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2026 Vol.59, Issue 3 Preview Page

Original research article

Optimal application rate and frequency of apple-pruning biochar for crop productivity, soil properties, and nitrous oxide mitigation of sweet potato uplands
Mi-Jeong Uhm1†
,
Hyo-Jung Choi2*†
,
Na Young Park2
,
Yong Jun Kim2
,
So-Ra Choi3
1Senior Researcher, Watermelon Experiment Station, Jeonbuk State Agricultural Research and Extension Services, Gochang 56469, Korea
2Researcher, Agricultural Environment Division, Jeonbuk State Agricultural Research and Extension Services, Iksan 54591, Korea
3Senior Researcher, Agricultural Environment Division, Jeonbuk State Agricultural Research and Extension Services, Iksan 54591, Korea
*Corresponding Author
†These authors contributed equally to this work.
31 August 2026. pp. 318-332
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Abstract

Purpose: This study evaluated the effects of the application rate and frequency of apple pruning-derived biochar on sweet potato productivity, soil properties, and nitrous oxide (N2O) emissions, with the aim of providing optiaml biochar application strategy that balances agronomic productivity and environmental sustainability.

Methods: A field experiment was conducted from 2023 to 2025 in a sandy loam upland field in Iksan, Jeonbuk State, Republic of Korea. Apple pruning-derived biochar produced by pyrolysis at 400°C for 4 h was applied at rates of 100, 200, 400, and 800 kg 10a-1 under annual, biennial, and triennial application regimes. Sweet potato growth, plant nutrient concentrations, and marketable yield, as well as soil physical and chemical properties, and nitrous oxide (N2O) emissions were investigated.

Results: Biochar application significantly affected soil physical and chemical properties depending on application rate and frequency. Soil bulk density decreased and porosity increased in most treatments, whereas soil organic carbon (SOC) and cation exchange capacity generally increased following biochar application. Most aboveground growth parameters showed marginal responses, although stem diameter (P = 0.0018), SPAD value (P < 0.001), and internode length (P = 0.0213), shoot fresh weight (P = 0.0371) differed among treatments. The highest marketable yield (5,578 kg 10a-1) was observed under the annual application of 400 kg 10a-1, while relatively high yields were also observed under the biennial and triennial applications of 400 kg 10a-1. Lower cumulative N2O emission were observed by biochar applications compared to the control (7.42 kg N2O ha-1), with the lowest value (6.25 kg N2O ha-1) recorded under the annual application at 400 kg 10a-1, representing a 15.8% lower value than the control.

Conclusions: This study shows that the annual application of biochar at 400 kg 10a-1 was is an optimal biochar application strategy to achieve multiple benefits of biochar application including marketable yield, soil physical properties, SOC sequestration, and N2O mitigation. These findings provide the biochar application strategy for climate-smart cultivation of sweet potato using apple pruning biomass.

Annual biochar application at 400 kg 10a-1 showed the lowest cumulative N2O emission, with a 15.8% lower value than the control.
Parameter Mean daily N2O emission (mg N2O m-2 day-1) Cumulative N2O emission (kg N2O ha-1) Global warming potential (kg CO2-eq. ha-1) Reduction (%)
Annual (once per year) BC 100 5.20 7.57 2,006 (102) -2.1
BC 200 4.60 6.70 1,774 (90) 9.7
BC 400 4.29 6.25 1,656 (84) 15.8
BC 800 4.34 6.31 1,672 (85) 14.9
Biennial (once every 2 years) BC 100 5.00 7.27 1,927 (98) 2.0
BC 200 4.79 6.97 1,846 (94) 6.0
BC 400 4.59 6.68 1,769 (90) 10.0
BC 800 4.49 6.54 1,732 (88) 11.8
Triennial (once every 3 years) BC 100 5.23 7.61 2,017 (103) -2.6
BC 200 4.92 7.16 1,898 (97) 3.4
BC 400 4.98 7.25 1,922 (98) 2.2
BC 800 4.71 6.86 1,817 (92) 7.5
CON 5.10 7.42 1,965 (100) 0
Keywords
Application frequency
Apple pruning residue
Biochar
Nitrous oxide
Soil carbon
Sweet potato
References
1

