Search Results (40)

This study evaluates the influence of different crushed gneiss contents on the mechanical, durability, environmental, and economic performance of sand–gravel/gneiss mixtures for sustainable road construction. Natural sand–gravel aggregate was blended with crushed gneiss at three proportions (10%, 30%, and 50% by mass). The experimental program included grain size analysis, compaction characteristics, California Bearing Ratio (CBR), deformation modulus, and freeze–thaw durability tests. Environmental performance was assessed using a cradle-to-site carbon footprint approach based on Life Cycle Assessment principles according to ISO 14040, ISO 14044, and ISO 14067, with the analysis focused on Global Warming Potential (GWP100), combined with a Total Cost of Ownership analysis. Increasing gneiss content improved mechanical performance, with CBR increasing from 45% to 95% and deformation modulus from 110 to 185 MPa. The 70/30 sand–gravel/gneiss mixture provided the most balanced performance among the investigated compositions, combining high bearing capacity, satisfactory freeze–thaw resistance, and favorable environmental and economic characteristics. Its carbon footprint was 3.90 kg CO₂ eq./t, with diesel consumption during aggregate handling identified as the dominant emission source (69%), followed by gneiss transportation (20%) and electricity consumption (12%). Higher gneiss contents and longer transport distances increased environmental impacts and production costs. The results indicate that selecting an appropriate aggregate composition and reducing transport-related emissions can support lower-carbon construction materials while maintaining required engineering performance. Full article

Cereal production is increasingly constrained by soil degradation, water scarcity, climate variability, and rising disease and weed pressure. This review synthesizes current knowledge on the role of regenerative agronomic practices in cereal production, with particular emphasis on soil health, plant disease management, water-use efficiency, and yield stability. Available evidence consistently indicates that the greatest benefits arise not from individual practices but from integrated systems combining reduced tillage, crop residue retention, diversified crop rotations including legumes, cover crops, organic fertilization, and biologically based pest management. Such practices can increase soil biological activity and its ability to limit disease by enriching functionally beneficial microbial communities and limiting pathogens through competition for resources and niches, antibiosis, hyperparasitism, and the induction of plant resistance. They can also improve soil structure, water infiltration, water retention, and crop resilience to drought stress and, under certain conditions, reduce erosion, nutrient losses, and yield variability. However, the effects of regenerative practices are strongly dependent on soil type, climate, nitrogen balance, pest pressure, and the extent of adoption of regenerative practices. Risks may arise during the transition period, including yield declines, nitrogen immobilization, weed infestation, and increased disease pressure. Evaluation of these systems should encompass not only yield but also the grain quality and phytosanitary status, soil organic carbon stocks throughout the soil profile, N₂O emissions, and production profitability. The review covers cereal systems from temperate, humid, arid and semi-arid zones, and the results were interpreted considering climate, soil quality, water availability, and agronomic practices, as the same practice can produce different effects in different agroecological zones. Further research should prioritize long-term, multifactorial experiments conducted across diverse agroecological environments that integrate agronomic performance, environmental sustainability, and crop quality. Full article

Deep placement of nitrogen fertilizer (DPN) is an effective fertilization strategy for improving nitrogen use efficiency in rice systems, but its effects on methane (CH₄) emissions and the associated microbial mechanisms remain insufficiently understood. This study aimed to determine whether DPN mitigates CH₄ emissions in a rice–wheat rotation system and to clarify how it regulates methanogenic and methanotrophic communities. A two-year field experiment was conducted in East China with two nitrogen management practices, i.e., conventional surface application and DPN. Compared with surface application, DPN significantly reduced cumulative CH₄ emissions by 22.9% in 2023 and 17.0% in 2024, while tending to increase rice grain yield. During the tillering stage, DPN decreased soil dissolved organic carbon by 19.0% and increased NH₄⁺-N and NO₃⁻-N concentrations by 35.8% and 44.1%, respectively. These changes were accompanied by a 24.7% reduction in methanogen abundance and a 26.9% decrease in methanogenic activity. Although total methanotroph abundance was not significantly affected, DPN increased methanotrophic activity by 24.6%. Amplicon sequencing further showed that DPN shifted the methanogenic community from acetoclastic taxa toward hydrogenotrophic taxa, as indicated by the decline in Methanosarcina and Methanothrix and the enrichment of Methanobacterium and Methanoregula. In parallel, DPN promoted Type I methanotrophs, especially Methylomonas, while suppressing the Type II methanotroph Methylocystis. These results demonstrate that DPN mitigates CH₄ emissions by reducing labile carbon availability, suppressing methanogenic abundance and activity, and enhancing the functional potential of methane oxidation through methanotrophic community restructuring. Overall, this study indicates that DPN mitigates CH₄ emissions through coordinated regulation of carbon substrate availability and functional microbial community restructuring, suggesting that DPN is a promising strategy for sustainable rice production and greenhouse gas mitigation. Full article

