Variation In Soil Respiration Rates Research Articles

Soil respiration across a variety of tree-covered urban green spaces in Helsinki, Finland

Abstract. As an increasing share of the human population is being clustered in cities, urban areas have swiftly become the epicentres of anthropogenic carbon (C) emissions. Understanding different parts of the biogenic C cycle in urban ecosystems is needed in order to assess the potential to enhance their C stocks as a cost-efficient means to balance the C emissions and mitigate climate change. Here, we conducted a field measurement campaign over three consecutive growing seasons to examine soil respiration carbon dioxide (CO2) fluxes and soil organic carbon (SOC) stocks at four measurement sites in Helsinki, representing different types of tree-covered urban green space commonly found in northern European cities. We expected to find variation in the main drivers of soil respiration – soil temperature, soil moisture, and SOC – as a result of the heterogeneity of urban landscape and that this variation would be reflected in the measured soil respiration rates. In the end, we could see fairly constant statistically significant differences between the sites in terms of soil temperature but only sporadic and seemingly momentary differences in soil moisture and soil respiration. There were also statistically significant differences in SOC stocks: the highest SOC stock was found in inactively managed deciduous urban forest and the lowest under managed streetside lawn with common linden trees. We studied the impacts of the urban heat island (UHI) effect and irrigation on heterotrophic soil respiration with process-based model simulations and found that the variation created by the UHI is relatively minor compared to the increase associated with active irrigation, especially during dry summers. We conclude that, within our study area, the observed variation in soil temperature alone was not enough to cause variation in soil respiration rates between the studied green space types, perhaps because the soil moisture conditions were uniform. Thus, irrigation could potentially be a key factor in altering the soil respiration dynamics in urban green space both within the urban area and in comparison to non-urban ecosystems.

Response of Soil Respiration Rates to Soil Temperature and Moisture at Different Soil Depths of Caragana korshinskii Plantation in the Loess-Hilly Region

It is of great significance to clarify the influence of soil temperature and moisture on soil respiration rate and its characteristics in ecologically fragile regions under the background of climate change for the accurate assessment and prediction of carbon budgets in this region. The average CO2 concentration and soil temperature and moisture at different soil depths (10, 50, and 100 cm) were measured using a CO2 analyzer and temperature and moisture sensors. The soil respiration rate was calculated using Fick's first diffusion coefficient method. The dynamic characteristics of soil temperature, soil moisture, and soil respiration rate in different soil depths were explored, and the response of soil respiration rate to soil temperature and moisture were further analyzed. The results showed that the diurnal variation in soil respiration rate decreased significantly with the increase in soil depth (P<0.05), and the peak time lagged behind. Soil respiration rate in adjacent soil depths (10, 50, and 100 cm) lagged 1 h from top to bottom. The monthly variation in soil respiration rate was a multi-peak curve, in which the maximum soil respiration rates of 10, 50, and 100 cm soil depths were on July 25th, August 6th, and August 10th, reaching 13.96, 2.96, and 1.47 μmol·(m2·s)-1, respectively. The effect of soil temperature on soil respiration rate decreased with the increase in soil depth. Soil temperature at 50 cm and below had no significant effect on soil respiration rate (P>0.05). The fitting index of 10 cm soil depth was the best (R2=0.96), but the fitting indexes of 50 cm and 100 cm soil depths were poor (R2=0.00 and R2=0.01, respectively). The temperature sensitivity coefficient Q10 decreased with the increase in soil depth. Soil moisture in different soil depths had significant effects on soil respiration rate (P<0.05), and the quadratic fitting indicated that 50 cm (R2=0.35)>10 cm (R2=0.22)>100 cm (R2=0.31). The combined effects of soil temperature and moisture in different soil depths could explain 96%, 6%-50%, and 22%-24% of soil respiration rate, respectively. In summary, the effects of soil temperature and moisture at different soil depths of the Caragana korshinskii plantation in the loess-hilly region on soil respiration rate differed. The soil respiration rate of the 10 cm soil depth was affected by the comprehensive effect of soil temperature and moisture; however, the relative contribution of soil temperature was higher, and soil moisture at and below a soil depth of 50 cm was the key factor. These results could help improve predictions on the impact of future climate change on the carbon cycle of terrestrial ecosystems in the region and provide a theoretical basis for greenhouse gas regulation in the future.

Spatial variation in soil respiration rate is controlled by the content of particulate organic materials in the volcanic ash soil under a Cryptomeria japonica plantation

