Factors controlling soil microbial respiration during the growing season in a mature larch plantation in Northern Japan

Abstract

Purpose Soil microbes contribute significantly to soil respiration (SR) in boreal forests; however, there is limited knowledge on microbial contributions from long field investigations. The objective of this study was to estimate soil microbial respiration, as well as its primary controlling factors, for a period of three consecutive years. Materials and methods A trenching method was used to distinguish soil microbial respiration (RMic) in a 55-year-old mature Japanese larch (Larix kaempferi) plantation in Northern Japan; the soil in which developed originally from volcanic soils containing pumice. We used a portable CO2 detection system to measure the soil respiration rate during the growing season. Environmental factors, soil physiochemical characteristics, and soil microbial biomass carbon and nitrogen (MBC and MBN) were analyzed to explain the seasonal variations of SR and RMic. Results and discussion The results showed that the estimated contribution of soil microbes to SR was 78, 62, and 55% during the three successive years, respectively. Respiration attributable to decomposition of aboveground litter contributed approximately 19% to SR. The major environmental factor that affected RMic was soil temperature at 5 cm depth, which accounted for more than 70% of the seasonal variation in RMic observed. There were close relations among MBC, MBN, and soil water content, but the soil water content showed no significant relation with RMic. Conclusions The RMic to SR varied from 78 to 55% following 3 years of trenching treatments. Our results demonstrated the important role of soil microbes on soil respiration in this larch forest. Soil temperature was the major positive factor that influ enced R-Mic, while soil water content had no significant effect. Global warming will increase the loss of C into the atmosphere by increasing the R-Mic, and could accelerate climate change.-Responsible editor: Yongfu Li Electronic supplementary material The online version of this article

Soil CO2 and CH4 concentration dynamics and their relationships with soil physicochemical properties, soil enzyme activity, and root biomass under shallow groundwater level

“…Soil CO 2 is primarily derived from soil respiration that includes heterotrophic respiration and autotrophic respiration. Soil temperature exerts a significant effect on heterotrophic respiration as the microbes that contribute to heterotrophic respiration are highly sensitive to soil temperature (Zhong, Yan, Zong and Shangguan, 2016;Qu, Kitaoka and Koike, 2018). Besides, microorganisms led nutrient transformation, and biochemical processes are also dependent on the soil temperature (Guan, 1986;Qu, Kitaoka and Koike, 2018).…”

“…Soil temperature exerts a significant effect on heterotrophic respiration as the microbes that contribute to heterotrophic respiration are highly sensitive to soil temperature (Zhong, Yan, Zong and Shangguan, 2016;Qu, Kitaoka and Koike, 2018). Besides, microorganisms led nutrient transformation, and biochemical processes are also dependent on the soil temperature (Guan, 1986;Qu, Kitaoka and Koike, 2018). Root exudation and root respiration rate, which serve as crucial drivers of autotrophic respiration, depends on plant growth and thus are closely associated with temperature (Liu et al, 2015;Tong, Li, Nolan and Yu, 2017).…”

“…Soil carbon pool is the largest natural terrestrial carbon resource and is closely related to soil fertility and environmental quality (Buysse et al, 2016;Qu et al, 2018;Sun et al, 2018;Zhang et al, 2018a). Soil respiration is the primary output of the soil carbon pool (Lou et al, 2017;Tong et al, 2017), and it embodies root respiration and microbial respiration (root and mycorrhizosphere respiration, surface-litter, organic matter decomposition, and so on) (Acosta et al, 2018;Li et al, 2018).…”

“…Soil respiration is the primary output of the soil carbon pool (Lou et al, 2017;Tong et al, 2017), and it embodies root respiration and microbial respiration (root and mycorrhizosphere respiration, surface-litter, organic matter decomposition, and so on) (Acosta et al, 2018;Li et al, 2018). Microbial respiration represents microbial decomposition and transformation rate (Lou, Gu and Zhou, 2017;Qu, Kitaoka and Koike, 2018), whereas root respiration represents the root metabolism rate that is affected by photosynthesis, plant phenology, root biomass, carbohydrate content in plant shoots, and net primary production, etc. (Savage et al, 2013;Li et al, 2018).…”

Ecophysiology of deciduous trees native to Northeast Asia grown under FACE (Free Air CO₂ Enrichment)

“…Ainsworth and Long, 2005). Plants in northern Japan, under high CO 2 , are likely to suffer from phosphorus deficiency, due to allophone soil (e.g., Makino, 1994;Wang et al 2015;Qu et al 2015). The influence of root symbiotic micro-organisms on CO 2 fluxes in forests affected by nitrogen deposition should also be considered (Högberg et al, 2010).…”