Search Results (654)

Composting is a well-known method for waste management, but it causes greenhouse gas emissions. Various techniques have been used to reduce emissions and improve the quality of compost, but they resulted in an increased composting time. Keeping in view the above points, the current study aimed to reduce the composting time and gas emissions along with improving the nutritional value of compost using FeSO₄ as an additive to cattle manure and corn straw composting. Seven treatments were established, including control (CK) without FeSO₄ and six levels of FeSO₄ (0.25%, 0.50%, 1%, 2%, 4%, 8%). The results revealed that FeSO₄ reduced the CH₄ (36.1–36.7%), H₂S (10.7–34.5%), N₂O (17.2–48.5%), and NH₃ (18.3–69.0%) emissions compared to CK. In addition, the total N (8.4–40.0%) content in compost products was also improved. The study showed that a higher dose of applied FeSO₄ can significantly reduce emissions, but it reduces the temperature at the start of composting resulting in an increase in the composting time, while the lower dose (0.5–1%) also has the capability to reduce the emissions compared with the control without negatively affecting the temperature rise. The study concludes that using 0.5–1% of FeSO₄ can effectively utilize its inhibitory action of decomposition that mitigates gas emissions and prepares an N-enriched compost. Full article

Non-point sources of pollution (NPSPs) originating from runoff from contaminated agricultural and populated areas are becoming a growing concern in developing countries, endangering the environment and public health. This requires systematic investigation, including modelling the likely impact using an appropriate hydrological model. This study quantified the spatiotemporal variation of the NPSP and prioritised the most vulnerable sub-watersheds for intervention planning. We investigated the effects of land use and cover (LULC) conversion on runoff generation and NPSP loads in terms of sediment, phosphate, total nitrogen, total phosphorus, and nitrate loading using the SWAT model. The principal source of data utilised to assess the change in NPSP loads was the 2003 and 2023 LULC. The analysis of the results showed that grassland and shrubland substantially changed, with 96.7% and 74.4% reductions, respectively, while the increase in agricultural land was 147.3% and that of built-up areas increased by 80.14%. The mean yearly increase in sediment yield ranges from 25.46 to 27,298.75 t, while the mean yearly increase in surface runoff ranges from 183.1 mm to 487.9 mm. The minimum recorded runoff was 10.69 mm (5.1%) in WS03, while the highest was 123.3 mm (66.5%) in WS02. The NO₃⁻ load increased from 127.6 to 20,739.7 kg, and the PO₄³⁻ load increased from 3.12 to 2459.7 kg. The TN load increased from 4465.5 to 482,014.5 kg, and the TP load increased from 1383.5 to 133,641.3 kg. The monthly analysis of nitrate loading revealed that the “Belg” season has the highest nitrate load than the rainy season, probably due to nitrification. The findings clearly showed that the inputs applied to the farms were not effectively utilised for the intended purpose. Hence, efforts must be made to ensure that nutrients remain in the catchment through an appropriate land management intervention. Full article

Water quality safety in the water source constitutes a crucial guarantee for public health and the ecological environment. This study undertakes a comprehensive assessment of the water quality conditions within the Jing River Basin of the Loess Plateau, emphasizing the spatial and temporal characteristics, as well as the determinants influencing surface water quality in the Shaanxi section. We utilized data from seven monitoring stations collected between 2016 and 2022, employing an enhanced comprehensive Water Quality Index (WQI) method, redundancy analysis (RDA), and Spearman’s correlation analysis. The results show that the average annual WQI value of the water quality of the Shaanxi section of the Jing River increased from 68.01 in 2016 to 76.18 in 2022, and the river’s water quality has gradually improved, with a significant improvement beginning in 2018, and a series of water quality management policies implemented by Shaanxi Province is the primary reason for the improvement. The river’s water quality has deteriorated slightly in recent years, necessitating stricter supervision of the coal mining industry in the upper section. The river has an average WQI value of 73.70 and is rated as ‘good’. The main pollution indicators influencing the river’s water quality are COD_Mn, COD, BOD₅, NH₃-N, and TP. From the upstream to the downstream, the water quality of the river shows a pattern of increasing and then decreasing, among which S4 (Linjing Bridge in Taiping Town) and S5 (Jinghe Bridge) have the best water quality. The downstream part (S6, S7) of the Jing River near the Weihe River has poor water quality, which is mostly caused by nonpoint source contamination from livestock and poultry rearing, agricultural activities, and sewage discharge. Redundancy analysis revealed that the spatial scale of the 2500 m buffer zone best explained water quality changes, and the amount of bare land and arable land in land use categories was the key influencing factor of river water quality. Full article

