Soil health is the foundation of the stability and health of terrestrial ecosystems, and a reasonable evaluation of soil health is directly related to the sustainability of agricultural production, the stability of ecological environment, and human health. In recent years, soil health research has increasingly become a core hotspot in the field of soil science research both at home and abroad. However, due to the diversity of ecosystem types, the extensiveness of spatial scales, the differences in land use patterns and agricultural structures, as well as the complexity of soil ecosystem functions, it poses great challenges to scientifically and accurately evaluate soil health. On the basis of summarizing the concept and development of soil health, this paper focuses on the mainstream soil health evaluation methods both at home and abroad, including methods based on soil health evaluation benchmarks, the Cornell method, soil functions-based methods, China's arable land quality (soil health) evaluation methods, and methods using machine learning and analytical diagnosis. On this basis, we preliminarily construct a soil health evaluation framework and general process suitable for China's national conditions, systematically elaborate on the application of soil health evaluation results, and the current soil health evaluation problems in China. Finally, we propose future research prospects for soil health, especially emphasizing the construction of a multi-objective collaborative evaluation system, innovation in adaptive evaluation methods across ecosystems and spatial scales, and the research and application of healthy soil cultivation technologies. These efforts aim to promote high-quality soil health research, thereby protecting and improving soil resources, supporting agricultural production, and maintaining environmental health.

It is of great significance for the sustainable development of the agriculture and forestry ecology of Chongming Island in Shanghai to scientifically evaluate the storage status of agricultural and forestry soil nutrients and expound their spatial distribution characteristics. According to four main agricultural and forestry planting types (grain field, vegetable field, orchard and ecological forest) and three representative soil types (paddy soil, tidal soil and coastal saline soil), 100 soil samples of 0-20 cm were collected to analyze the distribution characteristics and influencing factors of agricultural and forestry soil nutrients of Chongming Island. The results showed that the average pH and electrical conductivity (EC) values of agricultural and forestry soils of Chongming Island were 7.99, 0.56 mS/cm, respectively, and the average organic matter content was 17.29 g/kg, belonging to the lower middle level; the average total nitrogen content was 1.91 g/kg, belonging to the rich level; and the average total phosphorus content was 1.33 g/kg, belonging to the upper middle level. The agricultural and forestry soil of Chongming Island was basically alkaline, with lower EC value in the central part, higher soil organic matter in the southern and central part and lower in the eastern part. Total nitrogen content was at a relatively high level in the middle and low in the west. The distribution pattern of total phosphorus was higher in the middle and decreased gradually from south to northeast and southeast. There were significant differences in soil nutrient indexes under different planting methods. Grain field had the highest organic matter content (19.20 g/kg) and vegetable field had the highest total nitrogen content (2.17 g/kg). Soil EC value and total phosphorus content were in the order of vegetable field > orchard > grain field > ecological forest. The contents of total nitrogen and total phosphorus in different soil types were paddy soil > tidal soil > coastal salt soil, while the highest organic matter content of tidal soil was 18.00 g/kg, with the lowest EC value. The distribution of agricultural and forestry soil nutrients of Chongming Island was significantly affected by planting methods. In summary, the selection of rice planting mode is conducive to the improvement of agricultural and forestry soil nutrients of Chongming Island.

Exploring the effects of different water and nitrogen management practices on soil organic carbon (SOC), SOC components, and soil enzyme activities in wheat fields plays an important role in promoting SOC sequestration and contributing to the achievement of dual carbon goals. The experiment included two irrigation treatments, rainfed and irrigated, and three nitrogen application levels of 0, 180, and 360 kg/hm² (marked as N0, N180 and N360), totaling six treatments. During the wheat harvesting period, soil samples from 0-40 cm depth were collected to measure the contents of SOC, easily oxidizable organic carbon (EOC), particulate organiccarbon (POC), and mineral-associated organic carbon (MOC), as well as the activities of soil urease (UA), β-glucosidase (β-BG), invertase (IA), and catalase (HPA). The results showed that compared to rain-fed conditions, irrigation conditions reduced SOC content, which was unfavorable for maintaining SOC stability. Under N180 treatment, compared to irrigation conditions, SOC content under rain-fed conditions increased by 6.3% and 71.7% in the 0-20 and 20-40 cm layers, respectively. Furthermore, at three nitrogen levels, EOC content under rain-fed conditions was higher than that under irrigation conditions.The study showed that applying 180 kg/hm² of nitrogen combined with appropriate water management was beneficial for promoting SOC accumulation. Proper water and nitrogen management in farmland was not only crucial for increasing crop yields but also played an important role in enhancing SOC storage and helping achieve the "dual carbon" goals.

The soil dissolved organic carbon (DOC) is an important component of soil organic carbon (SOC) pool. Exploring the variations of SOC, DOC contents and the proportions of DOC to SOC under different land use types is of great significance to deeply understand the turnover and sustainable management of SOC. The DOC content data of surface soil (0-20 cm) under the three land use types, including cropland, forestland and grassland, were collected and extracted from published studies conducted in China from 2000 to 2024. A total of 116 target literature were obtained, yielding 549 matched data sets. A quantitative analysis was conducted to determine the impact of different land use types, climate zones and soil types on DOC content under different climate regions and soil types, as well as the relationship between SOC and DOC. The results showed there was a significant difference in the contents of SOC and DOC under the three land use types. The SOC and DOC contents under forestland were higher than those in grassland and cropland. In different climatic regions, there was a significant positive correlation between DOC and SOC under the three land use types (P<0.01), and the proportion of DOC was different. In subtropical monsoon climate region, the mean value of DOC proportion in forestland soil was 2.30%, which was significantly higher than that in cropland (0.87%) and grassland (0.66%, P<0.05); in temperate monsoon climate region, there was no significant difference in DOC proportion (P>0.05) under the three land use types, including forestland (1.27%) > cropland (1.18%) > grassland (1.03%); in temperate continental climate region, DOC proportion in cropland, forestland and grassland soil was 1.76%,1.43% and 1.28%, respectively, but there was no significant difference (P>0.05). The DOC proportion in different soil types of croplands is significantly different. Among them, the DOC proportion in cinnamon soil was the highest, and the mean value was 1.61%, followed by gray desert soil (1.38%), black soil (1.10%), red soil (0.99%) and fluvo-aquic soil (0.89%), while paddy soil was the lowest (0.74%). The research has important implications for revealing DOC changes and providing important theoretical significance for the management of DOC under different land use practices.

