Temperature Sensitivity Of Soil Respiration Research Articles

Decreased temperature sensitivity of soil respiration induced by warming slowed topsoil carbon turnover in a semi-arid grassland

The carbon feedback between soil and climate is partly determined by topsoil organic carbon turnover time (τ). However, the τ under future warmer climate still remains unclear. Herein, a manipulative experiment was conducted in a semi-arid grassland on the Loess Plateau of China to investigate the underlying mechanisms of the response of topsoil τ to warming. The results showed that warming significantly increased topsoil τ, which was directly regulated by the decreased temperature sensitivity of soil microbial respiration and indirectly due to the decreased pH and the increased aboveground biomass, soil inorganic nitrogen and soil carbon substrate quality. These results implied that short-term warming could potentially promote soil carbon sequestration in the semi-arid grassland.

Response of soil respiration to thinning is altered by thinning residue treatment in Cunninghamia lanceolata plantations

Forest thinning is a widely used practice in traditional and multiple function forest management. However, the effects of thinning residue treatment on soil respiration in forest are not fully understood. Here, a two-year field experiment quantified the effects of thinning intensity (medium and heavy thinning, 45% and 70% of volume removed, respectively) and the resulting residue treatment (retention and removal) on soil respiration in a subtropical Cunninghamia lanceolata plantation on a thin soil. Both thinning intensity and residue treatment significantly impacted on soil respiration. The control had a relative low mean soil respiration rate of 158 mg CO2 m−2 h−1 or 13.9 t ha−1 yr−1. Compared with the control, medium thinning with residue retained (MTR1) increased annual cumulative soil respiration by 13% only in the first year, while medium thinning with residue removal (MTR0) did not affect it in the two years. Heavy thinning with residue retention (HTR1) and removal (HTR0) elevated the mean annual cumulative respiration by 32% and 20%, respectively. Besides, there was no difference between MTR1 and HTR0. Soil respiration rate was correlated positively with soil temperature, moisture, and the concentrations of permanganate-oxidizable C and microbial biomass C, and inversely with the concentration of water-soluble organic C. Furthermore, heavy thinning with residue retention decreased the temperature sensitivity of soil respiration. Our findings highlight that the response of soil respiration to forest thinning was associated with thinning residue treatment.

Responses of Q10 to anthropogenic soil redistribution: Synthetic effects of SOM composition and r/K-shifts of microbial community

The temperature sensitivity of soil respiration (Q10) is a pivotal parameter for forecasting the fate of soil carbon (C) under global warming. Although a plethora of studies have elucidated the changes in Q10 in farmland or natural ecosystems, the response of Q10 to soil redistribution remains unclear. A simulated anthropogenic soil redistribution experiment by examining subsoil exposure (E20) and topsoil addition (A20) was performed to explore the influences of soil organic matter (SOM) composition and r/K-shifts of microbial community on Q10. Compared with the undisturbed soil, the average annual Q10 in the E20 plot was significantly increased, whereas the mean annual Q10 in the A20 plot decreased. The ratios of CC to COO and CC to CO, which indicate the stability of SOM, were significantly increased by 14.8%− 44.2% and 33.9%− 45.4% in the E20 plot but decreased by 18.6%− 28.1% and 3.8%− 11.2% in the A20 plot, respectively. The ratios of oligotrophs to copiotrophs in both the bacterial and fungal communities were significantly increased in the E20 plot (K-shift) but decreased in the A20 plot (r-shift). The β-D-xylosidase and cellobiohydrolase activities in the E20 plot were significantly decreased but prominently increased in the A20 plot, whereas the activity of polyphenol oxidase showed the opposite trend. The high aromaticity of recalcitrant SOM in the E20 plot determined the prevalence of K-shift in the bacterial and fungal communities, which might be attributed to the production of enzymes that decompose recalcitrant SOM, which then further enhanced Q10 and vice versa. Overall, our findings indicated that the feedback of ecological strategy of microbial community on the changes in SOM functional groups should be considered when evaluating the response of regional C cycling to anthropogenic soil redistribution.

Linkages between the temperature sensitivity of soil respiration and microbial life strategy are dependent on sampling season

The temperature sensitivity (Q10) of soil respiration (Rs) is crucial to assess the carbon (C) budget of terrestrial ecosystems under global warming. The Q10 changes along a climatic gradient as well as its seasonal dynamics remain unclear, and the underlying microbial mechanisms are not well known. Here, the seasonal Q10 of Rs at the northern, middle, and southern sites of a natural temperate mixed forest was examined. The mean annual temperature (MAT) of the sampling sites spanned from 0.5 to 4.9 °C. The Q10 pattern over the climatic zones was highly dependent on season, with Q10 increasing toward the southern region in spring and autumn, but having a similar level across the sampling sites in summer. In spring, Q10 was independent of microbial community composition and functions. Instead, spring Q10 increased with decreasing C availability from north to south, consistent with the Carbon-Quality-Temperature theory. In summer, Q10 was closely associated with the dominance of microbial r-strategy features, characterized by high copiotroph/oligotroph and labile/recalcitrant C degradation gene ratios. In autumn, however, Q10 was driven by the K-selected microbial communities, which might have been ascribed to the priming effects mediated by fresh plant litter. The seasonality of Q10 was site-dependent. The southern and middle sites had the lowest Q10 in summer, consistent with the Seasonal Plasticity Hypothesis, which predicts lower temperature sensitivity in warmer seasons. In contrast, the Q10 at the northern site remained stable during the growing season due to minor seasonal fluctuations in plant litter inputs and microbial community composition and functions. This work deepens our understanding on the complex relationships between Q10, carbon availability and microorganisms over spatial and temporal scales by translating microbial phylogenetic data into life strategies.

