Search Results (324)

There is a lack of systematic research on the comprehensive regulatory effects of urea and organic fertilizer application on soil quality and cotton yield in summer direct-seeded cotton fields in the Yangtze River Basin. Additionally, there is a redundancy of indicators in the cotton field soil quality evaluation system and a lack of reports on constructing a minimum dataset to evaluate the soil quality status of cotton fields. We aim to accurately and efficiently evaluate soil quality in cotton fields and screen nitrogen application measures that synergistically improve soil quality, cotton yield, and nitrogen fertilizer utilization efficiency. Taking the summer live broadcast cotton field in Jiangxi Province as the research object, four treatments, including CK without nitrogen application, CF with conventional nitrogen application, N1 with nitrogen reduction, and N2 with nitrogen reduction and organic fertilizer application, were set up for three consecutive years from 2022 to 2024. A total of 15 physical, chemical, and biological indicators of the 0–20 cm plow layer soil were measured in each treatment. A minimum dataset model was constructed to evaluate and verify the soil quality status of different nitrogen application treatments and to explore the physiological mechanisms of nitrogen application on yield performance and stability from the perspectives of cotton source–sink relationship, nitrogen use efficiency, and soil quality. The minimum dataset for soil quality evaluation in cotton fields consisted of five indicators: soil bulk density, moisture content, total nitrogen, organic carbon, and carbon-to-nitrogen ratio, with a simplification rate of 66.67% for the evaluation indicators. The soil quality index calculated based on the minimum dataset (MDS) was significantly positively correlated with the soil quality index of the total dataset (TDS) (R² = 0.904, p < 0.05). The model validation parameters RMSE was 0.0733, nRMSE was 13.8561%, and the d value was 0.9529, all indicating that the model simulation effect had reached a good level or above. The order of soil quality index based on MDS and TDS for CK, CF, N1, and N2 treatments was CK < N1 < CF < N2. The soil quality index of N2 treatment under MDS significantly increased by 16.70% and 26.16% compared to CF and N1 treatments, respectively. Compared with CF treatment, N2 treatment significantly increased nitrogen fertilizer partial productivity by 27.97%, 31.06%, and 21.77%, respectively, over a three-year period while maintaining the same biomass, yield level, yield stability, and yield sustainability. Meanwhile, N1 treatment had the risk of significantly reducing both boll density and seed cotton yield. Compared with N1 treatment, N2 treatment could significantly increase the biomass of reproductive organs during the flower and boll stage by 23.62~24.75% and the boll opening stage by 12.39~15.44%, respectively, laying a material foundation for the improvement in yield and yield stability. Under CF treatment, the cotton field soil showed a high degree of soil physical property barriers, while the N2 treatment reduced soil barriers in indicators such as bulk density, soil organic carbon content, and soil carbon-to-nitrogen ratio by 0.04, 0.04, 0.08, and 0.02, respectively, compared to CF treatment. In summary, the minimum dataset (MDS) retained only 33.3% of the original indicators while maintaining high accuracy, demonstrating the model’s efficiency. After reducing nitrogen by 20%, applying 10% total nitrogen organic fertilizer could substantially improve cotton biomass, cotton yield performance, yield stability, and nitrogen partial productivity while maintaining soil quality levels. This study also assessed yield stability and sustainability, not just productivity alone. The comprehensive nitrogen fertilizer management (reducing N + organic fertilizer) under the experimental conditions has high practical applicability in the intensive agricultural system in southern China. Full article