After coal dust sinks to the surface, it can significantly increase the content of soil organic carbon and change the soil physicochemical properties and soil microbial community structure. This article explored the mechanism of the effect of organic carbon input from coal dust on soil organic carbon mineralization and bacterial community structure through soil cultivation experiments with the addition of lignite dust. The results showed that under the influence of lignite dust, the amount and rate of CO₂ mineralization in soil increased by 55.02% and 54.58% compared to the control group on day 5; the contents of readily oxidation carbon (ROC) and microbial biomass carbon (MBC) in soil decreased by 40.75 and 141.39 mg/kg, respectively, compared to the maximum values after the end of cultivation. The addition of lignite led to a significant decrease in the relative abundance of Proteobacteria, while the relative abundance of Acidobacteria, Actinobacteria, and Firmicutes increased. The organic components input from lignite dust can produce stimulating effects in the short term. Its decomposition process by soil bacteria can also promote the accumulation of soil CO₂ mineralization, increasing the diversity and variation of soil bacterial communities. The organic carbon in lignite dust greatly participates in the turnover process of soil organic carbon pool.

In order to investigate the effects of different application rates and methods of humic acid-containing water-soluble fertilizers on the water spinach quality, nutrient contents, soil carbon contents, and soil enzyme activities, eight treatments were established. These treatments included: control group (CK), conventional fertilization (CF), root-applied humic acid water-soluble fertilizer with full substitution (RT₁), root-applied humic acid water-soluble fertilizer with 50% substitution (RT_0.5), root-applied humic acid water-soluble fertilizer with 25% substitution (RT_0.25), leaf application of humic acid water-soluble fertilizer with full substitution (LT₁), leaf application with 50% substitution (LT_0.5), and leaf application with 25% substitution (LT_0.25). The physical and chemical properties of the soil after harvest were determined, alongside the quality indices of water spinach yield, and the impact of fertilization methods was comprehensively evaluated using principal component analysis. The results indicated that RT₁ enhanced yield, soil organic carbon (SOC) content, and soluble solids content by 11.5%, 8.7%, and 8.8%, respectively, compared to CF. On the other hand, LT₁ improved soluble solids, crude protein, and vitamin C content by 17.6%, 15.5%, and 11.0%, respectively, relative to CF, although yield and SOC content decreased by 2.9% and 11.3%, respectively. Significant positive correlations (P<0.05) were found between water spinach yield and quick-acting nitrogen (AN) content as well as SOC, while significant negative correlations (P<0.05) were observed with pH, quick-acting potassium (AK), and quick-acting phosphorus (AP) content. These findings suggested that quick-acting nitrogen nutrients and organic matter played pivotal roles in enhancing the growth and yield of water spinach. Principal component analysis underscored that applying humic acid-containing water-soluble fertilizers was beneficial for producing high-quality vegetables and improving soil quality. Specifically, applying the full amount of humic acid-containing water-soluble fertilizers at the root level (RT₁) yielded the most favorable outcomes compared to conventional chemical fertilizers (CF). Overall, this study provides valuable insights into enhancing crop yield quality, improving soil health, reducing chemical fertilizer dependency, and boosting soil carbon sequestration capacity.

In order to reveal the relationship between soil environmental factors and tea quality in tea gardens on the Yunnan-Guizhou Plateau and to provide the theoretical basis for tea quality optimization more scientifically, 52 soil samples and corresponding tea samples were collected from three major tea-producing areas in Guizhou Province to determine the nutrient and trace element contents in the soil and tea quality parameters in June 2022. The results showed that the range of Fe, Cu, Zn, Mn, and Mo contents of tea plantation soils in Guizhou Province were 82.67-135.80, 0.53-1.68, 2.94-5.60, 16.26-97.80, and 0.03-0.07 mg/kg, respectively, which were rich in trace elements and able to provide a rich source of trace elements for the tea tree. Soil organic matter content and pH were 49.59~68.64 g/kg and 4.45~4.70, respectively, which could provide a good growing environment for tea trees. As a typical Mn-enriched plant, tea in Guizhou Province had the highest Mn enrichment coefficient, the lowest Mo and Fe enrichment coefficients, and Zn and Cu varied in different planting areas. Results based on the random forest model showed that Zn, TP and TN in tea garden soil had the greatest influence on free amino acid content in tea, TN, pH and TP had the greatest influence on polyphenol content, pH, TK and TN had the greatest influence on caffeine content, and TK, Mn and Fe had the greatest influence on water leachate content of tea. The study showed that soil nutrient contents had a greater influence on tea quality, while trace elements had a lesser effect on tea quality.

