Phyton-International Journal of Experimental Botany

DOI: 10.32604/phyton.2022.020323

REVIEW

Positive Effects of Biochar on the Degraded Forest Soil and Tree Growth in China: A Systematic Review

Jingkang Zhang1, Shiyuan Zhang1, Changhao Niu1,2, Jiang Jiang1,2 and Haijun Sun1,2,*

1Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, 210042, China
2Key Laboratory of Soil and Water Conservation and Ecological Restoration of Jiangsu Province, Nanjing Forestry, Nanjing, 210042, China
*Corresponding Author: Haijun Sun. Email: hjsun@njfu.edu.cn
Received: 17 November 2021; Accepted: 08 February 2022

1  Introduction

As an important constituent of the terrestrial ecosystem, forests play an irreplaceable role in regulating climate, conserving water sources and maintaining ecological balance [1–4]. However, the forest coverage rate and the per capita forest area in China are 1/3 and 3/4 lower than that of the global average, respectively [1]. What is more, according to the Soil Pollution Survey Bulletin issued in 2014, the soil degraded rate of forest lands in China exceeded the standard by 10.0%, of which 1.3% is under the rate of serious degradation, which is largely greater than that of cultivated land, grassland and other land types [5]. The problems of soil compaction and erosion caused by heavy machinery usage in forest production and climate change are becoming increasingly serious [6]. According to the Bulletin of Ecological Environment in 2020, the area of soil erosion has exceeded 2.7 million km2 in China [7]. Forest soil degradation will not only accelerate the loss of ecosystem diversity and the occurrence of natural disaster, but also become an obstacle to increasing forest productivity and improving climatic conditions. Therefore, it is urgent to restore the degraded forest soil considering its sustainable producing capacity.

At present, there are many managements to restore the degraded forest soil, which are mainly classified into the following three categories: physical, chemical and biological ways such us mulches, fertilization and agroforestry management, respectively. As shown in previous studies, for example, organic mulches can enhance soil fertility [8] and alleviate soil wind erosion [9]; long-term fertilization increased soil organic carbon content for sustainable woodland productivity [10] and underwood inter-planting and/or stockbreeding could provide abundant withered litter and thereby improve the soil quality [11]. However, most of these countermeasures are always time-consuming, laborious and expensive, which limit their suitable application for effectively restoring the degraded forest soil. Originating from the investigation of the black soil (Terra Preta) in the Amazon Basin, a pyrolysis product of biomass at high temperature, namely biochar, has attracted the attention of numerous researchers. After that, as an emerging soil additive, biochar has been extensively studied in the last two decades.

Biochar is a black solid substance derived from certain agricultural or forestry wastes, such as crop straw, wood chips, poultry manure as well as other organic substances, under a high-temperature (always >300°C) and hypoxic condition [12]. Biochar is rich in carbon, hydrogen, oxygen, nitrogen, potassium, phosphorus and other essential elements for plant growth [13,14]. It always has the characteristics of porosity, small bulk density and large specific surface area, and is generally alkaline with high stability and strong adsorption capacity. Therefore, biochar has shown promising application prospects in carbon and nitrogen sequestration, edatope remediation and new-energy materials preparation in agricultural and forestry ecosystems [15,16]. In particular, forest land distributed widely with large areas in China, however, some of them face severe degradation risks, which are caused by pest diseases, pollutant accumulation and human activities [17–19]. Biochar amendment can improve soil porosity condition, neutralize soil acidity and reduce the content of heavy metals in soil [20,21], thus having a meaningful potential for improving the degraded forest soil and promoting tree growth. Presently, more works have focused on the application of biochar to restore the degraded forest soil and tree growth. Therefore, we here summarize the research advances regarding the effects of biochar on restoring the degraded forest soil and clarify the roles that biochar plays in the enhancement of tree growth as well as in the mitigation of greenhouse gas emission (Fig. 1). The study will provide references for the sustainable application of biochar in enhancing forest production.

Figure 1: The effects of biochar amendment into forest soil involved in this review

2  Database and Data Selection

In order to obtain comprehensive information about the core topic of the current review, i.e., the effect of biochar on the degraded forest soil and tree growth, we used the academic journals database of China National Knowledge Infrastructure (CNKI) and the core collection database of Web of Science (WOS) for data collection. Both CNKI and WOS are internationally renowned journal citation index databases, from which we can fully and scientifically learn about the concerned information in any certain field [22,23]. This review takes “biochar”, “degraded forest soil”, and “tree growth” as the core topic. The main keywords used for search are: biochar, forest soil, trees, compaction, acidification, soil erosion and greenhouse gas emission, etc. We limited the publication time of literature from 2010 to 2021 and selected the relevant literatures. Then we made a preliminary sorting in Note Express according to the degree of relevance and the object type. The parameters that indicated the improving effects in this review included porosity, soil fertility, aggregate stability, pH, soil organic carbon, plant height, ground diameter, and greenhouse gas emission. The average values of quantifiable parameters were used for description, and the rest were described in qualitative words. Finally, based on the collected literature, how biochar impacts degraded forest soil and tree growth was reviewed and the underlying mechanisms were clarified. Meanwhile, the remaining problems and follow-up research directions were proposed (Fig. 2).

Figure 2: The flowchart showing the identification of publications from different sources

3  Results and Discussion

3.1 The Benefits of Biochar on Improving the Degraded Forest Soil

3.1.1 Alleviating the Compaction of Forest Soil

Compaction leads to an increase in soil bulk density, a decrease in porosity, and results in the constraint of aeration and water permeability, which threat tree growth and therefore the forest ecosystem stability [24]. Biochar, with porous porosity, large specific surface area and high hydrophilicity, provides an option for alleviating soil compaction [25]. For instance, Blanco-Canqui et al. [26] summarized that biochar incorporation decreased the bulk density of 19 of 22 tested soils by 3%–31% and increased the porosity of all tested soils by 2%–41%. In addition, Meng [27] found that the soil bulk density was on average reduced by 16%, and meanwhile the capillary porosity was increased by approximately 6% after amending wood and bamboo derived biochar into a Chinese Fir plantation soil. A similar effect was confirmed by one 10-year continuous experiment conducted by Pranagal et al. [28]. This benefit may be mainly due to the large specific surface area, and the irregular and fluffy granular structure of biochar, which consequently promoted the formation of a soil porous structure [29].

What is more, the stability of soil aggregates affects the soil structure and fertility, while compaction will retard the formation of soil aggregates [30,31]. Sun [32] found that the increases in average mass diameter and geometric average diameter of biochar-added soil contributed to the enhancement of the stability of soil aggregates, which effect was also confirmed by a 3-year study on a long-term scale [33]. In brief, biochar has an important application value to improve the compact condition of forest soil in both short-and long-term scales.

