Search

Agricultural production consumes land and water resources, and contributes to greenhouse gas emissions. Optimizing agricultural management to reduce environmental impacts is essential for regional ecological security. An evaluation framework was applied to assess the greenhouse gas emissions, water utilization, and land use of agricultural production in a typical agricultural region of the Huangshui River Basin on the Qinghai-Tibet Plateau, using footprint analysis. The results showed that agricultural production released 1.73 × 109 kg carbon equivalent (CO 2 -eq), and used 8.39 × 108 m3 of water and 2.96 × 105 ha of land. For the carbon footprint, agricultural material inputs (such as electricity, machinery, diesel, and nitrogen fertilizer) were the largest emission sources. For the water footprint, the blue water footprint was larger than the green water footprint. In addition, suitable management options were explored by establishing six scenarios according to the key factors influencing greenhouse gas emissions and water consumption. For technical strategy management options, using cleaner electricity in irrigation can reduce greenhouse gas emissions by 25.53%. Comprehensive strategies, including fertilizer application optimization and technical strategy management, proved to be more effective and reduced greenhouse gas emissions by 32.41%. The results of this study help to determine optimal agricultural management options for achieving both food security and environmental sustainability in agricultural areas on the Qinghai-Tibet Plateau. [Display omitted] • Multiple environmental footprints were assessed in typical agricultural systems on the Qinghai-Tibet Plateau. • Agricultural material inputs are the greatest GHG emission sources. • Water use depends heavily on irrigation conditions. • Technical strategy management can significantly reduce GHG emissions. [ABSTRACT FROM AUTHOR]

Energy, carbon, water and their interactions determine agricultural production efficiency and sustainability. On the Qinghai-Tibet Plateau (QTP), agricultural activities threaten the ecological security of the region, and agriculture itself is susceptible to climate change. In this study, we applied an energy-carbon-water nexus framework to assess the carbon emissions, water utilization, and energy flow, and their links with agricultural production on the QTP, using emergy analysis, footprint analysis (carbon footprint and water footprint) and a coupling model. The results showed that agricultural activities on the QTP released 2.17 × 1010 kgCO 2 -eq and absorbed 6.00 × 1010 kgCO 2 -eq, using 3.24 × 1022 sej of emergy and 8.19 × 109 m3 of water in 2018. Meanwhile, the energy-carbon-water nexus of agricultural production on the QTP was imbalanced, and the environmental footprint revealed large spatial heterogeneity at county scale. The coupling interaction among the energy-carbon-water nexus in agricultural production was investigated based on the coupling coordination model. Five categories of coupling interaction were identified by the degree of coordination. The largest emitter was agricultural input, especially electricity and nitrogen fertilizer, accounting for 24% and 7% of the total on average, respectively. With regard to emergy flows, renewable organic resources, accounted for 47%, making them the predominant in emergy inputs. The green water footprint (water from natural rainfall) at 51% was higher than the blue water footprint (water from irrigation) at 49%. More measurements to reduce carbon emission and improve the efficiency of energy usage and water usage are needed, such as optimizing planting patterns and structures, promoting cleaner energy, improving the efficiency of agrochemical use and proposing reasonable spatial planning for regional ecological development. Our findings provide a systematic reference for energy-carbon-water nexus analysis and sustainable agricultural development policy for decision-makers on the QTP. [Display omitted] • Footprints of agricultural activities at county scale were evaluated on the Qinghai-Tibet Plateau. • The imbalanced degree of energy-carbon-water nexus caused by agricultural activities was analyzed. • Key factors affecting energy-carbon-water nexus were identified on the Qinghai-Tibet Plateau. • Energy-carbon-water nexus framework of agricultural production was proposed. [ABSTRACT FROM AUTHOR]

