Biochar has been considered a promising material for soil carbon sequestration. However, there are huge knowledge gaps regarding the carbon reduction effects of biochar-plant-polluted soil. Here, rice straw biochar (RB) was applied in ryegrass-cadmium (Cd)-contaminated soil to investigate the full-cycle carbon dioxide (CO2) emission and intrinsic mechanism. RB resulted in a 37.00 %-115.64 % reduction in accumulative CO2 emissions and a 31.61 %-45.80 % reduction in soil bioavailable Cd throughout the whole phytoremediation period. CO2 emission reduction triggered by RB can be attributed to the regulation of plant and rhizosphere ecological functions. RB could bolster photosynthetic carbon fixation by maintaining the stability of the structure of the chloroplasts and thylakoids, accelerating the consumption of terminal photosynthate, upregulating photosynthetic pigments, and mitigating oxidative damage. Besides, RB reduced the metabolism of readily mineralizable carbon sources while reinforcing the utilization of certain nutrient substrates. Besides, the composition of rhizosphere microbial communities was altered, especially those associated with carbon cycling (Chloroflexi, Actinobacteriota, and Acidobacteriota phyla) to orient soil microbial evolution to lower soil CO2 emission. This study aims to establish a win-win paradigm of carbon reduction-pollution alleviation to deepen the understanding of biochar in carbon neutrality and soil health and provide a theoretical basis for field pilot-scale studies.

Changing climate and shifts in weather patterns have significantly affected food production systems, which is evident in the form of crop damage, reduced yield, and market instability. Water- and chemical-intensive agriculture practices have made the sector a major contributor of carbon emissions, affecting the global climate, nutrient cycling, food security, etc. The adoption of climate-smart agriculture practices can develop agricultural systems that effectively balance agricultural productivity and food security, and contribute to climate change mitigation. The present study is a synthesis of datasets from 116 published articles to assess the changes in soil and its carbon stocks while transitioning from conventional to climate-smart agricultural practices (CSA) in India. The effects of these practices in different edaphic and environmental conditions across the country have also been studied. The meta-analysis of the data was performed using OpenMEE and Jamovi software. Further, a review of existing literature on the impact of CSA practices on crop yield has also been presented. Conservational tillage, integrated nutrient management, and agroforestry-based systems increased the SOC buildup rate by 17.1%, 25.9%, and 39.2%, respectively, compared to the conventional agriculture practices. Climatic factors (temperature and precipitation); edaphic factors (soil pH, depth, and texture); and experiment duration significantly influence the sequestration potential of agroecosystems. Based on the results, the present study concludes that CSA practices curb CO2 emissions and improve soil quality and crop yield along with sequestering carbon. These practices, therefore, offer a win-win strategy for socio-economic development and achieving the target of net-zero emissions by 2070.

Tea is one of the most widely consumed non-alcoholic drink in the world. Green tea, black tea, white tea, and oolong tea are derived from the Camellia sinensis plant, a shrub native to China and India. It contains unique antioxidants. The most potent antioxidants may help against free radicals that can fight against cancer, heart disease, and clogged arteries. The polyphenols present in the tea help the cells from damage and reduce the risk of chronic diseases. The health benefits of these compounds remarkably increase the demand for tea. Tea production is rising drastically; consequently, enormous amounts of tea waste are also generated. Improper disposal and dumping of this tea waste creates a serious problem due to the incineration and the emission of greenhouse gases. This issue can be overcome by adopting suitable technology. Effective microbial degradation and composting of tea waste will contribute to high crop production and plant disease control. The value added products from tea waste can be used in different fields. Planned tea waste valorization processes could generate more income and create rural livelihood opportunities. This review highlights the valorization processes and value-added products from tea waste. The application of value added products for energy generation, wastewater treatment, soil conditioners, adsorbents, biofertilizers, food additives, dietary supplements, animal feed bioactive chemicals, dye, colorant, phytochemicals, bioplastics, cutlery products, scope, and future directions in sustainable utilization has been reviewed. This review article will be beneficial to the researchers for acquiring an in-depth knowledge on the versatile applications of tea waste.

