Seasonal variations in soil respiration and temperature sensitivity under three land-use types in hilly areas of the Sichuan Basin

Soil Research ◽  
2008 ◽  
Vol 46 (8) ◽  
pp. 727 ◽  
Author(s):  
XiaoGuo Wang ◽  
Bo Zhu ◽  
MeiRong Gao ◽  
YanQiang Wang ◽  
XunHua Zheng
Keyword(s):  
Land Use ◽  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Co2 Efflux ◽  
Forest Plantation ◽  
Soil Co2 ◽  
Q10 Value ◽  
Land Use Types ◽  
The Relationship

CO2 emissions from soils were measured under 3 land-use types at the adjacent plots of forest plantation, grassland, and cropland from January 2005 to December 2006. Mean soil CO2 efflux rates measured during the 2-year study varied from 59 to 527 mg CO2/m2.h in forest plantation, 37 to 498 mg CO2/m2.h in grassland, and 32 to 397 mg CO2/m2.h in cropland. Soil respiration in the 3 types of land-use showed a similar seasonal pattern in variation during both years, in which the single-peaked curve occurred in early summer and the minimum in winter. In particular, the date of maximum soil CO2 efflux rate in cropland occurred about 30 days earlier than in forest and grassland in both 2005 and 2006. The relationship of soil respiration rate (R) with soil temperature (T ) and soil moisture (W ) fitted well to the equation R = β0eβ1TW β2 (a, b, c were constants) than other univariate models which consider soil water content or soil temperature alone. Soil temperature and soil moisture together explained 69–92% of the temporal variation in soil respiration in the 3 land-use types. Temperature sensitivity of soil respiration (Q10) was affected positively by soil moisture of top 0.1 m layer and negatively by soil temperature at 0.05 m depth. The relationship between Q10 values and soil temperature (T ) or soil moisture (W ) indicated that a 1°C increase in soil temperature at 0.05 m depth will reduce the Q10 value by 0.07, 0.05, and 0.06 in forest, grassland, and cropland, respectively. Similarly, a 1% decrease in soil moisture of the top 0.1 m layer will reduce the Q10 value by 0.10, 0.09, and 0.11 in forest, grassland, and cropland.

scholarly journals Significance of soil respiration from biological activity in the degradation processes of different types of organic matter

2020 ◽  
Vol 1 (2) ◽  
pp. 171-179
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Temperature Sensitivity ◽  
Soil Co2 Efflux ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Total Soil

Soil respiration is a major component of global carbon cycle. Therefore, it is crucial to understand the environmental controls on soil respiration for evaluating potential response of ecosystems to climate change. In a temperate deciduous forest (located in Northern-Hungary) we added or removed aboveground and belowground litter to determine total soil respiration. We investigated the relationship between total soil CO2 efflux, soil moisture, and soil temperature. Soil CO2 efflux was measured at each plot using soda-lime method. Temperature sensitivity of soil respiration (Q10) was monitored via measuring soil temperature on an hourly basis, while soil moisture was determined monthly. Soil respiration increased in control plots from the second year after implementing the treatment, but results showed fluctuations from one year to another. The effect of doubled litter was less significant than the effect of removal. Removed litter and root inputs caused substantial decrease in soil respiration. We found that temperature was more influential in the control of soil respiration than soil moisture. In plots with no litter Q10 varied in the largest interval. For treatment with doubled litter layer, temperature sensitivity of CO2 efflux did not change considerably. The effect of increasing soil temperature is more conspicuous to soil respiration in litter removal treatments since lack of litter causes greater irradiation. When exclusively leaf litter was considered, the effect of temperature on soil respiration was lower in treatments with added litter than with removed litter. Our results reveal that soil life is impacted by the absence of organic matter, rather than by an excess of organic matter. Results of CO2 emission from soils with different organic matter content can contribute to sustainable land use, considering the changed climatic factors caused by global climate change.

scholarly journals Spatially variable soil water repellency enhances soil respiration rates (CO<sub>2</sub> efflux)

2017 ◽  
Author(s):  
Emilia Urbanek ◽  
Stefan H. Doerr
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Water ◽  
Water Distribution ◽  
Preferential Flow ◽  
Water Repellency ◽  
Water Repellent ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Soil Water Repellency

