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  • RESEARCH ARTICLE
    Tao SUN, Wenlong LI, Jiandong WEI, Long JI, Qingyao HE, Shuiping YAN
    Frontiers of Agricultural Science and Engineering, 2023, 10(3): 468-478. https://doi.org/10.15302/J-FASE-2022473

    ● Simultaneous H2S and CO2 removal from biogas is studied.

    ● Renewable absorbent from biogas slurry is used in membrane contactor.

    ● More than 98% of H2S can be removed by membrane absorption.

    ● The impurities have less influence on H2S removal efficiency.

    Upgrading biogas into biomethane not only improves the biogas utilization as vehicle fuel or natural gas substitute, but also reduces the greenhouse gases emissions. Considering the principle of engineering green energy process, the renewable aqueous ammonia (RAA) solution obtained from biogas slurry was used to remove H2S and CO2 simultaneously in the hollow fiber membrane contactor. RAA was mimicked in this study using the ammonia aqueous solution mixed with some typical impurities including ethanol, acetic acid, propionic acid, butyric acid and NH4HCO3. Compared with the typical physical absorption (i.e., pure water) removing 48% of H2S from biogas, RAA with 0.1 mol·L−1 NH3 could remove 97% of H2S. Increasing the NH3 concentration from 0.1 to 0.5 mol·L−1 could elevate the CO2 absorption flux from 0.97 to 1.72 mol·m−2·h−1 by 77.3%. Among the impurities contained in RAA, ethanol has a less impact on CO2 absorption, while other impurities like CO2 and acetic acid have significant negative impacts on CO2 absorption. Fortunately, the impurities have a less influence on H2S removal efficiency, with more than 98% of H2S could be removed by RAA. Also, the influences of operating parameters on acid gases removal were investigated to provide some engineering suggestions.

  • REVIEW
    Lianhai WU
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 210-225. https://doi.org/10.15302/J-FASE-2022474

    ● 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.

  • RESEARCH ARTICLE
    Yiwen WANG, Lei CHEN, Kaihang ZHU, Chenxi GUO, Yu PU, Zhenyao SHEN
    Frontiers of Agricultural Science and Engineering, 2023, 10(4): 607-626. https://doi.org/10.15302/J-FASE-2023517

    ● The source and sink status of ditches and ponds was studied in an upland area in the Jinglinxi catchment, China.

    ● Over the past 15 years, ditch length has increased by 32% and small pond number by 75%.

    ● Ditches and ponds are important nutrient sinks in the dry season.

    ● Retention of nutrients in ditches and ponds is up to 20%.

    As the common features of agroecosystems, ditches and ponds benefit the irrigation and drainage, as well as intercepting non-point source pollutants. However, most ditch-pond studies have been conducted in lowland areas. To test this source-sink assumption in upland areas, this study made observations on the ecological function of the ditch and pond system in a typical catchment in China. First, the changes in ponds in the catchment were analyzed using high-resolution remote sensing data. Then, the migration of agricultural pollutants in ditches and ponds were analyzed by field sampling and laboratory detection. The results showed that over the past 15 years the length of ditches in the catchment and the number of small ponds (< 500 m2) have increased by 32% and 75%, respectively. The rate of change in nutrient concentrations in the ditches and ponds were mostly from −20% to 20%, indicating ditches and ponds can be both sources and sinks for agricultural pollutants. Lastly, the contributing factors were explored and it was found that ditches and ponds are important sinks in dry season. However, during the rainy season, ditches and ponds become sources of pollutants, with the rapid drainage of ditches and the overflow of ponds in upland areas. The results of this study revealed that the ditches and ponds could be used for ecological engineering in upland catchments to balance drainage and intercept pollutants.

  • REVIEW
    Yulong YIN, Kai HE, Zhong CHEN, Yangyang LI, Fengling REN, Zihan WANG, Yingcheng WANG, Haiqing GONG, Qichao ZHU, Jianbo SHEN, Xuejun LIU, Zhenling CUI
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 262-267. https://doi.org/10.15302/J-FASE-2023496

    ● 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.

  • RESEARCH ARTICLE
    Jan Adriaan REIJNEVELD, Martijn Jasper van OOSTRUM, Karst Michiel BROLSMA, Oene OENEMA
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 248-261. https://doi.org/10.15302/J-FASE-2023499

    ● 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.