Optimizing nitrogen management is essential for maintaining high spring maize yield while mitigating nitrous oxide (N₂O) emissions in irrigated areas. However, the interactive effects of total nitrogen application rate and starter nitrogen proportion on yield and N₂O emissions remain insufficiently quantified. Reliable assessment of these interactions requires well-calibrated DeNitrification–DeComposition (DNDC) simulations, yet existing calibration studies often emphasize crop parameters while neglecting soil parameters critical for soil hydrothermal dynamics and N₂O production. In this study, field data from shallow-buried drip-irrigated spring maize in Tongliao during 2024–2025 were used to conduct Extended Fourier Amplitude Sensitivity Test (EFAST) sensitivity analysis on 12 crop and 13 soil parameters of the DNDC model. Sensitive parameters were calibrated using the differential evolution algorithm, and 64 nitrogen management scenarios were simulated by combining eight total nitrogen application rates (100, 150, 200, 250, 300, 350, 400, and 450 kg N ha⁻¹) with eight starter nitrogen proportions (0%, 15%, 25%, 30%, 35%, 40%, 45%, and 50% of the total nitrogen rate). The results showed that DNDC outputs were jointly controlled by crop and soil parameters, among which maximum yield, leaf carbon-to-nitrogen ratio, stem fraction, grain carbon-to-nitrogen ratio, thermal degree days for maturity, grain fraction, soil organic carbon (SOC) decrease rate below topsoil, soil clay content, soil porosity, wilting point and depth of top soil with uniform SOC content were dominant. Compared with the conventional crop-parameter calibration, the sensitivity-screened parameter set improved the simulation of both cumulative N₂O emissions and yield. Across the 64 scenarios, cumulative N₂O emissions ranged from 0.42 to 4.87 kg [N]/ha, while simulated maize yield ranged from 1597 to 6347 kg [C]/ha. N₂O emissions increased with total nitrogen rate, whereas yield increased initially and then reached a plateau. Increasing the starter nitrogen proportion did not substantially enhance yield but increased N₂O emission risk under high nitrogen rates. Overall, the scenario with 300 kg/ha and no nitrogen applied at sowing achieved a relatively high yield of 5519 kg [C]/ha while maintaining a low cumulative N₂O emission of 0.98 kg [N]/ha and was therefore identified as the preferred trade-off strategy under shallow-buried drip irrigation. This study provides an EFAST–DNDC framework for optimizing nitrogen management to sustain spring maize yield while reducing N₂O emissions in the West Liaohe Plain. Full article

