基于知识图谱的生物炭对水循环要素过程影响研究进展

以2007 ~ 2021年CNKI及Web of Science核心合集数据库共1874篇中英文文献为支撑,采用文献计量可视化方法,针对文献发表的时间分布、机构组成、代表团队、引用期刊、研究热点及技术手段等方面综述了生物炭对土壤性质、入渗和蒸发等水循环要素过程影响的现状研究进展及未来趋势。结果表明,相关研究发文量呈高速增长趋势;研究机构集中在中国科学院、美国农业部和西北农林科技大学等;高引期刊主要包括GEODERMA、CHEMOSPHERE和SCIENCE OF THE TOTAL ENVIRONMENT;研究热点集中在量化生物炭添加对土壤物理和水力学特性要素指标的影响大小,并关注上述影响对入渗和蒸发等水循环过程及其对作物生长和产量的互馈作用;技术手段主要包括实验研究和Meta分析方法两种。未来亟需集成实验数据,关注尺度转换,将不同环境条件下生物炭添加对要素过程的影响,融入水文模型水循环模拟计算模块,完善模型功能。     

Global research on soil contamination from 1999 to 2012: A bibliometric analysis

We evaluated soil contamination research based on a bibliometric analysis of 14,090 articles published in journals in the Science Citation Index and Social Sciences Citation Index bibliographic databases from 1999 to 2012, which revealed scientific outputs, subject categories and major journals, international collaboration and geographic distribution of authors and countries, keywords, and hot issues. The results suggested that research on soil contamination developed well with increasing scientific production and research collaboration. Environmental science, engineering environment, soil science, and applied microbiology were the most frequently used subject categories in soil contamination studies. Chemosphere was the most active journal in this field. The clusters of authors were more in the USA, Western European countries, China, Japan, and India. Q. X. Zhou of Nankai University was the most productive author, and S. P. Mcgrath of Rothamsted Research England published the most influential articles. The USA exceeded all other countries with the most independent and collaborative papers in research on global soil contamination. Heavy metal pollution was the hottest issue, and bioremediation is the most promising research topic in combating against heavy metal pollution of soils. The status of publication on soil contamination research described here is significant for researchers on soil contamination in their future work.     

Bibliometric analysis of research on soil health from 1999 to 2018

Purpose

Soil health has been a major focus of research by international scholars because it is an important factor that supports human survival and development. However, few scholars have performed bibliometric analyses of research on soil health. This study investigated the current research status and development characteristics of soil health.

Materials and methods

We performed a bibliometric analysis of documents on soil health from 1999 to 2018 in the Web of Science Core Collection. The bibliometric analysis tools, CiteSpace and HistCite software, were applied.

Results and discussion

A total of 1629 documents on soil health in the Web of Science Core Collection were identified. From the research status of soil health, the number of publications will continue to increase. Most of the research institutions examining soil health are located in the USA, and there is little cooperation and communication among countries, neither do research institutions in this field. Each country has its own research labs while lab cooperation within individual countries is relatively close. Most documents on the research of soil health have been published in the journal Applied Soil Ecology. In addition, research directions are expanding from the basic study of soil production, soil health indicators, and soil pollution to the comprehensive study of soil ecosystem.

Conclusions

Bibliometric analysis tools, CiteSpace and HistCite software, provide a comprehensive approach for making predictions regarding trends in the field. This method was used in this study to identify the hotspots, frontiers, and future development of soil health to provide guidance for future research.

     

污染农田土壤的重金属钝化技术研究 ——基于Web of Science数据库的计量分析

为全面直观了解全球农田土壤重金属污染钝化修复研究进展和发展趋势,本文基于Web of Science(简称WoS)核心合集数据库利用WoS数据库自带分析工具、HistCite引文图谱分析软件和VOSviewer可视化分析软件,从发文量或被引频次TOP10的国家、研究机构、作者、期刊、研究热点等方面对1990―2019年...     