3.1.2 Alleviating the Acidification and Aluminum Toxicity of Forest Soil

The acidification and aluminum toxicity of forest soil caused by anthropogenic and natural factors such as excessive chemical fertilizer application and atmospheric deposition have given rise to the decline in forest productivity [34,35]. The alkaline and buffering properties of biochar allowed it to be an effective additive to restore acidified and/or aluminum-toxic soils [36–38]. The acidification of the tea garden soil led to a dramatic decrease in tea production and its damage to the environment could not be underestimated as well [39]. Li et al. demonstrated that biochar pyrolyzed at 350°C–550°C improved the acidity of tea garden soils via decreasing the soil exchangeable acid and aluminum content but increasing the amount of base cations and base saturation degree [40]. In addition, a significant (P < 0.05) increase in soil pH value by 0.77–1.16 units was found following the biochar addition [40]. These changes are consistent with the results in previous studies that were also conducted in acidified tea garden and other acidic soils following biochar amendment [39,41–43]. Besides, the soil pH of the acidified eucalyptus plantation increased by 0.17–1.29 units after applying eucalyptus branch biochar (anaerobic pyrolysis under 500°C) [44]. The pH values of the Phyllostachys praecox stand, the rubber plantation and the nitrogen-applied bamboo forest soils also significantly (P < 0.05) increased after biochar addition [45–47]. These data suggest that biochar can immediately increase the pH value of different types of acidified forest soils. Given the sustainability of forest soil management, the long-term effect of biochar on relieving the soil acidic process needs to be further studied.

3.1.3 Restoring the Highly Erosive Forest Soil

Soil erosion dramatically reduces soil fertility, silts up downstream reservoirs, and deteriorates the ecological environment, which has severely hindered economic and social development [48]. Soil organic matter (SOM) content is one of the important indicators of soil fertility, which can be increased by biochar application [49]. Biochar can effectively restore soil fertility and support the land productivity via increased SOM content [50,51]. Consistently, previous studies have confirmed that biochar can increase SOM content by 0.30–0.36 g/kg soil [52], and can increase the alkaline hydrolysis of nitrogen and available potassium content in a long-term [53,54]. Interestingly, biochar can also enhance the resistance capacity of soils to heavy rain erosion [55,56]. For instance, Liu [57] reported that biochar application at a high rate (16 g/kg soil or more) can effectively promote the formation of water-stable aggregates and enhance soil anti-erodibility, reflected by reducing the amount of soil erosion in a rainfall event. However, biochar exerted a negative effect on soil erosion in some cases, which might be related to the plant cultivation time, biochar application rate and soil particle size [58,59].

Biochar could change the soil erosion resistance capacity, but generally improve the soil acidity, bulk density and other key physio-chemical properties [53,57,60,61], most of which are favorable for degraded forest soils. Nevertheless, more researches should be carried out to evaluate the improvement effect of biochar with varied application dosages in a long-term, and to clarify the underlying mechanisms involved meanwhile. Therefore, it is undoubtedly worth looking forward to using biochar as an effective additive to restore the degraded forest soil.

3.2 Biochar’s Effect on Tree Growth

3.2.1 Effect of Biochar on Tree Growth

Biochar is widely used as a soil additive to increase stable crop yield in recent years [62–64]. Meanwhile, some forestry workers have applied biochar to forest soil to evaluate the biochar’s effect on productivity of woodland. For example, applying wheat straw biochar into Chinese Torreya stand for half a year increased the soil nutrient contents and therefore enhanced the fresh weight of nuts by more than 15% on average [65]. Meanwhile, Wu et al. [66] applied biochar into a Pistacia chinensis plantation for one year and found that the plant height, ground diameter and crown width of Pistacia chinensis significantly (P < 0.05) increased by over 20% compared with the control. Moreover, biochar could increase the light and water use efficiencies of tree, and thereby enhanced tree’s stress resistance and biomass [66–68]. For Acer rubrum, biochar also exerted positive benefits on the pigment content, leaf color and the final economic value [69]. Biomasses of conifer and broad-leaved trees were increased following biochar amendment [70,71], owed to the improved physical properties, increased nutrient contents, and enhanced photosynthesis and gas exchange capacity [72,73].

In contrast, some studies have found that biochar alone application may inhibit the growth of tree seedlings. This is because the biochar’s restrictions on the nitrogen use efficiency of nursery-grown plants, which effect could be reversed by the co-application of biochar and a compound fertilizer [74,75]. Also, in some marginal soil environments, conifers only show an unobvious response to biochar because of the resource-conservative growth strategies [76]. In summary, biochar generally plays a positive role but may lead to inhibitory effects in some cases, which effects are as function of biochar type, application dosage and tree varieties [54,69].

3.2.2 How Biochar Affect Tree Growth

Generally, there are two mechanisms explaining how biochar affects plant growth [77]. Firstly, as a source of nutrients, biochar can directly communicate with the tree roots [78,79]. Biochar is always rich in nitrogen and phosphorus nutrients. Therefore, tree roots will be attracted (known as chemotropism) and more distributed between the bulk and rhizosphere soil after biochar addition. This effect makes the branch and spatial structure of tree roots more rational, thereby enhancing the absorption capacity of tree roots on soil nutrients [50,54]. Secondly, soil nutrient contents and forms as well as other physio-chemical properties would be changed following biochar amendment, which indirectly influences the tree growth [80,81]. For instance, Pan et al. found that biochar decreased soil bulk density but increased fertility, which made the nutrients more available to tree roots [74]. What’s more, the rhizosphere microbial abundance and their function can also be affected by biochar [74,82]. Biochar addition not only increased the content of dissolved organic carbon [83,84] but also provided habitats for microorganisms [85], thereby promoting the tree absorption ability for soil moisture and nutrients [86]. In addition, biochar could mitigate the reactive nitrogen losses via leaching [87], nitrification and denitrification [88,89], and accordingly enhance the nitrogen use efficiency of tree.

3.3 Biochar’s Effect on Greenhouse Gas Emission from Forest Soil

The forest ecosystem is an important sink or source of greenhouse gases (such as CO2, CH4, and NOX) in the atmosphere. Biochar application affects the physio-chemical properties and biochemical processes of forest soils, thereby directly or indirectly affecting the generation of greenhouse gases. However, the effects of biochar incorporation on greenhouse gas emissions from forest soils were not consistent, which was dependent with the biochar and soil types and their physio-chemical characteristics, as well as the vegetation type. One research with poplar plantation in the coastal area of Dongtai, China, showed that biochar treatment with 80–120 t/ha resulted in a significant (P < 0.05) increase in the average annual CO2 emission load by more than 20%, while it inhibited the emissions of CH4 and N2O from the saline soil [90]. For a pine forest soil, biochar application not only mitigated the N2O and CO2 emissions, but also significantly (P < 0.05) suppressed the CO2 emission by 31.5% [91]. However, the CO2 efflux was overall unaffected by biochar in a recent report [92]. In addition, the effect of chicken manure biochar on CH4 emission from a forest soil in Dinghushan Nature Reserve, China, was the combined results of biochar and soil moisture [93]. Of which, biochar played a role in reducing CH4 emission at low soil moisture content. However, it would reversely promote the transformation of soil CH4 from sink to source at increasing soil moisture. It can be seen that the effect of biochar on greenhouse gas emissions from forestland soils is variable, depending on three principal factors including the biochar type, soil property and vegetation type [81,90].

3.4 Factors Deciding the Effects of Biochar

3.4.1 The Raw Material and Pyrolysis Temperature of Biochar

Raw material and pyrolysis temperature decide the physical and chemical properties such as specific surface area, pore structure, stability and element composition of biochar [94], which may affect its effects on improving the degraded forest soil and tree growth. For instance, biochar derived from Chinese Fir (Cunninghamia lanceolata) sawdust had a greater impact on the community structure of the understory vegetation of a Chinese Fir plantation than the biochar derived from rice straw, which was indicated by the higher diversity index after sawdust biochar application [95]. Increases in pyrolysis temperature would lead to losses of aliphatic and oxygen-containing functional groups but produce more aromatic structures of biochar [96]. Consequently, biochar that pyrolyzed at high or low temperature was more suitable for adsorbing and immobilizing the organic or ionic pollutants in soils, respectively [96]. Therefore, raw material and pyrolysis temperature are the two major factors that decide the effects of biochar.

