Search Results (2,736)

This study examines magnesium potassium phosphate cements (MKPCs) modified with industrial wastes for extrusion-based 3D concrete printing, evaluating the rheological properties (workability, setting time), mechanical performance and printability of formulations incorporating secondary materials: Mg dross waste (up to 20 wt.%, replacing MgO), calcined sewage sludge (up to 10 wt.%, replacing KH₂PO₄), alternative fillers such as glass from municipal solid waste glass and from construction and demolition waste and ground blast furnace slag, benchmarked against volcanic ash. The baseline MKPC exhibited initial/final setting times of 34/109 min, good workability and compressive strengths of 29 MPa (1 day)/28 MPa (28 days). Optimal low-waste mixes (e.g., using municipal glass or 20 wt.% Mg dross) shortened the initial setting to 19–25 min (decreasing 24–42%), reduced the slump by 9–18% yet remained printable at laboratory-scale and achieved 1-day strengths > 23 MPa/28-day > 31 MPa (comparable or superior). Glass from municipal waste proved most promising, due to superior workability, lighter aesthetics and strength gains, supporting circular economy goals while substantially reducing material costs; higher waste levels compromised fluidity and buildability. Mineralogical analyses confirmed K-struvite formation alongside residual periclase, validating these formulations for upscaling sustainable 3D printing. Full article

Apple cultivation faces soil acidification and pollution due to excessive fertilization, compounded by a scarcity of potassium (K) fertilizers. Polyhalite, a natural multi-nutrient mineral, offers a potential sustainable alternative. Therefore, a three-year field experiment was conducted, comprising a no-potassium control (CK), two conventional potassium fertilizers (sulfate of potash-based and muriate of potash-based), and six polyhalite compound fertilizer treatments (with different basal and topdressing strategies), to evaluate their effects on apple growth and soil fertility. Results showed that the single topdressing application of potassium chloride-type polyhalite compound fertilizer (T6) achieved the highest yield in the final year, which was 10.11–28.03% higher than the other potassium-applied treatments. It also achieved the highest fruit vitamin C and soluble solids content (9.53 mg 100 g⁻¹ and 13.27%, respectively). The T6 treatment demonstrated the best performance in terms of agronomic efficiency and partial factor productivity of potassium fertilizer, reducing fertilizer waste and loss. Furthermore, the T6 treatment effectively increased soil pH, available potassium, and exchangeable calcium levels, thereby improving soil fertility. Thus, polyhalite proves effective in replacing conventional K fertilizers, with the single topdressing of MOP-type polyhalite compound fertilizer (T6) offering the most comprehensive agronomic and environmental benefits. Full article

Biochar is known to enhance soil potassium (K) availability and promote plant K uptake; however, its influence on the transformation pathways of fertilizer potassium and the mechanisms regulating crop potassium accumulation remains insufficiently understood. This study conducted a pot experiment using three soil types—Albic, Brown, and Sandy soils—with different biochar application rates (0, 10, and 20 g·kg⁻¹) in combination with potassium fertilizer, to systematically evaluate the regulation of soil K forms, K fertilizer transformation rates, K use efficiency, and K uptake and accumulation in soybeans. The results demonstrated that the combined application of biochar and K fertilizer significantly increased the contents of available, water-soluble, exchangeable, and non-exchangeable K across all three soils. At the highest biochar application rate (20 g·kg⁻¹), available K increased by 15.37%, 16.78%, and 11.77% in the Albic, Sandy, and Brown soils, respectively, compared to the control. Furthermore, biochar altered the transformation pathways of fertilizer K; it consistently reduced the conversion rate of fertilizer K into exchangeable K across all soils, redirecting it toward the water-soluble and non-exchangeable K pools, thus functioning as a potassium “scheduling center”. Adsorption–desorption experiments revealed that biochar exhibits a strong multilayer adsorption capacity for K ions, with most of the adsorbed K not easily desorbed, providing mechanistic support for the observed shift in transformation pathways. In terms of K use efficiency, biochar reduced the K of agronomic efficiency (KAE) due to a “dilution effect” from its inherent K content. Under the high application rate (20 g·kg⁻¹), the KAE decreased by 11.79% in Albic soil, 88.48% in Sandy soil, and 71.73% in Brown soil, while significantly increasing the partial factor productivity of K (PFPK) and apparent recovery efficiency of K (AREK). Ultimately, the co-application of biochar and K fertilizer significantly enhanced total K accumulation and seed yield in soybeans by increasing K concentrations in various plant parts and promoting dry matter accumulation. At the biochar application rate of 20 g·kg⁻¹, the potassium accumulation and soybean yield under biochar treatment reached maximum increases of 70.77% (in Brown soil) and 42.63% (in Albic soil), respectively. This study demonstrates that biochar can synergistically reduce potassium (K) leaching and improve fertilizer use efficiency by regulating K transformation pathways. This provides a practical guideline for utilizing biochar as a dual-function amendment, which acts as both a supplemental K source and a soil conditioner, thereby supporting the development of more sustainable potassium management practices in diverse cropping systems. Full article

