates and should therefore be interpreted only as an upper-bound statistical feature of the model fit. Random forest modeling identified the application rate, pyrolysis temperature, soil texture, and study type as the dominant factors controlling Cd reduction. Among soil properties, increases in cation exchange capacity (CEC) and soil organic carbon (SOC) were the most significant contributors to variability. Interaction analyses further revealed that while manure-derived biochar might increase soil Cd in controlled laboratory settings, it effectively inhibits Cd in fine-textured soils. These findings provide quantitative evidence for understanding the context-dependent performance of biochar in Cd-contaminated soils. By identifying drivers and nonlinear patterns, this study informs cautious site-specific biochar application strategies.

Biochar amendment holds promise for improving saline soils, yet its efficacy is often constrained by the uncertainty of application rates. In this study, a large field trial and associated statistical modeling were conducted to explore the mechanisms by which biochar affects wheat yield in coastal saline soils of northern China. Results showed that biochar application significantly increased soil organic carbon (SOC) content (R-2 = 0.615, p < 0.001) but induced marked spatial heterogeneity across the field, with the coefficient of variation (CV) reaching 30.2%. Given the difficulty of uniformly applying biochar in the field, subplot-level SOC was used as a proxy for effective biochar distribution. Stepwise regression identified soil electrical conductivity (EC) as the dominant yield constraint (standardized coefficient = -0.69), rather than water and nutrients, and a quadratic relationship was observed between SOC and EC. Structural equation modeling (SEM) further suggested a trade-off: SOC was associated with higher yield through reduced bulk density (BD) (path coefficient = -0.603), whereas high SOC levels were also associated with increased EC under this coastal saline field setting (path coefficient = 0.243), thereby indirectly constraining growth. Consequently, the agronomic response showed a threshold-like transition: the peak wheat yield occurred at an SOC threshold of 13.87 g kg(-1) (equivalent to 44.41 t ha(-1)), which exceeded the point of minimum salinity (11.71 g kg(-1), equivalent to similar to 29.90 t ha(-1) biochar). These results suggest that the agronomic benefit of biochar in saline soils depends on maintaining application within an estimated beneficial buffering zone.

Droughts represent a critical environmental stressor with cascading effects on hydrology, agriculture, ecosystem integrity, and societal stability. Characterized by prolonged deficits in precipitation, they reduce water availability, impair crop yields, elevate wildfire risk, and destabilize socio-economic systems through resource scarcity. Addressing these impacts necessitates a systems-based approach, which may involve integrating waste-derived moisture retention materials. In this study, common agricultural and forestry wastes were converted to cellulose-rich materials by oxidation and alkaline treatments. The raw biomass and cellulose-rich materials were characterized by scanning electron microscopy (SEM) analysis, Fourier transform infrared (FTIR) analysis, X-ray diffraction (XRD) analysis, thermogravimetric/differential thermogravimetric (TGA/DTG) analysis, and their potential for water retention in the soil was preliminarily explored. Results showed that most of the cellulose-rich materials have improved soil water retention properties significantly as compared to the control and raw biomass materials, due to the increase in cellulose content and removal of lignin and hemicellulose. This was confirmed by the FTIR analysis, where peak at 1740 cm-1 associated to lignin disappearance, and new absorbance peaks appeared at 560 cm-1, and 780 cm-1, which represent glycosidic linkages in cellulose, demonstrating the potential application of these materials as agricultural water retaining materials. From the perspective of waste resource utilization, the application potential of cellulose-rich materials derived from agricultural and forestry residues in water retention was explored, providing an experimental basis for resource recycling and sustainable development in agriculture.

Plant biomass and its allocation are fundamental for understanding biospheric matter production. However, the impacts of atmospheric phosphorus (P) deposition on species-specific biomass and its allocation in global terrestrial plants remain unclear. By synthesizing 5548 observations of plant biomass and its allocation related to P addition worldwide, we find that P addition increases plant biomass by an average of 35% globally. This increase varies across plant functional groups, with stronger responses in deciduous (45%), C3 (36%), and N2-fixing plants (54%) than in evergreen (28%), C4 (19%), and non-N2-fixing plants (31%), respectively. Plants possessing traits indicative of an acquisitive strategy, such as higher nutrient concentrations and specific leaf area, faster photosynthetic rates and shorter leaf lifespan, are particularly responsive to P addition. Furthermore, P addition promotes a greater allocation of biomass to aboveground than belowground organs, resulting in a 5% decrease in root-to-shoot ratio. Our findings provide global-scale quantifications of how P addition regulates biomass accumulation and allocation strategies in terrestrial plants, offering critical insights for predicting the response of terrestrial carbon storage to rising atmospheric P deposition.