Accurate quantification of soil organic matter (SOM) is crucial for improving soil fertility and maintaining ecosystem health. The content of SOM affects soil nutrient availability and is closely linked to the global carbon cycle. The use of an electronic nose to detect SOM contents has the advantages of rapidity, accuracy, and low pollution to the environment. This study proposes a method for obtaining SOM contents via pyrolysis coupled with an artificial olfaction system. To improve the accuracy of SOM content determination, the effects of three parameters (pyrolysis temperature, pyrolysis time, and soil sample mass) related to the pyrolysis process on the distinguishability of pyrolysis gases were investigated. Firstly, single-factor experiments were conducted to determine the optimal values of three parameters that can improve the differentiation of pyrolysis gases. Secondly, a regression model based on the Box–Behnken experiment was established to analyze the interrelationships between the three parameters and the discrete ratio. The experimental results showed that the three parameters exerted significant influences on the discrete ratio, with pyrolysis time having the greatest impact, followed by soil sample mass and pyrolysis temperature. The optimal discrimination and minimal dispersion ratio of the pyrolysis gases were achieved at a pyrolysis temperature of 384 °C, with a pyrolysis time of 2 min 41 s and a soil sample mass of 1.68 g. Finally, the Back-Propagation Neural Network (BPNN) and Partial Least-Squares Regression (PLSR) algorithms were used to establish an SOM prediction model after obtaining soil pyrolysis gases under the optimal combination of pyrolysis parameters. The experimental results demonstrated that the SOM prediction model based on PLSR achieved the best accuracy and the highest generalization capability, with R² > 0.85 and RMSE < 7.21. This study could provide a theoretical basis for the prediction of SOM contents via pyrolysis coupled with an artificial olfaction system. Full article

Excessive chemical fertilizers degrade soil and increase greenhouse gas (GHG) emissions. Organic substitution of nitrogen fertilizers is recognized as a sustainable agricultural-management practice, yet its dual role in carbon sequestration and emissions renders the net GHG balance (NGHGB) uncertain. To assess the GHG mitigation potential of organic substitution strategies, this study analyzed GHG fluxes, soil organic carbon (SOC) dynamics, indirect GHG emissions, and Net Primary Productivity (NPP) based on a long-term field positioning experiment initiated in 2016. Six fertilizer regimes were systematically compared: no fertilizer control (CK); only phosphorus and potassium fertilizer (PK); total chemical fertilizer (NPK); 1/3 chemical N substituted with sheep manure (OF1); dual substitution protocol with 1/6 chemical N substituted by sheep manure and 1/6 substituted by straw-derived N (OF2); complete chemical N substitution with sheep manure (OF3). The results showed that OF1 and OF2 maintained crop yields similar to those under NPK, whereas OF3 reduced yield by over 10%; relative to NPK, OF1, OF2, and OF3 significantly increased SOC sequestration rates by 50.70–149.20%, reduced CH₄ uptake by 7.9–70.63%, increased CO₂ emissions by 1.4–23.9%, decreased N₂O fluxes by 3.6–56.2%, and mitigated indirect GHG emissions from farm inputs by 24.02–63.95%. The NGHGB was highest under OF1, 9.44–23.99% greater than under NPK. These findings demonstrate that partial organic substitution increased carbon sequestration, maintained crop yields, whereas high substitution rates increase the risk of carbon emissions. The study results indicate that substituting 1/3 of chemical nitrogen with sheep manure in maize cropping systems represents an effective fertilizer management approach to simultaneously balance productivity and ecological sustainability. Full article

Partial substitution of mineral N fertilizer with manure (organic substitution) is considered as an effective way to reduce N input in intensive agroecosystems. Here, based on a 3-year field experiment, we assessed the influence of different organic substitution ratios (15%, 30%, 45%, and 60%, composted chicken manure applied) on vegetable productivity and soil physicochemical and biochemical properties as well as microbiome (metagenomic sequencing) in an intensive greenhouse production system (cucumber-tomato rotation). Organic substitution ratio in 30% got a balance between stable vegetable productivity and maximum N reduction. However, higher substitution ratios decreased annual vegetable yield by 23.29–32.81%. Organic substitution (15–45%) improved soil fertility (12.18–19.94% increase in soil total organic carbon content) and such improvement was not obtained by higher substitution ratio. Soil mean enzyme activity was stable to organic substitution despite the activities of some selected enzymes changed (catalase, urease, sucrase, and alkaline phosphatase). Organic substitution changed the species and functional structures rather than diversity of soil microbiome, and enriched the genes related to soil denitrification (including nirK, nirS, and nosZ). Besides, the 30% of organic substitution obviously enhanced soil microbial network complexity and this enhancement was mainly associated with altered soil pH. At the level tested herein, organic substitution ratio in 30% was suitable for greenhouse vegetable production locally. Long-term influence of different organic substitution ratios on vegetable productivity and soil properties in intensive greenhouse system needs to be monitored. Full article