基于文献计量学分析的全球生物质炭研究进展

为了深入了解国内外生物质炭的研究现状与研究热点，为相关研究领域的科研工作者与决策者提供参考，该文以Web of Science 核心数据库为数据源，采用文献计量学方法对2003-2020年间全球发表的生物质炭研究文献进行分析。全球生物质炭研究的发文量呈快速增长趋势，其中中国总发文量和总被引频次均位居世界首位。中国-美国是生物质炭研究最大的合作关系体。发文量最多的机构是中国科学院。中国有8名学者发文量进入世界前20名，上海交通大学曹心德的总发文量和总被引频次位列大陆学者榜首。发文量最大的学科方向是环境科学。中国在生物质炭研究方面发展快、成果产出多，但缺乏有国际影响力的核心成果，在研究创新性和发文质量上还有待提升。关键词分析表明，生物质炭在土壤改良和农业生产中的应用、利用生物质炭处理废水及修复污染土壤，以及生物质炭制备方法和工艺的创新是生物质炭的主要研究热点。而生物质炭制备材料与工艺的创新、各类功能型生物质炭纳米复合材料的开发，以及继续拓宽生物质炭在不同领域的高效利用可能成为今后的研究热点。     

Review of Trends in Soil Fertility Research (2007–2016) using Scopus Database

A critical analysis of publications on soil fertility was carried out using data from Scopus database for the period of 2007–2016. A total of 16,612 articles were found relating to soil fertility. An exponential increase was evident from the review of published literature and scientists involved in the soil fertility research also increased over period of time. The journals Soil Science and Plant Nutrition and Acta Ecologica Sinica were major publishers of the soil fertility research. Giller K. E. from Wageningen University, The Netherlands was a major contributor followed by Salvati L. of Centro Per Lo Studio Delle Relazioni Piñata-Suolo, Italy. China was the most productive country with 3323 articles. Cluster analysis of author-supplied keywords showed five clusters, namely, desertification, soil organic carbon, plant nutrition, nitrogen, and geostatic. This work will be useful to researchers to know the trends in soil fertility research.     

生物炭施用下中国农田土壤N2O排放的Meta分析

为明确施加生物炭对中国农田土壤N_2O排放的影响和主要控制因素,以公开发表的试验数据为研究对象,采用Meta-analysis法定量分析了施加生物炭条件下,气候、土壤性质、田间管理方式、生物炭性质与施加量对土壤N_2O排放的影响,并对各影响因素进行通径分析。结果表明,当年降雨量≥600 mm时,生物炭显著降低土壤N_2O排放量(P0.05),且随年降雨量的增加而增强;当年日照时数大于1 000 h时,生物炭对土壤N_2O的减排效果随年日照时数的增加而减弱。当土壤p H≥6.5时,生物炭对土壤N_2O的减排效果随土壤p H的增加呈先增后减趋势;在壤土中施加生物炭对N_2O的减排效果显著(P0.05),而砂土和黏土不显著(P0.05)。生物炭对覆膜土壤N_2O的减排效果优于不覆膜土壤;生物炭对土壤N_2O的减排效果随施氮肥量增加而减弱,而随生物炭比表面积的增加而增强。当生物炭C/N处于30~500时,生物炭施用下土壤N_2O排放量显著降低(P0.05);当生物炭施加量处于20~160 t×hm-2时,生物炭对土壤N_2O的减排效果随施加量增加而增强。生物炭对土壤N_2O减排的影响存在显著的区域性特征,对华南、华东、华中和东北地区影响显著(P0.05),而对西北地区不显著(P0.05);施氮肥量、生物炭施加量、年均温和年降雨量是影响生物炭减排效果的最主要因素,这些因素的相互作用共同影响生物炭对土壤N_2O的减排效果。该研究可为生物炭在我国农区的推广应用和农田N_2O减排提供参考。     

Characterization of biochar and their influence on microbial activities and potassium availability in an acid soil

Application of biochar to soil has increased considerably during recent years because of its effectiveness as a soil amendment causing beneficial effects on soil health. However, the effects have been reported to vary and depend upon types of feedstock and pyrolysis conditions during biochar production. Therefore, characterization of biochar is extremely important for its efficient utilization as a soil amendment. In the present study, biochar was prepared from agro-industrial by-products (rice husk and sugarcane bagasse) and weeds (Parthenium and Lantana) under similar pyrolysis conditions. Lantana biochar (LBC) showed the highest pH (10.4) while the lowest value (8.5) being recorded in rice husk biochar (RHBC). The energy-dispersive X-ray spectroscopy (EDS) analysis indicated that LBC and Parthenium biochar (PBC) were superior with respect to potassium (K) content than sugarcane bagasse biochar (SBBC) and RHBC. The Fourier-Transform Infrared Spectroscopy (FTIR) study exhibited the existence of different functional groups in biochar. All the biochar treated soils showed significantly higher microbial activities with different degrees. Application of LBC and PBC at 4.50 g kg^?1 soil significantly increased K availability in soil. Lantana biochar and PBC amended the soil at 9 g kg^?1 significantly increased the soil pH thus makes these biochar as potential liming materials.     