3.4.2 The Biochar Application Rate

Both soil fertility and structure could be improved following the biochar application [37]. The application rate decides the biochar’s effect in what degree and even in adverse direction. Lu et al. [97] added bamboo leaf biochar at four rates to chestnut forest soil and found that the inhibiting effect of biochar on soil N2O emission was increased with the application rate. This effect was confirmed by a study conducted under a poplar plantation ecosystem [90]. Nevertheless, there was also a work reporting that the N2O emission was increased when biochar was overused [98]. Biochar application rate also affect the growth vigor and survival rate of tree seedlings [99]. For example, application of biochar at a medium rate (600 kg/ha) could improve the survival rate of transplanting and the growth of camphor seedlings in a dryland red soil in Southern China, which was attributed to the increased soil nutrients following biochar application. Nevertheless, camphor seedlings are habituated to slightly acidic soil, but the high amount of biochar addition just increases the soil alkalinity, which conversely inhibited the plant seedlings’ growth [99]. Meanwhile, it is necessary to explore the underlying mechanisms regarding how biochar affects tree plant, in particular when it is amended at various rates.

3.4.3 The Aging Effect of Biochar

The process of alterations of the physicochemical properties of biochar exposed to the combined effects of soil organisms and soil environment is called biochar aging [100,101]. Aged biochar is different in its physicochemical properties from those of fresh biochar, which may either enhance or weaken the improvement effect of biochar after being amended to forest soils [102–104]. After three freeze-thaw cycles under natural conditions, the surface of aged biochar was partially broken and covered with more oxygen-containing functional groups, providing more Cd adsorption sites [105]. Pei et al. [106] found that eucalyptus biochar aged with 15% hydrogen peroxide increased the microbial carbon use efficiency and thereby benefitted the soil carbon sequestration, which might be the results of the changes in soil pH and the composition of fungal-bacterial communities [107,108]. However, some studies revealed that the improvement effect of biochar was weakened during its aged process [109–111]. For instance, both manure and sawdust biochar aged with dry-wet and freeze-thaw cycles had an increase in acidity, which is not conducive to Cd immobilization [109]. The pH of naturally aged biochar might also be decreased, and its effect on soil acidity was weakened with decreasing carbonate content, soluble and exchangeable alkaline cations [110,111]. Therefore, the effects of aged biochar exposed to different environments showed great uncertainties, which need more long-term investigations to have a comprehensive understanding of the aging effect of biochar.

3.4.4 Texture of the Tested Soil

According to the Chinese Soil Classification Standard, soil texture can be divided into sandy, loam and clay [112]. Soils with different textures and water holding capacity distinctly decided the functions of biochar after it was incorporated into forest soils [113,114]. Tian et al. [115] added straw and peanut shell derived biochar into silt loam and sandy soils and measured the changes of hydraulic characteristics. They found that sandy soil with more grit had a decreased bulk density and increased porosity and improved water holding capacity, but this effect did not occur in silt loam soil [115]. Dugan et al. [116] also reported similar finding in the comparative experiments with silt loam, sandy loam and sandy soils. What is more, Li et al. [117] demonstrated that biochar showed different effects on nitrate transport in soils with different textures in China, i.e., biochar decreased the nitrate leaching loads from coarse loess and aeolian sandy soils, but increased the nitrate leaching loads from Lou soil. The transference of soil solutes is affected by soil pore conditions, in particular the soil macro pores, which might be reduced as result of biochar addition. This change had adverse effect on the fixation of available nitrogen according to previous works [118,119].

Therefore, biochar has been widely used as a potential amendment used for forest production, degraded forest soil improvement, tree growth enhancement and greenhouse gas mitigation, which main details are presented in Table 1.

4  Conclusion

Both agricultural and forest wastes can be pyrolyzed into biochar as an additive applied into the degraded forest soil. In brief, biochar exerted the benefits as follows: 1) improving the physicochemical properties, in particular the chemical characteristics; 2) mitigating the greenhouse gas emissions in most cases; 3) enhancing the nutrient use efficiency and therefore the tree growth. These effects are a function of the raw material, pyrolysis temperature, application rate and the aging process of the biochar after application, as well as the soil and plantation types.

Meanwhile, more attentions should be paid to study the interaction effects between specific soil and tree and biochar as well as the underlying mechanisms, especially in a long-term. What is more, how biochar influences the forest soil animal needs urgent investigation.

Funding Statement: This study was financially supported by the College Students’ Innovation and Entrepreneurship Training Program of Jiangsu Province (202010298026Z), the National Natural Science Foundation of China (31972518), and the National Key Research and Development Program of China (2017YFC0505502).

Conflicts of Interest: The authors declare that they have no conflicts of interest to report regarding the present study.

References

 1.  Jin, L., Tian, G. (2021). Construction of eco-efficiency accounting model of forest resource based on green development. Arabian Journal of Geosciences, 14(10), 899. DOI 10.1007/s12517-021-07196-y. [Google Scholar] [CrossRef]

 2.  Wan, J. Z., Wang, C. J., Qu, H., Liu, R., Zhang, Z. X. (2018). Vulnerability of forest vegetation to anthropogenic climate change in China. Science of the Total Environment, 621, 1633–1641. DOI 10.1016/j.scitotenv.2017.10.065. [Google Scholar] [CrossRef]

 3.  Hanewinkel, M., Cullmann, D. A., Schelhaas, M. J., Nabuurs, G. J., Zimmermann, N. E. (2013). Climate change may cause severe loss in the economic value of European forest land. Nature Climate Change, 3(3), 203–207. DOI 10.1038/nclimate1687. [Google Scholar] [CrossRef]

 4.  Dixon, R. K. K., Solomon, A., Brown, S., Houghton, R., Trexier, M. et al. (1994). Carbon pools and flux of global forest ecosystems. Science, 263, 185–190. DOI 10.1126/science.263.5144.185. [Google Scholar] [CrossRef]

 5.  Chen, N. C., Zheng, Y. J., He, X. F., Li, X. F., Zhang, X. X. (2017). Analysis of the report on the national general survey of soil contamination. Journal of Agro-Environment Science, 36(9), 1689–1692 (in Chinese). DOI 10.11654/jaes.2017-1220. [Google Scholar] [CrossRef]

 6.  Lal, R. (2015). Restoring soil quality to mitigate soil degradation. Sustainability, 7(5), 5875–5895. DOI 10.3390/su7055875. [Google Scholar] [CrossRef]

 7.  Ministry of Ecological Environment of the People’s Republic of China (2020). Bulletin of China’s Ecological Environment (in Chinese). http://www.mee.gov.cn/hjzl/sthjzk/zghjzkgb/. [Google Scholar]

 8.  Liu, X. J., Li, Y., Yang, Q. S. (2011). Effect of yard wastes organic mulches on soil nutrient. International Symposium on Water Resource & Environmental Protection, 3, 1678–1681. DOI 10.1109/ISWREP.2011.5893363. [Google Scholar] [CrossRef]

