Seasonal variations in temperature sensitivity of soil respiration in a larch forest in the Northern Daxing’an Mountains in Northeast China

Abstract

Temperature sensitivity of respiration of forest soils is important for its responses to climate warming and for the accurate assessment of soil carbon budget. The sensitivity of temperature (Ti) to soil respiration rate (Rs), and Q10 defined by e10(lnRs−lna)/Ti has been used extensively for indicating the sensitivity of soil respiration. The soil respiration under a larch (Larix gmelinii) forest in the northern Daxing’an Mountains, Northeast China was observed in situ from April to September, 2019 using the dynamic chamber method. Air temperatures (Tair), soil surface temperatures (T0cm), soil temperatures at depths of 5 and 10 cm (T5cm and T10cm, respectively), and soil-surface water vapor concentrations were monitored at the same time. The results show a significant monthly variability in soil respiration rate in the growing season (April–September). The Q10 at the surface and at depths of 5 and 10 cm was estimated at 5.6, 6.3, and 7.2, respectively. The Q10@10 cm over the period of surface soil thawing (Q10@10 cm, thaw = 36.89) were significantly higher than that of the growing season (Q10@10 cm, growth = 3.82). Furthermore, the Rs in the early stage of near-surface soil thawing and in the middle of the growing season is more sensitive to changes in soil temperatures. Soil temperature is thus the dominant factor for season variations in soil respiration, but rainfall is the main controller for short-term fluctuations in respiration. Thus, the higher sensitivity of soil respiration to temperature (Q10) is found in the middle part of the growing season. The monthly and seasonal Q10 values better reflect the responsiveness of soil respiration to changes in hydrometeorology and ground freeze-thaw processes. This study may help assess the stability of the soil carbon pool and strength of carbon fluxes in the larch forested permafrost regions in the northern Daxing’an Mountains.

Thermal Properties and Temporal Dynamics of Red Latosol (Oxisol) in Sustainable Agriculture and Environmental Conservation

“…[62] a high coefficient of determination (R 2 ) indicates high reliability and precision in the response of what is being observed. A recent study [63] conducted in Northeast China (121 • 30 20 E, 50 • 49 40 N, 845 m altitude) investigated the transmission of surface temperature changes to various soil depths. The results indicated that this transmission occurs within a specific time frame and with exponentially damped amplitudes.…”

Fractionation of Inorganic Phosphorus in Cold Temperate Forest Soils: Associating Mechanisms of Soil Aggregate Protection and Recovery Periods after Forest Fire Disturbance

“…Therefore, in the early stage of post-fire recovery (1 year), the concentration of TP in the regenerating soils was relatively low. As secondary succession progressed following the fire disturbance, soil conditions favored an increase in species diversity, forest density and soil biomass, and vegetation flourish [45]. Consequently, there was an increase in the quantity of plant and animal residues entering the soil, contributing to the visible upward trend in soil fertility.…”

Changes in Soil Substrate and Microbial Properties Associated with Permafrost Thaw Reduce Nitrogen Mineralization

“…Over the course of recent years, both climatic shifts and human interventions have been catalysts for substantial permafrost degradation in this specific region [23,25]. Such degradation is evidenced by changes in ALT, shifts in soil properties, modifications in microbial dynamics, and transitions in plant community patterns [26][27][28]. To delve deeper into the intricacies of N min fluctuations and their shaping factors, our team collected soil samples from stable, attached permafrost zones and from those showing signs of degradation.…”