The application of biochar on soil acidity and other physico‐chemical properties of soils in southern Ethiopia

The aim of this research was to investigate the effect of biochar amendment on soil acidity and other physico‐chemical properties of soil in Southern Ethiopia using a field experiment of three treatments: (1) biochar made of corn cobs, (2) biochar made of chopped Lantana camara stem, and (3) biochar made of Eucalyptus globulus feedstock and a control, in which neither of the biochar was used. Each treatment had three levels of 6, 12 and 18 t ha⁻¹. The experiment was setup with RCBD in a factorial arrangement with three replications. In this regard, a total of 36 plots (each 2 × 2 m size) were applied with three replications to the depth of 0–15cm. From these 36 plots, composite soil samples were collected to the depth of 0–30 cm and analyzed for bulk density, total porosity, pH, soil organic carbon, total nitrogen, available phosphorus, potassium, and exchangeable acidity using standard procedures before and after biochar application. Two‐way ANOVA was also used to analyze the impact of the biochars on soil acidity and other properties. For the treatments that had significant effects, a mean separation was made using Least Significance Difference (LSD) test. The results showed the application of biochar significantly reduced, soil bulk density and exchangeable acidity when compared with a control (p < 0.05). Moreover, the total soil porosity, soil pH, total nitrogen, soil organic carbon, available phosphorus, and potassium were significantly increased in the soil. From among applied biochar treatments, Lantana camara applied at the level of 18 t ha⁻¹ had a higher impact in changing soil physico‐chemical properties. In general, the study suggests that the soil acidity can be reduced by applying biochar as it can amend other soil physico‐chemical properties.     

Effects of biochar and fertilizer management on sunflower (Helianthus annuus L.) feedstock and soil properties

The need for bioenergy is increasing with increase in global energy demand, and sustainable soil and fertilizer management practices for bioenergy feedstock production are gaining importance. In this greenhouse study, we evaluated the effects of biochar and fertilizer nitrogen on soil and energy crop sunflower (Helianthus annuus L. var. Giganteus). Sunflower plants were treated with three rates of biochar, control (0 Mg ha^?1), low (25 Mg ha^?1) and high (50 Mg ha^?1), and three rates of fertilizers, 0% (control), 50% (low) and 100% (high) of the recommended nitrogen dose. Plant height, quality (chlorophyll content), biomass yield, feedstock energy, ash content and tissue nutrients were measured along with soil moisture and pH. Results showed an 11% increase in mean plant height under low biochar compared to control biochar-treated plants. High nitrogen treatment produced 26% and 18% more stalk and total above-ground plant (whole plant) biomass, respectively, compared to the control nitrogen treatment. High biochar treatment resulted in higher soil moisture holding, but lower soil pH than the control biochar treatment. Plant quality, energy and ash contents were not affected by either biochar or nitrogen. The plant tissue analysis provides a complete tissue macro- and micronutrient information on sunflower cultivar Giganteus, which was not done previously.     

石灰性旱地土壤施用生物质炭对土壤节肢动物群落的影响

为探讨玉米秸秆生物质炭不同施用量对土壤节肢动物群落结构的影响，于2019年5—10月分别对0、5、10、20和50 t/hm²生物质炭处理下的贵州石灰性旱地农田土壤小型土壤节肢动物群落进行调查，并探讨土壤节肢动物群落与土壤温度、湿度、pH、电导率和有机碳等环境因子的关系。本研究共捕获土壤节肢动物14 133头，隶属于6纲21类群。研究表明：适量生物质炭添加（10 t/hm²）有助于提高土壤节肢动物个体数和类群数，高量施用（50 t/hm²）则不利于土壤节肢动物生存；典范对应分析结果显示，生物质炭施用导致环境因子的变化显著影响了土壤节肢动物群落结构（共解释了24.81%的物种变异，P<0.01），其中温度的影响最大，单独解释了物种变异的16.1%。总体上，施用生物质炭影响土壤微环境，进而影响土壤节肢动物群落组成和多样性，施用适量生物质炭（10 t/hm²）有益于农田土壤节肢动物的生存，但这一结论还需要在其他土壤类型和生物质炭中进行验证。     