The increasing demand for lithium-ion batteries (LIBs) has intensified the need for efficient lithium (Li) recovery from secondary sources. This study focuses on anti-solvent crystallization for the recovery of high-purity lithium hydroxide monohydrate (LiOH·H₂O) from a Li-rich leachate, derived from the flue dust of a pilot-scale pyrometallurgical process for LIB material recycling. To optimize product yield and purity, a series of experiments were performed, focusing on the influence of parameters such as solvent type, organic-to-aqueous (O/A) volumetric ratio, crystallization time, stirring rate, and anti-solvent addition rate. Acetone was identified as the most effective anti-solvent, producing rectangular cuboid crystals with approximately 90% Li recovery and around 95% purity, under optimized conditions (O/A = 4, 3 h, 150 rpm, and solvent flow rate of 5 mL/min). The flow rate influenced crystal morphology and impurity entrapment, with 5 mL/min favoring nucleation-dominated crystallization regime, producing ~20 μm of well-dispersed crystals with reduced impurity incorporation. SEM-EDS, surface washing, and gradual dissolution of obtained LiOH·H₂O crystals revealed that the impurities sodium (Na), potassium (K), aluminum (Al), calcium (Ca) and chromium (Cr) were crystallized as conglomerates. It was found that Na, K, Al, and Ca primarily crystallized as highly soluble conglomerates, while Cr was crystallized as a lowly soluble conglomerate impurity. In contrast Zn was distributed throughout the crystal bulk, suggesting either the entrapment of soluble zincate species within the growing crystals or the formation of mixed Li-Zn phase. Therefore, to achieve battery-grade purity, further purification measures are necessary. Full article

Biomass briquettes are an environmentally friendly fuel and have extensive utilization prospects. Compaction pressure is a crucial factor during the production of biomass briquettes, affecting its densification and subsequent potassium release behavior. The release of alkali metals during combustion is typically studied using offline analytical techniques. However, these methods fail to provide real-time measurement of alkali metals release during the combustion process. Therefore, FES, through its equipment simplicity, low operational cost, real-time measurement, and robust adaptability to industrial environments, is commonly employed. In this study, the effect of compaction pressure (80, 130, and 180 MPa) of camphor wood briquettes on potassium release in a premixed flame was investigated by means of Flame Emission Spectroscopy. A spectrometer was used to obtain flame spontaneous emission spectra at three heights above the burner. Based on the proposed spectral analysis method and a calibration procedure, time-resolved flame temperature and concentration of gas-phase potassium in camphor wood briquette combustion were simultaneously measured. The experimental results at the three measurement heights showed that both peak concentration and the amount of gas-phase potassium released from biomass briquettes decreased with the increase in compaction pressure. Furthermore, the amount of potassium released from biomass briquettes at a compaction pressure of 180 MPa was the lowest at all three measurement heights, at 28.0, 14.5, and 21.8 ppm·s. Moreover, the potassium release rate from 0 to 63 s was rapid, and there was an exponential increase in the release ratio curve. The release ratio of potassium reached 50% before entering the ash stage under a compaction pressure of 80 and 130 MPa; in comparison, it only reached 35% under 180 MPa. The potassium release ratio at HAB = 4 cm under compaction pressures of 80, 130, and 180 MPa was 54%, 50%, and 35%, respectively. The findings of this study directly link compaction pressure to K release and demonstrate the applicability of FES for real-time alkali metal detecting, offering both theoretical and practical pathways toward cleaner biomass combustion. Full article

