Rural revival: Navigating environmental engineering and technology.

The necessity for global engineering and technological solutions to address rural environmental challenges is paramount, particularly in improving rural waste treatment and infrastructure. This study presents a comprehensive quantitative analysis of 3901 SCI/SSCI and 3818 Chinese CSCD papers, spanning from 1989 to 2021, using tools like Derwent Data Analyzer and VOSviewer. Our key findings reveal a significant evolution in research focus, including a 716.67% increase in global publications from 1995 to 2008 and a 154.76% surge from 2015 to 2021, highlighting a growing research interest with technological hotspots in rural revitalization engineering and agricultural waste recycling. China and the USA are pivotal, contributing 784 and 714 publications respectively. Prominent institutions such as the Chinese Academy of Sciences play a crucial role, particularly in fecal waste treatment technology. These insights advocate for enhanced policy development and practical implementations to foster inclusive and sustainable rural environments globally.

Mitigating Tetracycline antibiotic contamination in chicken manure using ex situ fermentation system.

Excessive use of tetracycline antibiotics in poultry farming results in significant concentrations of these drugs and tetracycline resistance genes (TRGs) in chicken manure, impacting both environmental and human health. Our research represents the first investigation into the removal dynamics of chlortetracycline (CTC) and TRGs in different layers of an ex situ fermentation system (EFS) for chicken waste treatment. By pinpointing and analyzing dominant TRGs-harboring bacteria and their interactions with environmental variables, we've closed an existing knowledge gap. Findings revealed that CTC's degradation half-lives spanned 3.3-5.8 days across different EFS layers, and TRG removal efficiency ranged between 86.82% and 99.52%. Network analysis highlighted Proteobacteria and Actinobacteria's essential roles in TRGs elimination, whereas Chloroflexi broadened the potential TRG hosts in the lower layer. Physical and chemical conditions within the EFS influenced microbial community diversity, subsequently impacting TRGs and integrons. Importantly, our study reports that the middle EFS layer exhibited superior performance in eliminating CTC and key TRGs (tetW, tetG, and tetX) as well as intI2. Our work transcends immediate health and environmental remediation by offering insights that encourage sustainable agriculture practices.

Urbanization and energy equity: an urban-rural gap perspective.

A high-speed urban expansion in China over the past two decades has been accompanied by a great leap forward for energy consumption. However, such a significant socio-economic transition may increase the potential risk of energy inequality, which deserves special attention. Using China's provincial panel data covering the periods of 1997-2020, this paper mainly studies the impact of urbanization on urban-rural electricity consumption inequality with a modified STRIPAT model. The results of the Generalized Method of Moments (GMM) estimation show that there is a significant U-shaped relationship between urbanization and urban-rural electricity consumption inequality. The estimated short-run turning point arrives at the urbanization level of around 63.54% and 61.18% for the long-run estimates. We further carry out a regional heterogeneity analysis and then have two interesting findings: firstly, the colder northern region's turning point (70.95%) arrives later than the south (57.69%). Secondly, the baseline U-shaped relationship remains for developed eastern regions and the estimated turning point is 57.91%, while for the undeveloped midwestern regions, the relationship is not nonlinear but linearly negative. As an extension, we lastly explore the mechanism underlying the U-shaped relationship, and find that the interaction of urbanization's scale and efficiency effect determines the U-shaped relationship. Our findings remind policymakers that, to narrow the urban-rural development gap, the future preference of energy policy should be dynamically adaptive to varied regions and development stages.

Performance exploration and microbial dynamics of urine diverting composting toilets in rural China.