Crop rotation and wheat straw return have significant potential to regulate soil respiration (Rs) and enhance soil health by increasing carbon pools, which is crucial in mitigating drought effects. This study aimed to examine the influence of organic agro-waste addition on Rs under rotation and monoculture through a 70-day incubation experiment. During Phase I (0-28 days), soils under monoculture with moisture of 15%, 30%, and 55% water holding capacity (WHC) were labelled CS, CM, and CC, while soils under rotation were labelled IS, IM, and IC. In Phase II (29-70 days), half of the treatments received organic agro-waste (CSO, CMO, CCO, ICO, IMO, and ISO), and moisture was adjusted to 55% WHC. Labile carbon in CR treatments increased by 14.7%-19.3% compared to other treatments in Phase 1. Metabolic quotient (qCO2) was 46.4%-77.1% lower in rotation treatments in comparison to other treatments after rewetting. Statistical analysis also indicated that crop rotation mitigated drought impacts by increasing labile C content and total microbial activity. Crop rotation can be effective for alleviation of drought impact via boosting soil labile pool and microbial activities, while residue returning may mask this alleviation by stimulating soil CO2 emission. PCA results indicated that no significant difference was observed after organic waste addition on day 70. Overall, crop rotation and the addition of organic waste could mitigate the negative effects of drought conditions by increasing organic matter and microbial activity.

Microbial communities play a significant role in maintaining the health of Great Barrier Reef (GBR) ecosystems, however, the influence of sediment composition and other environmental factors such as temperature and wave regime on microbial communities are largely unknown. Here we show how sediment composition and exposure influences bacterial communities across the inner section of the GBR (Cleveland Bay, Halifax Bay and Dunk Island) between 2016 and 2018. Sediment traps were installed and routinely deployed ( every 3 months) at eight sites in the inshore GBR and analysed for water chemistry, sediment geochemistry and organic characteristics and associated bacterial communities. Results showed a significant variation in water turbidity, sediment collection rate and geochemistry across the trap sites. Bacterial communities also significantly varied along the inner GBR, with the shift in relative abundance of Actinobacteria, Acidobacteria, Planctomycete, Verrucomicrobia and Chloroflexi being the main cause of the bacterial community dynamics. The variation in spatial patterns of bacterial communities was highly correlated with water turbidity and the geochemical characteristics of associated sediments (e.g., K, Fe, Mn, Co, Al, Cr, Ca) collected across the marine trap sites. Our findings indicate that sediment composition and collection rate (and linked water turbidity) can change the spatial patterns of bacterial communities by creating environmental gradients along the inner section of the GBR.

Soils host enormous carbon stocks. Whilst considerable research has been dedicated towards soil organic carbon (C) dynamics, less attention has been paid to soil inorganic carbon (SIC). Here we investigated zeolite amendments for their potential to sequester SIC. The rationale underpinning the investigation is that zeolites - i.e., high-pH, alkaline-rich aluminosilicate minerals - could promote stabilisation of soil carbonate compounds. A four-month study was undertaken via an 80-container factorial laboratory incubation experiment comprising two soil types (a loamy Planosol and a clayey Vertisol), four manufactured zeolites, and a control (soil only), with four replicates for each treatment. An additional series of containers, containing crushed mafic (high magnesium) rock combined with the above treatments, was included as a benchmark inorganic carbon sequestration method. The zeolites increased soil pH by an average of 1.5 units (p < 0.05) at the trial's conclusion, whereas the crushed mafics had much less impact on soil pH. Zeolite addition resulted in a 70 % increase (p < 0.05) in SIC concentrations compared with controls when averaged across all treatments. They were particularly effective in the Planosol, with each zeolite yielding significantly (p < 0.05) and substantially higher (up to 230 %) SIC concentrations relative to the controls. Mass balance calculations confirmed these increases cannot have been caused by the relatively minor IC contents of the zeolites. X-ray diffraction analysis confirmed the presence of sparinglysoluble carbonate species in some of the zeolite soil treatments. Mafic rock alone did not cause appreciably higher SIC concentrations than the controls. Moreover, no synergistic effects were observed when combining zeolites with mafics. It is likely that mafics require a longer timeframe to be effective. Overall, our study revealed that zeolites can potentially increase SIC stocks and buffer against soil acidification, although confirmation of the method at field scale is needed. Given previous research has reported that zeolites can achieve other benefits, including enhanced soil organic C sequestration and improved soil water and nutrient retention, these minerals could be developed into high-value and multi-benefit amendments to support agriculture, landscape restoration and climate change mitigation.