Early-age strength development and carbon emissions represent specific operational constraints in underground cemented tailings backfill (CTB) operations. A pH and ionic pre-conditioning-assisted CO₂ mineralization process was evaluated for carbonate-rich cemented tailings backfill designed to improve early UCS while retaining measurable CO₂ uptake through systematic process control and optimization. Skarn-type tailings (CaO 16.74 wt%, total carbonates 34.7 wt%) were subjected to screening under nominal pH and ionic pre-conditioning treatments (4.0–11.5), CO₂ pressure (0–0.5 MPa), cement-to-tailings ratio (1:3–1:12), and slurry concentration (66–78%). Strength evolution (1–28 d), mineralization products were characterized using TGA as the primary CO₂-uptake method, with XRD used for semi-quantitative phase-trend assessment, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) with selected-area electron diffraction (SAED), X-ray computed tomography (CT), and nuclear magnetic resonance (NMR). Under optimal conditions (pH 8.5, 0.3 MPa CO₂ pressure, 48 h mineralization, 72–74% solids), mineralized specimens achieved 2-day uniaxial compressive strength equivalent to 1.47-times the 3-day control strength (p < 0.01), with peak net CO₂ sequestration of 37.1 g/kg. EBSD analysis of 347 grain boundaries and TEM-SAED examination of multiple foil sections supported the occurrence of syntaxial calcite overgrowth on primary carbonate debris as a major interfacial transition zone strengthening mechanism. Interconnected pore cluster volume decreased by 70.6%; Zn²⁺ and Pb²⁺ leaching decreased by 67.2% and 71.8%, respectively. A shrinking-core kinetics-Ryshkewitch model with pH-dependent correction functions predicted 3-day strength with acceptable accuracy for TW-A and TW-B, whereas TW-C showed a −27.3% deviation, identifying acidic and sulfate-rich wastewater as a boundary condition outside the reliable model domain. Field coring at −500 m depth provided pilot-scale evidence that a 23 mm mineralized shell was consistent with localized reduction of shallow exposed-face instability risk during the early free-standing period. Overall, the pH and ionic pre-conditioning-assisted CO₂ mineralization process is proposed as a laboratory-supported and field-informed screening framework for simultaneous early-strength enhancement and partial carbon sequestration in carbonate-rich cemented tailings systems. The resulting models and parameter guidance should be interpreted as preliminary design tools requiring further factorial optimization and long-term field validation before full site-specific deployment. Full article

The spatial mismatch between grain production and consumption (SMGPC) significantly affects the non-point source pollution and carbon emissions from grain production (NPCE). Based on provincial panel data in China from 2000 to 2023, this study explored the direct impact and transmission mechanism of the SMGPC on the NPCE using fixed-effect and mediating-effect models. The results showed that China’s SMGPC intensified significantly during 2000–2023. The average SMGPC degree increased with fluctuations, with positive mismatch strengthening in the northern region and negative mismatch deepening in the southern region. All four NPCE indicators—non-point source pollution per unit sown area (NPA), carbon emissions per unit sown area (CEA), non-point source pollution per unit yield (NPY), and carbon emissions per unit yield (CEY)—peaked in 2016 and declined thereafter. The NPA and CEA showed net increases, whereas the NPY and CEY exhibited net decreases, presenting a similar spatial pattern of “high in the eastern region, low in the central and western regions”. The SMGPC degree drove NPCE indicators with obvious heterogeneity: it increased all NPCE indicators in the negative mismatch region but increased the NPA and CEA while reducing the NPY and CEY in the positive mismatch region. Moreover, cultivated land management scale and chemical fertilizer application intensity significantly mediated the relationship between the SMGPC and the NPCE. The findings offer guidance for optimizing grain production layout and promoting a green agricultural transformation. Full article

Improving energy efficiency and reducing the carbon footprint of crop production are critical for sustainable agriculture, particularly in semi-arid regions where resource use efficiency is essential. This study evaluated the effects of different fertilization strategies on energy use efficiency and carbon footprint in maize production. A field experiment was conducted during the 2023 growing season in Konya Province, Türkiye, using a randomized block design with three treatments and three replications. The treatments included an unfertilized control (U1), inorganic fertilizer application (U2), and liquid animal manure application (U3). The results showed that the highest grain yield was obtained in the liquid manure treatment, which was 2.08 times higher than the unfertilized treatment and 1.18 times higher than the inorganic fertilizer treatment. The highest total energy input was recorded in the inorganic fertilizer treatment (26,235.12 MJ ha⁻¹), while the highest total energy output was observed in the liquid manure treatment (203,154 MJ ha⁻¹). The liquid manure treatment also showed higher net energy efficiency, output–input ratio, carbon efficiency, and carbon sustainability index, while producing the lowest carbon footprint per unit of product. These findings indicate that liquid animal manure can improve maize productivity while enhancing energy efficiency and reducing carbon emissions in semi-arid agroecosystems. Full article

