Particle size is an important factor influencing the effects of biochar return to woodland soils: An evaluation from the perspective of sapling growth and soil microbial carbon processes

Xiaoyu Gao; Haoting Liu; Wenxuan Mei; Wenwen Zhang; Haoyu Dong; Xiaohua Fu; Mengdi Xie; Yujie Han; Lei Wang

doi:10.1016/j.jenvman.2024.123272

Particle size is an important factor influencing the effects of biochar return to woodland soils: An evaluation from the perspective of sapling growth and soil microbial carbon processes

J Environ Manage. 2024 Nov 9:371:123272. doi: 10.1016/j.jenvman.2024.123272. Online ahead of print.

Authors

Xiaoyu Gao¹, Haoting Liu¹, Wenxuan Mei¹, Wenwen Zhang², Haoyu Dong¹, Xiaohua Fu³, Mengdi Xie⁴, Yujie Han⁵, Lei Wang⁶

Affiliations

¹ Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
² Shanghai Forestry General Station, Shanghai, 200040, China.
³ Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China. Electronic address: [email protected].
⁴ College of Ecology and Environment, Chengdu University of Technology, Sichuan, 610059, China.
⁵ Shanghai Academy of Landscape Architecture Science and Planning, Shanghai, 200030, China.
⁶ Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; College of Civil Engineering and Architecture, Xinjiang University, Xinjiang, 830046, China. Electronic address: [email protected].

PMID: 39527876
DOI: 10.1016/j.jenvman.2024.123272

Abstract

Biochar can increase ecosystem carbon sequestration by promoting plant growth and stabilizing soil organic carbon (SOC). Biochar produced from forest waste typically varies in particle size and is frequently applied directly for soil enhancement without pulverization. The effects of different biochar particle sizes on sapling growth, woodland soil properties and microbial carbon processes are unclear. This study used field experiments to compare the effects of different biochar particle sizes on sapling growth and microbial metabolic entropy (qCO₂). The impacting mechanisms were explored by examining soil physicochemical properties, enzyme activity, and microbial community structure. The application of forest waste (FW) and small particle biochar (SPBC, particle size<2 mm) did not significantly affect sapling growth. Conversely, middle particle biochar (MPBC, particle size 2-10 mm) and large particle biochar (LPBC, particle size>10 mm) reduced sapling biomass by 20.76% and 38.87%, respectively, compared to SPBC. MPBC and LPBC applications resulted in soil nutrient loss (total nitrogen and available phosphorus), inhibiting sapling growth. After 167 days, qCO₂ rankings were as follows: FW (30.37 ± 5.18) (P<0.05)> LPBC (20.91 ± 3.62) > CK (16.21 ± 2.71) > MPBC (15.99 ± 3.54) > SPBC (7.8 ± 0.80) (P < 0.05). The rankings of organic carbon retention rates rankings were as follows: SPBC (85.14%) > LPBC (70.35%) > FW (67.31%) > CK (54.53%) > MPBC (51.96%). SPBC increased biochar-soil-microbe interactions, raised the relative proportion of k/r-strategy bacteria, reduced extracellular cellulase activity thus inhibit qCO₂. In conclusion, small particle biochar (<2 mm), compared to larger-particle biochar, improves SOC sequestration without negatively affecting sapling growth. Therefore, particle size should be considered as a management indicator for biochar applications in artificial forest practices.

Keywords: Biochar from forest waste; Microbial carbon processes; Particle size; Sapling growth.