Cover illustration
COVER STORY Carbon neutrality and a low carbon economy have become key global objectives and one of China’s national policies. Agricultural ecosystems play a crucial role in climate change mitigation. Achieving carbon neutrality and a low carbon economy in agriculture includes mitigating greenhouse gas emissions from agriculture (cropland, livestock, horticulture) and/or entire food systems; sequestering soil organic carbon through land use change; adopting “climate-smart” [Detail] ...
Download cover ● Gaseous N emissions from orchards, vegetables and tea plantations (OVT) are reviewed. ● Gaseous N emissions from OVT are greater in China than the rest of the world. ● OVT are hotspots for gaseous N emissions from the agricultural sector in China.
Nitrogen fertilizer application has accelerated the agricultural soil N cycle while ensuring food security. Gaseous reactive N emissions from orchards, vegetables and tea plantations (OVT) are less understood than those from cereal crops. This paper presents a compilation of data on soil ammonia, nitrous oxide, and nitric oxide emissions from 1454 OVT systems at 184 unique experimental locations worldwide aiming to investigate their emission characteristics, emission factors (EF), and contribution to total farmland emissions. NH3 and N2O emissions from orchards and N2O and NO emissions from vegetable production were significantly higher in China than in the rest of the world, regardless of fertilizer application, while N2O emissions from tea plantations were lower than for vegetables. The EF of NH3 for vegetables was close to the global mean value with urea application but significantly higher than that of orchards. The EF of N2O in orchards and vegetables was comparable to the global median value, while in tea plantations, the value was 2.3 times higher than the global median value. Current estimates suggest that direct emissions of NH3, N2O, and NO from OVT systems are equivalent to approximately a quarter, two thirds and a half of the total farmland in China, respectively. Future research needs to strengthen observational field studies in establishing standard sampling methods for gaseous N emissions and implementing knowledge-based management measures to help achieve the green development of agriculture.
● A provincial stage-specific greenhouse gas (GHG) accounting model for the Chinese food system was developed. ● From 1992 to 2017, the net GHG emission from the Chinese food system increased by 38% from 785 to 1080 Tg CO2-eq. ● In 2017, top GHG emission regions were located in the central and southern China, the North China Plain and Northeast China, while GHG sink regions were Tibet, Qinghai and Xinjiang. ● Total GHG emission from the Chinese food system could be reduced to 355 Tg CO2-eq in a low-carbon scenario, with enhancing mitigation technologies, transforming diet and its related conditions and increasing agricultural activities contributing 60%, 25% and 15% of the GHG reductions, respectively.
In China, there has been insufficient study of whole food system greenhouse gas (GHG) accounting, which limits the development of mitigation strategies and may preclude the achievement of carbon peak and carbon neutrality goals. The paper presents the development of a carbon extension of NUFER (NUtrient flows in Food chain, Environment and Resources use model), a food system GHG emission accounting model that covers land use and land-use change, agricultural production, and post-production subsectors. The spatiotemporal characteristics of GHG emissions were investigated for the Chinese food system (CFS) from 1992 to 2017, with a focus on GHG emissions from the entire system. The potential to achieve a low-carbon food system in China was explored. The net GHG emissions from the CFS increased from 785 Tg CO2 equivalent (CO2-eq) in 1992 to 1080 Tg CO2-eq in 2017. Agricultural activities accounted for more than half of the total emissions during the study period, while agricultural energy was the largest contributor to the GHG increase. In 2017, highest emitting regions were located in central and southern China (Guangdong and Hunan), the North China Plain (Shandong, Henan and Jiangsu) and Northeast China (Heilongjiang and Inner Mongolia) and contributed to over half of the total GHG emissions. Meanwhile, Xinjiang, Qinghai and Tibet are shown as carbon sink areas. It was found that food-system GHG emissions could be reduced to 355 Tg CO2-eq, where enhancing endpoint mitigation technologies, transforming social-economic and diet conditions, and increasing agricultural productivities can contribute to 60%, 25% and 15%, respectively. Synergistic mitigation effects were found to exist in agricultural activities.
● 0.98 Mg·ha−1·yr−1 Corg accumulation under miscanthus over 26 years. ● Corg accumulation under miscanthus continued even up to 26 years. ● Reintegration of a miscanthus site into a crop rotation induced decreasing C stocks at first after 6 years.