Soil respiration is one of the major C fluxes in the global C cycle and is a key factor in understanding the global C balance associated with climate change, but the factors controlling its spatial variability have not been well explored. This study aimed to clarify the causes of spatial variation in soil respiration rate on volcanic ash soil. We established a standing-tree (ST) plot and a clear-cutting (CC) plot in December 2012 at a 35-year-old Cryptomeria japonica plantation in Tokyo, Japan. CC plot was logged in March 2013, and new organic matter supply was halted after clear-cutting. From January 2013 to August 2019, soil respiration rates were measured periodically at 21 and 19 measuring points in ST and CC plots, respectively. The measuring points were randomly distributed with varying distances in ST plot (0.24 ha) and CC plot (0.23 ha). In August 2019, the carbon content of the litter (Ao) layer, total carbon content of soil, carbon content of the low-density fraction (LF-C; < 1.6 g cm−3) of soil, fine root biomass, and bulk density of soil for 0–5, 5–15, and 15–30 cm mineral soil layers were measured at all measuring points. The spatial pattern of the variation in soil respiration rates remained stable in the ST plot throughout the 7-year study period. Results of the multiple regression analysis in the ST plot showed that the model with only the LF-C as an explanatory variable had the highest capability for predicting the respiration rate at a soil temperature of 20 °C (R20); the addition of other factors as explanatory variables did not increase the predictive capability. The organic carbon content in soil did not correlate with R20. The R20 in the CC plot significantly decreased six years after clear-cutting compared with the first year after clear-cutting, with values of 3.03 and 1.86 μmol CO2 m−2 s−1, respectively. This decrease tended to be greater in the measuring points where R20 was high in 2013. The LF-C stock for 0–30 cm soil layer in CC plot in the 7th year after clear-cutting was 0.33 kgC m−2 which was much lower than 1.60 kgC m−2 in ST plot. These results further support the conclusion that LF-C was the main factor responsible for the spatial variation in soil respiration rate in the ST plot, and suggest that LF-C is more suitable than SOC as an explanatory variable for the spatial variation in soil respiration rate in volcanic ash soil.

Effects of Warming and Increased Precipitation on Soil Respiration of Abandoned Grassland in the Loess-Hilly Regions

Clarifying the changing trends and driving factors of soil respiration in fragile habitats under the background of climate change is of great significance for understanding the regional carbon cycle and the conversion of ecosystem carbon source and sink functions. This research focused on grasslands that had been naturally abandoned and restored for 12 years in the loess hilly region of northern Shaanxi, using an open top chamber (OTC) and artificially increased natural rainfall to simulate climate warming and precipitation increase and their interaction. Furthermore, we used a combination of field monitoring and indoor analysis to explore soil water content, temperature, and nutrient characteristics and the response characteristics of soil respiration rate to warming and increased precipitation and further analyzed the key factors driving changes in soil respiration. The results showed that:① warming (W) significantly increased the 5 cm soil temperature, with an average increase of 1.34℃ throughout the sampling year, whereas the increased precipitation (P50%) treatment significantly reduced the 5 cm soil temperature, reducing the average 5 cm soil temperature during the entire sampling year by 0.88℃ and increasing the soil water content (SWC) at the same time. The SWC was 13.12% and 16.45% higher than that in the control (CK), respectively. In addition, compared with that in the CK, the treatment of warming and increased precipitation (WP50%) not only increased soil temperature but also increased SWC; in general, the increase in temperature and precipitation played an antagonistic effect on the influence of soil temperature and humidity. ② P50% significantly increased the content of soil organic carbon, dissolved organic carbon, and labile organic carbon, causing changes in the soil stoichiometric ratio and the distribution characteristics of labile-recalcitrant carbon components, whereas W did not have a significant impact on organic carbon. In addition, soil total nitrogen and phosphorus and available nitrogen and phosphorus nutrients were not significantly different between treatments. ③ P50% significantly increased the Rs rate, and the effect of W on the soil respiration rate mainly depended on the seasonal precipitation and temperature. It was demonstrated that warming in winter and seasons with abundant rainfall had a significant promotion effect on the soil respiration rate. The exponential fitting of soil respiration rate and 5 cm soil temperature found that the soil respiration temperature sensitivity (Q10) was the highest under the precipitation treatment, reaching 1.68, whereas the Q10 was the lowest under the warming treatment (1.50). ④ Linear regression analysis showed that soil organic carbon, dissolved organic carbon, and labile organic carbon were all significantly positively correlated with soil respiration rate. Variation partitioning analysis showed that soil temperature, SWC, and nutrient characteristics explained 64.43% of the variation in soil respiration rate. The soil temperature and SWC were the main controlling factors of the change in soil respiration rate, with an explanation degree of 31.16%. Correlation analysis also showed that there was a significant correlation between SWC, soil temperature and respiration rate, soil organic carbon, dissolved organic carbon, labile organic carbon, C:N, and C:P. In summary, the climate prediction of abandoned grassland tending toward warm temperatures and high humidity in the loess hilly region will significantly affect the regional hydrothermal environment and nutrient characteristics, change the distribution ratio of soil labile and recalcitrant carbon, and promote regional soil carbon emissions. The analysis results showed that the key factor driving the change in soil respiration rate of abandoned grassland in the loess hilly region was soil temperature and SWC characteristics.

Biotic and abiotic properties most closely associated with subtropical forest soil respiration differ in wet and dry seasons: A 10-year in situ study

Forest ecosystems greatly affect the global carbon (C) budget. Because subtropical regions typically have wet and dry seasons that are likely to differ in their effects on soil respiration, our estimates of carbon dioxide (CO2) emissions from subtropical soil would be improved by consideration of both wet and dry seasons rather than wet seasons alone. In this 10-year study, we determined soil respiration rates (SRRs) and soil properties in a typical subtropical forest in southern China, and we quantified the relationships between SRRs and soil abiotic and biotic properties during the dry and wet seasons. During the 10 years, soil organic carbon contents, microbial biomass, and fine root biomass were generally higher in the wet season than in the dry season. Microbial biomass C and fine root biomass were positively associated with precipitation in dry seasons but negatively associated with precipitation in wet seasons. The SRRs of wet season were consistently and significantly higher than the counterparts of dry season, with the average SRR being 5.94 ± 0.32 μmol CO2 m−2 s−1 in the wet season and 1.56 ± 0.41 μmol CO2 m−2 s−1 in the dry season. In the wet and dry seasons, cumulative CO2 emissions were positively correlated with microbial biomass C and fine root biomass, but the abiotic and biotic factors explaining variation in SRR differed in the wet and dry seasons. Most of the variation in SRRs was explained by fine roots in the wet season but by fine roots, microorganisms, and soil pH in the dry season. The results revealed that the precipitation generated significantly positive effects on the cumulative CO2 emissions in the dry seasons and that the fine root was the crucial factor contributing to the SRRs in wet and dry seasons.