Abstract. Soil CO2 emissions are strongly dependent on water distribution in soil pores, which in turn can be affected by soil water repellency (SWR; hydrophobicity). SWR restricts infiltration and movement of water, affecting soil hydrology as well as biological and chemical processes. Effects of SWR on soil carbon dynamics and specifically on soil respiration (CO2 efflux) have been studied in a few laboratory experiments but they remain poorly understood. Existing studies suggest that soil respiration is reduced in water repellent soils, but the responses of soil CO2 efflux to varying water distribution created by SWR are not yet known. Here we report on the first field-based study that tests whether soil water repellency indeed reduces soil respiration, based on in situ field measurements carried out over three consecutive years at a grassland and pine forest site under the humid temperate climate of the UK. CO2 efflux was reduced on occasions when soil exhibited consistently high SWR and low soil moisture following long dry spells. However, the highest respiration rates occurred not when SWR was absent, but when SWR, and thus soil moisture, was spatially patchy, a pattern observed for the majority of the measurement period. This somewhat surprising phenomenon can be explained by SWR-induced preferential flow, directing water and nutrients to microorganisms decomposing organic matter concentrated in hot spots near preferential flow paths. Water repellent zones provide air-filled pathways through the soil, which facilitate soil-atmosphere O2 and CO2 exchanges. This study demonstrates that SWR have contrasting effects on CO2 fluxes and, when spatially-variable, can enhance CO2 efflux. Spatial variability in SWR and associated soil moisture distribution needs to be considered when evaluating the effects of SWR on soil carbon dynamics under current and predicted future climatic conditions.

scholarly journals Soil CO<sub>2</sub> efflux of a larch forest in northern Japan

2010 ◽  
Vol 7 (11) ◽  
pp. 3447-3457 ◽  
Author(s):  
N. Liang ◽  
T. Hirano ◽  
Z.-M. Zheng ◽  
J. Tang ◽  
Y. Fujinuma
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Ecosystem Respiration ◽  
Late Summer ◽  
Early Summer ◽  
Larch Forest ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Soil C ◽  
Northern Japan

Abstract. We had continuously measured soil CO2 efflux (Rs) in a larch forest in northern Japan at hourly intervals for the snow-free period in 2003 with an automated chamber system and partitioned Rs into heterotrophic respiration (Rh) and autotrophic respiration (Rr) by using the trench method. In addition, we applied the soil CO2 concentration gradients method to continuously measure soil CO2 profiles under snowpack in the snowy period and to partition Rs into topsoil (Oa and A horizons) CO2 efflux (Ft) with a depth of 0.13 m and sub-soil (C horizon) CO2 efflux (Fc). We found that soil CO2 effluxes were strongly affected by the seasonal variation of soil temperature but weakly correlated with soil moisture, probably because the volumetric soil moisture (30–40% at 95% confidence interval) was within a plateau region for root and microbial activities. The soil CO2 effluxes changed seasonally in parallel with soil temperature in topsoil with the peak in late summer. On the other hand, the contribution of Rr to Rs was the largest at about 50% in early summer, when canopy photosynthesis and plant growth were more active. The temperature sensitivity (Q10) of Rr peaked in June. Under snowpack, Rs was stable until mid-March and then gradually increased with snow melting. Rs summed up to 79 gC m−2 during the snowy season for 4 months. The annual Rs was determined at 934 gC m−2 y−1 in 2003, which accounted for 63% of ecosystem respiration. The annual contributions of Rh and Rs to Rs were 57% and 43%, respectively. Based on the gradient approach, Rs was partitioned vertically into litter (Oi and Oe horizons) with a depth of 0.01–0.02 m, topsoil and sub-soil respirations with proportions of 6, 72 and 22%, respectively, on an annual basis. The vertical distribution of CO2 efflux was consistent with those of soil carbon and root biomass.

scholarly journals Effect of measurement time of the day on the relationship between temperature and soil CO2 efflux