 9.  Nzeyimana, I., Hartemink, A. E., Ritsema, C., Stroosnijder, L., Lwanga, E. H. et al. (2017). Mulching as a strategy to improve soil properties and reduce soil erodibility in coffee farming systems of Rwanda. Catena, 149, 43–51. DOI 10.1016/j.catena.2016.08.034. [Google Scholar] [CrossRef]

10. Fan, T. L., Stewart, B. A., Yong, W., Luo, J. J., Zhou, G. Y. (2005). Long-term fertilization effects on grain yield, water-use efficiency and soil fertility in the dryland of Loess Plateau in China. Agriculture, Ecosystems & Environment, 106(4), 313–329. DOI 10.1016/j.agee.2004.09.003. [Google Scholar] [CrossRef]

11. Araujo, A. S. F., Leite, L. F. C., Iwata, B. F., de Andrade Lira Jr, M., Xavier, G. R. et al. (2012). Microbiological process in agroforestry systems. A review. Agronomy for Sustainable Development, 32, 215–226. DOI 10.1007/s13593-011-0026-0. [Google Scholar] [CrossRef]

12. Tan, X. F., Liu, Y. G., Zeng, G. G., Wang, X., Hu, X. J. et al. (2015). Application of biochar for the removal of pollutants from aqueous solutions. Chemosphere, 125, 70–85. DOI 10.1016/j.chemosphere.2014.12.058. [Google Scholar] [CrossRef]

13. Liu, W., Jiang, H., Yu, H. (2015). Development of biochar-based functional materials: Toward a sustainable platform carbon material. Chemical Reviews, 115(22), 12251–12285. DOI 10.1021/acs.chemrev.5b00195. [Google Scholar] [CrossRef]

14. Kan, T., Strezov, V., Evans, T. J. (2016). Lignocellulosic biomass pyrolysis: A review of product properties and effects of pyrolysis parameters. Renewable & Sustainable Energy Reviews, 57, 1126–1140. DOI 10.1016/j.rser.2015.12.185. [Google Scholar] [CrossRef]

15. Lu, W. W., Geng, H. L., Zhang, Y. R., Ruan, H. H. (2020). Effects of biochars pyrolyzed at different temperatures on soil microbial community in a poplar plantation in coastal Eastern China. Journal of Nanjing Forestry University (Natural Sciences Edition), 44(4), 143–150 (in Chinese). DOI 10.3969/j.issn.1000-2006.201911014. [Google Scholar] [CrossRef]

16. El-Naggar, A., Lee, S. S., Rinklebe, J., Farooq, M., Song, H. et al. (2019). Biochar application to low fertility soils: A review of current status, and future prospects. Geoderma, 337, 536–554. DOI 10.1016/j.geoderma.2018.09.034. [Google Scholar] [CrossRef]

17. Li, Y. K., Xiao, Z. W. (2015). China’s forestland soil pollution, degradation, erosion problems and countermeasures. Forestry Economics, 37(9), 3–15 (in Chinese). DOI 10.13843/j.cnki.lyjj.2015.09.001. [Google Scholar] [CrossRef]

18. Zhou, Z. H., Wang, C. K., Luo, Y. Q. (2018). Effects of forest degradation on microbial communities and soil carbon cycling: A global meta-analysis. Global Ecology and Biogeography, 27(1), 110–124. DOI 10.1111/geb.12663. [Google Scholar] [CrossRef]

19. Wu, Q. F., Wang, J. S., Lu, Z. F. (2015). Research progress of poplar plantation degradation and recovery. Chinese Agricultural Science Bulletin, 31(31), 1–6 (in Chinese). DOI 10.11924/j.issn.1000-6850.casb15040164. [Google Scholar] [CrossRef]

20. Gui, L. Q., Zhang, Y. L., Wang, Y. J. (2020). Research advance on effects of biochar on soil fertility and crop’s yield and quality. Modern Agricultural Science and Technology, 2020(16), 136–139 (in Chinese). DOI 10.3969/j.issn.1007-5739.2020.16.085. [Google Scholar] [CrossRef]

21. Long, Q. N., Wang, R. S., Xu, H. M., Cao, G. H., Shen, C. Q. et al. (2020). Effects of biogas slurry and biochar on oribatida density in poplar plantation. Journal of Nanjing Forestry University (Natural Sciences Edition), 44(3), 211–215 (in Chinese). DOI 10.3969/j.issn.1000-2006.201904023. [Google Scholar] [CrossRef]

22. Hou, Q., Mao, G. Z., Zhao, L., Du, H. B., Zuo, J. (2015). Mapping the scientific research on life cycle assessment: A bibliometric analysis. The International Journal of Life Cycle Assessment, 20, 541–555. DOI 10.1007/s11367-015-0846-2. [Google Scholar] [CrossRef]

23. Li, M. Y., Cheng, H., Wang, B., Zheng, K. W., Li, P. et al. (2020). Bibliometric analysis of China’s green mining development based on CNKI database. 6th International Conference on Advances in Energy, Environment and Chemical Engineering, pp. 1–5. Jinan, Chian, PTS. [Google Scholar]

24. He, N., Wang, L. H., Meng, C. (2010). Effects of compaction on diurnal variation of soil respiration in Larix gmellinii plantation in summer. Chinese Journal of Applied Ecology, 21(12), 3070–3076 (in Chinese). DOI 10.13287/j.1001-9332.2010.0461. [Google Scholar] [CrossRef]

25. Liu, Q., Liu, B. J., Zhang, Y. H., Lin, Z. B., Zhu, T. B. et al. (2017). Can biochar alleviate soil compaction stress on wheat growth and mitigate soil N2O emissions? Soil Biology & Biochemistry, 104, 8–17. DOI 10.1016/j.soilbio.2016.10.006. [Google Scholar] [CrossRef]

26. Blanco-Canqui, H. (2017). Biochar and soil physical properties. Soil Science Society of America Journal, 81(4), 687–711. DOI 10.2136/sssaj2017.01.0017. [Google Scholar] [CrossRef]

27. Meng, L. Q. (2014). Effect of biochar application on Chinese fir plantation ecosystem (Master Thesis). Fujian Agriculture and Forestry University, China (in Chinese). [Google Scholar]

28. Pranagal, J., Kraska, P. (2020). 10-years studies of the soil physical condition after one-time biochar application. Agronomy, 10(10), 1589. DOI 10.3390/agronomy10101589. [Google Scholar] [CrossRef]

29. Xiao, L., Yuan, G. D., Feng, L. R., Bi, D. X., Wei, J. (2020). Soil properties and the growth of wheat (Triticum aestivum L.) and maize (Zea mays L.) in response to reed (Phragmites communis) biochar use in a salt-affected soil in the Yellow River delta. Agriculture Ecosystems & Environment, 303, 107124. DOI 10.1016/j.agee.2020.107124. [Google Scholar] [CrossRef]

30. Liang, A., McLaughlin, N. B., Zhang, X. P., Shen, Y., Shi, X. H. et al. (2011). Short-term effects of tillage practices on soil aggregate fractions in a Chinese Mollisol. Acta Agriculturae Scandinavica Section B–Soil and Plant Science, 61(6), 535–542. DOI 10.1080/09064710.2010.515601. [Google Scholar] [CrossRef]

31. Shah, A. N., Tanveer, M., Shahzad, B., Yang, G. Z., Fahad, S. et al. (2017). Soil compaction effects on soil health and crop productivity: An overview. Environmental Science and Pollution Research, 24(11), 10056–10067. DOI 10.1007/s11356-017-8421-y. [Google Scholar] [CrossRef]