  • RESEARCH ARTICLE
    Zhengxin FEI, Zijie DING, Xuan ZHENG, Liang FENG, Qingyao HE, Shuiping YAN, Long JI
    Frontiers of Agricultural Science and Engineering, 2023, 10(3): 479-491. https://doi.org/10.15302/J-FASE-2023480

    ● LFD was treated by fly ash-based chemical precipitation and CO2 mineralization.

    ● > 93% COD and > 98% TP removal efficiency, and < 2 mS·cm−1 EC was achieved.

    ● COD and TP removal was achieved by co-precipitation during CO2 mineralization.

    ● CO2 mineralization neutralized the alkaline LFD and removed heavy met.

    Chemical precipitation is a widely applied approach for a liquid fraction of digestate (LFD) of agricultural waste but its large-scale application requires low-cost and efficient precipitating agents and novel process design. This study evaluated novel approach for the efficient removal of contaminants from the LFD using fly ash-based chemical precipitation, followed by filtration and CO2 mineralization. The technical feasibility of this approach was evaluated using pH and electrical conductivity (EC), and removal efficiencies of total phosphorus (TP), chemical oxygen demand (COD) and heavy metals during the treatment. The fly ash used in this study showed a promising performance as a chemical precipitation agent for COD and TP removal from the treated LFD involving complex effects of precipitation and adsorption. CO2 bubbling after fly ash-based chemical precipitation provided further COD and TP removal by carbonation reactions between CO2 and the excessive alkaline minerals in fly ash. Although addition of fly ash to untreated LFD increased pH from 8.3 to 12.9 and EC from 7.01 to 13.7 mS·cm−1, CO2 bubbling helped neutralize the treated LFD and reduce the EC, and concentrations of toxic ions by carbonation reactions. The fly ash-based chemical precipitation and CO2 mineralization had > 93% COD and > 98% TP removal efficiencies, and resulted in an EC of < 2 mS·cm−1 and a neutral pH in the treated LFD, as well as the high purity calcite product.

  • RESEARCH ARTICLE
    Dongjia LI, Rui LIU, Li CHEN, Yu GAO, Xuanyu GU, Yu-hua SHI, Jiahuan LIU, Weifeng ZHANG
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 234-247. https://doi.org/10.15302/J-FASE-2022468

    ● 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.

  • RESEARCH ARTICLE
    Yicong XIN, Li RONG, Gunther SCHAUBERGER, Dejia LIU, Xiusong LI, Zhihua YANG, Songming ZHU, Dezhao LIU
    Frontiers of Agricultural Science and Engineering, 2023, 10(3): 374-389. https://doi.org/10.15302/J-FASE-2023501

    ● NH3 dispersion from a multi-floor pig building was compared to a single-floor building.

    ● NH3 dispersed much further from the multi-floor pig building.

    ● Wind speed, direction and source concentration were important for NH3 dispersion.

    ● NH3 tended to accumulate in the east and west yards of the multi-floor pig building.

    ● Higher wind speed was the likely cause of more NH3 accumulation in the yards.

    Multi-floor buildings for raising pigs have recently attracted widespread attention as an emerging form of intensive livestock production especially in eastern China, due to the fact that they can feed a much larger number of animals per unit area of land and thus alleviate the shortage of land available for standard single-floor pig production facilities. However, this more intensive kind of pig building will pose new challenges to the local environment in terms of pollutant dispersion. To compare the dispersion air pollutants (ammonia as a representative) emitted from multi- versus single-floor pig buildings, ammonia dispersion distance and concentration gradients were investigated through three-dimensional simulations based on computational fluid dynamics. The validation of an isolated cubic model was made to ensure the simulation method was effective. The effects of wind direction, wind speed and emission source concentration at 1.5 m (approximate human inhalation height) during summer were investigated. The results showed that the ammonia dispersion distance of the multi-floor pig building was far greater than that of the single-floor building on a plane of Z = 1.5 m. When the wind direction was 67.5°, the wind speed was 2 m·s−1 and the emission source concentration was 20 ppmv, the dispersion distance of the multi-floor pig building could reach 1380 m. Meanwhile, the ammonia could accumulate in the yard to 7.68 ppmv. Therefore, future site selection, wind speed and source concentration need to be given serious consideration. Based on the simulation used in this study with source concentration is 20 ppmv, the multi-floor pig buildings should be located 1.4 km away from residential areas to avoid affecting residents. The results of this study should guidance for any future development of multi-floor pig buildings.