The land-use conversion of Masson pine forests to tea fields is extensively practiced across subtropical China, primarily driven by its economic benefit. However, the effects of this conversion on soil fungal communities and functional guilds are poorly understood. Herein, a field experiment was conducted in a Masson pine forest (F), a 5-year-old tea plantation without (FT-CK) fertilization or with (FT-N), and a 30-year-old tea plantation (FT-O) to assess the impact of Masson pine forest-to-tea conversion on soil fungal abundance, community structure, and functional guilds by using qPCR and high-throughput sequencing. Compared to F, fungal abundance significantly decreased by 95%, 68%, and 79% in FT-CK, FT-N, and FT-O, respectively, probably caused by the decreased total nitrogen content and habitat disruption. Fungal alpha diversity significantly increased in FT-N and FT-O compared to FT-CK. FT-O presented the highest percentages of Mortierella among treatments, which favours soil organic carbon accumulation. FUNGuild-based predictions showed that FT-CK and FT-N had higher relative abundances of plant pathogens than F and FT-O. FT-O presented the highest percentages of litter and soil saprotrophs but exhibited the lowest percentages of ectomycorrhizal fungi among treatments, likely driven by increased soil organic carbon, total nitrogen, and total phosphorus content. Our findings demonstrate that Masson pine forest-to-tea conversion significantly degrades soil fungal community and function, highlighting the urgent need for soil management strategies (e.g., organic amendments) to enhance soil health in tea agroecosystems. Full article

Groundwater nitrate (NO₃⁻) contamination has emerged as a critical global environmental issue, posing serious human health risks. This study systematically investigated the hydrochemical processes, sources of NO₃⁻ pollution, the impact of land use on NO₃⁻ pollution, and drinking water safety in an urban area of southwestern China. Thirty-one groundwater samples were collected and analyzed for major hydrochemical parameters and dual isotopic composition of NO₃⁻ (δ¹⁵N-NO₃⁻ and δ¹⁸O-NO₃⁻). The groundwater samples were characterized by neutral to slightly alkaline nature, and were dominated by the Ca-HCO₃ type. Hydrochemical analysis revealed that water–rock interactions, including carbonate dissolution, silicate weathering, and cation exchange, were the primary natural processes controlling hydrochemistry. Additionally, anthropogenic influences have significantly altered NO₃⁻ concentration. A total of 19.35% of the samples exceeded the Chinese guideline limit of 20 mg/L for NO₃⁻. Isotopic evidence suggested that primary sources of NO₃⁻ in groundwater include NH₄⁺-based fertilizer, soil organic nitrogen, sewage, and manure. Spatial distribution maps indicated that the spatial distribution of NO₃⁻ concentration correlated strongly with land use types. Elevated NO₃⁻ levels were observed in areas dominated by agriculture and artificial surfaces, while lower concentrations were associated with grass-covered ridge areas. The unabsorbed NH₄⁺ from nitrogen fertilizer entered groundwater along with precipitation and irrigation water infiltration. The direct discharge of domestic sewage and improper disposal of livestock manure contributed substantially to NO₃⁻ pollution. The nitrogen fixation capacity of the grassland ecosystem led to a relatively low NO₃⁻ concentration in the ridge region. Despite elevated NO₃⁻ and F⁻ concentrations, the entropy weighted water quality index (EWQI) indicated that all groundwater samples were suitable for drinking. This study provides valuable insights into NO₃⁻ source identification and hydrochemical processes across varying land-use types. Full article

Labile organic carbon (OC), a dynamic component of soil organic carbon (SOC), is essential for improving soil health, fertility, and crop productivity, particularly when organic and inorganic amendments are combined. However, limited research exists on the best amendment strategies for restoring degraded gleyic solonetz soggy sodic (GSSS) soils in West Africa’s coastal zones. A three-year field study (2017–2019) assessed the effects of various combinations of organic (mature or composted cow dung, with or without biochar) and inorganic inputs on soil organic carbon fractions, total carbon stocks, and the Carbon Management Index (CMI) in GSSS soils of Sege, Ada West District, Ghana. The results showed that organic and inorganic combinations outperformed the sole inorganic NPK treatment and the control, particularly in the topsoil. Composted cow dung with mineral fertilizer (CCfert) was especially effective, significantly increasing labile OC, SOC stock, and CMI by 35.3%, 140.5%, and 26% in the topsoil compared to the control and by 28%, 77.8%, and 4.3% compared to NPK alone. In the subsoil, mature cow dung-based treatments performed better. These findings highlight the potential of integrated organic and inorganic strategies, especially those based on composted manure, to rehabilitate degraded sodic soils, build carbon stocks, and improve soil quality for sustainable agriculture in coastal West Africa. Full article