Miscanthus× giganteus may play an important role in replacing fossil energy resources by bio-based alternatives. One further advantage of miscanthus production is the generally high soil organic carbon (Corg) enrichment in soils. Due to declining yields, miscanthus stocks are commonly reintegrated into crop rotation after approximately 20 years. Currently there is only few information, whether these high amounts of Corg can be conserved while intensifying soil tillage and crop management after reintegration. Therefore, we monitored Corg stocks in a control with more than 20 years of continuous miscanthus and in a treatment with reintegration of a 20-years old miscanthus stock into an organic crop rotation. Based on δ13C soil values, we calculated an annual Corg enrichment of 0.98 Mg·ha−1·yr−1 C under miscanthus. More than 95% of the miscanthus-C was determined in the upper 0.25 m of soil. Continuing miscanthus cultivation did not affect yields during the first five extension years and Corg stocks increased further. Following reintegration, Corg stocks remained constant during five years, which was mainly attributed to the humification and/or stabilization of high amounts of destroyed roots and rhizomes. A significant decrease in Corg (−5.7 Mg·ha−1 C) compared to the continuing miscanthus cultivation was at first measured six years after reintegration into crop rotation, underlining the need of long-term investigations. Our data also show, that miscanthus production cycles can be extended in our region, and that sowing of the alfalfa grass mixture after rhizome/root destruction was efficient in preserving Corg stocks for at least first five years after reintegration.
● The contribution of fungal necromass C to SOC increased with aggregate sizes. ● Bacterial necromass had a higher proportion to SOC in silt and clay. ● Cropland management increased microbial necromass in macro- and microaggregates. ● Greater fungal necromass increases were found in macroaggregates under manure input and no or reduced tillage. ● Cover crops increased bacterial necromass in small macroaggregates.
The interactions of soil microorganisms and structure regulate the degradation and stabilization processes of soil organic carbon (SOC). Microbial necromass is a persistent component of SOC, and its magnitude of accumulation dependent on management and aggregate sizes. A meta-analysis of 121 paired measurements was conducted to evaluate the management effects on contributions of microbial necromass to SOC depending on aggregate fractions. Results showed that the contribution of fungal necromass to SOC increased with aggregate sizes, while bacterial necromass had a higher proportion in silt and clay. Cropland management increased total and fungal necromass in large macroaggregates (47.1% and 45.6%), small macroaggregates (44.0% and 44.2%), and microaggregates (38.9% and 37.6%). Cropland management increased bacterial necromass independent of aggregate fraction sizes. Greater fungal necromass was increased in macroaggregates in response to manure (26.6% to 28.5%) and no or reduced tillage (68.0% to 73.5%). Cover crops increased bacterial necromass by 25.1% in small macroaggregates. Stimulation of microbial necromass was proportional to the increases of SOC within soil aggregates, and the correlation was higher in macroaggregates. Increasing microbial necromass accumulation in macroaggregates can, therefore, be considered as a central component of management strategies that aim to accelerate C sequestration in agricultural soils.
● Either increasing C input to or reducing C release from soils can enhance soil C sequestration. ● Afforestation and reforestation have great potential in improving soil C sequestration. ● Long-term observations about the impacts of biochar on soil C sequestration are necessary.
Climate change vigorously threats human livelihoods, places and biodiversity. To lock atmospheric CO2 up through biological, chemical and physical processes is one of the pathways to mitigate climate change. Agricultural soils have a significant carbon sink capacity. Soil carbon sequestration (SCS) can be accelerated through appropriate changes in land use and agricultural practices. There have been various meta-analyses performed by combining data sets to interpret the influences of some methods on SCS rates or stocks. The objectives of this study were: (1) to update SCS capacity with different land-based techniques based on the latest publications, and (2) to discuss complexity to assess the impacts of the techniques on soil carbon accumulation. This review shows that afforestation and reforestation are slow processes but have great potential for improving SCS. Among agricultural practices, adding organic matter is an efficient way to sequester carbon in soils. Any practice that helps plant increase C fixation can increase soil carbon stock by increasing residues, dead root material and root exudates. Among the improved livestock grazing management practices, reseeding grasses seems to have the highest SCS rate.
● Livestock is major greenhouse gas source in agriculture in China. ● Greenhouse gas emissions in livestock shows an upward trend during 1994 to 2014. ● Main mitigation options are improving productivity, feed quality and manure recycling. ● Strengthening monitoring and standards is necessary for capacity building.