  • REVIEW
    Leli ZHANG, Reaihan E, Mahmoud M. ALI, Hongjian LIN, Shuai ZHANG, Shuqin JIN, Zhiping ZHU, Jianjun HU, Yiqing YAO, Yong SUN, Shuiping YAN, Zhidan LIU
    Frontiers of Agricultural Science and Engineering, 2023, 10(3): 341-362. https://doi.org/10.15302/J-FASE-2023509

    ● Carbon reduction potential of manure treatment technologies was summarized.

    ● Accounting methodologies of carbon emission and footprint of manure were analyzed.

    ● The quote of carbon trading market at home and abroad was analyzed.

    ● Some points for the boost of potential of manure carbon trading were advised.

    The rapid growth of the livestock and poultry production in China has led to a rise in manure generation, which contributes to the emissions of GHGs (greenhouse gases including CH4, N2O and CO2) and other harmful gases (NH3, H2S). Reducing and managing carbon emissions has become a critical global environmental imperative due to the adverse impacts of GHGs. Unlike previous reviews that focused on resource recovery, this work provides an unique insight of transformation from resource-oriented manure treatment to integration of resource recovery with pollution reduction, carbon accounting and trading, focusing on the sustainable development of manure management system. Considering the importance of accounting methodologies for carbon emission and trading system toward carbon neutrality society, suggestions and strategies including attaching high importance to the development of more accuracy accounting methodologies and more practical GHG emission reduction methodologies are given in this paper. This work directs the establishment of carbon reduction methodologies and the formulation of governmental policies for livestock and poultry manure management system in China.

  • NEWS & VIEWS
    Sarah BUCKINGHAM, Cairistiona F. E. TOPP, Pete SMITH, Vera EORY, David R. CHADWICK, Christina K. BAXTER, Joanna M. CLOY, Shaun CONNOLLY, Emily C. COOLEDGE, Nicholas J. COWAN, Julia DREWER, Colm DUFFY, Naomi J. FOX, Asma JEBARI, Becky JENKINS, Dominika J. KROL, Karina A. MARSDEN, Graham A. MCAULIFFE, Steven J. MORRISON, Vincent O'FLAHERTY, Rachael RAMSEY, Karl G. RICHARDS, Rainer ROEHE, Jo SMITH, Kate SMITH, Taro TAKAHASHI, Rachel E. THORMAN, John WILLIAMS, Jeremy WILTSHIRE, Robert M. REES
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 268-280. https://doi.org/10.15302/J-FASE-2023495

    ● 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.

  • EDITORIAL
    Zhidan LIU, Hongjian LIN, Shuai ZHANG, Shuqin JIN, Zhiping ZHU, Jianjun HU, Yiqing YAO, Yong SUN, Shuiping YAN, Fushuo ZHANG
    Frontiers of Agricultural Science and Engineering, 2023, 10(3): 333-340. https://doi.org/10.15302/J-FASE-2023513
  • EDITORIAL
    Jing TIAN, Keith GOULDING, Xuejun LIU
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 153-154. https://doi.org/10.15302/J-FASE-2023497
  • REVIEW
    Jian SUN, Guangyong ZHAO, Meng M. LI
    Frontiers of Agricultural Science and Engineering, 2023, 10(3): 390-402. https://doi.org/10.15302/J-FASE-2023504

    ● Microbial fermentation in the rumen is a main source of methane emissions.

    ● Nutritional strategies can effectively mitigate methane emissions by manipulating biochemical reactions in the methanogenesis pathways.

    ● Mitigation practices must be evaluated in an integrated animal production system instead of as isolated components.