32. Sun, T. P. (2018). Effects of biochar on stability of soil aggregates and active organic carbon in black soil (Master Thesis). Northeastern Agricultural University, China (in Chinese). [Google Scholar]

33. Burrell, L. D., Zehetner, F., Rampazzo, N., Wimmer, B., Soja, G. et al. (2016). Long-term effects of biochar on soil physical properties. Geoderma, 282, 96–102. DOI 10.1016/j.geoderma.2016.07.019. [Google Scholar] [CrossRef]

34. Lin, J. W., Li, Y., Zhou, Z. F., Liu, A. Q. (2014). Research advance on aluminum toxicity in forest ecosystems. World Forestry Research, 27(6), 21–26 (in Chinese). DOI 10.13348/j.cnki.sjlyyj.2014.06.003. [Google Scholar] [CrossRef]

35. Zhu, Q., De, V. W., Liu, X., Zeng, M. F., Hao, T. X. et al. (2016). The contribution of atmospheric deposition and forest harvesting to forest soil acidification in China since 1980. Atmospheric Environment, 146, 215–222. DOI 10.1016/j.atmosenv.2016.04.023. [Google Scholar] [CrossRef]

36. Wang, L., Butterly, C. R., Wang, Y., Herath, H. M. S. K., Xi, Y. G. et al. (2014). Effect of crop residue biochar on soil acidity amelioration in strongly acidic tea garden soils. Soil Use and Management, 30(1), 119–128. DOI 10.1111/sum.12096. [Google Scholar] [CrossRef]

37. Wu, Y., Xu, G., Lv, Y. C., Shao, H. B. (2014). Effects of biochar amendment on soil physical and chemical properties: Current status and knowledge gaps. Advances in Earth Science, 29(1), 68–79 (in Chinese). DOI 10.11867/j.issn.1001-8166.2014.01.0068. [Google Scholar] [CrossRef]

38. Dai, Z. M., Zhang, X. J., Tang, C., Muhammad, N., Wu, J. J. et al. (2017). Potential role of biochars in decreasing soil acidification–A critical review. Science of the Total Environment, 581, 601–611. DOI 10.1016/j.scitotenv.2016.12.169. [Google Scholar] [CrossRef]

39. Hu, Y., Li, R., Yang, Y. (2015). Effects of biochar on CO2 and N2O emissions and microbial properties of tea garden soils. The Journal of Applied Ecology, 26(7), 1954–1960 (in Chinese). DOI 10.13287/j.1001-9332.20150506.009. [Google Scholar] [CrossRef]

40. Li, Y. C., Chen, Z. P., Wang, Y. X., Jiang, Y. H., Li, Z. W. et al. (2018). Effect of biomass on amelioration of acidic soils at tea plantations. Fujian Journal of Agricultural Sciences, 33(11), 1190–1194 (in Chinese). DOI 10.19303/j.issn.1008-0384.2018.11.012. [Google Scholar] [CrossRef]

41. He, Z. L., Xia, W. J., Zhou, W., Tian, Y. N., Li, W. Y. et al. (2016). Effects of wheat-straw derived biochar on acidified tea garden soil N2O and CO2 emission in short-term laboratory experiments. Ecology and Environmental Sciences, 25(7), 1230–1236 (in Chinese). DOI 10.16258/j.cnki.1674-5906.2016.07.020. [Google Scholar] [CrossRef]

42. Xie, S. N., Zong, L. G., Zhang, Q. H., Dai, R. B., Pan, H. Y. et al. (2017). Effects of three amendments on selenium availability of highly acidic and Se-rich soil in tea garden and their relative mechanisms. Journal of Tea Science, 37(3), 299–307 (in Chinese). DOI 10.13305/j.cnki.jts.2017.03.010. [Google Scholar] [CrossRef]

43. Shi, R. Y., Li, J. Y., Jiang, J., Kamran, M. A., Xu, R. K. et al. (2018). Incorporation of corn straw biochar inhibited the re-acidification of four acidic soils derived from different parent materials. Environmental Science and Pollution Research, 25(10), 9662–9672. DOI 10.1007/s11356-018-1289-7. [Google Scholar] [CrossRef]

44. Duan, C. Y., Shen, Y. Y., Xu, G. P., Teng, Q. M., Zhang, D. N. et al. (2020). Effects of eucalyptus branches biochar application on soil physicochemical properties of acidified soil in a eucalyptus plantation in Northern Guangxi. Environmental Science, 41(9), 4234–4245 (in Chinese). DOI 10.13227/j.hjkx.202002180. [Google Scholar] [CrossRef]

45. Bao, J. Y., Zhao, Y. Z., Yan, S. X., Bai, S., Li, S. H. et al. (2018). Soil amelioration with biochars pyrolyzed from different feedstocks of an acidic bamboo (Phyllostachys violascens) plantation. Journal of Zhejiang A&F University, 35(1), 43–50 (in Chinese). DOI 10.11833/j.issn.2095-0756.2018.01.006. [Google Scholar] [CrossRef]

46. Wu, M., Wei, J. S., Sun, H. D., He, P., Wu, B. S. et al. (2017). Effects of biochar on acidify and exchangeable capacity of the granite-derived ferralsol in rubber plantation. Journal of Agricultural Science and Technology, 19(3), 98–107 (in Chinese). DOI 10.13304/j.nykjdb.2016.421. [Google Scholar] [CrossRef]

47. Chu, L., Sun, H., Hennayake, H. M. K. D., Sun, H. (2019). Biochar effectively reduces ammonia volatilization from nitrogen-applied soils in tea and bamboo plantations. Phyton-International Journal of Experimental Botany, 88(3), 261–267. DOI 10.32604/phyton.2019.07791. [Google Scholar] [CrossRef]

48. Zhuang, Y., Du, C., Zhang, L., Du, Y., Li, S. S. et al. (2015). Research trends and hotspots in soil erosion from 1932 to 2013: A literature review. Scientometrics, 105(2), 743–758. DOI 10.1007/s11192-015-1706-3. [Google Scholar] [CrossRef]

49. Mollinedo, J., Schumacher, T. E., Chintala, R. (2015). Influence of feedstocks and pyrolysis on biochar’s capacity to modify soil water retention characteristics. Journal of Analytical & Applied Pyrolysis, 114, 100–108. DOI 10.1016/j.jaap.2015.05.006. [Google Scholar] [CrossRef]

50. Zhang, M. Y., Gao, T., Wu, Y. B., Xue, J. H. (2019). Effects of biochar on physical and chemical properties of desertification and growth characteristics of Broussonetia papyrifera seedlings in karst mountain of Guizhou area. Jiangsu Agricultural Sciences, 47(12), 177–181 (in Chinese). DOI 10.15889/j.issn.1002-1302.2019.12.039. [Google Scholar] [CrossRef]

51. Li, Z. G., Gu, C. M., Zhang, R. H., Ibrahim, M., Zhang, G. S. et al. (2017). The benefic effect induced by biochar on soil erosion and nutrient loss of slopping land under natural rainfall conditions in central China. Agricultural Water Management, 185, 145–150. DOI 10.1016/j.agwat.2017.02.018. [Google Scholar] [CrossRef]