In order to investigates the photosynthetic characteristics and nitrogen use efficiency of Bainong207(BN207) under different nitrogen managements so as to establish optimal nitrogen management and achieve the goal of green, high-yield, and efficient cultivation, using BN207 as the experimental material, five different nitrogen gradients were set, namely 0 (N0), 120 (N120), 180 (N180), 240 (N240), and 360 (N360) kg/hm². The changes in photosynthetic performance, chlorophyll fluorescence parameters, and leaf area index (LAI) during the mid to late grain filling stages of wheat, as well as their effects on biomass, nitrogen use efficiency, and yield. were analyzed. The results indicated that compared to N0, in N180, N240 and N360 groups, the chlorophyll fluorescence parameters of BN207, including F_V/F_M (the maximum quantum yield of PS Ⅱ under dark adaptation), ET_O/RC (the energy captured by a unit reaction center for electron transport), LAI, the accumulation of grain nitrogen, biomass, and yield, increased by 0.71%-4.87%, 3.45%-5.70%, 117.22%-157.64%, 62.67%-53.98%, 39.30%-57.01%, and 27.87%-28.92%, respectively. The peak values of the OJIP curve and nitrogen use efficiency in all groups decreased, but there were no significant differences among the nitrogen treatments. Additionally, the net photosynthetic rate (P_n) of BN207 in the N180 group was significantly higher than in other groups, indicating that BN207 was more conducive to achieving the goal of green, high-yield, and efficient cultivation in the N180 group. The linear plus plateau results indicated that when the nitrogen application reached 172.14 kg/hm², the yield of wheat reached a plateau. In conclusion, the optimal fertilization rate for BN207 was 172.14 kg/hm², and this result could provide a theoretical basis for high-yield cultivation management of BN207 in the North China Plain region.

To explore the effects of biological measures on improving the soil environment of artificial forest slopes, five hedgerows of Lycium chinense Miller, Prunus humilis Bunge, Forsythia suspensa (Thunb.) Vahl, Lonicera japonica Thunb., and Mentha canadensis Linnaeus were set up on typical slopes in the eastern foothills of Taihang Mountains, with blank bare ground in a parallel position taken as the control. The effects of different hedgerows and their belts on surface soil water and fertilizer were analyzed. The results showed that: (1) Among the indicators related to soil water, the natural water content of soil in the upper and middle positions of different hedgerow belts increased by 14.55% to 62.69%, compared with the blank control group. The total soil porosity was higher than that of the blank control group, and the differences between different hedgerows were significant (P<0.05). The soil bulk density of hedgerows decreased significantly compared with the blank control group, and the content of soil clay particles in the upper and middle positions of the belt decreased by 1.25% to 18.56% compared with the blank control group. (2) Among the indicators related to soil fertilizer, the soil organic carbon content of different hedgerows increased by 8.93% to 64.00% compared with the blank control group. The soil carbon-to-nitrogen ratio was significantly higher than that of the blank control group, while the soil pH, conductivity, and total nitrogen content were mainly lower than that of the blank control group. The differences between different hedgerows were significant (P<0.05). (3) The correlation between soil water and fertilizer indicators of each hedgerow was significant, with significant positive and negative correlations observed between soil total nitrogen and electrical conductivity and natural water content, respectively (P<0.05). There were significant positive correlations between soil organic carbon and powder grains (P<0.05), and significant negative correlations between soil organic carbon and total porosity and sand grains (P<0.05). (4) Comprehensive scores of effects on soil water and fertilizer of different hedgerows were as follows: Lonicera japonica Thunb. (1.970)> Mentha canadensis Linnaeus (1.677)> Prunus humilis Bunge (1.670)> Lycium chinense Miller (1.655)> Forsythia suspensa (Thunb.) Vahl (1.643)>blank control group (1.527). All five hedgerows could maintain soil moisture and regulate soil fertilizer in the short term. Lonicera japonica Thunb. exhibited the best soil water and fertilizer regulation effect and could be used to rehabilitate Taihang Mountain slopes with more severe soil erosion.

In recent years, the planting mode of intercropping watermelon in orchards in the middle and lower reaches of the Yangtze River in China has garnered significant attention. In order to investigate the carbon emission of interplanting watermelon in orchards under different fertilization modes, the study was conducted in a young citrus orchard located at Yitang Town, Hunan Province, three treatments were considered: no fertilizer (CK), chemical fertilizer (NPK), and chemical fertilizer combined with manure (NPKM). It analyzed the difference in the yields and net benefits of intercropping watermelon in the young orchard under the three fertilization regimes. The life cycle assessment (LCA) was performed to evaluate the carbon footprint of the watermelon production system, and to identify the agricultural factors with the highest contribution to carbon emissions under different fertilization regimes. The results showed that compared with CK, the application of the fertilizer significantly increased watermelon yield and greenhouse gas (GHG) emissions, and the net benefit of NPK and NPKM increased by 176.9% and 185.2%, respectively. The total carbon emissions were 1 897.19, 20 682.54 and 19 889.19 kg/hm² (CO₂-eq) for CK, NPK and NPKM, respectively. The production stage of agricultural inputs (e.g. fertilizers) was the main contributor to GHG emissions in the life cycle of watermelon, starting from raw materials to final products. Compared with NPK, the carbon footprint per unit area, per unit yield, and per unit net benefit under NPKM reduced by 30.4%, 28.8% and 32.4%, respectively. The contribution analysis showed that fertilizer production was the primary factor contributing to the carbon footprint of NPK (78.2%) and NPKM (42.9%). In conclusion, considering the carbon footprint and economic benefit, NPKM was better than CK and NPK in intercropping watermelon in young orchards. Also, this study indicated that the fertilizer production technology was one of the key factors restricting the low-carbon emission reduction of watermelon production in the middle and lower reaches of the Yangtze River Basin in China.