The ongoing "toilet revolution" in China provides new opportunities to improve the rural living environment and sanitation, and the introduction of new sanitation facilities such as urine diverting composting toilets (UDCTs) is conducive to the effective treatment and resource utilization of feces. This study revealed the degradation performance and microbial community dynamics of UDCTs and clarified the influence mechanism of fecal volume in aerobic composting treatment. The results showed that UDCTs could effectively decompose human feces, with an organic matter degradation rate of 25%⁓30%. The temperature, water content, NH4+-N and nutrient accumulation were higher in the high fecal volume treatment than in the low fecal volume treatment. Bacterial community composition and structure in UDCTs varied with composting stage and fecal volume. The diversity and richness of bacterial community in compost were changed with different fecal volumes, but the dominant groups were similar. Redundancy analysis (RDA) showed that nitrogen and organic carbon were the main drivers of bacterial community changes during composting. Highly nutritious and non-phytotoxic compost products were suitable for agronomic uses. Based on these results, UDCTs can be an effective way to solve the problem of fecal pollution in rural areas, and fecal dosage is a potential influencing factor in the operation and maintenance of composting systems.

Influences of human waste-based ectopic fermentation bed fillers on the soil properties and growth of Chinese pakchoi.

The reuse of human wastes as biofertilizer resources offers a new option for meeting the growing demand for food and addressing poor soil productivity. Feces and black water are ubiquitous human wastes that usually require proper treatment, such as composting and anaerobic digestion, to remove potentially harmful substances before they can be applied as fertilizers. As an effective treatment technology for livestock farming wastes, the ectopic fermentation bed system (EFS) provides a new means of treating human waste and producing organic fertilizer from decomposed filler. Therefore, the objective of this study was to evaluate and compare the nutrient content and fertilizer potential of decomposed fillers obtained after EFS treatment of human feces and black water under different application conditions. The results showed that the application of fillers increased the yield of pakchoi by 3.60⁓29.32% and nutrient uptake by 8.09⁓83.45% compared to the CK, which could effectively promote the growth of pakchoi. This approach also improved the quality of pakchoi and enhanced soil fertility, and differences were observed in the effects of different kinds and application amounts of fillers. Soil EC was the soil property that had the greatest effect on the growth characteristics of pakchoi in this study. These findings help to better clarify the agronomic value of human wastes, but the effects of long-term filler application need to be further explored.

The biomass accumulation and nutrient storage of five plant species in an in-situ phytoremediation experiment in the Ningxia irrigation area.

Phytoremediation has been widely used and is considered an environmentally friendly and efficient method for mitigating nitrogen (N) and phosphorus (P) loads. However, the technique is rarely employed in the Ningxia irrigation area, which suffers from serious N and P pollution. To investigate ways of protecting the aquatic environment in this region, we conducted in-situ experiments along an agricultural ditch in 2014 and 2015. During the pre-experiment in 2014, five single species floating-bed systems (Zizania latifolia, Oryza sativa, Ipomoea aquatica, Lactuca sativa and Typha latifolia) and one multi-species floating-bed system with three replicates were evaluated over about two months. I. aquatica performed best with respect to biomass accumulation and nutrient storage among all plant systems. Multi-species system was not superior to single species systems: 42% and 37% of the N and P storage in the multi-species system were achieved by I. aquatica. In the formal experiment during 2015, I. aquatica was tested again and performed excellently with respect to biomass production (1.06 kg/m2), N (27.58 g/m2) and P (2.34 g/m2) uptake. Thus, this study demonstrated that I. aquatica could be used to reduce N and P loads under saline and alkaline conditions in the Ningxia irrigation area.

Performance of five plant species in removal of nitrogen and phosphorus from an experimental phytoremediation system in the Ningxia irrigation area.