    Within the agricultural sector, animal production contributes to 14.5% of global anthropogenic greenhouse gas emissions and produces around 37% of global CH4 emissions, mainly due to ruminal fermentation in ruminants. Over 90% of CH4 is synthesized by methanogens in the rumen during carbohydrate fermentation. According to different substrates, methanogenesis pathways can be divided into four categories: (1) hydrogenotrophic pathway; (2) acetoclastic pathway; (3) methyl dismutation pathway; and (4) methyl-reducing pathway. Based on the principle of biochemical reactions in the methanogenesis pathways, this paper reviews the latest publications on CH4 decreases in ruminants and described three nutritional strategies in terms of dietary nutrient manipulation (feeding management, feed composition, forage quality and lipids), microbial manipulation (ionophore, defaunation, methanogen inhibitors and probiotics), and chemical manipulation (nitrate, organic acids, plant secondary metabolites and phlorotannins, or halides in seaweeds). For each mitigation strategy, the review discusses effectiveness for decreasing CH4 emissions, application prescription, and feed safety based on results from in vitro and in vivo studies. This review summarizes different nutritional strategies to mitigate CH4 emissions and proposed comprehensive approaches for future feeding interventions and applications in the livestock industry.

  • REVIEW
    Jinyang WANG, Pinshang XU, Haiyan LIN, Shumin GUO, Zhaoqiang HAN, Jianwen ZOU
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 155-166. https://doi.org/10.15302/J-FASE-2022477

    ● 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.

  • RESEARCH ARTICLE
    Xinpeng JIN, Xiangwen FAN, Yuanchao HU, Zhaohai BAI, Lin MA
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 167-182. https://doi.org/10.15302/J-FASE-2023494

    ● 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.

  • REVIEW
    Zhiping ZHU, Yue WANG, Ting YAN, Zherui ZHANG, Shunli WANG, Hongmin DONG
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 226-233. https://doi.org/10.15302/J-FASE-2023486

    ● 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.

  • RESEARCH ARTICLE
    Jing LAN, Tonghui MA, Peng YIN, Kedao TENG, Yunfei MA
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 285-295. https://doi.org/10.15302/J-FASE-2022469

    ● 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.

  • REVIEW
    Xing LI, Chunyan GUO, Yumei YAN, Lijuan LV, Siqi LI, Wenxin GUO, Zhengnan LI, Minhui LI
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 306-332. https://doi.org/10.15302/J-FASE-2023488

    ● 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.

  • REVIEW
    Qianqian YANG, Lei MA
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 296-305. https://doi.org/10.15302/J-FASE-2022479

    ● 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.

  • RESEARCH ARTICLE
    Ranran ZHOU, Jing TIAN, Zhengling CUI, Fusuo ZHANG
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 198-209. https://doi.org/10.15302/J-FASE-2023498

    ● 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.

  • RESEARCH ARTICLE
    Jinzhi HUANG, Xiaoting YAN, Zhen LIU, Mengyi WANG, Yangyang HU, Zhenyu LI, Minsong LIN, Yiqing YAO
    Frontiers of Agricultural Science and Engineering, 2023, 10(3): 403-423. https://doi.org/10.15302/J-FASE-2022471

    ● Methane production from fresh straw was 7.50% higher than dry straw.

    ● The structure of fresh straw was more conducive to be degraded.

    ● Organic components of fresh straw was richer and higher than dry straw.

    Clostridium_sensu_stricto_1 , Sporosarcina and Methanosarcinia dominated AD.

    ● Metagenomics revealed Metanosarcinia adapted to high VFA stress via multiple pathways.

    Dry corn straw (DCS) is usually used in anaerobic digestion (AD), but fresh corn straw (FCS) has been given less consideration. In this study, the thermophilic AD of single-substrate (FCS and DCS) and co-digestion (straw with cattle manure) were investigated. The results show that when FCS was used as the single-substrate for AD, the methane production was 144 mL·g−1·VS−1, which was 7.5% and 19.6% higher than that of single DCS and FCS with cattle manure, respectively. In addition, the structure of FCS was loose and coarse, which was easier to be degraded than DCS. At the hydrolysis and acidification stages, Clostridium_sensu_stricto_1, Clostridium_sensu_stricto_7 and Sporosarcina promoted the decomposition of organic matter, leading to volatile fatty acids (VFAs) accumulation. Methanosarcina (54.4%) activated multifunctional methanogenic pathways to avoid the VFAs inhibition, which was important at the CH4 production stage. The main pathway was hydrogenotrophic methanogenesis, with genes encoding formylmethanofuran dehydrogenase (K00200-K00203) and tetrahydromethanopterin S-methyltransferase (K00577-K00584). Methanosarcina also activated acetotrophic and methylotrophic methanogenesis pathways, with genes encoding acetyl phosphate (K13788) and methyl-coenzyme M reductase (K04480, K14080 and K14081), respectively. In the co-digestion, the methanogenic potential of FCS was also confirmed. This provides a scientific basis for regulating AD of crop straw.