To elucidate the characteristics of yield formation and nitrogen uptake of water-saving and drought-resistance rice (WDR) under different irrigation conditions, five irrigation treatments were set up: 100% (0.63 L/kg), 80% (0.51 L/kg), 60% (0.38 L/kg), 40% (0.26 L/kg) and 20% (0.14 L/kg). Single factor analysis of variance was employed to investigate the impacts of different irrigation treatments on the yield components, the root wounding sap rate and the dry weight at maturity, and nitrogen accumulation of four test varieties, including HY73, WDR129, HY518 and YJ4038. The results demonstrated a reduction in yield, yield components, root wounding sap rate, and dry weight of the four test varieties with the reduction of irrigation. The decreases in the traditional rice varieties HY518 and YJ4038 were more severe than those of the WDR varieties HY73 and WDR129; the impacts of low irrigation treatments on the WDR varieties HY73 and WDR129 were slight, and the amount of nitrogen accumulated significantly higher than that of the traditional rice varieties HY518 and YJ4038. The research showed that the WDR varieties HY73 and WDR129 exhibited enhanced nitrogen accumulation and yield under low irrigation conditions, as a consequence of maintaining a higher rate of root wounding sap.

The development of modern green manure is one of the effective approaches to guide the green development of agriculture in China. It is of great significance to explore the effect of planting green manure on the high yield, high efficiency, and green low-carbon production of Chinese prickly ash in Chongqing municipality based on optimized fertilization. Using Zanthoxylum armatum v. novemfolius as test material, a field experiment was conducted from 2021 to 2022 in Jiangjin County, Chongqing, to investigate and compare the effects of farmers' conventional management and planting green manure under optimized fertilization on the yield, net above-biomass accumulation and quality of Chinese prickly ash, aboveground biomass and nutrients accumulation of green manure, soil chemistry, and economic benefit and environmental costs of Chinese prickly ash. The results showed that compared with conventional planting management, the contents of soil organic matter, alkali-hydrolyzed nitrogen and available phosphorus were significantly increased by planting green manure based on the optimized fertilization. Planting Vicia villosa Roth, Vicia sativa L., Trifolium dubium Sibth., Astragalus sinicus L. increased the yields of Chinese prickly ash by 51.2%, 17.3%, 4.52% and 4.03%; the concentrations of fruit numb-taste components and volatile aromatic oil were significantly increased by 10.7%-24.6% and 10.7%-22.7%, respectively. The net income increased by 3 871-21 968 yuan/hm² as affected by planting Vicia villosa Roth and Vicia sativa L. Environmental cost analysis showed that planting green manure based on the optimized fertilization could obviously reduce the active nitrogen loss and N footprint by 13.8% and 17.0%-42.9%, respectively, meanwhile reduce the greenhouse gas emission and C footprint by 12.7% and 16.2%-42.2%, respectively, in the annual production cycle of Chinese prickly ash. According to a comprehensive analysis of multiple indicators such as productivity, quality, economic and environmental benefits, planting green manure (such as Vicia villosa Roth and Vicia sativa L.) should be a suitable model to ensure high-quality, high yield, high efficiency, green and low-carbon production of Chinese prickly ash in Chongqing.

A 1.3 hm² paddy field was selected in Jiashan County, Zhejiang Province, and four treatment groups, briefly referred to as water-saving irrigation, water-saving non-returning, ordinary returning, and ordinary non-returning, were set up with two planting modes, namely water-saving drought pipe + straw returning/non-returning and ordinary inundation irrigation + straw returning/non-returning. The methane (CH₄) and nitrous oxide (N₂O) emission data from 336 rice fields in 28 batches obtained by static box gas chromatography, in combination with the analysis results of 12 samples of 6 environmental factors, including soil particulate organic carbon (POC), were used to explore the influence of planting mode and straw management on greenhouse gas emission characteristics of rice fields. The results showed as follows: (1) The cumulative CH₄ emissions were in the order of ordinary returning > ordinary non-returning > water-saving returning > water-saving non-returning, and the cumulative N₂O emissions were in the order of ordinary returning > water-saving non-returning > water-saving returning > ordinary non-returning. The global warming potential (GWP) and greenhouse gas emission intensity (GHGI) of ordinary returning group were the highest, being 7 696.03 kg/hm² (calculated as CO₂) and 0.97 kg/kg, and those of water-saving non-returning group were the lowest, being 2 110.12 kg/hm² and 0.21 kg/kg, respectively. (2) The analysis results of the least significant difference method showed significant differences in cumulative CH₄ emissions among the treatment groups. According to Pearson correlation analysis, the cumulative CH₄ emission was extremely significantly positively correlated with POC content (P <0.01) and significantly positively correlated with microbial carbon content (P <0.05). The cumulative emission of N₂O was significantly positively correlated with ${\mathrm{NO}}_3^- $-N content (P <0.05), and GWP and GHGI were extremely significantly positively correlated with POC content (P <0.01). (3) Both planting mode and straw management had extremely significant effects on CH₄ cumulative emissions (P <0.01), and their interaction had significant effects on CH₄ cumulative emissions and N₂O cumulative emissions (P <0.05). The research shows that rice water-saving and drought-tube planting combined with straw returning is a climate-friendly high-yield and economic planting model, which can ensure food security, reduce the cost of straw leaving the field, and play a positive role in slowing down the global greenhouse effect.

Hubei Province is a major agricultural province in China. The scientific measurement of the carbon sink of crops in Hubei Province, which clarifies the baseline, is of significant importance for carbon sink trading and the development of low-carbon agriculture. The study measured the carbon sink of crops in Hubei Province from 1997 to 2022, employing the Dagum Gini coefficient, Kernel density estimation, and Markov chains, to explore the regional differences and dynamic evolution characteristics of the crop carbon sink in Hubei Province. The results indicated that from 1997 to 2022, the crop carbon sink in Hubei Province exhibited a fluctuating upward trend, presenting a "W" shaped distribution with an average value of 120.853 million tons, with grain crops being the primary contributor to the crop carbon sink. Under the "dual carbon" context, an analysis of three major regions and cities (prefectures) in Hubei Province revealed that from 1997 to 2022, the eastern region of Hubei Province ranked first among the three major regions in terms of crop carbon sink. The Dagum Gini coefficient analysis showed certain regional differences in the crop carbon sink in Hubei Province, mainly coming from ultra-variable density, with an average contribution rate of 53.58%. The total crop carbon sink in Hubei Province exhibited strong stability and demonstrated certain characteristics of club convergence. Finally, this paper proposed the development of methodologies and standards for crop carbon sink accounting, the formulation of differentiated policies for increasing agricultural carbon sink, and suggestions for exploring countermeasures for carbon sink trading.