2011 ◽  
Vol 59 (6) ◽  
pp. 127-134
Author(s):  
Eva Dařenová ◽  
M. Pavelka ◽  
D. Janouš
Keyword(s):  
Soil Temperature ◽  
Carbon Flux ◽  
Continuous Measurement ◽  
Soil Co2 Efflux ◽  
Measurement Time ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Continuous Measurements ◽  
Proportional Change ◽  
The Relationship

In this study we investigated effect of the time of the day when manual measurements of soil CO2 efflux are performed on estimates of seasonal sums of released carbon from the soil. We subsampled continuous measurement of soil CO2 efflux into six sets of data in accordance to the time of the day when the measurements were taken – 0 h, 4 h, 8 h, 12 h, 16 h and 20 h. To estimate seasonal carbon flux from the soil we used continuously measured soil temperature and parameters R10 (soil CO2 efflux normalized for temperature of 10 °C) and Q10 (the proportional change in CO2 efflux caused by 10 °C increase in temperature) calculated from continuous measurements and from measurements taken at individual hours. Values of Q10 calculated from 12 h and 16 h data were lower than Q10 calculated from continuous measurements. On the contrary, Q10 at 0 h, 4 h, 8 h and 20 h were higher. Seasonal carbon flux from the soil based on 0 h, 4 h and 8 h measurements was overestimated compare to the flux calculated from continuous measurements. On the contrary, measurements at 12 h, 16 h and 20 h measurements underestimated the carbon flux. The under- or overestimation was significant for 0 h, 4 h, 8 h and 20 h data sub-sets.

scholarly journals Response of Soil CO2 Efflux to Shelterwood Harvesting in a Mature Temperate Pine Forest

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 304
Author(s):  
Robin Thorne ◽  
Myroslava Khomik ◽  
Emily Hayman ◽  
Altaf Arain
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Soil Co2 Efflux ◽  
Co2 Efflux ◽  
Carbon Exchange ◽  
Soil Co2 ◽  
Ecosystem Carbon ◽  
Significant Difference ◽  
Post Harvesting ◽  
Ecosystem Carbon Exchange

In forest ecosystems, soil CO2 efflux is an important component of ecosystem respiration (RE), which is generally driven by variability in soil temperature and soil moisture. Tree harvesting in forests can alter the soil variables and, consequently, impact soil CO2 efflux. This study investigated the response of total soil CO2 efflux, and its components, to a shelterwood harvesting event of a mature temperate white pine (Pinus strobus L.) forest located in Southern Ontario, Canada. The objective was to explore the response of soil CO2 effluxes to changes in the forest microclimate, such as soil temperature and soil moisture, after shelterwood harvesting removed approximately one-third of the overstory canopy. No significant differences were found in both soil temperature and soil moisture between the pre-harvesting (2008–2011) and post-harvesting (2012–2014) periods. Despite similar soil microclimates, total soil CO2 effluxes were significantly reduced by up to 37%. Soil CO2 effluxes from heterotrophic sources were significantly reduced post-harvesting by approximately 27%, while no significant difference in the mineral-soil horizon sources were measured. An analysis of RE, measured with an eddy covariance tower over the study area, showed an increase post-harvesting. However, the overall net ecosystem carbon exchange showed no significant difference between pre- and post-harvesting. This was due to an increase in the gross ecosystem productivity post-harvesting, compensating for the increased losses (i.e., increased RE). This study highlights the complexities of soil CO2 efflux after a disturbance, such as a harvest. The knowledge gained from this study adds to our understanding of how shelterwood harvesting may influence ecosystem carbon exchange and will be useful for forest managers focused on carbon sequestration and forest conservation.

scholarly journals Interdependencies between temperature and moisture sensitivities of CO<sub>2</sub> emissions in European land ecosystems

2015 ◽  
Vol 12 (20) ◽  
pp. 5981-5993 ◽  
Author(s):  
C. Gritsch ◽  
M. Zimmermann ◽  
S. Zechmeister-Boltenstern
Keyword(s):  
Carbon Dioxide ◽  
Land Use ◽  
Soil Respiration ◽  
Co2 Emissions ◽  
Temperature Sensitivity ◽  
Positive Relationship ◽  
Co2 Efflux ◽  
Moisture Contents ◽  
Laboratory Incubation ◽  
Land Use Types