Animal husbandry is a major source of greenhouse gas (GHG) emissions in agriculture. Mitigating the emissions from the livestock sector is vital for green development of agriculture in China. Based on National Communication on Climate Change of United Nations, this study aims to investigate the characteristics of GHG emissions of animal husbandry during 1994 to 2014, introduce major emission reduction technologies and their effectiveness, and investigate options for emission reduction for the livestock sector in China. It proposes that control of pollution and carbon emissions can be realized through increased animal productivity, improved feed quality and recycling of animal manure. This paper thus concludes with suggestions of green and low-carbon development of animal husbandry, including the research and development of new technology for emission reduction and carbon sequestration of the livestock sector, enhancement of monitoring and evaluation, and establishment of emission reduction and carbon sequestration standards.
● The carbon footprint of the nitrogen fertilizer chain has decreased significantly over the last decade. ● Different nitrogen fertilizer products have different carbon footprints. ● Structural improvement of N fertilizer products can achieve carbon reduction.
Globally, the reduction of excessive N losses and greenhouse gas (GHG) emissions is a central environmental challenge in the 21 century. China has huge associated emissions during both production and land application phases. In addition, 70% of N fertilizer in China is produced and land applied as urea, which has high associated emissions. This study utilized life cycle analysis to compare the carbon emission capacity of different N fertilizers and quantified GHG emissions from different N fertilizer chains within China. This enabled a new innovative reform model to be proposed, which aims to decrease the carbon footprint and increase the net ecosystem carbon budget of China. The results showed that the carbon footprint of the N fertilizer industry was about 229 Tg·yr−1 CO2-eq in 2020. Through changes away from urea through the production and land application of a mix of newly emerging fertilizers, liquid fertilizers and standard fertilizer reductions to 174–182 Tg·yr−1 CO2-eq. Through the upgrading of mineral N fertilizer production technology, the carbon footprint of N fertilizer chain can be reduced by 34.8 Tg·yr−1 CO2-eq. Such reductions would reduce China’s total GHG emissions to 140–147 Tg·yr−1 CO2-eq.
● Establishment of a rapid tool for monitoring soil carbon sequestration in farmer fields. ● Novel linkage of multiconstituent soil analyses with a carbon mineralization model. ● Extensive calibration and validation of the results of the near-infrared spectroscopy NIRS analyses. ● Soil bulk density derived from NIRS analyses and pedotransfer functions.
In 2015, 17 Sustainable Development Goals (SDGs) were approved, including SDG13, which addresses actions to increase carbon capture (CO2-C storage) for climate change mitigation. However, no analytical procedures have been defined for quantifying soil organic carbon (SOC) sequestration. This paper presents a rapid tool for guiding farmers and for monitoring SOC sequestration in farmer fields. The tool consists of multiconstituent soil analyses through near-infrared spectroscopy (NIRS) and an SOC mineralization model. The tool provides forecasts of SOC sequestration over time. Soil analyses by NIRS have been calibrated and validated for farmer fields in European countries, China, New Zealand, and Vietnam. Results indicate a high accuracy of determination for SOC (R2≥ 0.93), and for inorganic C, soil texture, and soil bulk density. Permanganate oxidizable soil C is used as proxy for active SOC, to detect early management-induced changes in SOC contents, and is also quantified by NIRS (R2 = 0.92). A pedotransfer function is used to convert the results of the soil analyses to SOC sequestration in kg·ha−1 C as well as CO2. In conclusion, the tool allows fast, quantitative, and action-driven monitoring of SOC sequestration in farmer fields, and thereby is an essential tool for monitoring progress of SDG13.
● To achieve food security, Chinese agriculture– food system could not achieve C neutrality. ● China’s dual carbon goals has put forward more strict requirements for the green development of agriculture. ● The realization of C mitigation potential lies in the extensive application of existing technologies and technological innovation.
The agricultural sector, a major source of greenhouse gas emissions, and emissions from agriculture must be reduced substantially to achieve carbon (C) neutrality. Based on a literature analysis and other research results, this study investigated the effects and prospects of C reduction in agricultural systems under different scenarios (i.e., methods and approaches) in the context of China’s dual C goals, as those working in the agricultural sector have yet to reach a consensus on how to move forward. Different views, standards, and countermeasures were analyzed to provide a reference for agricultural action supporting China’s C neutrality goal.
● An expert survey highlighted the most effective strategies for GHG and ammonia mitigation. ● Interventions considered to have the highest mitigation potential are discussed. ● Experts agreed that no single mitigation measure can uniquely deliver GHG and ammonia mitigation. ● Experts noted a need for further investment in research, knowledge exchange, education and to develop implementation pathways. ● There is a need for more data to better quantify mitigation potentials and implement effective management strategies.