  • RESEARCH ARTICLE
    Yulin HU, Kang KANG, Iker Zulbaran ALVAREZ, Nasim MIA, Aadesh RAKHRA
    Frontiers of Agricultural Science and Engineering, 2023, 10(3): 448-457. https://doi.org/10.15302/J-FASE-2023490

    ● Low-value biowaste including wood chip and potato peel was valorized to syngas.

    ● O2-blown co-gasification of wood chip and potato peel was simulated.

    ● Different reaction conditions on CCE, gas composition, and LHV were studied.

    ● Positive interaction between wood chip and potato peel in co-gasification was found.

    Potato is the fifth largest agricultural crop in Canada and contributes to the generation of an abundant amount of potato peel. However, disposal/recycling this peel remains a challenge due to the stringent environmental regulations. Consequently, there is a lack of an appropriate recycling and valorization methods of potato peel. Gasification is an effective technology for producing syngas and an ecofriendly waste disposal approach. Syngas is an important industrial intermediate to produce synthetic fuels and chemicals. To develop an ecofriendly and cost-effective valorization approach for potato peel, this study used a mixture of woody biomass (i.e., wood chips) and potato peel to produce syngas by co-gasification using O2 as the gasifying agent at a constant equivalence ratio of 0.3 using Aspen Plus simulation software. The influences of gasification temperature and wood chip/potato peel weight ratio on the carbon conversion efficiency (CCE), and product gas composition (molar fraction) and lower heating value (LHV) of product gas were investigated. This simulation indicated that a positive synergistic interaction occurs between wood chips and potato peel in co-gasification process in terms of an increase in CCE by comparing the arithmetic value and real value at all simulated wood chip to potato peel weight ratios (44.9% to 85.8%, 46.5% to 76.2%, and 48.1% to 78.6% at ratios of 25:75, 50:50, and 75:25, respectively, for wood chips to potato peel). While the molar fraction of H2 and CO decreased continuously with increase in the weight percentage of wood chips in the wood chip-potato peel mixture from 0 wt% to 100 wt% (H2, at 42.1 mol% to 41.4 mol%; and CO at 44.0 mol% to 40.4 mol%), accompanied by a decrease of the LHV of the product gas (10.3 to 9.78 MJ·Nm−3). The study concluded that co-gasification for producing syngas is feasible and environmental-friendly option to recycle and valorize potato peel.

  • EDITORIAL
    Wen XU, Jie ZHANG, Linzhang YANG, Xuejun LIU, Fusuo ZHANG
    Frontiers of Agricultural Science and Engineering, 2023, 10(4): 503-509. https://doi.org/10.15302/J-FASE-2023528
  • RESEARCH ARTICLE
    Danmeng FENG, KouRay MAO, Yujie YANG, Yu HU
    Frontiers of Agricultural Science and Engineering, 2023, 10(4): 518-529. https://doi.org/10.15302/J-FASE-2023525

    ● This paper examines the historical evolution of crop-livestock integration in China with a specific focus on its role in mitigating non-point source pollution.

    ● Extensive examination of existing literature has unearthed the roots of crop-livestock integration dating back to the Western Zhou Dynasty (1046 to 771 BCE), ultimately culminating in a multifaceted and intricately interwoven system of rural development policies seen in contemporary China.

    ● This paper illuminates the diverse contributions of crop-livestock integration in different epochs of rural development within China, which contributes to a nuanced and more theoretically grounded comprehension of circular agriculture.