The increasing atmospheric concentration of carbon dioxide (CO₂) poses a critical threat to global climate stability, highlighting the need for efficient carbon capture technologies. While amine-based solvents such as monoethanolamine (MEA) are widely used for industrial CO₂ capture, they are subject to limitations such as high energy requirements for regeneration, solvent degradation, and environmental concerns. This study investigates potassium carbonate/bicarbonate system as an alternative solution for CO₂ absorption. The absorption mechanism and reaction kinetics of potassium carbonate in the presence of bicarbonates were reviewed. A rate-based model was developed in Aspen Plus, using literature kinetics, to simulate CO₂ absorption using 20 wt% potassium carbonate (K₂CO₃) solution with 10% carbonate-to-bicarbonate conversion under different industrial conditions. Three flue gas compositions were evaluated: cement industry, biomass combustion, and anaerobic digestion, each at 3000 m³/h flow rate. The simulation was conducted to determine minimum column height and solvent loading requirements with a target output of 90% CO₂ removal from the gas streams. Results demonstrated that potassium carbonate systems successfully achieved the target removal efficiency across all scenarios. Column heights ranged from 18 to 25 m, with molar K₂CO₃/CO₂ ratios between 1.41 and 4.00. The biomass combustion scenario proved most favorable due to lower CO₂ concentration and effective heat integration. While requiring higher column heights (18–25 m) compared to MEA systems (6–12 m) and greater solvent mass flow rates, potassium carbonate demonstrated technical feasibility for CO₂ capture. The findings of this study provide a foundation for technoeconomic evaluation of potassium carbonate systems versus amine-based technologies for industrial carbon capture applications. Full article

Potassium (K) fertilization plays a key role in regulating stem morphology, particularly stem diameter, yet the influence of different K fertilizer formulations on stem structure and tensile strength remains insufficiently understood. Cereal straw is a key lignocellulosic by-product with growing importance in the circular bioeconomy. Thus, the aim of this study was to determine the links between potassium nutrition, stem structure, and mechanical behavior for four cereal species: wheat, barley, rye, and oats. There were three potassium fertilization levels (0, 60, and 120 kg K ha⁻¹) conducted in a field experiment in eastern Croatia (2021/2022). At maturity, stem morphology, macroelements (Ca, K, P, C, N), acid detergent fiber (ADF), neutral detergent fiber (NDF), and uniaxial tensile properties (maximum force, tensile strength, Young’s modulus) were determined. Cereal species was the dominant source of variation (p < 0.0001) for all traits, whereas the main effect of K was generally weak and significant only for stem diameter at the midpoint and N concentration, although K × species interactions were frequent. Oats and rye showed the most vigorous biomass production, whereas wheat exhibited by far the highest tensile strength (about 120 MPa) and stiffness (6.23 GPa), together with the highest ADF, while barley had the greatest NDF. Oat stems had the lowest ADF and NDF, indicating less lignified, more digestible tissues but mechanically weaker straw. Mechanical traits were tightly and positively correlated with ADF, NDF, and CN ratio, whereas P showed weak or negative associations with plant size and strength. Therefore, for targeted straw valorization, cereal species selection is paramount, with potassium fertilization playing a secondary, species-dependent role. Full article

Irrigation practices and nitrogen (N) addition play pivotal roles in wheat production, and their rational coordination can significantly enhance N, phosphorus (P), and potassium (K) use efficiency and yield of wheat. However, the comprehensive effects of irrigation practices and N addition rates on N, P, and K accumulation and utilization and yield of wheat in dryland remain unclear. A field experiment with two irrigation practices (W0, zero-irrigation and W1, one-off irrigation), and four N addition rates (0, 120, 180, and 240 kg N ha⁻¹, represented by N0, N120, N180, and N240, respectively) was conducted in 2021–2022 and 2023–2024. Compared to W0N0, W1N180 significantly increased wheat grain yield, spike number, and grains per spike by 46.4%, 35.9%, and 18.9%, respectively. Wheat yield and N, P, and K accumulation reached the maximum value at N180 or N240. One-off irrigation significantly improved the uptake efficiency and fertilizer partial factor productivity for N, P, and K, whereas increased N addition enhanced these parameters specifically for P and K. However, N180 treatment increased N uptake efficiency, N fertilizer partial factor productivity, P internal efficiency, and K internal efficiency by 22.2%, 31.1%, 9.4%, and 5.9%, respectively, compared to N240 under one-off irrigation. In addition, W1N180 significantly increased above-ground N, P, and K accumulation by 45.8%, 52.8%, and 51.8%, as well as pre-anthesis N and P translocation by 48.5% and 47.0%, respectively, compared to W0N120. Consequently, the W1N180 strategy not only improved wheat yield but also optimized N, P, and K accumulation, pre-anthesis N and P translocation, and nutrient use efficiency. Therefore, one-off irrigation combined with N180 can be recommended for enhancing wheat yield and nutrient use efficiency in dryland. Full article