52. Deng, J. Q. (2017). Soil erosion control and effect of biochar on soil improvement in land consolidation region of southwest Hubei (Ph.D. Thesis). Nanjing Agricultural University, China (in Chinese). [Google Scholar]

53. Song, D. D. (2018). The effects of biochar on soil physical and chemical in Karst area (Master Thesis). Southwest University, China (in Chinese). [Google Scholar]

54. Sun, J. M., Bu, X. L., Wu, Y. B., Xue, J. H. (2016). Effects of biochar application on the growth of Robinia pseudoacacia L. seedlings and soil properties in limestone soil in a karst mountain site. Chinese Journal of Ecology, 35(12), 3250–3257 (in Chinese). DOI 10.13292/j.1000-4890.201612.036. [Google Scholar] [CrossRef]

55. Li, T. X., Yu, P. F., Fu, Q., Liu, D. (2021). Effects of biochar on sediment transport and rill erosion after two consecutive years of seasonal freezing and thawing. Sustainability, 13(13), 6984. DOI 10.3390/su13136984. [Google Scholar] [CrossRef]

56. Li, Y. Y., Feng, G., Tewolde, H., Yang, M. Y., Zhang, F. B. (2020). Soil, biochar, and nitrogen loss to runoff from loess soil amended with biochar under simulated rainfall. Journal of Hydrology, 591, 125318. DOI 10.1016/j.jhydrol.2020.125318. [Google Scholar] [CrossRef]

57. Liu, X. H. (2013). Effect of biochar application on soil improvement on the Loess Plateau (Ph.D. Thesis). Research Center of Soil and water Conservation and Ecological Environment, Chinese Academy of Sciences and Ministry of Education, China (in Chinese). [Google Scholar]

58. Wu, Y. Y. (2016). Effect of biochar application on soil erosion of Loess Slopes (Master Thesis). Research Center of Soil and Water Conservation and Ecological Environment, Chinese Academy of Sciences and Ministry of Education, China (in Chinese). [Google Scholar]

59. Li, Y. Y., Zhang, F. B., Yang, M. Y., Zhang, J. Q., Xie, Y. G. (2018). Impacts of biochar application rates and particle sizes on runoff and soil loss in small cultivated loess plots under simulated rainfall. Science of the Total Environment, 649, 1403–1413. DOI 10.1016/j.scitotenv.2018.08.415. [Google Scholar] [CrossRef]

60. Blanco-Canqui, H. (2021). Does biochar application alleviate soil compaction? Review and data synthesis. Geoderma, 404(4), 115317. DOI 10.1016/j.geoderma.2021.115317. [Google Scholar] [CrossRef]

61. You, J. K., Hyun, J., Yoo, S. Y., Yoo, G. (2021). The role of biochar in alleviating soil drought stress in urban roadside greenery. Geoderma, 404, 115223. DOI 10.1016/j.geoderma.2021.115223. [Google Scholar] [CrossRef]

62. Cheng, X. Y., Meng, J., Huang, Y. W., Liang, H. E. Y. et al. (2016). Effect of biochar on root growth, absorption of nitrogen and maize yield. Journal of Shenyang Agricultural University, 47(2), 218–223 (in Chinese). DOI 10.3969/j.issn.1000-1700.2016.02.015. [Google Scholar] [CrossRef]

63. Ye, L. L., Arbestain, M. C., Shen, Q. H., Lehmann, J., Singh, B. et al. (2020). Biochar effects on crop yields with and without fertilizer: A meta-analysis of field studies using separate controls. Soil Use and Management, 36(1), 2–18. DOI 10.1111/sum.12546. [Google Scholar] [CrossRef]

64. Zhang, A. F., Cui, L. Q., Pan, G. X., Li, L. Q., Hussain, Q. et al. (2010). Effect of biochar amendment on yield and methane and nitrous oxide emissions from a rice paddy from Tai Lake Plain, China. Agriculture, Ecosystems and Environment, 139(4), 469–475. DOI 10.1016/j.agee.2010.09.003. [Google Scholar] [CrossRef]

65. Zhang, R., Zhang, Y. L., Song, L. L., Song, X. Z., Hanninen, H. et al. (2017). Biochar enhances nut quality of Torreya grandis and soil fertility under simulated nitrogen deposition. Forest Ecology and Management, 391, 321–329. DOI 10.1016/j.foreco.2017.02.036. [Google Scholar] [CrossRef]

66. Wu, Z. Z., Wang, D. J., Li, Y. Q., Du, X. H., Shao, Q. et al. (2015). Effects of biochar fertilizer application on growth properties and photosynthetic and physiological characteristics of Pistacia chinensis Bunge. Ecology and Environmental Sciences, 24(6), 992–997 (in Chinese). DOI 10.16258/j.cnki.1674-5906.2015.06.013. [Google Scholar] [CrossRef]

67. Tanazawa, Y., Tomotsune, M., Suzuki, T., Koizumi, H., Shinpei, Y. (2021). Photosynthetic response of young oaks to biochar amendment in field conditions over 3 years. Journal of Forest Research, 26(2), 116–126. DOI 10.1080/13416979.2020.1866231. [Google Scholar] [CrossRef]

68. Licht, J., Smith, N. (2018). The influence of lignocellulose and hemicellulose biochar on photosynthesis and water use efficiency in seedlings from a northeastern US pine-oak ecosystem. Journal of Sustainable Forestry, 37(1), 25–37. DOI 10.1080/10549811.2017.1386113. [Google Scholar] [CrossRef]

69. Huang, X. L., Gegen, T. N., Mei, M., Lu, X. J. (2017). Effects of biochar on seedling growth and leaf color of autumn blaze maple. Journal of Shenyang Agricultural University, 48(5), 530–536 (in Chinese). DOI 10.3969/j.issn.1000-1700.2017.05.003. [Google Scholar] [CrossRef]

70. Robertson, S. J., Rutherford, P. M., Lopez-Gutierrez, J. C., Massicotte, H. B. (2012). Biochar enhances seedling growth and alters root symbioses and properties of sub-boreal forest soils. Canadian Journal of Soil Science, 92(2), 329–340. DOI 10.4141/cjss2011-066. [Google Scholar] [CrossRef]

71. Palviainen, M., Aaltonen, H., Lauren, A., Koster, K., Berninger, F. et al. (2020). Biochar amendment increases tree growth in nutrient-poor, young Scots pine stands in Finland. Forest Ecology and Management, 474, 118362. DOI 10.1016/j.foreco.2020.118362. [Google Scholar] [CrossRef]

72. Sackett, T. E., Basiliko, N., Noyce, G. L., Winsborough, C., Schurman, J. et al. (2015). Soil and greenhouse gas responses to biochar additions in a temperate hardwood forest. Global Change Biology Bioenergy, 7(5), 1062–1074. DOI 10.1111/gcbb.12211. [Google Scholar] [CrossRef]

73. Tarin, M. W. K., Fan, L., Cai, Y., Tayyab, M., Chen, L. et al. (2020). Biochar amendment regulated growth, physiological, and biochemical responses of conifer in red soil. iForest-Biogeosciences and Forestry, 13, 490–498. DOI 10.3832/ifor3416-013. [Google Scholar] [CrossRef]

74. Pan, L. B., Xu, F. Z., Sha, L. Q. (2015). Effect of biochar on soil properties and rubber (Hevea brasilensis) seedling biomass. Mountain Research, 33(4), 449–456 (in Chinese). DOI 10.16089/j.cnki.1008-2786.000056. [Google Scholar] [CrossRef]