The sustainability of rice-cropping systems hinges on balancing resources, output, and environmental impacts. China is revitalizing the ancient ratoon rice (RR) system for input savings and environmental benefits. Prior research has explored the RR system’s performance using various individual indicators, but few studies have focused on its overall balance of these factors. Environmental efficiency (EE) analysis addresses this gap. Using field survey data from Hunan Province in China and the slacks-based data envelopment analysis method, we quantified the EE of the RR, double-season rice (DR), and single-season rice (SR) systems. Key findings include: (1) the RR system outperforms in carbon emissions and non-point source pollution; (2) the RR system’s EE is 0.67, significantly higher than the DR (0.58) and SR (0.57) systems, indicating superior performance; and (3) despite its relatively high EE, the RR system can still improve, mainly due to input redundancy and production value shortfall. These findings provide strategies for optimizing RR systems to enhance agricultural sustainability. Full article

Light non-aqueous phase liquids (LNAPLs), which include various petroleum products, are a significant source of groundwater contamination globally. Once introduced into the subsurface, these contaminants tend to accumulate in the vadose zone, causing chronic soil and water pollution. The vadose zone often contains lens-shaped bodies with diverse properties that can significantly influence the migration and distribution of LNAPLs. Understanding the interaction between LNAPLs and these lens-shaped bodies is crucial for developing effective environmental management and remediation strategies. Prior research has primarily focused on LNAPL behavior in homogeneous media, with less emphasis on the impact of heterogeneous conditions introduced by lens-shaped bodies. To investigate the impact of lens-shaped structures on the migration of LNAPLs and to assess the specific effects of different types of lens-shaped structures on the distribution characteristics of LNAPL migration, this study simulates the LNAPL leakage process using an indoor two-dimensional sandbox. Three distinct test groups were conducted: one with no lens-shaped aquifer, one with a low-permeability lens, and one with a high-permeability lens. This study employs a combination of oil front curve mapping and high-density resistivity imaging techniques to systematically evaluate how the presence of lens-shaped structures affects the migration behavior, distribution patterns, and corresponding resistivity anomalies of LNAPLs. The results indicate that the migration rate and distribution characteristics of LNAPLs are influenced by the presence of a lens in the gas band of the envelope. The maximum vertical migration distances of the LNAPL are as follows: high-permeability lens (45 cm), no lens-shaped aquifer (40 cm), and low-permeability lens (35 cm). Horizontally, the maximum migration distances of the LNAPL to the upper part of the lens body decreases in the order of low-permeability lens, high-permeability lens, and no lens-shaped aquifer. The low-permeability lens impedes the vertical migration of the LNAPL, significantly affecting its migration path. It creates a flow around effect, hindering the downward migration of the LNAPL. In contrast, the high-permeability lens has a weaker retention effect and creates preferential flow paths, promoting the downward migration of the LNAPL. Under conditions with no lens-shaped aquifer and a high-permeability lens, the region of positive resistivity change rate is symmetrical around the axis where the injection point is located. Future research should explore the impact of various LNAPL types, lens geometries, and water table fluctuations on migration patterns. Incorporating numerical simulations could provide deeper insights into the mechanisms controlling LNAPL migration in heterogeneous subsurface environments. Full article

With the constant advancement of irrigation technology and the continuous expansion of irrigation areas, non-point source pollution (NPS) caused by agricultural activities has posed a persistent threat to ecosystems and biological safety. Against this backdrop, it is imperative to lay scientific foundations for green, sustainable, and high-quality agricultural development through a thorough review of the relevant research progress. In this study, bibliometric methods are adopted to comprehensively analyze and visualize the current state and key literature on agricultural irrigation and NPS pollution from 2010 to July 2024. The focus of this study is specifically on summarizing the research hotspots and development trends of different irrigation methods and the mechanisms behind their impacts on NPS pollution. The results indicate that publications from the United States and China account for 63.8% of the total, but the fragmentation of research efforts remains, suggesting a necessity to strengthen international and regional collaboration. There are three institutions with the highest publication output, namely Northwest A&F University, Hohai University, and the Chinese Academy of Sciences. The subjects identified as the key areas of research on irrigation-related NPS pollution (IRR-NPS) include precision irrigation, rapid water pollution response, spatiotemporal management, interdisciplinary integration, wastewater treatment, and crop models. Regarding future research, it is necessary to focus attention on real-time precision irrigation, standardized crop models, data accuracy, spatiotemporal pollution coordination, pollution purification technology development, interdisciplinary integrated governance, and the innovative applications of soil improvement technologies. In addition to offering theoretical support and practical guidance for the management of agricultural NPS pollution, this study also provides management and technical support for policymakers, which is beneficial for advancing agricultural irrigation technology and environmental preservation. Full article