Water quality assessment is crucial for the sustainable use and management of groundwater resources. This study was carried out in the irrigated plains of Vehari District, Punjab, Pakistan, to evaluate groundwater suitability for a managed aquifer recharge (MAR) project. Twenty groundwater samples were collected in June 2021 from an area of 1522 km² and analysed for major physicochemical parameters including electrical conductivity (EC), total dissolved solids (TDS), pH, turbidity, calcium (Ca), magnesium (Mg), chloride (Cl), alkalinity (Alk), bicarbonate (HCO₃⁻), hardness, potassium (K), sulphate (SO₄²⁻), sodium (Na), and nitrate (NO₃⁻). Water quality was assessed using WHO and PID standards, alongside derived hydrochemical indices such as sodium percentage (%Na), Kelly’s ratio (KR), sodium adsorption ratio (SAR), residual sodium carbonate (RSC), and the water quality index (WQI). The dataset was interpreted using geo-statistical, geospatial, multivariate, and correlation analyses. Cations and anion dominance followed the order Na⁺ > Ca²⁺ > Mg²⁺ > K⁺ and HCO₃⁻ > SO₄²⁻ > Cl⁻ > NO₃⁻. According to the WQI analysis, 35% of the water samples are classified as “poor,” half (50%) as “very poor,” and the remaining 15% as “unsuitable” for drinking purposes. However, irrigation suitability indices confirmed that groundwater is generally acceptable for agricultural use, though unfit for drinking. The outcomes of this study provide essential insights for groundwater management in the region, where the Punjab Irrigation Department (PID) has initiated a MAR project. Considering that the irrigation sector is the major groundwater consumer in the area, the compatibility of groundwater and surface water quality supports the implementation of MAR to enhance agricultural sustainability. Full article

Refractory geopolymers derived from aluminosilicate sources and alkaline activation are a promising alternative to traditional fired bricks, particularly when low-cost, waste-derived raw materials are used. This study improves the workability of a refractory brick formulated with clays (Kaolin and Tepozan–Bauwer), seashell waste, sodium silicate, potassium hydroxide, and water by incorporating sodium lignosulfonate (LS) and polycarboxylate (PC) plasticizers. Clays from Comonfort, Guanajuato, Mexico, and seashells were ground and sieved to pass a 100 Tyler mesh. A base mixture was prepared and evaluated using the Mini Slump Test, varying plasticizer content from 0 to 2% relative to the solid fraction. Based on workability, 0.5% LS and 1% PC (by solids) increased the slump, and a blended plasticizer formulation (1.5% by solids, 80%PC+20%LS) produced the highest workability. These additives act through different mechanisms, with LS primarily promoting electrostatic repulsion and PC steric repulsion. Bricks with and without plasticizers exhibited thermal resistance up to 1200 °C. After four calcination cycles, compressive strength values were 354.74 kg_f/cm² for the brick without plasticizer, 597.25 kg_f/cm² for 1% PC, 433.63 kg_f/cm² for 0.5% LS, and 519.05 kg_f/cm² for 1.5% of the 80%PC+20%LS blend. Strength was consistent with changes in porosity and apparent density, and 1% PC provided a favorable combination of high workability and high compressive strength after cycling. Because the cost of clays and seashells is negligible, formulation selection was based on plasticizer cost per brick. Although 1% PC and the 1.5% of 80%PC+20%LS blend showed statistically comparable strength after cycling, 1% PC was selected as the preferred option due to its lower additive cost ($0.0449 per brick) compared with the blend ($0.0633 per brick). Stereoscopic microscopy indicated pore closure after calcination with no visible cracking, and SEM–EDS identified O, Si, and Al as the significant elements, with traces of S and K. Overall, the study provides an integrated assessment of workability, multi-cycle calcination, microstructure, and performance for refractory bricks produced from readily available clays and seashell waste. Full article