Soil respiration and its temperature sensitivity among different vegetation types in Beijing mountain area, China.

As an important component of terrestrial ecosystem carbon cycle, soil respiration is a hot topic in the studies of carbon cycle. The temperature sensitivity (Q10) of soil respiration is a critical index to estimate the effects of global warming on soil respiration. Understanding Q10 of different vegetation types is of important significance for assessing the carbon budget of forest ecosystems. We examined soil respiration and its temperature sensitivity in three typical forests (Pinus tabuliformis, Platycladus orientalis, and Quercus variabilis) in the Beijing mountainous area by measuring the soil physical and chemical properties, soil temperature, soil moisture, and soil respiration rate (Rs) during the growing season. The results showed that Rs of three typical vegetation types showed a similar trend with changes of soil temperature and humidity, which showed a unimodal pattern, with minimum value (0.45 μmol·m-2·s-1) in early April and maximum value (3.95 μmol·m-2·s-1) in early July. There were significant differences in Rs and Q10 values among the three vegetation types. Soil temperature and humidity were the important factors affecting soil respiration, together they could explain the seasonal variation of soil respiration rate from 48.1% to 56.7%. The range of Q10 value was between 2.05 and 3.19. There was a significant negative correlation between soil organic carbon content and Q10 under each vegetation type (R2>0.9). Vegetation type, elevation, and soil organic carbon content were important drivers for the variation of Q10.

Response of Soil Respiration and Heterotrophic Respiration to Returning of Straw and Biochar in Rape-Maize Rotation Systems

Soil respiration has become the main way of farmland ecosystem carbon emissions. Soil respiration and its responses to soil moisture and soil temperature under straw and biochar returning were investigated. Combined soil CO2 fluxes system(ACE-002/OPZ/SC) with the method of root exclusion, this study conducted a long-term field experiment in the national monitor station of soil fertility and fertilizer efficiency of purple soils. The total soil respiration and heterotrophic respiration rate and the soil hydrothermal factors were measured during the growth period of rape and maize in rape-maize rotation systems, and the difference between total soil respiration and heterotrophic respiration was calculated as the contribution of root respiration to soil respiration. There were five treatments including CK(no organic material), CS(straw), CSD(straw+microorganism), BC(biochar), CSBC(50%straw+50%biochar), which were replicated three times. The results showed that straw and biochar returning significantly affected the seasonal variations and the peak of soil respiration. In addition to BC treatment, other treatments promoted soil respiration and cumulative emissions of soil CO2. Soil respiration rate was significantly different under different treatments, the changes in soil respiration rates showed a single peak curve under all treatments, the seasonal variations in soil respiration rates under rape was 0.12-2.29 μmol·(m2·s)-1, displaying an order of CS > CSD > CSBC > CK > BC. Soil respiration was pretty complex in maize season, the seasonal variation in soil respiration rates under rape was 1.02-15.32 μmol·(m2·s)-1, displaying an order of CSD > CS > CSBC > CK > BC, the changes in soil respiration rate presented a double peak curve under CS and CSD and CSBC treatments and a single peak curve under BC and CK treatments. Heterotrophic respiration could explain 86.50%-93.94% of seasonal variations in the soil total respiration, and the contribution of root respiration(26.49%-32.86%) was significantly lower than CK treatment(53.65%).Straw and biochar returning did not change soil temperature and soil moisture. Soil temperature at 5 cm depth had significant effects on the change dynamics of soil respiration rates, but soil moisture did not. Soil temperature at 5 cm depth could explain 82%-94% of the variations in soil respiration. The values of temperature sensitivity coefficient changed from 3.28 to 4.47. Compared with CK treatment, Q10 of CS, CSD and CSBC decreased by 26.62%, 18.12%, 20.58%, respectively, while BC increased by 12.53%. There was no synergistic effect between soil temperature and soil moisture on soil respiration, the dynamic changes of soil respiration rate could be simulated by single factor index function of soil temperature. Overall, soil respiration was significantly promoted by returning of straw, straw+microorganism, straw+biochar, while it was inhibited by returning of biochar.