Groundwater serves as a crucial resource, with its quality significantly impacted by both natural and human-induced factors. In the highly industrialized and urbanized Yangtze River Delta region, the sources of pollutants in shallow groundwater are more complex, making the identification of groundwater pollution sources a challenging task. In this study, 117 wells in Wujiang District of Suzhou City were sampled, and 16 groundwater quality parameters were analyzed. The fuzzy synthetic evaluation method was used to assess the current status of groundwater pollution in the study area; the principal component analysis (PCA) was employed to discern the anthropogenic and natural variables that influence the quality of shallow groundwater; and the absolute principal component scores–multiple linear regression (APCS-MLR) model was applied to quantify the contributions of various origins toward the selected groundwater quality parameters. The results indicate that the main exceeding indicators of groundwater in Wujiang District are I ($28\%$), $N{H}_4\text{-}N$ ($18\%$), and Mn ($14\%$); overall, the groundwater quality is relatively good in the region, with localized heavy pollution: class IV and class V water are mainly concentrated in the southwest of Lili Town, the north of Songling Town, and the south of Qidu Town. Through PCA, five factors contributing to the hydrochemical characteristics of groundwater in Wujiang District were identified: water–rock interaction, surface water–groundwater interaction, sewage discharge from the textile industry, urban domestic sewage discharge, and agricultural non-point source pollution. Additionally, the APCS-MLR model determined that the contributions of the three main pollution sources to groundwater contamination are in the following order: sewage discharge from the textile industry ($10.63\%$) > urban domestic sewage discharge ($8.69\%$) > agricultural non-point source pollution ($6.26\%$). Full article

Climate change scenarios have been used to evaluate future climate change impacts and develop adaptation measures to mitigate potential damage. This study investigated strategies to reduce nonpoint source loads in an agriculturally dominated watershed and adapt to climate change despite uncertainty. We also investigated strategies for adapting to future meteorological conditions characterized by uncertainty. We utilized the latest future climate change scenarios—shared socioeconomic pathways—and explored measures to reduce nonpoint source loads by implementing nonpoint pollution abatement facilities in a watershed model. The simulation results indicate that the future frequency of rainfall events may decrease based on observations and the types and features of rainfall events in the scenarios. However, the variability of runoff loads in the context of future climate scenarios may increase because of factors influencing surface runoff, including the amount and intensity of rainfall. Nonpoint source loads are expected to exhibit high uncertainty in the future. Finally, the optimal solution can be determined through a simulated evaluation of the cost–benefit of installing the abatement facilities, considering the abatement efficiency and maintenance period. Overall, implementing effective management practices is crucial for reducing nonpoint source loads resulting from agricultural activities while adapting to increasingly variable meteorological conditions. Full article

Due to the multiple pressures from human activities, many freshwater ecosystems are facing degradation. To address this issue, a new approach for assessing stream water quality and ecological (WQE) risk using a multi-criteria analysis through a GIS-based policy tool has been developed. The suggested methodology integrates eight different factors along the contaminant pathway from source to streams, including: (a) rainfall variability, (b) soil texture, (c) soil erodibility, (d) slope, (e) river buffer zone, (f) point source contamination buffer zone, (g) non-point source contamination of NO₃, and (h) non-point source contamination of PO₄. Utilizing fuzzy GIS tools, the above factors and their related maps were spatially overlaid (raster-based suitability for raster reclassification) to obtain the final stream WQE risk map. The final map depicts the spatial distribution of streams concerning their water quality risk and is represented by two classes of WQE risk. The first class is characterized as “appropriate”, in which there is no need for any further actions, while the other one is characterized as “non-appropriate”, indicating that actions should be taken to ensure the sustainability of streams’ water quality. The proposed approach was implemented for the island of Crete, which is located in the Southeast Mediterranean region. The developed methodology was validated using the Hellenic evaluation system (HESY2), an especially established and adapted to the Mediterranean river systems ecological quality metric method, obtained by in situ measurements that were conducted during different monitoring programs (1989–2015). Moreover, this study summarizes appropriate measures and practices that ensure the sustainable management of Mediterranean river basins. These practices can be adopted by local authorities, owners of polluting units, and farmers/breeders to improve the resiliency of streams’ water quality issues in the Mediterranean region. Full article