Conventional and organic agriculture can both cause soil microbial community structure (SMCS) destruction, infertility, and abandonment. The application of soil productivity-improving biofertilizers is a sustainable practice that requires holistic knowledge, including complex biointeractions, diverse microbial metabolism, and culture requirements, the last of which rely on methodology and technology. In this study, a holistic culture-based and meta-analysis approach was employed to explore pristine and domesticated soils for presumptive plant growth-promoting (PGP) bacteria. Various soil samples were logistically acquired and processed using enrichment and heat alternatives. Morphologically diverse isolates were streak-purified and analyzed for 16S rRNA bacterial identification. Meta-analysis of PGP bacteria in domesticated environments was conducted using Google Search and NCBI PubMed. Soil fertility was analyzed for the pH and nitrogen/phosphorus/potassium (NPK) contents using biochemical tests. Notably, 7 genera and 15 species were differentially recovered, with Bacillus being the most prevalent and diverse in species. Conversely, Aeromonas, Lactobacillus, Lelliottia, Pseudomonas, and Staphylococcus were found only in pristine soil. While soil pH was consistent in all pristine soil samples, NPK contents ranged widely across the pristine (i.e., P/K) and domesticated samples (i.e., N/P/K). These findings could enhance biofertilizer SMCS, function, and effectiveness in the agricultural productivity needed to feed the expanding population. Full article

Soil fertility plays a crucial role in crop productivity, particularly in cocoa cultivation, which is highly dependent on soil quality that directly influences both productivity and sustainability. Understanding how to achieve and maintain soil fertility on cocoa farms is fundamental to sustaining higher yields. Cocoa production in Ghana and Togo remains low, at 350–600 kg/ha, compared to the potential yield of over 1–3 tons per hectare. Given the growing demand for cocoa and limited arable land, adequate soil nutrients are essential to optimise productivity. Soil fertility indices (SFIs) have been widely used as soil metrics by integrating multiple physical, chemical, and biological soil properties. In this study, standard analytical methods were employed to evaluate the SFI through laboratory analyses of 49 surface soil samples collected at a depth of 0–30 cm with an auger. Eleven soil chemical indicators were analysed: pH (water), organic matter (OM), potassium (K), calcium (Ca), magnesium (Mg), available phosphorus (P), total nitrogen (N), cation exchange capacity (CEC), electrical conductivity (EC), and carbon-to-nitrogen ratio (C/N). Principal component analysis, followed by normalisation, was used to select a minimum dataset, which was then integrated into an additive SFI. Results indicated that N, Ca, Mg, CEC, and pH were within the optimal range for most surveyed locations (96%, 94%, 92%, 73%, and 63%, respectively), while OM and C/N were within the optimal range in approximately half of the study area. Available P, K, and C/N were highly deficient in 100%, 67%, and 96% of surveyed locations, respectively. Soil fertility varied significantly among locations (p = 0.007) and was generally low, ranging from 0.15 to 0.66. Only 20% of the soils in the study area were classified as adequately fertile for cocoa cultivation. Therefore, it is necessary to restore soil nutrient balance, especially the critically low levels of K and P, through appropriate management practices that improve fertility over time and help close the yield gap. Full article

Silicon (Si) plays a critical role in regulating plant physiological processes, particularly through its influence on non-enzymatic antioxidant systems and amino acid metabolism. This study aims to assess soybean performance in response to both soil and foliar Si applications under well-watered and drought conditions, with the goal of enhancing Si accumulation in plant tissues and potentially strengthening the crop’s physiological responses to water deficit stress. This is especially pertinent given that the mechanisms underlying Si fertilization and its contribution to drought tolerance in soybean remain poorly understood. Greenhouse experiments were conducted using a 3 × 2 factorial design. The factors were: (i) three foliar Si treatments: control (no Si), potassium silicate (SiK; 128 g L⁻¹ Si, 126.5 g L⁻¹ K₂O, pH 12.0), and sorbitol-stabilized potassium silicate (SiKe; 107 g L⁻¹ Si, 28.4 g L⁻¹ K₂O, 100 mL L⁻¹ sorbitol, pH 11.8); and (ii) two soil water levels: well-watered (80% field capacity) and water-restricted (40% field capacity), the latter simulating tropical dry spells. Silicon was applied to the soil via irrigation and to the leaves via foliar spraying prior to the onset water restriction. All Si solutions were adjusted to pH 7.0 with 1 M HCl immediately before application. Potassium (K) levels were standardized across treatments through supplementary applications of KCl to both soil and foliage. Biometric and physiological parameters were subsequently measured. Sorbitol-stabilized Si enhanced Si accumulation in soybean tissues and improved plant resilience under both well-watered and drought conditions by promoting key physiological traits, including increased levels of daidzein and ascorbic acid levels, along with reduced amino acid concentrations. It also improved biometric parameters such as leaf area, root development, and number of pods per plant. These findings further support the role of Si as a beneficial element in enhancing stress tolerance and contributing to sustainable agricultural practices. Full article