Dynamic characteristics of soil respiration in Yellow River Delta wetlands, China

The stable soil carbon (C) pool in coastal wetlands, referred to as “blue C”, which has been extensively damaged by climate change and soil degradation, is of importance to maintain global C cycle. Therefore, to investigate the dynamic characteristics of soil respiration rate and evaluate C budgets in coastal wetlands are urgently. In this study, the diurnal and seasonal variation of soil respiration rate in the reed wetland land (RL) and the bare wetland land (BL) was measured in situ with the dynamic gas-infrared CO2 method in four seasons, and the factors impacted on the dynamic characteristics of soil respiration were investigated. The results showed that the diurnal variation of soil respiration rate consistently presented a “U” curve pattern in April, July, and September, with the maximum values at 12:00 a.m. and the minimum values at 6:00 a.m. In the same season, the diurnal soil respiration rate in RL was significantly greater than those in BL (P < 0.05). In April, July, and September, the mean diurnal soil respiration rate was 0.14, 0.42, and 0.39 μmol m−2 s−1 in RL, 0.05, 0.22, 0.13, and 0.01 μmol m−2 s−1 in BL, respectively. Soil surface temperature was the primary factor that influenced soil respiration, which was confirmed by the exponential positive correlation between the soil respiration rate and soil surface temperature in BL and RL (P < 0.05). In addition, the high salinity of soils suppressed soil respiration, confirming by the significantly negative correlation between soil respiration rate and the content of soluble salt. These results will be useful for understanding the mechanisms underlying soil respiration and elevating C sequestration potential in the coastal wetlands.

Influence of Environmental Factors on Variation of Soil Respiration Rate in a Wheat-Maize Rotation Field in China

Soil respiration in agroecosystem, especially in wheat-maize rotation system is a important component in carbon cycle, which is a key index of soil $CO_2$ efflux from soil to atmosphere. To discern the dynamic variation of soil respiration and the relationship between soil respiration and environmental factors, a experiment was conducted in the experimental field of Qingdao agricultural university. In this study $CO_2$ soil efflux was measured by automated soil $CO_2$ flux system (LI-8100A) during the periods from March to June (maize season) and from June to October (wheat season) in 2014, meanwhile the driving environmental factors were measured by eddy covariance system. The $CO_2$ emission rate from wheat soil varied from $1.093 \:μmol \:CO^2 \:m^{-2}s^{-1}$ in March to $6.028 \:μmol \:CO^2 \:m^{-2}s^{-1}$ in June and that for maize soil from $1.80 \:μmol \:CO_2 \:m^{-2}s^{-1}$ in October to $10.36 \:μmol \:CO_2 \:m^{-2}s^{-1}$ in July. The dynamics of GPP was similar to a shape

城市绿地土壤呼吸速率的变化特征及其影响因子

PDF HTML阅读 XML下载 导出引用 引用提醒 城市绿地土壤呼吸速率的变化特征及其影响因子 DOI: 10.5846/stxb201601080058 作者: 作者单位: 广东工业大学,广东省环境科学研究院,广东省环境科学研究院,福建农林大学,广东省环境科学研究院,广东工业大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学青年基金资助项目（31470703） Controlling factors of variation in soil respiration rate in urban green-space ecosystems Author: Affiliation: Guangdong University of Technology,Guangdong Provincial Academy of Environmental Science,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:城市绿地土壤呼吸作用深刻影响着城市生态系统碳循环过程，强化城市绿地土壤呼吸速率（Rs）的变化特征及其影响因素的研究，可揭示绿地在城市生态系统碳循环过程中的作用，为优化布局城市绿地和实现低碳排放目标提供科学依据。以广州市海珠湖公园的疏林、灌丛和草地3种典型植被类型的土壤为研究对象，于2013年11月-2014年10月采用静态箱-气相色谱法对公园绿地Rs进行跟踪观测。结果表明：海珠湖公园城市绿地在干湿季节中Rs差异显著；干季Rs较低且波动幅度较小，疏林、灌丛和草地的Rs变化范围分别为（1.66±0.18）-（3.26±0.20）μmol m-2 s-1、（1.27±0.15）-（3.67±0.16）μmol m-2 s-1和（1.94±0.08）-（6.82±1.13）μmol m-2 s-1；湿季Rs较高且波动幅度较大，疏林、灌丛和草地的Rs变化范围分别为（3.53±0.46）-（13.81±1.31）μmol m-2 s-1、（2.82±0.22）-（12.72±1.16）μmol m-2 s-1和（2.80±0.30）-（9.83±0.96）μmol m-2 s-1。T10和VWC10均对土壤呼吸过程有重要的影响，进一步通过回归分析得出，土壤10cm处温度（T10）和体积含水量（VWC10）分别解释Rs时间变异的40%左右和10-24%左右。T10和VWC10相互影响、共同作用于土壤呼吸过程，双因素复合模型的解释能力较单因素模型明显提高，均在50%以上，复合模型为Rs=α·exp（β·T10+γ·VWC10）。干湿季土壤呼吸的温度敏感性（Q10）有明显差异，湿季的Q10比干季的分别高0.44、0.70和0.46。 Abstract:Soil respiration is a major component of the carbon cycle in terrestrial ecosystems, and small changes have a significant effect on CO2 concentration in the atmosphere. Previous studies from different terrestrial ecosystems have confirmed that soil respiration is related to both global climate change and the carbon cycle. However, many studies have focused on non-urban ecosystems, such as forests, farmlands, and grasslands, while fewer studies have examined soil respiration in urban green-space ecosystems. In particular, few studies have addressed whether soil respiration is affected by different vegetation types in urban green-space ecosystems. This research explored soil respiration rate (Rs) in three different vegetation types in urban green-space, to provide basic scientific data on the contribution of urban green-space to the carbon cycle in urban ecosystems. Results will also facilitate the optimization of landscape patterns in urban green-spaces to reduce carbon emissions. In this study, Rs of three representative vegetation types (woodland, scrubland, and grassland) were investigated in Haizhu Lake Park of Guangzhou, Guangdong Province, China. From November 2013 to October 2014, we measured Rs monthly using a static chamber and gas chromatography, while simultaneously measuring soil temperature and volumetric water content. Results showed a significant difference in Rs between the wet and dry seasons. A relatively lower Rs, with less fluctuation, was noted in the dry season:(1.66±0.18)-(3.26±0.20) μmol m-2 s-1 for woodland, (1.27±0.15)-(3.67±0.16) μmol m-2 s-1 for scrubland, and (1.94±0.08)-(6.82±1.13) μmol m-2 s-1 for grassland. Conversely, a relatively higher Rs, with much more fluctuation, was noted in the wet season:(3.53±0.46)-(13.81±1.31) μmol m-2 s-1 for woodland, (2.82±0.22)-(12.72±1.16) μmol m-2 s-1 for scrubland, and (2.80±0.30)-(9.83±0.96) μmol m-2 s-1 for grassland. In addition, environmental factors that influenced soil respiration were very complicated in these urban green-space ecosystems, and two relatively important factors were soil temperature at 10 cm depth (T10) and soil volumetric water content at 10 cm depth (VWC10). Regression analysis showed that the exponential model explained the relationship between T10 and Rs well; T10 explained approximately 40%, while VWC10 explained 10%-24% of Rs variation across months. Notably, a dual-factor (including both T10 and VWC10) model:Rs=α·exp (βT10+γVWC10), better explained Rs variation across months, accounting for over 50% of Rs variation. Furthermore, a significant difference was noted in temperature sensitivity of soil respiration (expressed as Q10) between the wet and dry seasons; the wet season had a greater Q10 value than did the dry season (0.44, 1.15and 0.46, respectively). This study analyzed the differences in soil respiration and influential factors (T10 and VWC10) between three typical vegetation types in urban green-space ecosystems. However, there are many other potentially influential factors that were not considered, and further researcher is needed to explore these in the future. 参考文献 相似文献 引证文献