Nitrogen loss in water from farmland has become an environmental issue. Nitrogen fertilizer is the main cause of agricultural non-point source pollution in the Lake Basin, Yunnan. However, it is unclear how different nitrogen fertilizer forms affect water loss from farmland and how the root systems of crops respond. We established five nitrogen fertilizer treatments (100–0% [T1], 75–25% [T2], 50–50% [T3], 25–75% [T4], and 0–100% [(T5)] nitrate–ammonium) and performed an investigation to determine nitrogen loss in water and root morphological parameters of tobacco in Mile County and Chengjiang County. Compared with in the T1, T4, and T5 treatments, the total nitrogen loss in surface runoff was reduced by 4.67%, 11.85% and 9.56% in the T2 treatment and 27.32%, 23.20%, and 31.43% in the T3 treatment, respectively. Similar results were observed for the nitrogen loss due to infiltration. The root biomass was negatively correlated with nitrogen loss. There was greater root biomass, root surface area, and root spatial distribution in T2 and T3 compared with in T1, T4, and T5. These results indicate that 50–50% nitrate–ammonium nitrogen fertilizer can facilitate the root growth of tobacco and reduce nitrogen loss, which provides a reference for agricultural sustainable development. Full article

The Nyabarongo river catchment in Rwanda has experienced significant changes in its land use and land cover (LULC) in recent decades, with profound implications for non-point source pollution. However, there are limited studies on non-point pollution caused by nutrient loss associated with land use and land cover changes in the catchment. This study investigates the spatiotemporal impacts of these changes on water quality considering nitrogen and phosphorus within the catchment from 2000 to 2020 and 2030 as a projection. The SWAT model was used in analysis of hydrological simulations, while the CA–Markov model was used for the future projection of LULC in 2030. The results revealed (1) the important changes in LULC in the study area, where a decrease in forestland was observed with a considerable increase in built-up land, grassland, and cropland; (2) that the R² and NSE of the TN and TP in the runoff simulation in the catchment were all above 0.70, showing good applicability during calibration and validation periods; (3) that from 2000 to 2020 and looking to the projection in 2030, the simulated monthly average TN and TP levels have progressively increased from 15.36 to 145.71 kg/ha, 2.46 to 15.47 kg/ha, 67.2 to 158.8 kg/ha, and 9.3 to 17.43 kg/ha, respectively; and (4) that the most polluted land use types are agriculture and urban areas, due to increases in human activities as a consequence of population growth in the catchment. Understanding the patterns and drivers of these changes is critical for developing effective policies and practices for sustainable land management and protection of water resources. Full article

Non-point source (NPS) pollution has a complex formation mechanism, and identifying its primary controlling factors is crucial for effective pollution treatment. In this study, the Baixi Reservoir Watershed, characterized by low-intensity development, was selected as the study area. A new methodology combining the Soil and Water Assessment Tool (SWAT) with the Random Forest (RF) algorithm was proposed to comprehensively identify the primary controlling factors of NPS pollution and analyze the interaction between factors. The results of the validated SWAT model showed that the annual intensity of total nitrogen (TN) load range was 0.677–11.014 kg ha⁻¹ yr⁻¹, and the total phosphorus (TP) load per unit area range was 0.020–0.110 kg ha⁻¹ yr⁻¹. Loads of sediment, TP, and TN exhibited significant seasonal variations, particularly in the Baixi basin, where sediment yield had the highest absolute change rate, with a value of up to 232.26. Random Forest models for TN and TP displayed high accuracy (R² > 0.99) and robust generalization ability. Fertilization, sediment yield, and terrain slope were identified through RF models as the primary factors affecting TN and TP. By graphing partial dependency plots (PDPs) based on the results of the RF models to analyze the interaction between factors, the findings suggest a strong synergistic effect of two combined factors: fertilization and sediment yield. When fertilizer application exceeds 15 kg ha⁻¹ yr⁻¹ and sediment yield exceeds 3 kg ha⁻¹ yr⁻¹, there is a sharp increase in nitrogen and phosphorus load. Through the identification and analysis of the primary controlling factors of NPS pollution, this study provides a solid scientific foundation for developing effective watershed management strategies. Full article