    This paper examines the historical evolution of crop-livestock integration in China with a specific focus on its role in mitigating non-point source pollution. Extensive examination of existing literature has unearthed the roots of crop-livestock integration dating back to the Western Zhou Dynasty (1046 to 771 BCE), ultimately culminating in a multifaceted and intricately interwoven system of rural development policies seen in contemporary China. This paper identifies and characterizes four distinct stages in the historical trajectory of crop-livestock integration: the era of self-sufficient subsistence production in traditional times (1046 BCE to 1948); the period where crop-livestock integration emerged as a pivotal strategy for augmenting grain and meat production under collectivist policies (1949‒1977); the phase marked by the industrialization and expansion of the livestock sector during the early years of economic reforms (1978‒2011); and the present era in which crop-livestock integration is harnessed as a mechanism for pollution control and ecological preservation in contemporary China (2012 to present). This paper illuminates the diverse contributions of crop-livestock integration in different epochs of rural development within China, which contributes to a nuanced and more theoretically grounded comprehension of circular agriculture. This understanding has the potential to be leveraged to promote sustainable rural development in broader contexts.

  • RESEARCH ARTICLE
    Danni ZHOU, Yi ZHOU, Pengguang HE, Lin YU, Jinming PAN, Lilong CHAI, Hongjian LIN
    Frontiers of Agricultural Science and Engineering, 2023, 10(3): 363-373. https://doi.org/10.15302/J-FASE-2023510

    ● An automatic weighing system for monitoring bodyweight of broilers was developed.

    ● The new system was compared to the established live-bird sales weighing system data and tested in various conditions.

    ● The system demonstrated superior accuracy and stability for commercial houses.

    Bodyweight is a key indicator of broiler production as it measures the production efficiency and indicates the health of a flock. Currently, broiler weight (i.e., bodyweight) is primarily weighed manually, which is time-consuming and labor-intensive, and tends to create stress in birds. This study aimed to develop an automatic and stress-free weighing platform for monitoring the weight of floor-reared broiler chickens in commercial production. The developed system consists of a weighing platform, a real-time communication terminal, computer software and a smart phone applet user-interface. The system collected weight data of chickens on the weighing platform at intervals of 6 s, followed by filtering of outliers and repeating readings. The performance and stability of this system was systematically evaluated under commercial production conditions. With the adoption of data preprocessing protocol, the average error of the new automatic weighing system was only 10.3 g, with an average accuracy 99.5% with the standard deviation of 2.3%. Further regression analysis showed a strong agreement between estimated weight and the standard weight obtained by the established live-bird sales system. The variance (an indicator of flock uniformity) of broiler weight estimated using automatic weighing platforms was in accordance with the standard weight. The weighing system demonstrated superior stability for different growth stages, rearing seasons, growth rate types (medium- and slow-growing chickens) and sexes. The system is applicable for daily weight monitoring in floor-reared broiler houses to improve feeding management, growth monitoring and finishing day prediction. Its application in commercial farms would improve the sustainability of poultry industry.

  • PERSPECTIVE
    Oene OENEMA
    Frontiers of Agricultural Science and Engineering, 2023, 10(2): 281-284. https://doi.org/10.15302/J-FASE-2022470
  • RESEARCH ARTICLE
    Yajun ZHANG, Sen YAO, Jianjun HU, Jiaxi XIA, Tao XIE, Zhibin ZHANG, Hai LI
    Frontiers of Agricultural Science and Engineering, 2023, 10(3): 458-467. https://doi.org/10.15302/J-FASE-2023500

    ● Gasification of cow dung was evaluated using Aspen Plus software.

    ● Optimum reaction conditions were utilized to maximize hydrogen production.

    ● Steam gasification can effectively increase hydrogen production.

    ● Optimum hydrogen production was achieved at 800 °C and steam/biomass of 1.5 and 0.1 MPa.

    In this study, a biomass gasification model was developed and simulated based on Gibbs free energy minimization by using software Aspen Plus. Two reactors, RYIELD and RGIBBS, were moslty used. The biomass feedstock used was cow dung. The model was validated. The composition, H2/CO ratio and low heating value (LHV) of the resulting synthetic gas (also known as syngas) was estimated by changing the operating parameters of gasification temperatures, steam and biomass ratios and pressures. Simulation results showed that increased gasification temperature helped to elevate H2 and CO content and H2 peaked at 900 °C. When steam increased as the gasification agent, H2 production increased. However, the steam/biomass (S/B) ratio negatively affected CO and CH4, resulting in lower LHV. The optimal S/B ratio was 1.5. An increase in pressure lead to a decrease in H2 and CO content, so the optimal pressure for gasification was 0.1 MPa.