Agricultural non-point source (ANPS) pollution is an important contributor to elevated nitrogen (N) and phosphorus (P) in surface waters, which can cause serious environmental problems. Considerable effort has therefore gone into the development of methods that control the ANPS input of N and P to surface waters. Phytoremediation has been extensively used because it is cost-effective, environmentally friendly, and efficient. The N and P loads from agricultural drainage are a potential threat to the water quality of the Yellow River in Ningxia, China. Yet, phytoremediation has only rarely been applied within the Ningxia irrigation area. In an experimental set-up, five species (Ipomoea aquatica, IA; Lactuca sativa, LS; Oryza sativa, OS; Typha latifolia, TL; Zizania latifolia, ZL) were evaluated for their ability to reduce N and P loads over 62 days and five observation periods. Total N and P concentrations, plant biomass, and nutrient content were measured. The results showed that OS, LS, and IA performed better than ZL and TL in terms of nutrients removal, biomass accumulation, and nutrients storage. The highest overall removal rates of N and P (57.7 and 57.3%, respectively) were achieved by LS treatment. In addition, plant uptake contributed significantly to nutrient removal, causing a 25.9-72.0% reduction in N removal and a 54.3-86.5% reduction in P removal. Thus, this study suggests that OS, LS, and IA would be more suitable than ZL and TL for controlling nutrient loads in the Ningxia irrigation area using phytoremediation.

Environmentally-friendly agricultural practices and their acceptance by smallholder farmers in China-A case study in Xinxiang County, Henan Province.

Intensive agriculture with high inputs has resulted in rapid development of crop production in China, accompanied by negative environmental effects such as serious non-point source agricultural pollution. Implementation of environmentally-friendly agricultural practices can effectively prevent such pollution. However, the acceptance and adoption of such practices are related not only to associated risks and potential benefits, but also to farmers' attitudes to and knowledge of scientifically validated practices. In the presented study we surveyed views of a stratified sample of 150 smallholder farmers and 10 extension service experts from Xinxiang, a high grain-producing county in Henan Province, China. Their opinions were explored in personal interviews using a questionnaire with three sections. The first section mainly sought information on surveyed farmers' demographic characteristics like gender, age and education. The second section concerned their awareness of the environmental problems and losses of yields associated with customary over-fertilization practices, and their main concerns about new practices. The third section addressed farmers' attitudes to, and the extension service experts' professional evaluations of, five selected practices in terms of the importance of seven factors (time demands, costs, risks, compatibility, complexity, trialability and observability). Acceptance indices were calculated from the responses to rank farmers' willingness to accept the five environmentally-friendly agricultural practices, and thus identify the most appropriate to promote in the study area. The results show that costs, followed by risks and observability, are the more important factors affecting farmers' decisions to adopt a practice. The results also indicate that no or minimum tillage and returning straw to the field are the most appropriate practices to promote initially at large scale in Xinxiang. The others could be popularized gradually after providing effective incentives and training. The finding that cost is the main factor influencing Chinese farmer contrasts with reports that EU farmers rank risk and observability as most important, possibly due to differences in income.

Assessment of nitrate leakage and N2O emission from five environmental-friendly agricultural practices using fuzzy logic method and empirical formula.

Agricultural nonpoint source pollution in China has been the major environmental problem, so environmental-friendly agricultural practices (EAPs) must be promoted to improve environmental quality. However, the most suitable practices for each agricultural region must first be identified. Thus, in the presented study a fuzzy-logic method and a revised empirical formula were used to assess nitrate leakage and N2O emissions, respectively, and to compare five EAPs in Xinxiang, a major grain-producing county in Henan Province, China. The required information was collected in face-to-face interviews with 10 extension service experts from the county, using a questionnaire to explore their opinions of the EAPs currently adopted by smallholder farmers, as well as the amounts, frequencies, varieties and proportions of nitrogen fertilizers applied annually. The results indicate that reduced tillage, soil testing and fertilizer recommendations would be the most appropriate practices to initially promote on a large scale in Xinxiang.

Soil respiration in different agricultural and natural ecosystems in an arid region.