75. Gale, N. V., Thomas, S. C. (2019). Dose-dependence of growth and ecophysiological responses of plants to biochar. Science of the Total Environment, 658, 1344–1354. DOI 10.1016/j.scitotenv.2018.12.239. [Google Scholar] [CrossRef]

76. Thomas, S. C., Gale, N. (2015). Biochar and forest restoration: A review and meta-analysis of tree growth responses. New Forests, 46(5), 931–946. DOI 10.1007/s11056-015-9491-7. [Google Scholar] [CrossRef]

77. Prendergast-Miller, M. T., Duvall, M., Sohi, S. P. (2014). Biochar-root interactions are mediated by biochar nutrient content and impacts on soil nutrient availability. European Journal of Soil Science, 65, 173–185. DOI 10.1111/ejss.12079. [Google Scholar] [CrossRef]

78. Zhou, C. F., Heal, K., Tigabu, M., Xia, L. D., Hu, H. Y. et al. (2020). Biochar addition to forest plantation soil enhances phosphorus availability and soil bacterial community diversity. Forest Ecology and Management, 455, 117635. DOI 10.1016/j.foreco.2019.117635. [Google Scholar] [CrossRef]

79. Sackett, T. E., Basiliko, N., Noyce, G. L., Winsborough, C., Jonathan, S. et al. (2015). Soil and greenhouse gas responses to biochar additions in a temperate hardwood forest. Global Change Biology Bioenergy, 7(5), 1062–1074. DOI 10.1111/gcbb.12211. [Google Scholar] [CrossRef]

80. Lu, S., Sun, F., Zong, Y. (2014). Effect of rice husk biochar and coal fly ash on some physical properties of expansive clayey soil (Vertisol). Catena, 114, 37–44. DOI 10.1016/j.catena.2013.10.014. [Google Scholar] [CrossRef]

81. Li, Y. F., Hu, S. D., Chen, J. H., Mueller, K., Li, Y. C. et al. (2018). Effects of biochar application in forest ecosystems on soil properties and greenhouse gas emissions: A review. Journal of Soils and Sediments, 18(2), 546–563. DOI 10.1007/s11368-017-1906-y. [Google Scholar] [CrossRef]

82. Kolb, S. E., Fermanich, K. J., Dornbush, M. E. (2009). Effect of charcoal quantity on microbial biomass and activity in temperate soils. Soil Science Society of America Journal, 73(4), 1173–1181. DOI 10.2136/sssaj2008.0232. [Google Scholar] [CrossRef]

83. Bruun, E. W., Ambus, P., Egsgaard, H., Hauggaard-Nielsen, H. (2021). Effects of slow and fast pyrolysis biochar on soil C and N turnover dynamics. Soil Biology & Biochemistry, 46, 73–79. DOI 10.1016/j.soilbio.2011.11.019. [Google Scholar] [CrossRef]

84. Hagner, M., Kemppainen, R., Jauhiainen, L., Tiilikkala, K., Setala, H. (2016). The effects of birch (Betula spp.) biochar and pyrolysis temperature on soil properties and plant growth. Soil & Tillage Research, 163, 224–234. DOI 10.1016/j.still.2016.06.006. [Google Scholar] [CrossRef]

85. Li, Y. F., Hu, S. D., Chen, J. H., Muller, K., Li, Y. C. et al. (2018). Effects of biochar application in forest ecosystems on soil properties and greenhouse gas emissions: A review. Journal of Soils and Sediments, 18(2), 546–563. DOI 10.1007/s11368-017-1906-y. [Google Scholar] [CrossRef]

86. Ogawa, M., Okimori, Y. (2010). Pioneering works in biochar research, Japan. Australian Journal of Soil Research, 48(7), 489–500. DOI 10.1071/SR10006. [Google Scholar] [CrossRef]

87. Singh, B. P., Hatton, B. J., Singh, B., Cowie, A. L., Kathuria, A. (2010). Influence of biochars on nitrous oxide emission and nitrogen leaching from two contrasting soils. Journal of Environmental Quality, 39(4), 1224–1235. DOI 10.2134/jeq2009.0138. [Google Scholar] [CrossRef]

88. Ball, P. N., Mackenzie, M. D., Deluca, T. H., Montana, W. E. H. (2010). Wildfire and charcoal enhance nitrification and ammonium-oxidizing bacterial abundance in dry montane forest soils. Journal of Environmental Quality, 39(4), 1243–1253. DOI 10.2134/jeq2009.0082. [Google Scholar] [CrossRef]

89. Song, Y., Zhang, X., Ma, B., Chang, S. X., Gong, J. (2014). Biochar addition affected the dynamics of ammonia oxidizers and nitrification in microcosms of a coastal alkaline soil. Biology and Fertility of Soils, 50(2), 321–332. DOI 10.1007/s00374-013-0857-8. [Google Scholar] [CrossRef]

90. Wang, G. B., Xu, J., Wang, R., Deng, F. F., Shen, C. Q. et al. (2019). Long term effects of biochar addition on three greenhouse gases emission under a poplar plantation in Dongtai coastal region. Ecology and Environmental Sciences, 28(6), 1152–1158 (in Chinese). DOI 10.16258/j.cnki.1674-5906.2019.06.010. [Google Scholar] [CrossRef]

91. Sun, L. Y., Lu, L., Chen, Z. Z., Wang, J. Y., Xiong, Z. Q. (2014). Combined effects of nitrogen deposition and biochar application on emissions of N2O, CO2 and NH3 from agricultural and forest soils. Soil Science & Plant Nutrition, 60(2), 254–265. DOI 10.1080/00380768.2014.885386. [Google Scholar] [CrossRef]

92. Grau-Andres, R., Pingree, M. R. A., Oquist, M. G., Wardle, D. A., Nilsson, M. et al. (2021). Biochar increases tree biomass in a managed boreal forest, but does not alter N2O, CH4, and CO2 emissions. Global Change Biology Bioenergy, 13(8), 1329–1342. DOI 10.1111/gcbb.12864. [Google Scholar] [CrossRef]

93. Yu, L. Q., Tang, J., Zhang, R. D., Wu, Q. H., Gong, M. M. (2013). Effects of biochar application on soil methane emission at different soil moisture levels. Biology and Fertility of Soils, 49(2), 119–128. DOI 10.1007/s00374-012-0703-4. [Google Scholar] [CrossRef]

94. Ding, S. H., Fang, S. Z., Tian, Y., Song, Z. Q., Zhang, Y. H. (2020). Analysis and evaluation on physicochemical properties of poplar biochar at different pyrolysis temperature. Journal of Nanjing Forestry University (Natural Sciences Edition), 44(6), 193–200 (in Chinese). DOI 10.3969/j.issn.1000-2006.201910005. [Google Scholar] [CrossRef]

95. Liu, Z. G., Liu, A. Q., Zhu, C. X., Zhu, C. X., Zhuang, Z. et al. (2019). Effect of biochar on understory vegetation of Cunninghamia lanceolata plantation at different ages. Jiangsu Agricultural Science, 47(6), 131–136 (in Chinese). DOI 10.15889/j.issn.1002-1302.2019.06.029. [Google Scholar] [CrossRef]