Soil respiration under different land uses in Eastern China.

Land-use change has a crucial influence on soil respiration, which further affects soil nutrient availability and carbon stock. We monitored soil respiration rates under different land-use types (tea gardens with three production levels, adjacent woodland, and a vegetable field) in Eastern China at weekly intervals over a year using the dynamic closed chamber method. The relationship between soil respiration and environmental factors was also evaluated. The soil respiration rate exhibited a remarkable single peak that was highest in July/August and lowest in January. The annual cumulative respiration flux increased by 25.6% and 20.9% in the tea garden with high production (HP) and the vegetable field (VF), respectively, relative to woodland (WL). However, no significant differences were observed between tea gardens with medium production (MP), low production (LP), WL, and VF. Soil respiration rates were significantly and positively correlated with organic carbon, total nitrogen, and available phosphorous content. Each site displayed a significant exponential relationship between soil respiration and soil temperature measured at 5 cm depth, which explained 84–98% of the variation in soil respiration. The model with a combination of soil temperature and moisture was better at predicting the temporal variation of soil respiration rate than the single temperature model for all sites. Q10 was 2.40, 2.00, and 1.86–1.98 for VF, WL, and tea gardens, respectively, indicating that converting WL to VF increased and converting to tea gardens decreased the sensitivity of soil respiration to temperature. The equation of the multiple linear regression showed that identical factors, including soil organic carbon (SOC), soil water content (SWC), pH, and water soluble aluminum (WSAl), drove the changes in soil respiration and Q10 after conversion of land use. Temporal variations of soil respiration were mainly controlled by soil temperature, whereas spatial variations were influenced by SOC, SWC, pH, and WSAl.