Rice methane emissions are an important source of agricultural methane emissions, and timely and accurate estimation of rice methane emissions can provide valuable information for policymakers. The data sources, methods, and uncertainties of remote sensing monitoring of rice methane emissions, as well as its current status of development and future outlook, were summarized by means of conceptual analysis and literature research. The results show that remote sensing technology is largely promising for rice methane emission monitoring. It can not only directly monitor rice methane emissions through top-down methods but also indirectly estimate rice methane emissions by combining them with bottom-up methods. However, how to improve the accuracy of top-down and bottom-up methods and narrow the differences between the two types of methods is the key issue that needs to be addressed. In the future, new remote sensing technologies and sensors with better performance can provide additional assurance for accurate estimation of rice methane emissions. The fusion of remote sensing data from multiple sources and the combination of top-down and bottom-up methods are important research directions for quantifying the uncertainty of remote sensing monitoring of rice methane emissions.

As an important part of achieving the goal of "zero waste in urban and rural areas", returning the agricultural organic waste to farmland is a resource-saving and environmentally friendly utilization path, which is of great significance for improving the rural pollution control level, promoting sustainable development of agriculture, and helping China to achieve the goal of carbon peak and carbon neutrality. Based on the systematic summary of the main paths and research status of returning agricultural organic waste to farmland, the authors analyzed the impacts of returning agricultural organic waste to farmland on improving soil health and greenhouse gas emissions and proposed feasible solutions to the current problems. The studies showed that returning to farmland could resolve most agricultural organic waste utilization outlets, improving soil fertility and carbon sequestration. However, it also brought new problems, such as increasing pests and diseases in farmland, methane emissions, and the overload of soil manure consumption. In addition, market factors for returning organic waste to farmland were imperfect, making it difficult to form an effective market-closed loop in the short term. Scientific research and institutional construction of returning agricultural waste to farmland should be accelerated from the aspects of constructing a long-term and systematic in situ monitoring network, improving the monitoring and evaluation standard system on the farmland utilization effect of organic waste along with replenishing market elements, in order to offer theoretical support for promoting the sustainable development of agricultural ecosystem, ensuring food security and coping with global climate change.

Composting livestock and poultry manure through aerobic composting technology using agricultural and forestry wastes is an effective way to reduce environmental pollution and avoid waste of resources. Fresh cow manure supplemented with agricultural and forestry wastes was used for composting in pilot experiments. The effects of different agricultural and forestry wastes on the composting process were investigated by characterizing the differences in physical and chemical properties, the evolution of the material structure of organic matter and humus, and the changes in enzyme activities during the composting process. The results showed that in the early stage of composting, the easily degradable organic matter was degraded by microorganisms, resulting in an increase in the temperature of the compost. In addition, the contents of ammonium nitrogen (${\mathrm{NH}}_4^+ $-N), humic acid (HS) and fulvic acid (FA) decreased gradually. As the high-temperature period continued, microorganisms began to accelerate the degradation of difficult-to-degrade macromolecular organic matter, leading to a decrease in cellulose and hemicellulose contents and a rapid increase in the proportion of lignin content. When the temperature dropped, the activity of nitrifying bacteria was gradually increased, and a large amount of ammonium nitrogen was converted into nitrate nitrogen (${\mathrm{NO}}_3^- $-N). Furthermore, the reduction of organic matter content in the pile body diminished the urease activity. In the later stage of composting, the proportion of refractory lignin was higher, the utilization of organic matter was slow, and the activities of polyphenol oxidase and catalase were inhibited. The research results can provide a scientific basis for optimizing the composting process and improving the quality of composting.

Biochar application in facility agriculture soil has a significant impact on the forms of soil nitrogen. Clarifying the effects of different fertilization treatments with the addition of biochar on various forms of nitrogen in the soil of facility agriculture can provide a scientific basis for emission reduction through the application of biochar in facility agriculture. The dissolved organic nitrogen (DON) and inorganic nitrogen (N_min) in soil were measured in greenhouse vegetable soil (brown fluvio-aquic soil) after biochar application under different fertilization regimes (no fertilizer (CK), manure (M), chemical fertilizer (F), chemical fertilizer plus manure (M+F), using indoor constant temperature aerobic cultivation and gas chromatography. Incubation was carried out to investigate N₂O release and the contents of DON, N_min after 2% (biochar/dry soil) and 4% biochar application under the different fertilization regimes. The influence of biochar addition on soil N₂O releases was studied, and the correlation between the changes in DON and N_min contents and soil N₂O releases was analyzed. The research indicated that the application of biochar had different effects on the release rate and cumulative release of soil N₂O under different conditions. Under CK and M patterns, biochar application significantly increased the rate and amount of soil N₂O release in the early period (0-1.5 d). During 2-60 d, biochar application had no significant effect on the rate and amount of soil N₂O release in CK pattern. Biochar application had no significant effect on the soil N₂O release rate, but 4% biochar at the end of the incubation significantly increased the cumulative soil N₂O release in M pattern. In F and M+F treatments, biochar application reduced the soil N₂O release rate in the early period (0-2 d), with an increasingly apparent effect as the amount of biochar applied increased. In F and M+F treatments, biochar application significantly increased the soil N₂O release rate during 2-25 and 3-14 d, respectively, but the effect on the rate was not significant in the subsequent stages. After cultivation, the cumulative soil N₂O release in F and M+F treatments with 2% and 4% biochar application were significantly increased by 78% and 90%, 80% and 67%, respectively. The correlation analysis results showed that there was an obvious positive correlation between DON and N_min contents and N₂O emission with biochar application. The addition of biochar had a direct impact on N₂O release by adjusting the contents of DON and N_min in the soil. The release rate and cumulative release of N₂O from different fertilized soils showed different trends when biochar was added. However, due to the diversity of biochar properties, the variation in types of chemical and organic fertilizers, and differences in fertilization methods and timing, a reasonable analysis was required based on the specific conditions of the study when assessing the impact of biochar addition on soil N₂O cumulative release.