生物炭对铜矿区污染土壤微生物活性及香根草富集铜、镉、铅的影响

矿区土壤易发生重金属污染,是土地资源利用和维护的一大难题。以铜矿区污染土壤为研究对象,按质量比添加0,1%,2%,4%,10% (w/w)的生物炭,进行香根草室内盆栽试验。研究添加生物炭对土壤pH和微生物活性、香根草富集与转运重金属的影响,探明重金属形态含量与生物炭、微生物活性的相关性,旨在为生物炭与香根草联合修复矿区重金属污染土壤提供理论参考。结果表明:生物炭的添加能提高土壤pH,显著提高土壤FDA水解酶、蔗糖酶和脲酶活性,显著促进土壤基础呼吸,但对土壤微生物量碳无显著影响;生物炭的添加使香根草生物量显著增大,降低土壤Cu和Pb的有效态占比,Cd的变化与此相反;添加生物炭促进香根草对Cd和Pb的富集,降低香根草对Cu的富集,减少Cu、Cd和Pb在香根草体内的转运,因此香根草可作为Cu、Cd和Pb的稳定化植物。土壤蔗糖酶活性与香根草叶片Cu、Cd和Pb含量、有效态和残渣态Cu含量呈显著正相关,土壤基础呼吸与叶片Cu、Cd和Pb含量、有效态Cu、Pb含量呈显著负相关,而与有效态Cd含量呈显著正相关。总之,生物炭可减弱矿区土壤重金属对香根草生长的毒害作用,并促进香根草对重金属的富集,两者结合可改善铜矿区污染土壤的理化性质和微生物活性,有利于重金属污染土壤修复,改善土壤质量。     

基于文献计量分析的土壤表面电化学发展脉络研究

为了全面深入了解全球土壤表面电化学研究进展及发展趋势，本文基于Web of Science核心合集数据库并利用其自带的分析工具和Citespace可视化分析软件，从该学科的发文量及时间特征、合作研究空间特征、共现网络特征、共被引图谱和发展特征五个方面对1995-2019年发表的土壤表面电化学文献进行计量分析。结果表明，美国、中国和法国在本领域的发文量居前三，而中介中心性则表明法国、美国和英国位列三甲，我国位于第六位且表现出上升趋势。基于引文的突发性关键词检测表明“阳离子交换(cation exchange)”、“系统(system)”和“络合作用(complexation)”是近十年来的研究热点；文献共被引聚类分析表明生物炭对土壤改良、黏土层间电荷与罗丹明6g的相互作用、表面电位变化对胶体吸附解吸影响是领域内的研究重点；生物炭对土壤的改良、带电粒子在双电层中的相互作用机制、土壤黏土矿物表面的水动力特征是本领域研究的前沿问题。     

生物质炭添加对重金属污染稻田土壤理化性状及微生物量的影响

分析了生物质炭添加对红壤性水稻土理化性状、重金属含量及微生物生物量的影响。通过田间小区长期定位试验,一次性施入不同量生物质炭(0,10,20,30,40t/hm2),于2017年9月采集各处理表层土样(0—15cm),研究土壤理化性状、重金属含量及微生物生物量的变化。结果表明:生物质炭添加对土壤理化性状、重金属含量及微生物生物量均有显著影响。与对照相比,供试土壤的pH、EC和有机质含量随生物质炭添加量的增加而增大,增幅分别为5.11%~18.43%,37.62%~104.31%和1.72%~22.41%,而有效磷和铵态氮含量随生物质炭添加量的增加呈先增大后减小趋势,分别在生物质炭添加量为10t/hm2和30t/hm2时达到最大值。随生物质炭添加量的增加,土壤有效态Cd和有效态Pb含量均呈降低趋势,而土壤有效态As含量呈先增加后减少的趋势,三者均在生物质炭添加量为40t/hm2时达到最小值。土壤微生物生物量碳、氮和微生物商随生物质炭添加量的增加均呈先升高后降低的趋势,均在生物质炭添加量为20t/hm2时达到最大值。相关分析表明,生物质炭添加量分别与土壤有效态Cd和Pb含量之间呈极显著负相关(P0.01);通径分析表明,生物质炭主要是通过直接作用影响土壤有效态Cd含量,而土壤pH、EC、有机质、微生物生物量碳、氮和有效磷主要是通过间接作用影响土壤有效态Cd含量。因此,添加适量生物质炭不仅可以改善土壤重金属污染现状和土壤理化性状,提高土壤养分含量,还可以改良土壤生物学性质,增加土壤微生物量。研究结果可为提高稻田土壤肥力和改善土壤重金属污染状况提供科学依据。     