黑河天涝池五种植被类型土壤呼吸速率动态特征及其影响因子

PDF HTML阅读 XML下载 导出引用 引用提醒 黑河天涝池五种植被类型土壤呼吸速率动态特征及其影响因子 DOI: 10.5846/stxb201311102706 作者: 作者单位: 兰州大学生命科学学院干旱农业生态研究所草地农业生态系统国家重点实验室,兰州大学生命科学学院干旱农业生态研究所草地农业生态系统国家重点实验室,兰州大学生命科学学院干旱农业生态研究所草地农业生态系统国家重点实验室,兰州大学生命科学学院干旱农业生态研究所草地农业生态系统国家重点实验室,兰州大学生命科学学院干旱农业生态研究所草地农业生态系统国家重点实验室,兰州大学生命科学学院干旱农业生态研究所草地农业生态系统国家重点实验室 作者简介: 通讯作者: 中图分类号: S154.4 基金项目: 国家自然科学基金项目(91025015) Variation in soil respiration rate and factors affecting it in five vegetation types in Tianlaochi catchment in Heihe River Author: Affiliation: State Key Laboratory of Grassland AgroEcosystem,Institute of Arid AgroEcology,School of Life Sciences,Lanzhou University,甘肃,甘肃,甘肃,甘肃,甘肃 Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:对黑河天涝池流域的5种典型植被类型(干草原、亚高山草原、亚高山灌丛、祁连圆柏林和青海云杉林)的土壤呼吸速率及其影响因子进行测定分析。结果表明:5种植被类型土壤呼吸速率具有典型的日变化和月变化模式;5种植被类型土壤呼吸速率大小表现为亚高山草原 > 干草原 > 亚高山灌丛 > 祁连圆柏林 > 青海云杉林,土壤呼吸速率的变化范围因植被类型的不同而有所差异;5种植被类型土壤呼吸速率与土壤温度、地表温度和大气温度呈显著的指数关系,且与地表温度和大气温度的相关性强于土壤温度;5种植被类型的土壤呼吸速率与湿度呈显著的线性负相关,R2为 0.55-0.93,与风速呈显著的线性正相关关系;通过主成分分析表明影响5种植被类型土壤呼吸速率的主要因素各不相同,整体表现为在整个生长季 0-60 cm土壤的水热状况是主要的影响因素,其次是土壤表层的环境因子,最后为太阳辐射。 Abstract:Soil respiration (Rs) is an important component of an ecosystem's carbon cycle and the main pathway for carbon release from the ecosystem into the atmosphere. The transfer of carbon between the ecosystem and atmosphere is of interest in the study of greenhouse gas emission. In order to understand characteristics of the Rs dynamics and the factors controlling it, this study was conducted in five typical vegetation types in Tianlaochi catchment area of the Heihe River, located in Qilian Mountains, Northwestern China. Rs, soil temperature, and soil moisture were measured by an automated soil CO2 flux system (LI-8100) from May to September in 2013, and weather data for the corresponding study period were obtained from the weather station located in the experimental plot. The results showed that Rs in the five vegetation types displayed clear diurnal dynamic pattern. The Rs rate differed in different vegetation types, from the highest in subalpine steppe (2.01 to 12.10 μmol m-2 s-1), followed by Stipa purpurea steppe (1.40 to 8.45 μmol m-2 s-1), subalpine shrub (0.85 to 9.24 μmol m-2 s-1), Sabina przewalskii forest (1.09 to 4.14 μmol m-2 s-1), to the lowest in Picea crassifolia forest (1.25 to 3.19 μmol m-2 s-1). The daily change of Rs followed the fluctuations in surface air temperature, and there was a hysteresis between Rs and soil temperature. Rs rate had obvious seasonal variation, increasing from May and reaching the maximum in July, and then decreasing until the final measurements in September. The statistical analysis indicates that Rs rate was significantly positively correlated with soil temperature, surface air temperature, and air temperature, which relationship can be expressed with an exponential function. In relation to the temperature, Rs rate was more correlated to surface air temperature and air temperature than to soil temperature. For example, surface air temperature explained 79%-95% of the variation of Rs rate during the observation period, and air temperature explained 50%-77%, whereas soil temperature in the top 10 cm layer explained only 23%-47%; Rs rate had a significantly negative correlation with soil moisture in five vegetation types with R2 ranging from 0.55 to 0.93. Further analysis indicated the positive linear correlation between Rs rate and wind speed. Principal component analysis showed that soil temperature and moisture in the top 0-60 cm layer of the soil are the first-line impact factors for Rs rate in five vegetation types. The temperature and moisture in surface soil are the second main impact factor, and solar radiation is the third main factor to affect Rs rate. The results indicate that Rs was significantly different in different vegetation types, and changes in vegetation alter the pattern of the Rs rate. This study has important implications as it helps to understand the role that different vegetation types play in reduction of carbon emission. Such information will lay a foundation for assessing carbon source or carbon sequestration of different vegetation types in Qilian mountainous area. 参考文献 相似文献 引证文献

INFLUENCE OF SILVOPASTORAL SYSTEM “LIVE FENCES” OF Gliricidia sepium ON SOIL RESPIRATION IN TACOTALPA, TABASCO, MEXICO

&lt;p&gt;The aim of this study was to quantify rates of soil respiration on livestock systems with live fences (LF) formed by &lt;em&gt;Gliricidia sepium&lt;/em&gt; trees and on livestock systems in signal grass monoculture (MP) (&lt;em&gt;Brachiaria decumbens&lt;/em&gt;); examine the variation of flows in the rainy and dry seasons, and fluctuations during the day, as well as soil temperature and relative humidity. Soil respiration was measured twice a month, four times a day between the hours of 00:00 to 06:00 h, 6:00 to 12:00 h, 12:00 to 18:00 h, and 18:00 to 24:00 h, in both seasons. Soil temperature and the relative humidity were simultaneously measured. The results show that the rate of soil respiration is similar between these systems, LF issued 0.97 and MP 1.01 mol CO&lt;sub&gt;2&lt;/sub&gt; m&lt;sup&gt;2&lt;/sup&gt; h&lt;sup&gt;-1&lt;/sup&gt;. In contrast, there was influence of the time of year and time of collection of the samples. In both systems the soil flows were higher in the rainy season (1.1 mol CO&lt;sub&gt;2&lt;/sub&gt; m&lt;sup&gt;2&lt;/sup&gt; h&lt;sup&gt;-1&lt;/sup&gt; on average) and slightly lower in the dry season (0.90 mol CO&lt;sub&gt;2&lt;/sub&gt; m&lt;sup&gt;2&lt;/sup&gt; h&lt;sup&gt;-1&lt;/sup&gt; on average) and were higher during the night (00:00 to 06:00 hours), during the early morning hours (6:00 to 12:00 hours). Soil temperature was higher in the MP, and the relative humidity in LF. It is concluded that the main factor that caused the variation in soil respiration rates was the presence of &lt;em&gt;G. sepium&lt;/em&gt; trees in LF, which led to lower temperatures and more stable humidity, which resulted in lower soil CO&lt;sub&gt;2&lt;/sub&gt; fluxes.&lt;/p&gt;

The effect of fire disturbance on short-term soil respiration in typical forest of Greater Xing’an Range, China