With the advancement of agricultural modernization, issues related to resource conservation, intensive utilization, and green, low-carbon development have become increasingly prominent. To enhance water and fertilizer use efficiency in Henan Province and promote green, low-carbon, and sustainable agricultural development, field experiments were conducted during 2023–2024. The experiment employed a randomized complete block design with three replications. Each plot measured 30 m² (5 m × 6 m), totaling 36 plots. An IoT-based real-time coordinated water-fertilizer regulation technology, driven by continuous WSH-TDR310S sensor monitoring of soil moisture and nitrogen status with automated threshold-based control logic, was implemented. By transforming the traditional static scheduling approach into a dynamic feedback mechanism driven by real-time sensor data, the synchronization between resource supply and crop demand was achieved. This study aimed to elucidate the response characteristics of summer maize growth dynamics and farmland N₂O emissions under the proposed regulation strategy. The experiment included three levels of water deficit (mild, moderate, and severe) and three fertilization levels (low, medium, and high), resulting in a total of nine real-time water–fertilizer coordinated regulation treatments, along with three local border irrigation control treatments. The results showed that under real-time water–fertilizer regulation, plant height, stem diameter, and leaf area index of summer maize exhibited unimodal variation patterns, with the medium irrigation–medium fertilization (B2) treatment performing optimally. Compared with the border-irrigation medium-fertilization control (D2), plant height and stem diameter under the B2 treatment increased significantly. Cumulative farmland N₂O emissions increased with higher irrigation and fertilization levels, with the border-irrigation high-fertilization treatment producing the highest emissions. Yield formation was mainly governed by structural growth traits, with plant height showing the strongest predictive ability, followed by stem diameter, whereas leaf area index showed weaker explanatory power. Summer maize yield exhibited a unimodal response to both irrigation and nitrogen input levels. Compared with the D2 treatment, the B2 treatment increased grain yield by 41.33%, while achieving water-saving and fertilizer-saving rates of 38.10% and 35.75%, respectively, thereby achieving an optimal balance between high yield and efficient water–fertilizer utilization. These findings provide theoretical support for summer maize production in the North China Plain and contribute to the promotion of green and sustainable agricultural development. Full article

Regional reassessments of agricultural carbon emission efficiency are essential for improving the sustainability of food production systems under climate constraints. This study evaluates agricultural carbon emission efficiency (ACEE) across China’s major grain-producing zone (GPZ), major grain-consuming zone (GSZ), and grain production–consumption balanced zone (GBZ) during 2003–2022, excluding Hong Kong, Macao, Taiwan, and Tibet due to data limitations. A super-efficient EBM–GML model incorporating both desirable and undesirable outputs is employed to measure ACEE at the provincial level, with comparisons conducted within each functional zone and nationally unified efficiency values used as a benchmark. Spatial dependence is examined using Moran’s I, and a spatial Durbin model is applied to identify driving factors and spatial spillover effects. The results indicate that the average efficiency levels differ systematically across functional grain zones, following the order GBZ > GPZ > GSZ, while several provinces experience notable changes in their relative rankings. Carbon emissions increase in the earlier period and decline in later years, whereas efficiency exhibits an opposite temporal pattern, reflecting a gradual transition of grain production systems from extensive input-driven growth toward more sustainability-oriented practices. Substantial regional disparities in ACEE are also observed. Rational industrial organization and efficient allocation of production resources contribute to positive spillover effects on neighboring regions, whereas natural disasters and inefficient resource distribution tend to weaken such effects. These findings suggest that functional grain zones provide an effective framework for capturing intra-regional heterogeneity and should be adopted as the basic unit for efficiency assessment and the formulation of differentiated governance strategies. Full article

Agricultural chemicals are indispensable in the process of traditional grain production and are also a major contributor to agricultural carbon emissions. Exploring the relationship between agricultural chemical carbon emissions and grain production is of significant importance for reducing agricultural emissions and promoting environmentally friendly grain production. To this end, this study employs the Tapio model and the LMDI factor decomposition model to analyze the decoupling relationship between agricultural chemical carbon emissions and grain production in Shandong Province—a typical grain-producing region in northern China—from a production perspective, focusing on the period from 2011 to 2023. The results indicate that during this period, Shandong Province achieved improvements in grain production technology, leading to a gradual improvement in the decoupling relationship between grain production and agricultural chemical carbon emissions. The factors influencing agrochemical carbon emissions during grain production initially shifted from being suppressed by output scale effects and promoted by technological effects to being suppressed by technological effects and promoted by output scale effects. Ultimately, synergistic development was achieved in Shandong Province by reducing agrochemical emissions and increasing grain production. This study provides a theoretical basis for synergistic development in agrochemical emission reduction and grain yield enhancement, while also offering a new perspective for research on reducing emissions during grain production. Full article