The variation of different ecosystems on the terrestrial carbon balance is predicted to be large. We investigated a typical arid region with widespread saline/alkaline soils, and evaluated soil respiration of different agricultural and natural ecosystems. Soil respiration for five ecosystems together with soil temperature, soil moisture, soil pH, soil electric conductivity and soil organic carbon content were investigated in the field. Comparing with the natural ecosystems, the mean seasonal soil respiration rates of the agricultural ecosystems were 96%-386% higher and agricultural ecosystems exhibited lower CO(2) absorption by the saline/alkaline soil. Soil temperature and moisture together explained 48%, 86%, 84%, 54% and 54% of the seasonal variations of soil respiration in the five ecosystems, respectively. There was a significant negative relationship between soil respiration and soil electrical conductivity, but a weak correlation between soil respiration and soil pH or soil organic carbon content. Our results showed that soil CO(2) emissions were significantly different among different agricultural and natural ecosystems, although we caution that this was an observational, not manipulative, study. Temperature at the soil surface and electric conductivity were the main driving factors of soil respiration across the five ecosystems. Care should be taken when converting native vegetation into cropland from the point of view of greenhouse gas emissions.

Leaching behavior of nitrogen in a long-term experiment on rice under different N management systems.

The leaching behavior of nitrogen was studied in single rice paddy production ecosystems in Tsukuba, Japan after 75 years of consistent fertilization regimes (no fertilizer, ammonium sulfate, a combination of composted rice straw with soybean cake, and fresh clover). During the 75-year period, management was unchanged with respect to rice planting density, irrigation, and net N fertilization for each field to which an N-source was added. Percolation water was collected, from May 2001 to April 2002, using porous suction cups installed in the fields at depths of 15, 40, and 60 cm. All water samples were taken to the laboratory for the measurement of both NH(4) ( + )-N and NO(3) ( - )-N concentrations using a continuous-flow nitrogen analyzer. The result indicated that there were significant differences in N leaching losses between treatments during the rice growing season. Total N leaching was significantly lower with the application of composted rice straw plus soybean cake (0.58 kg N ha( - 1)) than with ammonium sulfate (2.41 kg N ha( - 1)), which resulted in N leaching at a similar level to that with the fresh clover treatment (no significant difference). The majority of this N leaching was not due to NO(3) ( - )-N loss, but to that of NH(4) ( + )-N. The mean N leaching for all fertilizer treatments during the entire rice growing season was 1.58 kg N ha( - 1). Composted rice straw plus soybean cake produced leaching losses which were 65-75% lower than those with the application of fresh clover and ammonium sulfate. N accumulation resulting from nitrification in the fallow season could be a key source of nitrate-N leaching when fields become re-flooded before rice transplanting in the following year; particular attention should be paid to this phenomenon.

[N2O and CH4 emission from Japan rice fields under different long-term fertilization patterns and its environmental impact].

This study intended to investigate the greenhouse gases emission from Japan single cropping paddy fields after 75-year continuous application of ammonium sulfate, composted rice straw with soybean cake, and fresh clover, as well as the environmental impact of the emission. During this long period, field management remained constant in terms of rice cultivation density, irrigation, and equivalent net N fertilization. No significant differences were observed in N2O emission among the fertilization treatments, but the CH4 emission differed significantly between organic amendment and ammonium sulfate application, indicating that long-term organic fertilization didn' t increase N2O emission but promoted CH4 emission. The cumulative global warming potential (GWP) of the CH4 and NO2O from the paddy ecosystem was the greatest (310.7 g CO2e x m(-2)) under fresh clover application, followed by composted rice straw plus soybean cake addition (151 g CO2e x m(-2)), and the least (60.6 g CO2e x m(-2)) under ammonium sulfate application. This study showed that for paddy system, it was CH4 instead of N2O the major factor affecting global warming, and thereby, to control and reduce the CH4 emission from paddy system would be the core in mitigating greenhouse gases emission from paddy field. Long-term consecutive application of composted rice straw plus soybean cake could increase soil organic matter, improve soil fertility, promote rice high-yielding, and as well, mitigate CH4 emission, being the recommendable paddy rice production mode in practice.