The effects of different exogenous carbon types on the chemical structural characteristics and stability of soil organic carbon in dryland farmland remain unclear. Based on a four-year fixed-site experiment in a typical dryland farmland on China’s Loess Plateau, this study systematically analyzed the impacts of different carbon sources on soil enzyme activities, organic carbon content, chemical structural characteristics, and their interrelationships under five treatments: (i) no fertilization (T₀); (ii) 100% chemical nitrogen, phosphorus, and potassium fertilizers (CK); (iii) 50% CK + fermented cattle manure (T₁); (iv) 50% CK + corn straw (T₂); (v) 50% CK + mixed fermented cattle manure/corn straw (T₃). The results showed that the activities of β-glucosidase and N-acetylglucosidase ranked in the order T₁ > T₂ > T₃ and T₃ > T₂ > T₁, respectively. Specifically, β-glucosidase activity under T₁ increased by 35.26% compared to CK, while N-acetylglucosidase activity under T₃ increased by 30.78% relative to CK. Compared to CK, the T₁, T₂, and T₃ treatments increased soil organic carbon by 26.84%, 11.27%, and 18.63%, and alkyl carbon content by 7.67%, 2.91%, and 5.57%, respectively. Additionally, T₁ and T₃ treatments elevated aromatic carbon content by 20.59% and 176.47% relative to CK. The organic carbon activity index under T₁ was the lowest, decreasing by 10.04% compared to CK. Structural equation modeling (SEM) path analysis revealed that the addition of different exogenous carbon sources in dryland farming primarily influenced the structure and stability of soil organic carbon by directly or indirectly enhancing the activities of glucosidase, β-acetylglucosidase, and alkaline phosphatase, with T₁ demonstrating the most significant improvement. Full article

Integrated soil fertility management is essential for improving soil productivity, rice yield, and nitrogen use efficiency (NUE). This study investigated the combined effects of the chemical fertilizer rate, humic acid (HA), and flue gas desulfurization gypsum (FG) on the soil chemical properties, rice yield, NUE, and nitrogen agronomic efficiency (NAE) in acidic paddy soil. The following three factors were evaluated: (1) fertilization based on farmer practices and rice nutrient requirements; (2) HA at 0 and 975 kg ha⁻¹; and (3) FG at 0, 23, and 636 kg ha⁻¹. Fertilization based on rice requirements reduced the nitrogen (N) input by 14.5% compared to farmer practices while still maintaining similar grain yields. Under farmer practice, HA enhanced total N content, cation exchange capacity (CEC), rice yield, NUE, and NAE. HA with FG (636 kg ha⁻¹) increased total organic carbon (TOC) levels, total N levels, and exchangeable ammonium nitrogen (NH₄-N), but decreased the yield. In contrast, HA combined with FG at 23 kg ha⁻¹ enhanced the soil exchangeable Ca and S levels, as well as resulting in a high rice yield (7.7 t ha⁻¹), NUE (39%), and NAE (32 kg kg⁻¹). The findings suggest that to maintain farmer fertilization practices while improving soil properties and rice yield, HA should be applied with FG (23 kg ha⁻¹). Full article