The Hetao Irrigation District in Inner Mongolia is a major spring wheat production region in China. To synergize high wheat yield, water conservation, and carbon emission reduction in this region, a 2023 and 2024 field experiment was conducted. This study systematically analyzed the effects of organic fertilizer substitution for chemical nitrogen (T1:0%, T2:25%, T3:50%, T4:75%, T5:100%) on soil carbon emissions dynamics and carbon footprint of wheat fields, under two irrigation regimes: water-saving irrigation (twice at jointing and heading stages, 2W) and conventional irrigation (four times at tillering, jointing, heading, and grain-filling stages, 4W). The results showed that during the wheat-growing season, soil CO₂ emission rate exhibited a single-peak trend (peak at flowering stage), while cumulative soil CO₂ emission showed a “decrease-increase-decrease” pattern (peak at jointing to heading). At different growth stages, both CO₂ emission and its rate increased with higher organic fertilizer substitution ratios, and were higher under 4W than 2W. Irrigation and substitution treatments significantly affected the total carbon emissions, carbon sequestration, and carbon footprint: total emissions increased with substitution ratios, while sequestration and footprint first increased then decreased; all three indices were higher under 4W than 2W. Regression analysis revealed that maximum net carbon budget was achieved at 21.6–31.7% substitution (1402.3–1879.9 kg ha⁻¹) under 2W, and 31.0–33.8% substitution (2295.5–2822.0 kg ha⁻¹) under 4W. In conclusion, water-saving irrigation (900 m³ ha⁻¹ per application at jointing and heading stages) combined with an optimal organic-nitrogen ratio (1008.0 kg ha⁻¹ organic fertilizer, 193.1 kg ha⁻¹ chemical nitrogen) effectively coordinates water conservation and carbon emission reduction. This study provides a basis for synergizing these goals in Hetao’s wheat production. Full article

Global temperature rise has become a critical challenge to agricultural sustainability, severely affecting crop growth, productivity, and survival. Human-induced climate change and greenhouse gas emissions cause heat stress, disrupting plant metabolism and physiology at all developmental stages from germination to harvest. Elevated temperatures during germination impair water uptake, enzyme activity, and energy metabolism, leading to poor or uneven seedling emergence. At key phases such as flowering and grain filling, heat stress limits photosynthesis and transpiration by inducing stomatal closure, restricting carbon dioxide intake, and reducing photosynthetic efficiency. The reproductive stage is particularly vulnerable to high temperatures, impairing pollen viability, preventing anther dehiscence, and reducing fertilization success. Membrane instability further accelerates chlorophyll degradation and leaf senescence. Heat stress also alters biochemical and hormonal balances by disrupting the synthesis and signaling of auxins, gibberellins, and abscisic acid (ABA). Elevated ABA promotes stomatal closure to enhance stress tolerance, while increased ethylene levels trigger premature leaf senescence and abscission. These hormonal shifts and oxidative stress hinder plant growth and reproduction, threatening global food security. Although plants employ adaptive mechanisms such as heat shock protein expression and stress-responsive gene regulation, current strategies remain inadequate, highlighting the urgent need for innovative approaches to improve crop resilience under rising temperatures. Full article