Coastal salt marshes have been significantly suffering degradation worldwide, turning these wetlands from carbon sink to carbon source. The additions of carbon-rich substrates in degraded coastal wetlands have been documented to alleviate this situation; however, the microbial responses as well as their carbon metabolisms to the input are not well explored. Here, we investigated the effects of different addition levels (0.1%, 1%, and 3%) of reed straw and biochar addition on microbial communities (bacteria and fungi) and predicted functions of carbon metabolism in degraded coastal salt marshes. The effects of the carbon-rich substrates on microbial communities are more pronounced under 3% of reed straw and biochar than other levels, straw increased opportunistic bacteria (e.g., Bacillus and Cellvibrionaceae) and biochar increased low carbon turnover bacteria (e.g., Acidobacteria and Actinobacteria). The addition of higher doses of reed straw and biochar promoted the carbon metabolism of soil bacteria as predicted by the PICRUSt 2. Interestingly, the addition of reed straw increased the abundance involved in fungal carbon metabolism, but this was not the case for the biochar input. The addition of reed straw and biochar promoted the growth of some bacteria (e.g., Rhizobiales and Bacillus) that are beneficial to plant growth, and decreased some fungal pathogen (e.g., Magnaporthaceae and Phaeosphaeria). Our findings revealed that the carbon-rich substrates addition can reshape the microbial structure and shift their carbon metabolisms, specially, biochar has a higher potential to improve the ecosystem services, such as blue carbon sequestration, of these degraded coastal salt marshes. [Display omitted] • Higher doses of carbon-rich substrate addition reduced microbial diversity. • Adding reed straw increased copiotrophic bacteria but decreased oligotrophic bacteria. • Higher doses of carbon-rich substrate addition promoted bacteria carbon metabolism. • A lower dose of biochar input decreased the carbon metabolism of soil fungi. [ABSTRACT FROM AUTHOR]

Incinerated sewage sludge ash (ISSA) can be used as raw materials for producing construction materials. However, high content of phosphorus in ISSA distinctly lowers the compressive strength of construction materials. This work presented a new method for phosphorus removal from ISSA with thermo-chemical reduction assisted by calcium chloride (CaCl 2) based on carbon reduction reaction and converted phosphate to gas P. It was shown that 82 wt% phosphorus was removed under the addition of 40 wt% CaCl 2 and 40 wt% C at 1373 K, and the removal rate of P was significantly enhanced by CaCl 2. Results showed that the addition of CaCl 2 lowered the treating temperature, increased the reactivity and decreased CO 2 production as well. CaCl 2 molten salt effectively contributed to both solid-state reaction and Ca 5 (PO 4) 3 Cl formation, acting both as a flux and chlorine source. According to metallographic analysis, phosphorus in Ca 5 (PO 4) 3 Cl could be easily deoxidized by C into gas phase P 2 at 1373K. • 82.8% Phosphorus in ISSA was transferred to gas phase by thermo-chemical method. • ISSA was calcined to redox under an inorganic chlorinating agent with carbon. • CaCl 2 molten salt acted as flux in the solid-state reaction. • This method promoted P removal efficiency with lower temperature than former technologies. [ABSTRACT FROM AUTHOR]

Optimizing decision-making to reduce the environmental impact of remediation activities is critical for green and sustainable remediation. Currently, the environmental impact assessment for remediation technologies is primarily based on site-specific data, which makes the assessment results difficult to apply to different site conditions. In our study, an abandoned rubber factory site in the Jiangsu Province of China was used as an example to evaluate the life cycle impact of three frequently used soil remediation strategies including cement kiln co-processing, onsite ex-situ thermal desorption, and offsite ex-situ thermal desorption. The results show that when considering the subsequent disposal of contaminated soil after remediation, the environmental impacts of remediating 1 ton of contaminated soil decrease according to the following order: offsite ex-situ thermal desorption, onsite ex-situ thermal desorption, and cement kiln co-processing. The results also indicate that contaminated soil volume and transport distance profoundly affect the environmental impacts of contaminated soil remediation. Based on these findings, we proposed a generalized method for selecting the most environmentally friendly remediation technology under various site characteristics. Within the developed method, we examined remediation options for 43 sites contaminated by organic chemicals in Jiangsu Province. The simulation results suggest that the optimized remediation options could have reduced environmental impacts by as much as 61.1%. Our study provides insights and valuable information for reducing remediation decision-making costs and promoting sustainable remediation of contaminated soil on a regional scale. [Display omitted] • Soil volume and transport distance have impacts on LCA of remediation strategies. • Site characteristics could be used for remediation decision-making. • New decision-making method could avoid repeated evaluation of life cycle impact. • Contaminated soil reuse decreases the environmental impact of remediation activities. [ABSTRACT FROM AUTHOR]