We investigated the effect of fire disturbance on short-term soil respiration in birch (Betula platyphylla Suk.) and larch (Larix gmelinii Rupr.) forests in Greater Xing’an range, northeastern China for further understanding of its effect on the carbon cycle in ecosystems. Our study show that post-fire soil respiration rates in B. platyphylla and L. gmelinii forests were reduced by 14% and 10%, respectively. In contrast, the soil heterotrophic respiration rates in the two types of forest were similar in post-fire and control plots. After fire, the contribution of root respiration to total soil respiration was dramatically reduced. Variation in soil respiration rates was explained by soil moisture (W) and soil temperature (T) at a depth of 5 cm. Exponential regression fitted T and W models explained Rs rates in B. platyphylla control and post-fire plots (83.1% and 86.2%) and L. gmelinii control and post-fire plots (83.7% and 88.7%). In addition, the short-term temperature coefficients in B. platyphylla control and post-fire plots were 5.33 and 5, respectively, and 9.12, and 5.26 in L. gmelinii control and post-fire plots, respectively. Our results provide an empirical baseline for studying the effect of fire disturbance on soil carbon balance and estimation of soil carbon flux in boreal forest.

Variable effects of nutrient enrichment on soil respiration in mangrove forests

Mangrove forests are globally important sites of carbon burial that are increasingly exposed to nutrient pollution. Here we assessed the response of soil respiration, an important component of forest carbon budgets, to nutrient enrichment over a wide range of mangrove forests. We assessed the response of soil respiration to nutrient enrichment using fertilization experiments within 22 mangrove forests over ten sites. We used boosted regression tree (BRT) models to determine the importance of environmental and plant factors for soil respiration and its responsiveness to fertilizer treatments. Leaf area index explained the largest proportion of variation in soil respiration rates (LAI, 45.9 %) followed by those of site, which had a relative influence of 39.9 % in the BRT model. Nutrient enrichment enhanced soil respiration only in nine out of 22 forests. Soil respiration in scrub forests showed a positive response to nutrient addition more frequently than taller fringing forests. The response of soil respiration to nutrient enrichment varied with changes in specific leaf area (SLA) and stem extension, with relative influences of 14.4 %, 13.6 % in the BRT model respectively. Soil respiration in mangroves varied with LAI, but other site specific factors also influenced soil respiration and its response to nutrient enrichment. Strong enhancements in aboveground growth but moderate increases in soil respiration with nutrient enrichment indicated that nutrient enrichment of mangrove forests has likely increased net ecosystem production.

浙江古田山亚热带常绿阔叶林不同干扰强度下土壤呼吸的日动态与季节变化

The aims of this study were to investigate the diurnal and seasonal variations in soil respiration in different broad-leaved forest types with different degrees of human disturbance, to identify the major abiotic and biotic factors affecting the daily and seasonal patterns of soil respiration, and to evaluate the effects of different forest management types and human disturbance on soil respiration in subtropical forests. We selected four different 1 hm2 forests with different degrees of human disturbance in Gutianshan, Zhejiang Province: An old-growth forest (OF, almost no human disturbance); two secondary forests (SF1, a secondary forest regrown after clear cutting about 50 years ago, and SF2, a secondary forest regrown after clear cutting about 50 years ago and selective cutting about 20 years ago); and a plantation forest (AF, planted about 20 years ago). We measured the diurnal and seasonal changes in soil respiration rates in each plot every month from May 2011 to July 2012. We also measured soil temperature and water content of the surface soil layer during sampling. The annual means of daily accumulated soil carbon release were 1.48, 1.48, 1.51, and 0.87 g C m-2 d-1 in OF, SF1, SF2, and AF plots, respectively. The soil respiration rate in AF was significantly lower than those in the other three forest types. On the diurnal scale, there were no significant variations in soil respiration rates among the four forest types. Our results indicated that the rate of soil respiration measured any time during the day can be used to predict daily accumulated soil carbon release. Significant positive relationships were found between soil respiration and surface soil temperature ( R 2=0.88-0.94) for all four forest types. There were no significant relationships between soil respiration and soil water content. The Q10 value of OF was significantly higher than those of the other three forest types. The results showed that the soil respiration rate and its sensitivity to temperature were significantly decreased in the plantation with the most intense human disturbance (AF). The soil respiration rates and Q10 values of both SF forests were similar to those of OF forest. Soil temperature was the most important driving factor for soil respiration. Together, our results implied that different degrees of human disturbance had different effects on soil respiration in these forests. This information is important to estimate the role of human interference in regional carbon cycles. Also, the finding that there was no significant variation in the diurnal soil respiration rates is very important for guiding further research on soil respiration in related regions.

Short-term effects of thinning on soil respiration in a pine (Pinus tabulaeformis) plantation

Respiration was measured at daytime during the growing seasons (May–October) of 2011 and 2012 in a young Pinus tabulaeformis plantation with heavy, medium and light intensity thinning and unthinned control plots in Shanxi province in northern China. Soil temperature, moisture, fine root biomass, amounts of soil organic C and litterfall biomass were also measured. We found that immediately following thinning treatments, soil respiration increased by 8 %–21 % compared with the unthinned control plots during both growing seasons. Thinning significantly affected soil respiration and soil temperature with different thinning intensities, while there were no significant differences in soil moisture among the various treatments. During the growing seasons, the soil respiration rates were positively correlated with the soil moisture: the 19.4 %–54.0 % variation in soil respiration rates in the four thinning regimes are explained by the changes in soil moisture. Meanwhile, a positive correlation was found between soil temperature and soil respiration rates at all sites. The best fitting model with temperature and moisture explained 44.3 % of the variation in soil respiration in the high thinning treatment, 27.6 % in the light thinning treatment, 18.6 % in medium thinning and in the control sites during the measuring periods. Overall, soil respiration is better predicted by soil moisture, soil organic C, live fine root biomass and soil temperature when data are pooled for all thinning treatments over the two growing seasons. The best regression model explained 74.7 % of the total variation in soil respiration over the different thinning intensities for the two sampling periods.