  • PERSPECTIVE
    Weili ZHANG, Renlian ZHANG, Hongjie JI, Anja SEVERIN, Zhaojun LI
    Frontiers of Agricultural Science and Engineering, 2023, 10(4): 648-653. https://doi.org/10.15302/J-FASE-2023505

    Enhancement of farming management relies heavily on enhancing farmer knowledge. In the past, both the direct learning approach and the personnel extension system for improving fertilization practices of smallholders has proven insufficiently effective. Therefore, this article proposes an interactive knowledge learning approach using artificial intelligence as a promising alternative. The system consists of two parts. The first is a dialog interface that accepts information from farmers about their current farming practices. The second part is an intelligent decision system, which categorizes the information provided by farmers in two categories. The first consists of on-farm constraints, such as fertilizer resources, split application times and seasons. The second comprises knowledge-based practices by farmers, such as nutrient in- and output balance, ratios of different nutrients and the ratios of each split nutrient amount to the total nutrient input. The interactive knowledge learning approach aims to identify and rectify incorrect practices in the knowledge-based category while considering the farmer’s available finance, labor, and fertilizer resources. Investigations show that the interactive knowledge learning approach can make a strong contribution to prevention of the overuse of nitrogen and phosphorus fertilizers, and mitigating agricultural non-point source pollution.

  • RESEARCH ARTICLE
    B. Brian HE, Zheting BI, Lide CHEN
    Frontiers of Agricultural Science and Engineering, 2023, 10(3): 437-447. https://doi.org/10.15302/J-FASE-2023507

    ● Content of heavy metals in hydrochar varies considerably, from 50% to 100%.

    ● Concentrations of heavy metals in hydrochar can be higher than those in the dairy manure.

    ● Concentrations of heavy metals in hydrochar are far below the regulatory level.

    Hydrochar produced from dairy manure is a regulated biosolid if being promoted for agricultural applications thus must have the properties that comply with all environmental standards and government regulations, including the levels of heavy metals (HMs). In this study, systematic research was conducted on HM levels in hydrochar from dairy manure and on the effects of processing conditions, including processing temperature (180–255 °C), holding time (30120 min) and solid content of manure slurry (2%15%), through a central composite design and statistical analyses. It was found that HMs can be retained in hydrochar, ranging from 40% to 100%. The processing temperature and solid content in the feed were the most influential process parameters that affected HMs retention in hydrochar. Statistical analysis showed that there was no single optimal point to minimize HMs retained in hydrochar, but there were minimization points at given processing time and solid content. Most HMs concentrations were higher in hydrochar than those initially in dairy manure but were greatly below the thresholds as set by the US government regulations. Thus, hydrochar is feasible for use as a phosphorus-enriched organic fertilizer and/or soil amendment for agricultural applications without serious concerns about HMs it might contain.

  • RESEARCH ARTICLE
    Yiting XIAO, Yang TIAN, Yuanhang ZHAN, Jun ZHU
    Frontiers of Agricultural Science and Engineering, 2023, 10(3): 492-502. https://doi.org/10.15302/J-FASE-2023503

    ● Titanate NFs were synthesized and photodegraded liquid digestate for the first time.

    ● The long titanate NFs (bandgap of 3.16 eV) have a high VFA removal rate of 72.9%.

    ● RSM has been used to optimize the VFA, COD, and color removal rate.

    ● The quadratic model and the effects of photocatalytic dosage were significant.

    Titanate nanofibers (TNFs) were synthesized using a hydrothermal method and were employed for the first time in this study to photocatalytically degrade organic pollutants found in flocculated liquid digestate of poultry litter. The photocatalytic performance of TNFs, with a bandgap of 3.16 eV, was tested based on degradation of organic pollutants and removal of color. Five combinations of pollutant concentration and pH were examined (0.2 to 1.3 g·L−1 at pH 4 to 10). Central composite design (CCD) and response surface methodology (RSM) were applied in order to optimize the removal rates of volatile fatty acids (VFA) and chemical oxygen demand (COD), and the decolorization rate. There were no significant differences between the regression models generated by the CCD/RSM and the experimental data. It was found that the optimal values for pH, dosage, VFA removal rate, COD removal rate and decolorization rate were 6.752, 0.767 g·L−1, 72.9%, 59.1% and 66.8%, respectively. These findings indicates that photocatalytic TNFs have potential for the posttreatment of anaerobic digestion effluent, as well as other types of wastewater.