Process-based crop growth models, as an important analytical tool in agricultural production, face the problem of calibrating many parameters during the application process, and sensitivity analysis (SA) can quantify the effects of the model input parameters on the model output and provide an important basis for parameter calibration. In this study, we combined the good performance of the Agricultural Production Systems sIMulator Next-Generation (APSIM NG) model in simulating crop growth, soil carbon and nitrogen cycles, and soil N₂O emissions with the efficient computational efficiency of the extended Fourier amplitude test (EFAST) method. The sensitivity of the APSIM NG model to the simulation of soil N₂O emissions was systematically investigated using the EFAST method in a dry-crop wheat field in the semi-arid region of the Loess Plateau in Longzhong, China, where 28 crop cultivar parameters, 15 soil parameters, 4 meteorological parameters, and 4 field management parameters were selected. The parameters were selected based on the existing literature and the official documents of the model, and the parameter boundaries were determined based on the initial values of the APSIM NG model and the measured data and adjusted upward and downward by the standard normal distribution. In this study, parameters with a first-order sensitivity index ($S_i$) > 0.05 and a total sensitivity index ($S_{Ti}$) > 0.10 were identified as having a significant influence on the model outputs. The results of this study demonstrated that soil N₂O emission modeling in dry-crop wheat fields showed high sensitivity to the following parameters: (1) Among the crop cultivar parameters, the sensitivity from high to low was the leaf appearance rate, maximum leaf area, maximum nitrogen concentration of the grain, and thermal time from the starting grain-fill stage to end grain-fill stage. (2) Among the soil parameters, the sensitivity from high to low was a lower effective moisture limit, wilting coefficient, and ammonium nitrogen content. (3) Among the meteorological parameters, precipitation and solar radiation showed high sensitivity. (4) Among the field management parameters, the nitrogen application rate exhibited the most significant sensitivity. For this reason, we believe that by prioritizing the calibration of the most sensitive parameters through the results of the sensitivity analysis in this study, the workload of the APSIM NG model in the calibration process can be effectively reduced, which is conducive to the rapid localization and application of the model. Full article

The global production of brewers’ spent grains (BSG) is 37 million tons yearly. Composting represents an eco-friendly method to manage and valorize organic by-products in a circular economy model. This project aims to compare two BSG bin-composting mixtures (BSG and wheat straw with pig slurry solid fraction, MIX1, or sheep manure, MIX2) and approaches (manual turning, MT, and static composting, ST). The two mixtures’ physicochemical characteristics and greenhouse gas (GHG) emissions were assessed during the process. The evolution of physicochemical properties is reported in detail. Headspace samples of GHG emissions were collected and analyzed with gas chromatography coupled with specific detectors. Carbon dioxide (CO₂) emissions were 34.3 ± 0.03 and 31.0 ± 0.06 g C kg⁻¹ fresh matter (FM) for MIX1-MT and MIX2-MT, and 28.8 ± 0.01 and 31.2 ± 0.02 g Ckg⁻¹ FM for MIX1-ST and MIX2-ST. Methane emissions were negligible (all conditions < 0.086 ± 0.00 mg C kg⁻¹ FM). Nitrous oxide (N₂O) emissions from composting are affected by the substrate, bulking material, pile dimension, and manure. Particularly, the total emissions of N₂O, estimated as CO₂ equivalents, were 45.8 ± 0.2 and 63.0 ± 0.4 g CO₂ eq kg⁻¹ FM for MIX1-MT and MIX1-ST, respectively. In both composting approaches, MIX2 showed a low CO₂ equivalent (1.8 ± 0.02 and 9.9 ± 0.05 g CO₂ eq kg⁻¹ FM for MT and ST), likely due to incomplete decomposition. The bin-composting process represents a solution for recycling and reusing organic waste and livestock manure in small to medium-sized breweries. The solid fraction of the pig slurry resulted in the most suitable manure. Full article

In response to climate change, the reduction of carbon emissions during agricultural production has garnered increasing global focus. This study takes high-standard farmland construction (HSFC) implemented in 2011 as the standard natural experiment and adopts the continuous differences-in-differences (DID) model to explore the impact and internal mechanism of HSFC on agricultural carbon emissions based on a panel data of 31 provinces, municipalities, and autonomous regions in China from 2003 to 2021. The results show that HSFC can effectively reduce the carbon emissions in agricultural production, and the average annual reduction can reach 53.8%. The effects of HSFC on agriculture carbon emissions could be associated with reducing agricultural fossil energy consumption and reducing agricultural chemical use. Further, the heterogeneity study shows that the carbon reduction effect of HSFC was mainly reflected in non-major grain-producing areas, while there was no significant impact in major grain-producing areas. Policymakers should unswervingly continue to promote HSFC, considering their own economic and geographical conditions. This study can provide valuable information and references for developing countries similar to China to formulate policies on agricultural carbon reduction. Full article