Search

Exploring nutrient limitation in forest soil holds significant implications for forest tending and management. However, current research on nutrient limitation status of microorganisms in Robinia pseudoacacia plantations within the Loess Plateau remains insufficient. To investigate soil microbial nutrient limitation of R. pseudoacacia plantations on the Loess Plateau, we selected R. pseudoacacia plantations with different afforestation time series (15, 25, 35, and 45 years) and a pile of barren slope cropland (control) in Yongshou County, Shaanxi Province as the research objects. We analyzed the contents of soil organic matter, total nitrogen, and total phosphorus, and the activities of β-1, 4-glucosidase (BG), cellobiose hydrolase (CBH), leucine aminopeptidase (LAP), β-1,4-N-acetylglucoside (NAG) and phosphatase (AP). We analyzed the soil nutrient limitation by stoichiometry and enzyme metrology. The results showed a shift in soil pH from alkaline to acidic during vegetation restoration process, and that total phosphorus exhibited a gradual decrease over the course of 0 to 25 years. Soil organic matter, total nitrogen and enzyme activities exhibited an increasing trend during the same time frame. However, between 25 and 45 years of age, soil total phosphorus, soil organic matter, total nitrogen, AP and LAP gradually declined while NAG, BG, and CBH initially increased and then decreased. Notably, the values of (BG+CBH)/(LAP+NAG), (BG+CBH)/AP and (LAP+NAG)/AP in R. pseudoacacia plantations were higher than the global average throughout the process of vegetation restoration. In the study area, the vector length was less than 1 and gradually increased, indicating that a progressive increase in microbial carbon limitation during the process of vegetation restoration. The vector angle exceeded 45° and exhibited an overall decreasing trend, suggesting that soil microorganisms were constrained by phosphorus (P) with a gradual deceleration of P limitation, without any nitrogen (N) limitation. The restoration of R. pseudoacacia plantation resulted in significant change in soil physical and chemical properties, while the time series of afforestation also influenced nutrient limitation of soil microorganisms. [ABSTRACT FROM AUTHOR]

China has proposed a shift from the dual control of energy consumption (control of its total amount and intensity) to the dual control of carbon emissions, demonstrating its firm determination and great responsibility to achieve the goals of reaching peak carbon emissions and carbon neutrality. As the largest carbon-emitting country, China needs to carry out mandatory emission reductions to control carbon emissions and encourage extensive carbon sequestration to achieve socialized negative emissions. As a valuable supplement to the mandatory emission reduction market, the voluntary emission reduction market takes into consideration national participation, citizens' initiative, and market operation. The synergy of these two markets is indispensable for green, low-carbon, and high-quality development in the future. This study focused on the ocean carbon sink ('blue carbon') trading and constructed a DSGE model. Using pulse response, this study determined whether ocean carbon sink trading based on the voluntary emission reduction mechanism could achieve the dual benefits of 'economy development and environmental improvement.' By conducting a sensitivity analysis, the study examined the fluctuation of the dual benefits, and combining with a welfare analysis, it also explored strategies for enhancing the dual benefits and social welfare. The results showed that: 1 Ocean carbon sink trading based on the voluntary emission reduction mechanism could achieve the dual benefits, among which the environmental improvement benefit was more significant. 2 After expanding and strengthening the marine economy and moderately increasing government subsidies, the fluctuation of the dual benefits converged, which helped the smooth operation of the ocean carbon sink market. The efficiency of ocean carbon sinks had a significant impact on the environmental improvement benefit, while the impact of carbon sink prices on the dual benefits was weak. 3 After the implementation of ocean carbon sink trading, social welfare significantly improved, and the welfare improvement effect of the proportion of marine output value was the most significant, followed by government incentive subsidies. The impact of transaction price and carbon sink efficiency on welfare was relatively weak. Finally, this study recommends the further strengthening of the implementation of the strategies of building a 'strong maritime country' and a 'marine community with a shared future' and the acceleration of the high-quality development of the marine economy. It also suggests that we should strengthen the research and technological innovation of ocean carbon sink methodology and continue to improve carbon sink efficiency. The government needs to improve the construction of various systems for voluntary emission reductions, appropriately increase incentive subsidies, and accelerate the implementation of the ocean carbon sink market through the exploration of regional voluntary emission reduction markets. [ABSTRACT FROM AUTHOR]

The vapor-liquid equilibrium (VLE) of CO2 in a reactive solvent is essential for the proper simulation and design of CO2 absorption processes. This work presents a systematic investigation on CO2 absorption in various aqueous monoethanolamine (MEA) solutions. CO2 solubility in MEA was measured at 298, 313, 333, and 353 K with CO2 partial pressure ranging from 34.5 to 78.0 kPa. A modified Kent-Eisenberg model was developed based on the measured solubility data, showing good predictions over the liquid phase speciation for the CO2-H2O-MEA system. We presented a new analysis based on the first-order difference curve of distribution profiles of the species. Based on the main reactions that occurred, the CO2 absorption process was demonstrated to be divided into four regions with increasing CO2 loading from 0 to 1. Accordingly, kinetic study was proposed to be conducted in the first region, whereas measuring of mass transfer in the first three regions. The findings in this work extend the existing knowledge of CO2 absorption process in terms of speciation and can provide important guidance for further study of the process characteristics using aqueous amine absorbents. [ABSTRACT FROM AUTHOR]