Chin J Plant Ecol ›› 2020, Vol. 44 ›› Issue (12): 1273-1284.DOI: 10.17521/cjpe.2020.0097

• Research Articles • Previous Articles     Next Articles

Effects of dissolved organic matter from different plant sources on soil enzyme activities in subtropical forests

MEI Kong-Can1,2, CHENG Lei1,2, ZHANG Qiu-Fang1,2, LIN Kai-Miao2,3, ZHOU Jia-Cong1,2, ZENG Quan-Xin1,2, WU Yue1,2, XU Jian-Guo3, ZHOU Jin-Rong1,2, CHEN Yue-Min1,2,*()   

  1. 1School of Geographical Science, Fujian Normal University, Fuzhou 350007, China
    2Cultivation Base of State Key Laboratory of Humid Subtropical Mountain Ecology, Fuzhou 350007, China
    3Daiyun Mountain National Nature Reserve Administration Bureau, Quanzhou, Fujian 362500, China
  • Received:2020-04-07 Accepted:2020-07-07 Online:2020-12-20 Published:2021-04-01
  • Contact: CHEN Yue-Min
  • Supported by:
    National Natural Science Foundation of China (31670620),(31670620);Fujian Provincial Training Program of Innovation and Entrepreneurship for Undergraduates(S201910394028)


Aims This study aims to explore the effects of dissolved organic matter (DOM) from different plant sources on subtropical forest soil enzyme activities in order to provide a scientific basis for soil carbon cycling under rainfall leaching conditions in different forest ecosystems of subtropical areas.
Methods Three kinds of DOM, extracted from the fresh leaves of Cunninghamia lanceolata, Schima superb, and Phoebe zherman, were added to the soils of C. lanceolata plantation. Soil treated with deionized water of the same amount as the DOM solution served as the control. Incubation of treated and control soils was conducted for 25 days in the laboratory. The physical and chemical properties, microbial biomass, and enzyme activities of the soils were determined after incubation.
Important findings The results showed that, compared with the control treatment (CT), soil total organic carbon (SOC) content, soil total nitrogen (TN) content, and carbon-nitrogen ratio had no significant changes after adding DOM. However, the TN of treatment with added C. lanceolata leaf DOM (CL) was significantly lower than that of treatments with added S. superb leaf DOM (SL) and P. zherman leaf DOM (PL), and the carbon-nitrogen ratio in CL was significantly higher than that in SL and PL. The three treatments with added DOM increased soil dissolved organic carbon (DOC) content and dissolved organic nitrogen (DON) content overall. There was no significant change in soil microbial biomass carbon (MBC) content after all three DOM inputs, while the microbial biomass nitrogen (MBN) content in CL and SL treatments was reduced by 50.9% and 51.1%, respectively, compared to CT. However, MBN content in PL treatment was increased by 54.0% than CT. DOM input significantly increased the activities of β-glucosidase, cellobiohydrolase, and peroxidase in comparison with CT, but significantly decreased the activity of polyphenol oxidase. In addition, both β-glucosidase and cellobiohydrolase activities showed the following characteristics: CL > SL > PL. The results of correlation analysis showed that the contents of SOC, TN and MBN and the activities of β-glucosidase and cellobiohydrolase of the treatments with DOM were significantly correlated with the DOC content and humification index (HIX) of added DOM. In addition, soil MBN content and polyphenol oxidase activity were positively correlated with the pH value of added DOM. The results of redundancy analysis (RDA) showed that the key factors causing the change in soil enzyme activities after DOM input were DON and DOC content. In general, differences in the properties of DOM obtained from different plant sources affect the activities of soil carbon-acquisition hydrolase. DOM input increases the availability of soil carbon and nitrogen, and elicits different responses from the four carbon-acquisition enzymes. This study provides a theoretical basis for exploring the process of carbon cycling in the rain-rich subtropical forest ecosystem.

Key words: dissolved organic matter, soil enzyme, soil nutrient availability, fresh leaves, subtropical forest