Continuous excessive CO₂ emissions have a negative impact on the environment. In order to address the issue of CO₂ emission control, its conversion to some valuable commodities is the way forward in dealing with this issue. Additionally, the conversion of CO₂ to some valuable product such as methanol fuel will not only tackle the issue but also result in producing energy. Here, the co-precipitation method was used to synthesize Cu-ZnO bimetallic catalysts based on TiO₂ support to be applied for CO₂ conversion to methanol fuel. To elucidate the role of potassium (K) as a promoter, varied concentrations of K were added to parent Cu-ZnO/TiO₂ catalysts. A number of analytical techniques were used to scrutinize the physico-chemical properties of calcined Cu-ZnO/TiO₂ catalysts. The crystalline nature of TiO₂ catalyst support with high metal oxide dispersion were the major findings disclosed based on X-ray diffraction examinations. The combination of the mesoporous and microporous character of the K-promoted Cu-ZnO/TiO₂ catalysts was discovered using the N₂ adsorption–desorption technique. Similarly, N₂ adsorption–desorption studies also revealed surface defects by K-promotion. The creation of surface defects was also endorsed by X-ray photoelectron spectroscopy (XPS) by showing additional XPS peaks for O1s in higher binding energy (BE) regions. XPS also showed the oxidation states of K-promoted Cu-ZnO/TiO₂ catalysts as well as metal–support interactions. Activity results demonstrated the active profile of K-promoted Cu-ZnO/TiO₂ catalysts for methanol synthesis via CO₂ reduction in a liquid phase slurry reactor. The methanol synthesis rate was accelerated from 35 to 53 g.MeOH/kg.cat.h by incorporating of K to parent Cu-ZnO/TiO₂ catalysts at reaction temperature and pressure of 210 °C and 30 bar, respectively. Structure–activity investigations revealed a promoting role of K by facilitating Cu reduction as well metal–support interaction. The comparative study further revealed the importance of K promotion for the title reaction. Full article

This study evaluated the effects of applying fecal sludge-based co-compost (CC) integrated with chemical fertilizers on soil nutrient status, organic carbon (OC) storage, and economic returns in paddy soils. Ten integrated nutrient management (INM) treatments were tested, i.e., BRRI recommended dose of fertilizer (RDF), CC 5.0 t ha⁻¹, RDF + CC 2.0 t ha⁻¹, RDF + CC 1.5 t ha⁻¹, RDF + CC 1.0 t ha⁻¹, RDF + CC 0.5 t ha⁻¹, 75% RDF + CC 2.0 t ha⁻¹, 75% RDF + CC 1.5 t ha⁻¹, 75% RDF + CC 1.0 t ha⁻¹, and 75% RDF + CC 0.5 t ha⁻¹. Two rice varieties were cultivated over two consecutive seasons—winter rice (boro) and monsoon rice (aman)—in the experimental field. Soil samples (0–15 cm) were collected before and after the seasons and fractionated into labile particulate organic matter (>53 µm) and stable mineral-associated organic matter (<53 µm). Bulk soils and CC were analyzed for OC, nitrogen (N), phosphorus (P), potassium (K), sulfur (S), and heavy metals, while the fractions were analyzed for OC and N. Across both seasons, 75% RDF combined with 2.0 t ha⁻¹ or 1.5 t ha⁻¹ of CC consistently showed the highest OC, total N, and soil C stock, with moderate P, K, and S levels. Sole RDF produced the lowest OC and N. Among fractions, stable OC was the highest in the 75% RDF + 2.0 t ha⁻¹ CC treatment, statistically similar to 75% RDF + 1.5 t ha⁻¹ CC, and the lowest under RDF alone. Economically, sole RDF yielded the highest profit, while full RDF + CC achieved competitive returns. Reduced RDF + CC treatments (75% RDF + 1.5 or 2.0 t ha⁻¹ CC) offered slightly lower returns but improved soil sustainability indicators. Overall, applying 75% RDF + 1.5 t ha⁻¹ CC provided the most cost-effective balance of nutrient enrichment, soil C stock, and profitability. This CC-based INM approach reduces chemical fertilizer dependency, enhances soil health, and promotes sustainable waste management, supporting environmentally resilient rice production. Full article