Agbede TM. 2010. Tillage and fertilizer effects on some soil properties, leaf nutrient concentrations, growth and sweet potato yield on an Alfisol in southwestern Nigeria. Soil Tillage Res. 110:25-32. https://doi.org/10.1016/j.still.2010.06.003

10.1016/j.still.2010.06.003
2

Blanco-Canqui H. 2017. Biochar and soil physical properties. Soil Sci. Soc. Am. J. 81:687-711. https://doi.org/10.2136/sssaj2017.01.0017

10.2136/sssaj2017.01.0017
3

Burrell LD, Zehetner F, Rampazzo N, Wimmer B, Soja G. 2016. Long-term effects of biochar on soil physical properties. Geoderma 282:96-102. https://doi.org/10.1016/j.geoderma.2016.07.019

10.1016/j.geoderma.2016.07.019
4

Cayuela ML, Sánchez-Monedero MA, Roig A, Hanley K, Enders A, Lehmann J. 2013. Biochar and denitrification in soils: When, how much and why does biochar reduce N2O emissions? Sci. Rep. 3:1732. https://doi.org/10.1038/srep01732

10.1038/srep0173223615819PMC3635057
5

Cayuela ML, van Zwieten L, Singh BP, Jeffery S, Roig A, Sánchez-Monedero MA. 2014. Biochar’s role in mitigating soil nitrous oxide emissions: A review and meta-analysis. Agric. Ecosyst. Environ. 191:5-16. https://doi.org/10.1016/j.agee.2013.10.009

10.1016/j.agee.2013.10.009
6

Choi HJ, Seo SY, Choi SW, Lee CK, An MS, Yun SI. 2022. Crop growth and nitrous emission in red pepper soils: Effects of chemical fertilizer and livestock manure compost treatments. Korean J. Soil Sci. Fert. 55:162-174. https://doi.org/10.7745/KJSSF.2022.55.2.162

10.7745/KJSSF.2022.55.2.162
7

Domingues RR, Sánchez-Monedero MA, Spokas KA, Melo LCA, Trugilho PF, Valenciano MN, Silva CA. 2020. Enhancing cation exchange capacity of weathered soils using biochar: Feedstock, pyrolysis conditions and addition rate. Agronomy 10:824. https://doi.org/10.3390/agronomy10060824

10.3390/agronomy10060824
8

Hardie M, Clothier B, Bound S, Oliver G, Close D. 2014. Does biochar influence soil physical properties and soil water availability? Plant Soil 376:347-361. https://doi.org/10.1007/s11104-013-1980-x

10.1007/s11104-013-1980-x
9

IPCC (Intergovernmental Panel on Climate Change). 2013. Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New York, NY, USA. https://doi.org/10.1017/CBO9781107415324

10.1017/CBO9781107415324
10

Jeffery S, Verheijen FGA, van der Velde M, Bastos AC. 2011. A quantitative review of the effects of biochar application to soils on crop productivity using meta-analysis. Agric. Ecosyst. Environ. 144:175-187. https://doi.org/10.1016/j.agee.2011.08.015

10.1016/j.agee.2011.08.015
11

Kim GY, Song BH, Roh KA, Hong SY, Ko BG, Shim KM, So KH. 2008. Evaluation of greenhouse gases emissions according to changes of soil water content, soil temperature and mineral N with different soil texture in pepper cultivation. Korean J. Soil Sci. Fert. 41:399-407.