Peanut shells lignocellulose/β-cyclodextrin/acrylic acid composite hydrogel (PS(H)/β-CD/PAA) was prepared by free radical polymerization, using peanut shells(PS) and acrylic acid(AA) as polymerization monomers, potassium persulfate(APS) as initiator, N,N-methylenebisacrylamide(MBA) as crosslinking agent, β-cyclodextrin(β-CD) as reinforcing material. The surface properties and size morphology of the composite hydrogel adsorbent were characterized. The adsorption behavior and mechanism of PS(H)/β-CD/PAA on Cd²⁺ and Pb²⁺ under different environmental factors were investigated. As a result, PS(H)/β-CD/PAA had a porous network structure and positive mechanical properties when β-CD was added. PS(H)/β-CD/PAA presented lower synthesis cost and recyclability. The adsorption of PS(H)/β-CD/PAA on Cd²⁺ and Pb²⁺ reached adsorption equilibrium within 60 min and worked effectively in a wide pH range of 3-8. The maximum adsorption capacity of PS(H)/β-CD/PAA composite hydrogel for Cd²⁺ and Pb²⁺ was 115.67 and 181.71 mg/g, respectively. The adsorption process of PS(H)/β-CD/PAA on Cd²⁺ and Pb²⁺ was mainly carried out through ion exchange, complexation or coordination interaction. In addition, when treating actual wastewater, the removal efficiency of PS(H)/β-CD/PAA on Pb, Cd²⁺, Cu²⁺ and Ni²⁺ was 76.4%, 88.6%, 72.9% and 31.6%, respectively. In a word, PS(H)/β-CD/PAA exhibited good effectiveness in treating heavy metals in water, took full advantage of resources and saved costs, and could serve as a potential new material for heavy metal wastewater treatment.

Efficient and high-capacity adsorption materials are crucial for improving the phosphorus removal efficiency of constructed wetlands. This study focuses on preparing porous phosphorus removal filter media using construction wastes (mainly waste concrete and waste foam bricks) as the main raw materials. The filter material was characterized for their main chemical composition and morphological features using X-ray diffraction and scanning electron microscope. The adsorption performance of the filter material for phosphorus in water was evaluated through adsorption kinetics and adsorption isotherm experiments, static comparative experiments, and dynamic experiments. The results showed that the material had a large specific surface area and well-developed pore structure, featuring a layered pore structure of internal microstructure with a specific surface area of 22.7 m²/g. The adsorption process fitted the pseudo-second-order adsorption kinetics model and Langmuir adsorption isotherm model, with the adsorption mechanism being primarily monolayer physical and chemical composite adsorption with a maximum adsorption capacity of 693.21 mg/g. In static adsorption experiments with a total phosphorus concentration of 0.4 mg/L, the average phosphorus removal rate of the porous material within 4 hours was 65.38%, which was 4.10, 1.98, 3.52, 2.29 and 1.59 times higher than that of waste concrete, waste foam bricks, ceramic granules, diatomaceous earth, and activated carbon, respectively. In dynamic experiments simulating horizontal subsurface flow wetlands with an influent total phosphorus concentration of 0.40 mg/L and hydraulic loads of 0.48, 0.96, 1.20, and 2.40 m³/(m²·d), the average phosphorus removal rates were 95.74%, 93.56%, 80.42% and 55.34%, respectively. Under a hydraulic load of 0.96 m³/(m²·d), an influent average phosphorus concentration of 0.52 mg/L, and continuous inflow for 45 days, the average phosphorus removal rate of the porous material was 92.65%. The filter material had the advantages of a simple preparation method, excellent phosphorus removal performance, effective utilization of construction waste, and application potential as constructed wetland filler.

To mitigate the environmental and climate impacts of industrial solid waste management and disposal processes, and to enhance recycling efficiency, this study developed a multidimensional optimization method for the recycling of industrial waste. The method integrated three indicators: environmental-resource interaction attribute, life cycle assessment, and economic resource value assessment. The findings indicated that compared to landfill methods, recycling pathways through upcycling and downcycling of industrial solid waste significantly reduced ecotoxicity and human health toxicity by 96.86% and 98.53%, respectively. The method can also diminish soil pollution and preserve soil ecological health. It was anticipated that by 2035, the proportions of upcycling, downcycling, and reuse of copper smelting slag would reach 30%, 50%, and 10%, respectively, achieving optimal target values. However, an increased proportion of upcycling would lead to higher carbon emissions and reduced overall benefits. Based on these results, downcycling could process a large volume of industrial solid waste in the short term but was constrained by the construction industry and product quality management. Therefore, long-term planning requires rationally allocating the proportions of industrial solid waste recycling pathways to maximize environmental and economic benefits.

