Forest conversion effects on soil organic carbon are regulated by soil aggregate stability and not by recalcitrance: Evidence from a reforestation experiment

Chao Xu, Teng Chiu Lin*, Zhijie Yang, Xiaofei Liu, Decheng Xiong, Shidong Chen, Fuzhong Wu, Yusheng Yang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Preservation of biochemically recalcitrant organic matter and protection within soil aggregates are two important mechanisms of soil organic carbon (SOC) preservation, but their relative importance remains unclear. In this study, we converted part of a mature secondary forest to two young plantation forests (Castanopsis carlesii and Chinese fir) and an assisted naturally regenerated (ANR) forest in 2012. The three young forests (five years old at the time of study) and the remaining mature secondary forest constitute a soil disturbance intensity gradient ideal for exploring effects of forest conversion on soil aggregate size classes and stability as well as SOC concentration and chemical composition. Taking advantage of the disturbance gradient, we examined the relative importance of physical protection versus recalcitrance in SOC preservations. We found that the young ANR forest conserved a similar amount of SOC to that of the mature secondary forest, which was 18 %–21 % higher than those retained in the two young plantations. Compared with the mature secondary forest, the young ANR forest retained 87 % of >2 mm aggregates, whereas the two young forest plantations retained only 45 %–53 %. Compared to the mature secondary forest, aggregate mean weight diameter (MWD) decreased by 10 % in the young ANR forest and 37 %–43 % in the two young plantations. Moreover, the young Castanopsis carlesii plantation had proportionally more recalcitrant aromatic carbon (C) and less labile O-alkyl C compared to the mature secondary forest. Total SOC was positively related to >2 mm aggregates mass percent, soil aggregate MWD, and labile O-alkyl C, but not with recalcitrant alkyl and aromatic C. Our results indicate that SOC preservation is more related to soil aggregate stability than recalcitrant C abundance, and advocate that reducing soil disturbance is key to future forest management aiming to maximize C sequestration.

Original languageEnglish
Article number106613
JournalCatena
Volume219
DOIs
Publication statusPublished - 2022 Dec

Keywords

  • Forest conversion
  • Soil aggregate stability
  • Soil organic carbon
  • Soil recalcitrant organic matter

ASJC Scopus subject areas

  • Earth-Surface Processes

Fingerprint

Dive into the research topics of 'Forest conversion effects on soil organic carbon are regulated by soil aggregate stability and not by recalcitrance: Evidence from a reforestation experiment'. Together they form a unique fingerprint.

Cite this