96. Hassan, M., Liu, Y., Naidu, R., Parikh, S. J., Du, J. H. et al. (2020). Influences of feedstock sources and pyrolysis temperature on the properties of biochar and functionality as adsorbents: A meta-analysis. Science of the Total Environment, 744, 140714. DOI 10.1016/j.scitotenv.2020.140714. [Google Scholar] [CrossRef]

97. Lu, X. H., Li, Y. F., Wang, H. L., Singh, B. P., Hu, S. D. et al. (2019). Responses of soil greenhouse gas emissions to different application rates of biochar in a subtropical Chinese chestnut plantation. Agricultural and Forest Meteorology, 271, 168–179. DOI 10.1016/j.agrformet.2019.03.001. [Google Scholar] [CrossRef]

98. Hawthorne, I., Johnson, M. S., Jassal, R. S., Black, T. A., Grant, N. J. et al. (2017). Application of biochar and nitrogen influences fluxes of CO2, CH4 and N2O in a forest soil. Journal of Environmental Management, 192, 203–214. DOI 10.1016/j.jenvman.2016.12.066. [Google Scholar] [CrossRef]

99. Chen, J., Gao, X. B., Guo, Y., Yang, C., Hu, Y. R. et al. (2016). Impacts of biochar application on growth of tea tree seedlings. Guizhou Tea, 44(2), 11–15 (in Chinese). [Google Scholar]

100. Yuan, H. J., Deng, G. S., Zhou, S. G., Qin, S. P. (2019). Biochar ageing and its effects on greenhouse gases emissions: A review. Ecology and Environment Science, 28(9), 1907–1914 (in Chinese). DOI 10.16258/j.cnki.1674-5906.2019.09.024. [Google Scholar] [CrossRef]

101. Heitkötter, J., Marschner, B. (2015). Interactive effects of biochar ageing in soils related to feedstock, pyrolysis temperature, and historic charcoal production. Geoderma, 245–246, 56–64. DOI 10.1016/j.geoderma.2015.01.012. [Google Scholar] [CrossRef]

102. Mukherjee, A., Zimmerman, A. R., Hamdan, R., Cooper, W. T. (2014). Physicochemical changes in pyrogenic organic matter (biochar) after 15 months of field aging. Solid Earth, 5(2), 693–704. DOI 10.5194/se-5-693-2014. [Google Scholar] [CrossRef]

103. Mukherjee, A., Lal, R. (2013). Biochar impacts on soil physical properties and greenhouse gas emissions. Agronomy, 3, 313–339. DOI 10.3390/agronomy3020313. [Google Scholar] [CrossRef]

104. Spokas, K. (2013). Impact of biochar field aging on laboratory greenhouse gas production potentials. GCB Bioenergy, 5(2), 165–176. DOI 10.1111/gcbb.12005. [Google Scholar] [CrossRef]

105. Chen, Y., Liang, Y., Zheng, Z. Q., Shi, W. L. (2016). Effect of ageing on Cd adsorption ability by rice-straw derived biochar. Environmental Chemistry, 35(11), 2337–2343 (in Chinese). DOI 10.7524/j.issn.0254-6108.2016.11.2016031601. [Google Scholar] [CrossRef]

106. Pei, J. M., Li, J. Q., Mia, S., Singh, B., Wu, J. H. et al. (2020). Biochar aging increased microbial carbon use efficiency but decreased biomass turnover time. Geoderma, 382, 114710. DOI 10.1016/j.geoderma.2020.114710. [Google Scholar] [CrossRef]

107. Silva-Sánchez, A., Soares, M., Rousk, J. (2019). Testing the dependence of microbial growth and carbon use efficiency on nitrogen availability, pH, and organic matter quality. Soil Biology and Biochemistry, 134, 25–35. DOI 10.1016/j.soilbio.2019.03.008. [Google Scholar] [CrossRef]

108. Johannes, R., Philip, C. B., Erland, B. (2009). Contrasting soil pH effects on fungal and bacterial growth suggest functional redundancy in carbon mineralization. Applied and Environmental Microbiology, 75(6), 1589–1596. DOI 10.1128/AEM.02775-08. [Google Scholar] [CrossRef]

109. Xu, Z. B., Xu, X. Y., Tsang, D. C. W., Cao, X. D. (2018). Contrasting impacts of pre-and post-application aging of biochar on the immobilization of Cd in contaminated soils. Environmental Pollution, 242, 1362–1370. DOI 10.1016/j.envpol.2018.08.012. [Google Scholar] [CrossRef]

110. Zhao, R. D., Coles, N., Kong, Z., Wu, J. P. (2015). Effects of aged and fresh biochars on soil acidity under different incubation conditions. Soil and Tillage Research, 146, 133–138. DOI 10.1016/j.still.2014.10.014. [Google Scholar] [CrossRef]

111. Cheng, C., Lehmann, J. (2009). Ageing of black carbon along a temperature gradient. Chemosphere, 75(8), 1021–1027. DOI 10.1016/j.chemosphere.2009.01.045. [Google Scholar] [CrossRef]

112. Wu, K. J., Zhao, R. (2019). Soil texture classification and its application in China. Acta Pedologica Sinica, 56(1), 227–241 (in Chinese). DOI 10.11766/trxb201803120129. [Google Scholar] [CrossRef]

113. Tian, D., Qu, Z. Y., Gou, M. M., Li, B., Lv, Y. J. (2015). Experimental study of influence of biochar on different texture soil hydraulic characteristic parameters and moisture holding properties. Polish Journal of Environmental Studies, 24(3), 1435–1442. [Google Scholar]

114. Razzaghi, F., Obour, P. B., Arthur, E. (2020). Does biochar improve soil water retention? A systematic review and meta-analysis. Geoderma, 361, 114055. DOI 10.1016/j.geoderma.2019.114055. [Google Scholar] [CrossRef]

115. Tian, D., Qu, Z. Y., Gou, M. M., Li, B., Lv, Y. J. (2013). Influence and mechanism analysis of biochar on water diffusivity of different soil textures. Chinese Journal of Soil Science, 44(6), 1374–1378 (in Chinese). DOI 10.19336/j.cnki.trtb.2013.06.016. [Google Scholar] [CrossRef]

116. Dugan, E., Verhoef, A., Robinson, J. S., Sohi, S. (2010). Biochar from sawdust maize stover and charcoal: Impact on water holding capacities (WHC) of three soils from Ghana. Proceedings of the 19th World Congress of Soil Science, Soil Solutions for a Changing World, Brisbane, Australia. [Google Scholar]

117. Li, W. J., Yan, Y. H., Zheng, J. Y., Zhang, X. C., Li, S. Q. (2013). Effect of biochar on the transfer of nitrate in three different soils on the Loess Plateau. Research of Soil and Water Conservation, 20(5), 60–63 (in Chinese). [Google Scholar]

118. Zhen, Q., Zheng, J. Y., He, H. H., Han, F. P., Zhang, X. C. (2016). Effects of Pisha sandstone content on solute transport in a sandy soil. Chemosphere, 144, 2214–2220. DOI 10.1016/j.chemosphere.2015.10.127. [Google Scholar] [CrossRef]

119. Lv, D. Q., Wang, H., Pan, Y., Wang, L. (2010). Effect of bulk density changes on soil solute transport characteristics. Journal of Natural Science of Hunan Normal University, 33(1), 75–79 (in Chinese). DOI 10.3969/j.issn.1000-2537.2010.01.017. [Google Scholar] [CrossRef]

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