Agriculture is essential for providing food and maintaining food security while concurrently delivering multiple other ecosystem services. However, agricultural systems are generally a net source of greenhouse gases and ammonia. They, therefore, need to substantively contribute to climate change mitigation and net zero ambitions. It is widely acknowledged that there is a need to further reduce and mitigate emissions across sectors, including agriculture to address the climate emergency and emissions gap. This discussion paper outlines a collation of opinions from a range of experts within agricultural research and advisory roles following a greenhouse gas and ammonia emission mitigation workshop held in the UK in March 2022. The meeting identified the top mitigation priorities within the UK’s agricultural sector to achieve reductions in greenhouse gases and ammonia that are compatible with policy targets. In addition, experts provided an overview of what they believe are the key knowledge gaps, future opportunities and co-benefits to mitigation practices as well as indicating the potential barriers to uptake for mitigation scenarios discussed.
● Transport stress declined the level of leukocytes including lymphocytes in rat serum. ● Transport stress destroyed intestinal integrity of rat. ● The muscular layer thickness of intestine was decreased after transport stress. ● nNOS expression and nNOS-positive neurons were reduced in rat after transport stress.
Transport stress is commonly suffered by animals with gastrointestinal dysfunction a common symptom. Currently, the mechanisms of transport stress-induced intestine impairment are largely unknown. The aim of this study was to investigate the effects of transport stress on the expression of neuronal nitric oxide synthase (nNOS) and the distribution of nNOS-positive neurons of the intestines in rats and to explore the neuroendocrine mechanism of transport stress. In this study, Sprague Dawley rats (n = 6) were subjected on a constant temperature shaker for 1 (S1d) or 3 d (S3d). Rats exhibited increased serum glucose and diminished total number of leukocytes, in which lymphocytes level was also decreased in the S1d group (P < 0.05). Also, normal intestinal morphology was disrupted in the S1d rats, and the thickness of muscle layers was decreased in duodenum, jejunum and colon of S3d rats. In addition, it was found that nNOS expression, as well as the number of nNOS-positive neurons in the myenteric plexus were downregulated in duodenum, jejunum and colon of S3d rats compared with that of unstressed rats (P < 0.05). These data reveals that transport stress induced intestinal damage and uncovers potential action mechanisms that nNOS-positive neurons and nNOS expression might be involved in modulating this process.
● Summaries on sgRNAs design. ● Overview of the features of 43 web sgRNA designers. ● A platform to select optimal sgRNA design tool.
CRISPR-mediated gene-editing technology has arguably driven an unprecedented revolution in biological sciences for its role in elucidating gene functions. A multitude of software has been developed for the design and analysis of CRISPR/Cas experiments, including predictive tools to design optimally guide RNA for various experimental operations. Different in silico sgRNA design tools have various application scenarios and identifying the optimal design tools can often be a challenge. This paper describes the sgRNA design workflow in experiments, the classification of sgRNA designers, previously published benchmarking work of in silico designers, and the criteria involved how to select an sgRNA web server. Through basic testing, this paper comprehensively overviews and compares the features of 43 web server designers to provide a reference for the readers. Ultimately, the project developed an integrated platform, called Aid-TG, which helps users find appropriate tools quickly.
● Using visual analysis to predict the trend of natural product pest resistance. ● Summarized the anti-insect activity and mechanism of natural products. ● Natural compounds insecticide will be the general trend.
To help in the prevention of large-scale loss of agricultural production caused by crop pests, a visual analysis was performed on the main research areas, key countries, organizational cooperation, citation sources and current trends in pest research by searching the literature of Web of Science database and using CiteSpace 5.8.R3 and VOSviewer 1.6.18 software. Additionally, the effects and mechanisms of natural products with anti-insect activity were summarized through visual analysis. According to the bibliometric analysis, keywords such as mortality (232 occurrences), natural enemy (232 occurrences) and spinosad (110 occurrences) were common, and insecticides and natural enemies of pests were the main methods for killing pests. However, pesticide use exhibits numerous limitations. Co-occurring terms in visualization analysis mainly included residue (193 occurrences), detection (153 occurrences), degradation (133 occurrences), recovery (103 occurrences), pyrethroid (97 occurrences) and pesticide residues (65 occurrences). Thus, pesticides cannot fundamentally solve food security; pesticides also pollute the environment and endanger human health. Therefore, green and efficient pesticides that can replace synthetic pesticides are urgently needed. Natural products have recently gained attention in Brazil, China, the USA and other countries because they are green and pollution-free, and new natural pesticides have been developed. This visual analysis combined data mining with literature review and summarize the anti-pest activities and mechanisms of action of natural products. This information provides a foundation and ideas for researchers to study the application and development of natural products in pest control.
