JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2022, Vol. 46 ›› Issue (1): 25-32.doi: 10.12302/j.issn.1000-2006.202002048

Special Issue: "双碳”视域下的土壤碳

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Advances in effects of root input on forest soil carbon pool and carbon cycle

HUANG Zijing1(), XU Xia1,*(), ZHANG Huiguang2, CAI Bin2, LI Liangbin2   

  1. 1. College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
    2. Center for Scientific Research and Monitoring, Wuyishan National Park, Wuyishan 354300, China
  • Received:2020-02-28 Accepted:2020-09-22 Online:2022-01-30 Published:2022-02-09
  • Contact: XU Xia E-mail:zijinghuang@163.com;xuxia.1982@yahoo.com

Abstract:

Plant root inputs are an essential source of forest soil carbon pools. Climate change may cause variations in the carbon flux below ground, affecting forest soil carbon pools and carbon cycles. In this article, we have reviewed the effects of root input on soil carbon accumulation, soil active carbon pools (including soil microbial biomass carbon and soluble organic carbon), and the stability of soil carbon pools. Furthermore, we have discussed the impacts of forest soil respiration, soil microorganisms, and soil enzyme activities on root inputs. We found that : (1) Decreased root input may reduce the priming effect of the rhizosphere and subsequently increase soil organic carbon in the short term but decrease it in the long term; (2) Root exudates may promote the initial formation of aggregates, but its effect on the stability of the metal-organic complex is unclear; (3) Decreased root input reduces soil respiration; (4) The response of the microbial community structure to root input mainly depends on the adaptation of microorganisms to substrate quality and quantity, which vary among forest ecosystems. In addition, whether enzyme synthesis is upregulated depends mainly on the cost efficiency of allocating resources for microbial growth to enzyme production. Many studies have investigated the carbon cycle of root input, especially soil respiration; however, the composition of root input is complex, and the response mechanisms of microorganisms and enzymes to different root inputs are unclear. These responses also differed among forest ecosystems. In addition, the effect of root input on the stability of the soil carbon pool is often neglected; the influence of the interaction between the root system and microorganisms on the carbon cycle and the stability of the soil carbon pool remains uncertain. We suggest strengthening the research on the links among plant roots, soil, and microorganisms, which would contribute to a deeper understanding of the carbon cycle of forest ecosystems in the context of climate change.

Key words: forest ecosystem, root input, soil carbon pool, carbon cycle

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