Ecological restoration is the most promising way to combat ecological degradation and improve ecological stability. However, it remains unclear at what scale ecological restoration is needed for the ecological degradation region related with ecosystem services under ongoing and future climate change. Based on that, this study assessed carbon sequestration (CS), water supply index (WSI), and mean species abundance (MSA) from 2000 to 2020 on the Qinghai-Tibet Plateau (QTP). Moreover, utilizing the Offset Portfolio Analyzer and Locator model to map and quantify the impacts of ecological degradation on CS, WSI, and MSA. Furthermore, this study explored the compensation area based on protection and restoration two compensation types under the shared socioeconomic pathway (SSP) and representative concentration pathway (RCP) scenarios between 2030 and 2060. The results showed that the spatial distribution of CS and WSI had a generally gradual declining trend, and MSA had an increasing trend from the southeast to the northwest. Ecological degradation of 1.21 × 106 ha has impacted 1.39 × 106 ha of terrestrial ecosystems on the QTP, and at least 7.47 × 106 ha of compensation area is needed. Regarding the protection scenario, the compensation area is mainly located in the western and northeastern parts of the QTP, with the highest CS of 8.05 × 105 Mg ha−1 in the SSP1-RCP1.9 scenario and the highest WSI of 0.09 in the SSP4-RCP6.0 scenario. Regarding the restoration scenarios, SSP2-RCP4.5 showed a strong CS capacity with a value of 3.30 × 105 Mg ha−1, while the SSP4-RCP6.0 scenario had an adequate water supply capacity with a WSI value of 0.61. Our findings indicate that a multifaceted assessment can determine the extent of ecological restoration required to mitigate different scales of degradation. This will help conservation managers develop more targeted sustainable management policies. [Display omitted] • Grazing leads to the loss of ecosystem services and biodiversity. • Compensation area should be extended to the northeast of the Qinghai-Tibet Plateau. • Compensation area will be larger than the loss caused by ecological degradation. • SSP1-RCP19 scenarios can benefit ecological sustainability management. [ABSTRACT FROM AUTHOR]

Recycling of waste electrical and electronic equipment (WEEE) reduces the waste of resources, environmental pollution, and human health risks. WEEE recycling involves multiple stakeholders and a complex array of interacting factors that influence the behavior of those stakeholders. Identifying the key influencing factors for these stakeholders helps in the effective development of the WEEE recycling industry. Most previous research has only considered the perspective of consumers, however, this study considered the influencing factors for four key stakeholders: manufacturers, consumers, recyclers and disposers, and the government. The Decision Making Trial and Evaluation Laboratory (DEMATEL) model was used to determine the main factors affecting the typical social recycling behaviors in China. The results show that the most critical influential factor is the government policies that promote WEEE recycling (incentive), whereas the most important centrality factor is the producers that take responsibility for recycling. The disclosure of the environmental product information by manufacturers is the least important influencing factor in the system, which is contrary to conventional understanding. Although the government plays a powerful role, the production, recycling, and processing companies constitute central links in the entire WEEE recycling industry and are therefore important. These results are helpful in formulating relevant policies and affecting the behavior of relevant stakeholders. [ABSTRACT FROM AUTHOR]