生物炭对水稻-再生稻体系吸收土壤中Cd和Pb的影响

以矿区周边Cd—Pb复合污染的农田土壤为供试材料,设置0,2.5%和5%(w/w)3个生物炭添加处理,通过盆栽试验探讨生物炭对再生稻吸收土壤中Cd和Pb的影响。结果表明,生物炭施加提高土壤pH和有机质含量,使Cd和Pb从移动性较强的弱酸提取态转化为较稳定的可还原态,且土壤CaCl2提取的有效态Cd和Pb含量分别降低33.23%~53.23%和66.52%~91.45%。同时,生物炭抑制Cd在头季和再生季水稻叶到糙米中的迁移,降低Pb从茎到叶和糙米的迁移,从而减少Cd和Pb在糙米中的累积;在5%生物炭处理下,再生季糙米Cd含量为0.15mg/kg,低于食品安全国家标准限量值(0.2mg/kg);Pb含量比对照处理降低68.18%。此外,再生季糙米中Cd和Pb含量低于头季稻糙米中相应的含量。因此,生物炭可以抑制Cd和Pb在再生稻体内的累积,降低糙米的重金属污染风险。     

农田土壤黑碳应用研究进展

在应对全球气候变暖和保障粮食安全的双重背景下,如何增加土壤碳库容量、 提升土壤生产力以及减少环境危害已成为农学家、 土壤学家和环境学家在二十一世纪的研究重点和热点,黑碳（或生物碳）在农田土壤中的应用作为一种增加土壤碳库和提高土地生产力的新方法引起了极大关注。本文综述了黑碳在农业土壤中的含量,应用黑碳（生物碳）对作物产量、 土壤肥力和温室气体排放的影响; 探讨了应用黑碳影响作物生产力和土壤环境行为的机理以及农田土壤应用黑碳在不同区域、 作物类型、 用量和黑碳性质上的差异表现; 展望了农田应用黑碳未来研究的方向和热点。     

不同配方生物炭改良盐渍土对小白菜和棉花生长及光合作用的影响

针对盐渍土壤理化性质差、肥料利用率低和作物长势弱的问题,利用不同配方生物炭进行土壤改良。采用盆栽试验的方法,以小白菜和棉花为研究对象,设置5个不同的处理:不施肥(对照CK0)、常规施肥(CK)、常规施肥+生物炭(C1)、常规施肥+生物炭+硝化抑制剂(C2)和常规施肥+生物炭+硫酸钙(C3),研究不同配方的生物炭处理对小白菜和棉花生长及光合作用的影响。结果表明,与常规施肥比较,C3处理效果更明显。小白菜的株高和株重分别增加32.7%和112.0%,叶绿素含量与净光合速率分别提高45.5%与32.9%;胞间CO_2浓度和蒸腾速率分别下降15.0%和59.2%。光谱分析表明,C3处理反射率更高,叶片组织更完好。与CK比较,生物炭处理同样促进棉花生长,显著提高叶绿素含量,降低叶片中丙二醛含量和过氧化氢酶活性,增强抗逆性,减少棉花损伤。同时,降低了棉花叶片中胞间CO_2浓度,提高水分利用率。土壤分析表明,生物炭配施改良剂能显著改善土壤理化性质,与常规施肥相比,C2处理的土壤有机质、速效磷和碱解氮含量分别提高57.3%,22.9%和40.8%,而对土壤速效钾和pH影响较小,C3处理对土壤电导率有较大提高。因此,实践中在改良盐渍土壤时,需注意改良剂的合理施用,防止土壤盐分的进一步积累。     

Sorption-desorption behaviors of heavy metals by biochar-compost amendment with different ratios in contaminated wetland soil

Purpose

Heavy metal pollution in soils has become a global environmental concern. The combination of biochar and compost has already been proved to be an attractive method in contaminated soil. The objective was to study the sorption-desorption characteristics of Cd, Cu, and Zn onto soil amended with combined biochar-compost.

Materials and methods

In this study, the soil was amended with combinations of biochar and compost with different ratios at 10% (w/w). To determine the sorption-desorption behaviors of heavy metals by biochar-compost amendment with different ratios, we determine the effects of different ratios on soil properties and use batch experiments to investigate sorption-desorption behaviors of Cd, Cu, and Zn.