With the growing world population, food demand has also increased, resulting in increased agricultural waste and livestock manure production. Wheat straw and cow dung are rich nutrient sources and, if not utilized properly, may lead to environmental pollution. Keeping in view the cultivation of Agaricus bisporus on straw/manure-based substrate, the current study aimed to optimize the conventional manure preparation technique to reduce nutrient losses and keep the quality of manure at its best. The treatments were considered as traditional and optimized schemes for mushroom substrate preparation. The results achieved herein indicated that the nutrient losses were low in the optimum scheme. For carbon (C), the loss was 43.55% at the substrate stage in the traditional scheme and reduced to 37.75% in the optimum scheme. In the case of nitrogen (N), the loss was 22.01% in the traditional scheme and was lower (18.49%) in the optimum scheme. The nutrient concentration in Agaricus bisporus was higher with the optimum scheme compared with the traditional scheme. It was 1.74% for C, 7.17% for N, 3.58% for phosphorus (P), and 4.92% for potassium (K). The optimum scheme also improved the Agaricus bisporus yield per unit area (84.55%) and the total yield (28.92%). The net income of the optimum scheme was 102.95% higher compared to the traditional scheme. The economic analysis also revealed that the benefit–cost ratio of the optimum scheme was high (48.86%) compared with the traditional scheme. This study concludes that the use of the optimum scheme can better utilize the wheat straw and cow manure waste for substrate preparation and reducing nutrient losses. In addition, the final mushroom residue can also be used as a leftover substrate for further utilization. Full article

China’s agricultural sector faces significant challenges, including fragmented farming practices, limited farmer knowledge of sustainable production, and outdated pest control technologies. These issues result in improper fertilization, pesticide application, and disposal of agricultural inputs, contributing to agricultural non-point source pollution and hindering the transition to a green economy. Thus, promoting green production behavior among farmers is critical for achieving carbon peaking, carbon neutrality, and harmonious coexistence between humans and nature. However, the existing literature on this topic is still relatively scarce. This study aims to investigate the impact of farmers’ cognition on their green production behavior (GPB). Considering the role of policy, this study also examines the moderating effect of government regulation in this relationship. An analysis of 306 survey responses from tea farmers in Jingmai Mountain, Pu’er City, Yunnan Province, reveals that farmers’ cognition exerts a significant and positive impact on GPB. Social norms and personal norms serve as chain mediators in the relationship between farmers’ cognition and GPB. Moreover, government regulation moderates the influence of farmers’ cognition on social norms, further amplifying its impact on them. This study advances the theoretical understanding of farmers’ behavior and offers practical insights for fostering the sustainable development of the tea industry. Full article

This study examines the economic and environmental impacts of green production practices among farmers. It aims to contribute to sustainable agricultural development, mitigate agricultural non-point source (NPS) pollution, and align environmental protection with economic growth. This paper utilizes survey data from 1345 farm households in the main rice production areas of Jiangxi Province, China, using the example of reduced fertilizer application (RFA) among rice farmers. This study constructs a slack-based measure data envelopment analysis (DEA—SBM) model with undesirable outputs to measure environmental effects and applies an endogenous switching regression model (ESRM) to test the economic and environmental effects of farmers’ adoption of green production technologies. We found the following: (1) The RFA behavior of farmers has a significant positive impact on their net profit per hectare (NPH), helping farmers increase their income, with the increase ranging from 2.05% to 6.54%. (2) Farmers’ RFA behavior has a significant positive impact on agricultural green productivity (AGP), contributing to the improvement of the environment, ranging from 44.09% to 45.35%. (3) A heterogeneity analysis found inconsistencies in the income-enhancing and environmental-enhancing effects at different quantiles of NPH and AGP. Therefore, attention should be placed on improving the agricultural product quality supervision system under the market circulation mechanism, creating land scale conditions conducive to the promotion and application of fertilizer reduction technologies and promoting the implementation of externality internalization compensation systems. Full article