Continuous rainfall on the slope may yield surface runoff and subsurface flow. Surface runoff can transfer a large amount of nutrients in the topsoil (usually 0-20 mm thick) from the soil to the receiving environment through dissolution, erosion, and transportation. The change of rainfall intensity and slope can affect the intensity of slope runoff, thus changing the concentration and flux process of total nitrogen (TN), total phosphorus (TP), dissolved organic carbon (DOC) and other nutrients in runoff. A rainfall experiment considering three typical rainfall intensities (40, 60, 90 mm/h) and slopes (6°, 12°, 18°) was conducted, and the characteristics of runoff and the loss of TN, TP, and DOC on purple soil slopes in hilly areas under different conditions were explored. The results showed that: (1) The critical slope gradient for runoff was not a fixed value. When the rainfall intensity was 60 mm/h or less, the critical slope gradient ranged from 6° to 18°. However, no distinct critical slope was observed when the rainfall intensity reached 90 mm/h. (2) Under the same rainfall intensity, the concentration of TN and DOC in runoff was positively correlated with the slope gradient (18°>12°>6°). However, at a rainfall intensity of 90 mm/h, the relationship between TP concentration in runoff and slope was 6°>12°>18°, whereas under other rainfall intensities, it was 12°>18° >6°. With the exception of the 12° slope, the loss of DOC increased as rainfall intensity increased. The maximum loss of TP occurred on the slope of 6° under a rainfall intensity of 90 mm/h, reaching 0.91 mg/m², belonging to the source limitation type. In contrast, TP losses on other slopes belonged to the transport limitation type. (3) The runoff and sediment yield on the slope were primarily influenced by rainfall intensity. Significant correlations existed between runoff and rainfall intensity, as well as between runoff and the losses of TP and DOC. The correlation between the slope gradient and the losses of carbon, nitrogen, and phosphorus was not significant. However, a significant correlation was observed between the loss of TN in runoff and the losses of TP and DOC. Comprehensive research showed that under the combination of high-intensity rainfall and a small slope gradient, the runoff, TP and DOC loss were significantly higher than the other combinations of rainfall intensity and slope. In contrast, in the combination of heavy rainfall intensity and a steep slope gradient, TN loss reached its peak. Therefore, special attention needs to be paid to the loss of TP and DOC in purple soil on small slopes under heavy rainfall and the loss of TN on steep slopes under heavy rainfall.

Non-point source pollution from farmland drainage in the Hetao Irrigation District of Inner Mongolia is identified as the main source of pollution in Wuliangsuhai, exhibiting unique pollution characteristics and generation/discharge pathways. Through literature review and on-site investigation, this study summarized the current status of the irrigation/drainage system, analyzed the characteristics of farmland drainage pollution in the district, clarified the generation/discharge pathways of farmland drainage pollutants, and proposed specific prevention/control measures considering the influencing factors of farmland drainage pollution. The results showed that: (1) The drainage system in the district played a crucial role in transporting farmland drainage pollutants, but its drainage function was gradually weakened in recent years. (2) A significant portion of water used for irrigation during non-growing seasons accounted for 55%-60% of annual water consumption, among which the water used for washing salt in autumn every year accounted for 1/3 of the annual irrigation water with a low utilization rate of irrigation water resources. (3) Pollutants, such as chemical oxygen demand (COD), ammonia nitrogen (${\mathrm{NH}}_4^+ $-N), and total nitrogen (TN), originated within the Hetao Irrigation District, with the autumn irrigation period posing the highest risk for non-point source pollution. (4) Agricultural activities were a major source of nitrogen pollution, with nitrogen seeping into the soil, migrating to shallow ground, and ultimately draining into water bodies. (5) Factors such as irrigation systems, on-farm drainage processes, and external drainage processes significantly affected farmland drainage pollution. Considering the specific characteristics of farmland drainage pollution, generation/discharge pathways, and key influencing factors in the Hetao Irrigation District, it was recommended to establish a comprehensive management model tailored to local conditions, which could be achieved through regulating source water, optimizing drainage ditches, and intercepting ecosystem process to improve the water environment in the Wuliangsuhai Basin.

Under the background of "Peak Carbon Dioxide Emissions" and "Carbon Neutrality", the technology type of China's soil remediation projects is continuously shifting towards low-carbon, low-energy, green and sustainable remediation technologies. The environmental footprint of remediation activities has been widely noticed and evaluated. SiteWise^TM, an environmental footprint assessment tool, was used to quantitatively assess the environmental footprint of the whole remediation process of a mercury and PAHs contaminated site in a steel plant in Chongqing. The results showed that the remediation of 3483 m³ of contaminated soil emitted a total of 990.52 t of greenhouse gases (GHGs), consumed 1.57×10⁷ MJ of energy and emitted 4.94×10³ kg of air pollutants. GHG emissions, energy consumption and air pollutant emissions at the construction preparation stage accounted for 6.0%-9.1% of the project, while those at the chemical oxidation stage accounted for 43.6%-48.1%. The GHG emissions, energy consumption and air pollutant emissions at the chemical oxidation + ex-situ thermal pile desorption stage accounted for 45.9%-47.5%. The chemical oxidation + ex-situ thermal pile desorption technology had a greater environmental impact compared to the chemical oxidation technology, and the environmental footprint for remediation of a single cubic volume of contaminated soil was about 5.28-5.97 times that of the chemical oxidation technology. The case study results showed that material consumption was the largest contributor to the environmental footprint, followed by equipment use, transport and residual handling.

Immobilized microbial technology is considered as an effective and environmentally friendly technology for the remediation of polycyclic aromatic hydrocarbons (PAHs)-contaminated soil. With this technology, microorganisms are protected from the surrounding harsh environment so that functional microorganisms remain active in PAHs-contaminated soil for a long time, overcoming the problems of low efficiency and long cycle of traditional microbial remediation. The current status of soil PAHs pollution in China and common bioremediation technologies were introduced. The current research status of immobilized microbial technology and the important factors affecting bacterial immobilization were summarized from carrier materials, PAHs-degrading bacteria and immobilization conditions. The remediation mechanisms of PAHs-contaminated soil with immobilized microbial technology were analyzed from soil environment, microbial community and adsorption-degradation process. Finally, the problems of immobilized microbial technology in the remediation of PAHs-contaminated soil were summarized and future research prospects were proposed from carrier materials, functional microorganisms, immobilization methods, evaluation systems, ecological risks and practical applications.