Results and discussion

The results show that the Langmuir and Freundlich model can well describe the adsorption isotherm of Cd, Cu, and Zn in the soils with or without biochar-compost combinations. The incorporation of amendment combinations into soil significantly promotes the sorption affinity of soil on metals. The sorption capacity of Cd and Zn was improved as the compost percentage rose in biochar-compost more likely due to the increase of organic matter and available phosphorus, while that of Cu was stronger with 10 and 20% biochar addition in biochar-compost combinations likely as the result of the formation of new specific adsorption sites and the mobile Cu adsorption in compost after adding a certain amount of biochar in amendment mixtures. Additionally, a certain proportion of biochar applied into amendment mixtures could suppress desorption of Cd and Cu by pH change, and the Zn desorption rate gradually decreased as the compost ratio increased in amendment mixtures.

Conclusions

The results indicated that the various ratios between biochar and compost have a significant effect on sorption-desorption of metals in soil, which helps us consider the effective combination of biochar and compost in soil.

     

Impact of fresh and aged palm shell biochar on N2O emissions,soil properties,nutrient content and yield of Komatsuna (Brassica rapa var. perviridis) under sandy soil conditions

ABSTRACT

Biochar can reduce N₂O emissions and it can be added to the soil once, whereas fertilizers are often applied every cultivation season. The aging of biochar in soil affects its functioning but it is unclear whether palm shell biochar (PSB) could still mitigate N₂O emissions even when additional basal N fertilizers are applied 1 year after the initial biochar application. We studied the impact of fresh and aged PSB (0%, 6%, 12%, and 18% w/w of dry soil) on N₂O emissions, soil properties, nutrient content and yield of Komatsuna (Brassica rapa var. perviridis) under sandy soil conditions. The aged PSB non-significantly reduced N₂O emissions but significantly offset soil acidification, and maintained a high soil nutrient status. Biochar application with fertilizer significantly increased plant tissue K and Ca content but decreased N, P and Mg content compared to the treatments without biochar. At higher application rates, biochar had negative effects on crop yield but as it aged, the negative effects were offset as a result of the similar variation in plant N uptake. Since seasonal N fertilizer application seems to be inevitable in Komatsuna cultivation, addition of biochar could be a possible way of counteracting the effects of excessive fertilizer use. Further research is needed to assess the feasible biochar application rates for Komatsuna fields in various soil types under field conditions.     

Effects of biochar addition on greenhouse gas emissions during freeze–thaw cycles in a black soil region,Northeast China

As global warming intensifies, the soil environment in middle to high latitudes will undergo more extensive and frequent freeze–thaw cycles (FTCs), which will significantly affect the carbon and nitrogen cycles of soil ecosystems and aggravate greenhouse gas (GHG) emissions. Biochar can increase soil organic carbon storage and mitigate climate change. To effectively control GHG emissions, soil supplemented with biochar at different application rates (0%, 2%, 4% and 6% [w/w]) under different numbers of FTCs (0, 3, 6, 9, and 12) was selected as the research object. The soil GHG emission characteristics in different experimental treatments and their relationships with soil physical and chemical properties were determined. Our results showed that N₂O and CO₂ emissions were promoted during FTCs, with values of 3.13–50.37 and 16.22–135.50 μg m⁻² h⁻¹, respectively. The order of N₂O and CO₂ emissions with respect to biochar application rate was as follows: 2% > 0% > 4% > 6%. CH₄ emissions were negative during FTCs, varying from −1.62 to −10.59 μg m⁻² h⁻¹, and negative CH₄ emissions were promoted by biochar. Correlation analysis showed that N₂O, CO₂ and CH₄ emissions were significantly correlated with pH, soil moisture and soil organic matter (SOM), total nitrogen (TN) and ${\mathrm{NH}}_4^{+}$–N contents (p < .01). The conceptual path model demonstrated that GHG emissions were significantly influenced by FTCs, moisture, SOM and biochar application rate. Our results indicate that the effects of FTCs on GHG emissions were greater than those of biochar application. Biochar application rates of 4% or 6% should be considered in the future to reduce soil GHG emissions in the black soil region of Northeast China. Our results can help provide a theoretical basis and effective strategy to reduce soil GHG emissions during FTCs in seasonally frozen regions.