Abstract. Soil respiration is one of the largest terrestrial fluxes of carbon dioxide (CO2) to the atmosphere. Hence, small changes in soil respiration rates could have large effects on atmospheric CO2. In order to assess CO2 emissions from diverse European soils with different land-use types and climate (soil moisture and temperature), we conducted a laboratory incubation experiment. Emission measurements of CO2 under controlled conditions were conducted using soil monoliths of nine sites from a European flux network (ÉCLAIRE). The sites are located all over Europe – from the United Kingdom in the west to Ukraine in the east, and from Italy in the south to Finland in the north – and can be separated according to four land-use types (forests, grasslands, arable lands and one peatland). Intact soil cores were incubated in the laboratory in a two-way factorial design, with temperature (5, 10, 15, 20 and 25 °C) and water-filled pore space (WFPS; 5, 20, 40, 60 and 80 %) as the independent variables, while CO2 flux was the response variable. The latter was measured with an automated laboratory incubation measurement system. Land use generally had a substantial influence on carbon dioxide fluxes, with the order of CO2 emission rates of the different land-use types being grassland > peatland > forest/arable land (P < 0.001). CO2 efflux responded strongly to varying temperature and moisture content with optimum moisture contents for CO2 emissions between 40 and 70 % WFPS and a positive relationship between CO2 emissions and temperature. The relationship between temperature and CO2 emissions could be well described by a Gaussian model. Q10 values ranged between 0.86 and 10.85 and were negatively related to temperature for most of the moisture contents and sites investigated. At higher temperatures the effect of water and temperature on Q10 was very low. In addition, under cold temperatures Q10 varied with moisture contents, indicating a stronger prospective effect of rain events in cold areas on temperature sensitivity. At both coniferous forest sites we found a strong increase in the temperature sensitivity at a moisture range between 20 and 40 % WFPS. We developed a new approach to calculate moisture sensitivity (MS) of CO2 efflux. MS was calculated as the slope of a polynomial function of second degree. Moisture sensitivities were highest under dry and wet conditions. In addition we found a positive relationship between MS of CO2 efflux and temperature for both arable lands.

scholarly journals Sloping land use affects the complexity of soil moisture and temperature changes in the loess hilly region of China

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262445
Author(s):  
Chao Zhang ◽  
Min Tang ◽  
Xiaodong Gao ◽  
Qiang Ling ◽  
Pute Wu
Keyword(s):  
Land Use ◽  
Soil Moisture ◽  
Soil Temperature ◽  
Soil Depth ◽  
Soil Layer ◽  
Temperature Changes ◽  
Growing Seasons ◽  
Land Use Types ◽  
Hilly Region ◽  
Sloping Land

Various land use types have been implemented by the government in the loess hilly region of China to facilitate sustainable land use. Understanding the variability in soil moisture and temperature under various sloping land use types can aid the ecological restoration and sustainable utilization of sloping land resources. The objective of this study was to use approximate entropy (ApEn) to reveal the variations in soil moisture and temperature under different land use types, because ApEn only requires a short data series to obtain robust estimates, with a strong anti-interference ability. An experiment was conducted with four typical land use scenarios (i.e., soybean sloping field, maize terraced field, jujube orchard, and grassland) over two consecutive plant growing seasons (2014 and 2015), and the time series of soil moisture and temperature within different soil depth layers of each land use type were measured in both seasons. The results showed that the changing amplitude, degree of variation, and active layer of soil moisture in the 0–160 cm soil depth layer, as well as the changing amplitude and degree of variation of soil temperature in the 0–100 cm soil layer increased in the jujube orchard over the two growing seasons. The changing amplitude, degree of variation, and active layer of soil moisture all decreased in the maize terraced field, as did the changing amplitude and degree of variation of soil temperature. The ApEn of the soil moisture series was the lowest in the 0–160 cm soil layer in the maize terraced field, and the ApEn of the soil temperature series was the highest in the 0–100 cm layer in the jujube orchard in the two growing seasons. Finally, the jujube orchard soil moisture and temperature change process were more variable, whereas the changes in the maize terraced field were more stable, with a stable soil moisture and temperature. This work highlights the usefulness of ApEn for revealing soil moisture and temperature changes and to guide the management and development of sloping fields.

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