Effects of short-term warming and increasing precipitation on soil respiration of desert steppe of Inner Mongolia

Aims Our objective was to examine the effects of global warming inducing environmental and biological changes on soil respiration of desert steppe. Methods We used infrared heaters to carry out the interactive simulation of warming and increasing precipitation in a desert steppe of Inner Mongolia from June to September 2011. Our experimental design was set up with two temperature levels (control and warming) and three precipitation treatments (control, 15% and 30% increase of the average precipitation during 1987–2007), using a complete randomized block arrangement. Soil respiration rate was measured by a LI-8100 carbon flux system in these six different treatments. We analyzed the relationships between soil respiration and environmental factors, aboveground biomass, and belowground biomass at different soil layers (0–10, 10–20 and 0–20 cm). Important findings Soil respiration in the desert steppe reached its peak value in the middle of the growing season. The average soil respiration rate of the desert steppe from July to August was 1.35 μmol CO 2 ·m –2 ·s –1 . The soil respiration rate was 2.08 and 0.63 μmol CO 2 ·m –2 ·s –1 in July and August, respectively. Increasing soil moisture and temperature significantly influenced daily soil respiration, but their interaction had no significant effect on soil respiration. Soil moisture had greater impact on monthly soil respiration than soil temperature. Soil respiration rate showed a power function relationship with belowground biomass at different soil depths. The belowground biomass at 0–10 cm soil was the major part of the belowground biomass and could explain more variation of soil respiration rate (79.2%) than that at 10–20 cm (31.6%). Under the future climatic changes scenarios, soil moisture was a principal environmental factor affecting plant biomass, while belowground biomass was a major biological factor controlling soil respiration in the desert steppe. Soil moisture might control the heterogeneity of soilrespiration by influencing the distribution of belowground biomass at different soil depths.

Field Soil Respiration Rate on a Sub-Antarctic Island: Its Relation to Site Characteristics and Response to Added C, N and P

Botanical, soil chemistry and soil microbiology variables were tested as predictors of in situ soil respiration rate in the various terrestrial habitats on sub-Antarctic Marion Island (47oS, 38oE). Inorganic P and total N concentration were the best predictors amongst the chemistry variables and bacteria plate count the best of the microbiology variables. However, while these chemistry and microbiology variables could accurately predict soil respiration rate for particular habitats, they proved inadequate predictors across the whole range of habitats. The best suite of predictors comprised only botanical variables (relative covers of five plant guilds) and accounted for 94% of the total across-habitat variation in soil respiration rate. Mean field soil respiration rates (2.1 - 15.5 mmol CO2 m-2 h-1) for habitats not influenced by seabirds or seals are similar to rates in comparable Northern Hemisphere tundra habitats. Seabird and seal manuring enhances soil respiration rates to values (up to 27.6 mmol CO2 m-2 h-1) higher than found at any tundra site. Glucose, N, P or N plus P were added to three habitats with contrasting soil types; a fellfield with mineral, nutrient-poor soil, a mire with organic, nutrient-poor soil and a shore-zone herbfield heavily manured by penguins and with organic, nutrient-rich soil. Glucose addition stimulated soil respiration in the fellfield and mire (especially the former) but not in the coastal herbfield soil. N and P, alone or together, did not stimulate respiration at any of the habitats, but adding glucose to fellfield soils that had previously been fortified with P or NP caused a similar increase in respiration rate, which was greater than the increase when adding glucose to soils fortified only with N. This suggests that fellfield soil respiration is limited by P rather than N, and that there is no synergism between the two nutrients. For the mire and coastal herbfield, adding glucose to soils previously fortified with N, P or NP did not enhance rates more than adding glucose to soils that had received no nutrient pre-treatment.

Spatial and temporal variation in soil respiration in a seasonally dry tropical forest, Thailand

Abstract:Spatial and seasonal variation in soil respiration rates were investigated in a tropical dry forest in Thailand. The spatial variation was examined at 50 points within a 2-ha plot in the forest floor during the dry and wet seasons. The seasonal and diurnal variations in soil respiration were measured at 16 and 5 points, respectively. The mean soil respiration rate during the wet season was 1041 ± 542 mg CO2 m−2 h−1 (mean ± SD), which is about twice that during the dry season. Soil respiration rate was negatively correlated with soil water content during the wet season. A polynomial equation using seasonal data describes soil respiration and water content: soil respiration rate increased with soil water content, but started to drop when soil water content exceeded 21%. The diurnal variation in soil respiration rate during the wet season was positively correlated with soil temperature, whereas during the wet season it was not correlated with soil temperature. The diurnal variation in soil respiration rate during the dry season showed a midday depression. The estimation of soil carbon flux with polynomial equations should incorporate different functions for the wet and dry seasons in tropical dry forests.