12

Kim SU, Ruangcharus C, Lee HH, Park HJ, Hong CO. 2018. Effect of application rate of composted animal manure on nitrous oxide emission from upland soil supporting for sweet potato. Korean J. Environ. Agric. 37:172-178. https://doi.org/10.5338/KJEA.2018.37.3.28

10.5338/KJEA.2018.37.3.28
13

Kim YS, Kim KH, Han JW, Jeong TG, Kim MJ, Kim IJ. 2022. Effect of rice hull-derived biochar application on watermelon growth, and soil physico-chemical properties under greenhouse. Korean J. Soil Sci. Fert. 55:175-184. https://doi.org/10.7745/KJSSF.2022.55.3.175

10.7745/KJSSF.2022.55.3.175
14

Lehmann J, Joseph S (Eds.). 2015. Biochar for environmental management: Science, technology and implementation (2nd ed.). Routledge, London, UK. https://doi.org/10.4324/9780203762264

10.4324/9780203762264
15

Liang Q, Chen H, Chang H, Liu Y, Wang Q, Wu J, Liu Y, Kumar S, Chen Y, Chen Y, Zhu G. 2023. Influence of planting density on sweet potato storage root formation by regulating carbohydrate and lignin metabolism. Plants 12:2039. https://doi.org/10.3390/plants12102039

10.3390/plants1210203937653956PMC10221243
16

Lin Y, Ding W, Liu D, He T, Yoo G, Yuan J, Chen Z, Fan J. 2017. Wheat straw-derived biochar amendment stimulated N2O emissions from rice paddy soils by regulating the amoA genes of ammonia-oxidizing bacteria. Soil Biol. Biochem. 113:89-98. https://doi.org/10.1016/j.soilbio.2017.06.001

10.1016/j.soilbio.2017.06.001
17

Liu B, Xv B, Si C, Shi W, Ding G, Tang L, Xv M, Shi C, Liu H. 2024. Effect of potassium fertilization on storage root number, yield, and appearance quality of sweet potato (Ipomoea batatas L.). Front. Plant Sci. 14:1298739. https://doi.org/10.3389/fpls.2023.1298739

10.3389/fpls.2023.129873938455375PMC10917953
18

NAAS (National Academy of Agricultural Science). 2010. Methods of soil analysis. Rural Development Administration, Suwon, Korea.

19

NAS (National Institute of Agricultural Sciences). 2019. Fertilizer application recommendations for crops (4th ed.). Rural Development Administration, Wanju, Korea.

20

Park DG, Kim HW, Lee HS, Lee MJ, Park HR, Oh TK, Lee SI. 2024. Evaluation of the impact of continuous use of rice hull biochar on greenhouse gas emissions and net ecosystem carbon balance in Kimchi cabbage cultivation. Korean J. Environ. Agric. 43:117-127. https://doi.org/10.5338/KJEA.2024.43.12

10.5338/KJEA.2024.43.12
21

Parton WJ, Mosier AR, Ojima DS, Valentine DW, Schimel DS, Weier K, Kulmala AE. 1996. Generalized model for N2 and N2O production from nitrification and denitrification. Global Biogeochem. Cycles 10:401-412. https://doi.org/10.1029/96GB01455

10.1029/96GB01455
22

Seyedsadr S, Šípek V, Jačka L, Sněhota M, Beesley L, Pohořelý M, Kovář M, Trakal L. 2022. Biochar considerably increases the easily available water and nutrient content in low-organic soils amended with compost and manure. Chemosphere 293:133586. https://doi.org/10.1016/j.chemosphere.2022.133586

10.1016/j.chemosphere.2022.133586
23

Spokas KA, Cantrell KB, Novak JM, Archer DW, Ippolito JA, Collins HP, Boateng AA, Lima IM, Lamb MC, McAloon AJ, Lentz RD, Nichols KA. 2012. Biochar: A synthesis of its agronomic impact beyond carbon sequestration. J. Environ. Qual. 41:973-989. https://doi.org/10.2134/jeq2011.0069

10.2134/jeq2011.0069
Information
  • Publisher :Korean Society of Soil Science and Fertilizer
  • Publisher(Ko) :한국토양비료학회
  • Journal Title :Korean Journal of Soil Science and Fertilizer
  • Journal Title(Ko) :한국토양비료학회 학회지
  • Volume : 59
  • No :3
  • Pages :318-332
  • Received Date : 2026-08-06
  • Revised Date : 2026-08-25
  • Accepted Date : 2026-08-27
  • DOI :https://doi.org/10.7745/KJSSF.2026.59.3.318
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