This study aimed to (i) identify soil management practices implemented by farmers at the local level, (ii) determine the local soil fertility indicators recognized by farmers along an altitudinal gradient, (iii) evaluate the influence of altitude on soil properties, and (iv) integrate local and scientific knowledge of soil indicators and soil management. A total of 368 surveys were conducted to document traditional knowledge, visible indicators of soil fertility, and perceptions of soil health. These were compared with field-based measurements of soil organic carbon, texture, and environmental variables. A significant convergence was found between farmers’ perception of soil texture and scientific classification. A moderate correlation was observed between soil color and soil carbon stocks. Altitude showed a clear influence on carbon stocks, with soil at a higher elevation, characterized by greater rainfall and lower temperatures, storing more carbon. This integration of local and scientific knowledge offers practical value for farmers, extension agents, and institutions by supporting context-specific soil management decisions. It empowers farmers to actively participate in the design of sustainable agricultural practices that are both ecologically sound and culturally relevant. The study demonstrates that combining experiential knowledge with scientific data contributes to more resilient agroecosystems in mountainous rural areas. Full article

Microbial necromass carbon (MNC) is the dominant contributor to soil organic carbon (SOC). However, the contribution of MNC in different soil compartments to SOC sequestration has not been comprehensively studied, especially under the organic fertilizers input. To address this gap, we conducted a rice root box experiment by adding organic fertilizer (straw and straw biochar) and chemical fertilizer alone to red loamy paddy soil, respectively. We found that although SOC accumulation was stimulated by both biochar and straw in the rhizosphere, more substantial SOC was sequestered in the rhizosphere due to biochar addition (increased by 25.82% compared to straw addition). Additionally, the input of organic fertilizers resulted in varying degrees of MNC retention in the different soil compartments. Compared with that in bulk soil, fungal necromass carbon (FNC) content was reduced by 1.37% and 7.06%, and bacterial necromass carbon (BNC) content was reduced by 5.53% and 9.49% in the rhizosphere and hyphosphere, respectively, following straw addition. Conversely, the addition of biochar leads to a significant increase of FNC (increased by 2.92%) and BNC (increased by 2.00%) in the rhizosphere compared with bulk soil. However, straw addition also significantly enhanced SOC thermal stability within the rhizosphere and hyphosphere soils. Based on partial least squares path modeling, we found that SOC thermal stability was significantly and positively influenced by FNC, which was strongly associated with carbon degradation gene abundance. These results emphasize the critical role of soil compartments in SOC sequestration under organic fertilizer application and underscore the importance of FNC in enhancing SOC stability in the rhizosphere. Full article

Biochar may represent a sustainable and eco-friendly strategy to recycle agroforestry wastes, sequester carbon and improve soil health. With the aim of proving these benefits in a real scenario, we treated several soil parcels with 0 (CTRL), 1 (LOW) and 3 (HIGH) kg/m² of wood biochar, in open-field trials. The heterotrophic soil respiration (SR) was monitored continuously for two months via a Closed Dynamic Chamber (CDC) associated with an innovative pilot system, and the most important soil chemical parameters were measured 9 and 54 days after biochar application. Biochar induced an immediate dose-dependent increase in organic matter content and CEC (up to 41.6% and 36.8% more than CTRL, respectively), which tended to slightly and gradually decrease after 54 days. In all cases, biochar induced a more pronounced SR, although the most enhanced microbial response was detected for the LOW parcel (19.3% higher than CTRL). Fennels were grown in treated soils and only LOW microplots gave a significantly better response (weight and size). Finally, NMR, FT-IR and Pyr-GC/MS analyses of LOW SOM extracts revealed a relevant impact on the composition, which was accompanied by a higher content of carbohydrates, indole-based compounds and FAME species correlating with enhanced microbial activity. Our findings demonstrate that the proper biochar dose improves soil fertility by creating an environment favorable to plants and promoting microbial activity. Full article

Trees and forests are nature-based solutions of strategic importance for climate change mitigation. Policy and popular media are focused on the number of trees to plant, but that cannot be a definitive solution. A growing number of scientific papers address the problems concerning tree plantations and forest restoration for climatic purposes. In this review, we analyze ecological limitations and trade-offs to be considered for the realization and management of these interventions. Terrestrial sinks (forests and other terrestrial natural ecosystems) can absorb only a fraction of the carbon emitted, and the establishment of new effective forests is constrained by ecological limitations. Moreover, the stimulation of tree growth due to carbon fertilization is offset by the harshening of ecological conditions due to climate change (higher temperatures beyond the optimum for photosynthesis, increasing drought, and nutritional imbalances). The increase in frequency and severity of disturbances can turn forests from sinks to sources of carbon. Finally, physiological mechanisms connected to albedo and the emission of organic volatile compounds (VOCs) reduce the efficacy of climate cooling. Although such constraints exist, the establishment of new plantations and the restoration of existing forests are still necessary but are just one of the actions to fight climate change and must not be seen as an alternative to reducing carbon emissions. Considering limitations and trade-offs in the models to estimate tree growth and carbon storage will allow us to produce more realistic plans for climate mitigation. Full article