Carbon neutrality is an important goal for addressing global warming. It can be achieved by increasing carbon storage and reducing carbon emissions. Vegetation plays a key role in storing carbon, but it is often lost or damaged, especially in areas affected by desertification. Therefore, restoring vegetation in these areas is crucial. Using advanced techniques to improve ecosystem structure can support ecological processes, and enhance soil and environmental conditions, encourage vegetation growth, and boost carbon storage effectively. This study focuses on optimizing Ecological Spatial Networks (ESNs) for revitalization and regional development, employing advanced techniques such as the MCR model for corridor construction, spatial analysis, and Gephi for mapping topological attributes. Various ecological and topological metrics were used to evaluate network performance, while the EFCT model was applied to optimize the ESN and maximize carbon sinks. In the Thal Desert, ecological source patches (ESPs) were divided into four modularity levels (15.6% to 49.54%) and five communities. The northeastern and southwestern regions showed higher ecological functionality but lower connectivity, while the central region exhibited the reverse. To enhance the ESN structure, 27 patches and 51 corridors were added to 76 existing patches, including 56 forest and 20 water/wetland patches, using the EFCT model. The optimized ESN resulted in a 14.97% improvement in carbon sink capacity compared to the unoptimized structure, primarily due to better functioning of forest and wetland areas. Enhanced connectivity between components contributed to a more resilient and stable ESN, supporting both ecological sustainability and carbon sequestration.

Global warming and algal blooms have been two of the most pressing problems faced by the world today. In recent decades, numerous studies indicated that global warming promoted the expansion of algal blooms. However, research on how algal blooms respond to global warming is scant. Global warming coupled with eutrophication promoted the rapid growth of phytoplankton, which resulted in an expansion of algal blooms. Algal blooms are affected by the combined effects of global warming, including increases in temperatures, CO2 concentration, and nutrient input to aquatic systems by extreme weather events. Since the growth of phytoplankton requires CO2, they appear to act as a carbon sink. Unfortunately, algal blooms will release CH4, CO2, and inorganic nitrogen when they die and decompose. As substrate nitrogen increases from decompose algal biomass, more N2O will be released by nitrification and denitrification. In comparison to CO2, CH4 has 28-fold and N2O has 265-fold greenhouse effect. Moreover, algal blooms in the polar regions may contribute to melting glaciers and sea ice (will release greenhouse gas, which contribute to global warming) by reducing surface albedo, which consequently would accelerate global warming. Thus, algal blooms and global warming could form feedback loops which prevent human survival and development. Future researches shall examine the mechanism, trend, strength, and control strategies involved in this mutual feedback. Additionally, it will promote global projects of environmental protection combining governance greenhouse gas emissions and algal blooms, to form a geoengineering for regulating the cycles of carbon, nitrogen, and phosphorus.

China has built the world's largest high-speed railway (HSR) network, which has fueled regional economic growth. Mounting photovoltaics (PV) on the roofs of HSR station houses and platforms can potentially provide electricity for high-speed trains, change the energy mix, and reduce emissions. Therefore, it is crucial to assess the technical potential and economic environmental performance of PV for the HSR infrastructure. In this study, the PV potential of 973 stations of 108 HSR lines in China was studied in conjunction with geographic infor-mation system (GIS). The results showed that the PV capacity that can be deployed in China's HSR stations at horizontal and optimum tilt angles was 4.36 GW and 2.81 GW, with a total power generation capacity of 108.55 TWh and 74.88 TWh, respectively, which presented a huge power generation potential. The economic analysis showed that the All-consumption scenario and optimum tilt angle had better economic profits than the All-feed-into-grid scenario and the horizontal angle, respectively. Moreover, the use of PV could reduce carbon emissions by HSR stations by 79,895.73 kilotons and 55,112.53 kilotons at horizontal and optimum tilt angles, respec-tively. The study revealed that the combination of PV and HSR infrastructure was a good strategy for sustainable transportation and carbon neutrality goals.