In order to clarify the current situation and influencing factors of farmland mulch film residue in Xinjiang, samples were taken from typical areas in the north and south of Xinjiang to test and analyze the mulch film residual situation and its influencing factors of film-mulched crops in different regions. The results showed that among the six types of mulch film-covered crops (cotton, processed tomatoes, melons, corn, vegetables, and sunflowers), cotton had the highest residue of mulch film at 129.34 kg/hm², while vegetables had the lowest residue at 71.85 kg/hm². By region, the residual amount of film in Aksu area (145.76 kg/km²) was the highest, and that in Tacheng area (92.71 kg/km²) was the lowest. During the first 15 years, the residual amount of film in farmland was positively correlated with the years of mulching. During the 15 to 25 years of mulching, the residual amount of film first decreased and then increased. The residual amount of film in the 0-30 cm layer increased with the decrease of the film thickness, while there was no significant difference in the 0-20 cm and 20-30 cm layers. For the entire 0-30 cm soil layer zone in Xinjiang, the amount of residual film in the sandy soil zone (184.55 kg/km²) was 1.36 times (P˃0.05 ) and 1.49 times (P<0.05 ) as much as that in the loamy soil zone (135.63 kg/km²) and clay soil zone (124.25 kg/km²), respectively, and the difference between the loamy soil zone and clay soil zone was not significant. The further the farmland was from the village, the smaller the residual amount of film was. The residual amount of film was related to crop type, region, mulching year, recycling method, mulch thickness, soil texture and distance from village. The mulching year and recycling method were the main factors affecting the residual amount of farmland mulch film.

Acid mine drainage (AMD) generated in the process of coal gangue storage poses a serious pollution risk to the surrounding water environment. Based on the concept of "waste to waste", fly ash from coal combustion was selected for the study of contaminant removal in AMD. In response to the poor treatment effect of fly ash (raw ash), we compared the removal effect of fly ash under different modification conditions on the pollutants in AMD, screened out the fly ash-modified materials with the best removal effect, and analyzed the mechanism of the fly ash-modified materials in the process of pollutant removal at the microscopic level. The results showed that the Fe and Mn contents in the simulated AMD wastewater were reduced from 100 mg/L to less than 1 mg/L with 99% pollutant removal after treatment by Ca(OH)₂ flux roasting modified fly ash. The adsorption of Fe and Mn by Ca(OH)₂ flux-roasted modified fly ash was mainly monolayer chemisorption, and the adsorption was close to the equilibrium in 0-2 h. In addition, Ca(OH)₂ flux roasting modification increased fly ash surface roughness and pore number, and formed a hexahedral crystalline phase structure on the surface. Meanwhile, Ca(OH)₂ flux roasting activated Si and Al elements on the surface of the fly ash particles, increased their Zeta potential, reduced the free hydroxyl groups, and increased the fixed hydroxyl groups, which enhanced their adsorption capacity. The Ca(OH)₂ flux roasting modification significantly improved the removal efficiency of pollutants in AMD by fly ash, which provided a material and methodological basis for treating AMD by fly ash.

In order to efficiently remove ammonia nitrogen (${\mathrm{NH}}_4^+ $-N) and phosphates (${\mathrm{PO}}_4^{3-} $-P) from contaminated water and screen mineral-based fillers with excellent adsorption performance used in ecological restoration projects, three natural fillers (zeolite, vermiculite, volcanic rock) and three artificial fillers (ceramsite, biological filter, phosphorus removal filter) were selected to carry out experiments on the adsorption kinetics and isotherm of ammonia nitrogen and phosphorus. The adsorption properties and mechanisms of different mineral-based fillers were compared and analyzed by characterization methods such as X-ray diffraction and scanning electron microscopy. The results showed that the adsorption kinetics of ${\mathrm{NH}}_4^+ $-N and ${\mathrm{PO}}_4^{3-} $-P of the six mineral-based fillers complied with the pseudo-second-order kinetic equation, and the chemisorption process mainly controlled the adsorption rates. Both Langmuir and Freundlich equations could well describe the isothermal adsorption curves, and the theoretical adsorption capacity of ${\mathrm{NH}}_4^+ $-N was ranked as zeolite (5.9416 mg/g) > vermiculite (3.6953 mg/g) > biological filter (3.2500 mg/g) > phosphorus removal filter (3.1389 mg/g) > volcanic rock (1.0000 mg/g) > ceramsite (0.8571 mg/g). The adsorption capacity of ${\mathrm{PO}}_4^{3-} $-P was as follows: phosphorus removal filter (4.2424 mg/g) > biological filter (2.7917 mg/g) > vermiculite (1.6250 mg/g) > ceramsite (1.2105 mg/g) > volcanic rock (1.1579 mg/g) > zeolite (0.5625 mg/g). The adsorption properties of different mineral-based fillers for ${\mathrm{NH}}_4^+ $-N and ${\mathrm{PO}}_4^{3-} $-P were related to their specific surface area, micropore structure, mineral composition and metal element content, etc. Among them, zeolite had the largest specific surface area and cation exchange capacity, thus exhibiting the strongest adsorption capacity for ${\mathrm{NH}}_4^+ $-N. The biological filter and phosphorus removal filter contained tobermolite, calcium, iron and other components with strong phosphorus binding ability, which removed ${\mathrm{PO}}_4^{3-} $-P from contaminated water obviously. On the whole, zeolite and vermiculite could be used for the treatment of ammonia nitrogen contaminated water, and biological filter and phosphorus removal filter could be chosen to remove phosphorus. When treating contaminated water containing both ammonia nitrogen and phosphorus, a variety of mineral-based fillers could be combined. Compared with other mineral fillers, the self-developed biological and phosphorus removal filters had obvious advantages in the simultaneous removal of nitrogen and phosphorus, and could be used as the optimal substrate fillers for ecological restoration projects of contaminated water.