Africa’s rapidly growing population is driving unprecedented demands on agricultural production systems. However, agricultural yields in Africa are far below their potential. One of the challenges leading to low productivity is Africa‘s poor soil quality. Effective soil fertility management is an essential key factor for optimizing agricultural productivity while ensuring environmental sustainability. Key soil fertility properties—such as soil organic carbon (SOC), nutrient levels (i.e., nitrogen (N), phosphorus (P), potassium (K), moisture retention (MR) or moisture content (MC), and soil texture (clay, sand, and loam fractions)—are critical factors influencing crop yield. In this context, this study conducts an extensive literature review on the use of hyperspectral remote sensing technologies, with a particular focus on freely accessible hyperspectral remote sensing data (e.g., PRISMA, EnMAP), as well as an evaluation of advanced Artificial Intelligence (AI) models for analyzing and processing spectral data to map soil attributes. More specifically, the study examined progress in applying hyperspectral remote sensing technologies for monitoring and mapping soil properties in Africa over the last 15 years (2008–2024). Our results demonstrated that (i) only very few studies have explored high-resolution remote sensing sensors (i.e., hyperspectral satellite sensors) for soil property mapping in Africa; (ii) there is a considerable value in AI approaches for estimating and mapping soil attributes, with a strong recommendation to further explore the potential of deep learning techniques; (iii) despite advancements in AI-based methodologies and the availability of hyperspectral sensors, their combined application remains underexplored in the African context. To our knowledge, no studies have yet integrated these technologies for soil property mapping in Africa. This review also highlights the potential of adopting hyperspectral data (i.e., encompassing both imaging and spectroscopy) integrated with advanced AI models to enhance the accurate mapping of soil fertility properties in Africa, thereby constituting a base for addressing the question of yield gap. Full article

This research aims to develop mitigation and adaptation strategies for greenhouse gas emissions Thailand in accordance with Climate-Smart Agriculture policies. The research employs a mixed-methods approach, integrating both quantitative and qualitative research as a crucial framework for impact analysis and an early warning tool for the government in achieving sustainability. On the quantitative side, an advanced model called the Longitudinal Mediated Moderation Analysis Based on the Fuzzy Autoregressive Hierarchical Process (LMMA-FAHP) model has been developed. This model meets all validity criteria, shows no signs of spuriousness, and outperforms previous models in terms of performance. It is highly suitable for policy formulation and strategic planning to guide the country’s long-term governance toward achieving net-zero emissions by 2065. The findings indicate that the new scenario policy, with an appropriateness rating of over 80%, includes factors such as the clean technology rate, biogas energy, biofertilizers, organic fertilizers, anaerobic digestion rate, biomass energy, biofertilizer rate, renewable energy rate, green material rate, waste biomass, and organic waste treatments. All indicators demonstrate a high sensitivity level. When the new scenario policy is incorporated into future greenhouse gas emissions forecasts (2025–2065), the research reveals a declining growth rate of emissions, reaching 78.51 Mt CO₂ Eq., with a growth rate of 11.35%, which remains below the carrying capacity threshold (not exceeding 101.25 Mt CO₂ Eq.). Moreover, should the government adopt and integrate these indicators into national governance frameworks, it is projected that greenhouse gas emissions by 2065 could be reduced by as much as 36.65%, significantly exceeding the government’s current reduction target of 20%. This would enable the government to adjust its carbon sequestration strategies more efficiently. Additionally, qualitative research was conducted by engaging stakeholders from the public sector, private sector, and agricultural communities to develop adaptive strategies for future greenhouse gas emissions. If the country follows the research-driven approach outlined in this research, it will lead to effective long-term policy and governance planning, ensuring sustainability for Thailand. Full article