Contrasting effects of biological soil crusts on soil respiration in a typical steppe

Biological soil crusts (biocrusts), specialized communities of cyanobacteria, lichens, mosses, fungi and bacteria occurring on the ground surface, are key drivers of soil carbon (C) cycles in drylands, yet our understanding of how biocrusts directly and indirectly (through soil temperature or moisture) affect soil respiration and the contributions of biocrusts to soil C efflux is very limited. Using continuous field measurements in bare and biocrusted soils, we assessed the influence of biocrusts on soil respiration and the biocrust contribution to soil respiration over a one-year period and explained the mechanisms by which biocrusts directly and indirectly regulate soil respiration. Although the overall effect of biocrusts on soil respiration was positive, contrasting effects of biocrusts on soil respiration were also found. Unfortunately, the indirect effect of biocrusts on soil respiration through soil temperature or moisture was nonsignificant. The driving factor of total soil respiration was soil temperature, but soil moisture, photosynthetically active radiation and precipitation were driving factors for soil respiration in the biocrust layer. We proposed conceptual frameworks to explain the contrasting mechanisms by which biocrusts modulate soil respiration. In addition, biocrusts decreased the temperature sensitivity of soil respiration. Our findings indicate that biocrusts may alter the driving factors, forming contrasting mechanisms to regulate soil respiration in the biocrust layer, and emphasize the important roles of biocrusts as modulators of C cycles in dryland soils. Incorporating biocrusts into terrestrial C process models may improve predictions of climate change impacts on dryland ecosystems.

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.

Microbial assemblies associated with temperature sensitivity of soil respiration along an altitudinal gradient

Identifying the drivers of the response of soil microbial respiration to warming is integral to accurately forecasting the carbon-climate feedbacks in terrestrial ecosystems. Microorganisms are the fundamental drivers of soil microbial respiration and its response to warming; however, the specific microbial communities and properties involved in the process remain largely undetermined. Here, we identified the associations between microbial community and temperature sensitivity (Q10) of soil microbial respiration in alpine forests along an altitudinal gradient (from 2974 to 3558 m) from the climate-sensitive Tibetan Plateau. Our results showed that changes in microbial community composition accounted for more variations of Q10 values than a wide range of other factors, including soil pH, moisture, substrate quantity and quality, microbial biomass, diversity and enzyme activities. Specifically, co-occurring microbial assemblies (i.e., ecological clusters or modules) targeting labile carbon consumption were negatively correlated with Q10 of soil microbial respiration, whereas microbial assemblies associated with recalcitrant carbon decomposition were positively correlated with Q10 of soil microbial respiration. Furthermore, there were progressive shifts of microbial assemblies from labile to recalcitrant carbon consumption along the altitudinal gradient, supporting relatively high Q10 values in high-altitude regions. Our results provide new insights into the link between changes in major microbial assemblies with different trophic strategies and Q10 of soil microbial respiration along an altitudinal gradient, highlighting that warming could have stronger effects on microbially-mediated soil organic matter decomposition in high-altitude regions than previously thought.

Relationship between basal soil respiration and the temperature sensitivity of soil respiration and their key controlling factors across terrestrial ecosystems

Relationship between basal soil respiration and the temperature sensitivity of soil respiration and their key controlling factors across terrestrial ecosystems

Seasonal Changes in Soil Respiration with An Elevation Gradient in Abies nephrolepis (Trautv.) Maxim. Forests in North China

Soil respiration (Rs) plays an important role in regulating carbon cycle of terrestrial ecosystems and presents temporal and spatial heterogeneity. Abies nephrolepis is a tree species that prefers the cold and wet environment and is mainly distributed in Northeast Asia and East Asia. The Rs variations of Abies nephrolepis forests communities are generally environmental-sensitive and can effectively reflect the adaptive responses of forest ecosystems to climate change. In this study, the growing-seasonal variations of Rs, soil temperature, soil water content and soil properties of Abies nephrolepis forests were analyzed along an altitude gradient (2000, 2100, 2200 and 2300 m) over two years on Wutai Mountain in North China. As the main results showed, soil respiration keeps the same change trend as soil temperature and reached peaks in July at 2000 m in 2019 and 2020. During 26th July to 25th October in 2019 and 27th May to 23rd October in 2020, on the whole, the soil temperature independently explained 76.2% of Rs variations while the soil water content independently explained 26.8%. Soil temperature and soil water content jointly explained 81.8% of Rs variations. Soil properties explained 61.8% and 69.6% of Rs variation in 2019 and 2020, respectively. Soil organic carbon content and soil enzyme activity had the signifi- cant (P < 0.01) negative and positive relationships, respectively, with Rs variation. With altitudes evaluated from 2000 to 2300 m, soil respiration temperature sensitivity (Q10) and the soil organic carbon content increased by 12.4% and 10.4%, respectively, while invertase activity, cellulase activity and urease activity dropped by 41.2%, 29.45% and 38.19%, respectively. The results demonstrate that (1) soil temperature is the major factor affecting Rs variations in Abies nephrolepis forests; (2) weakened microbial carbon metabolism in high-altitude areas results in the accumulation of soil organic carbon; (3) with a higher Q1, forest ecosystems in high-altitude areas might be more easily affected by climate change; (4) climate warming might accelerate the consumption of soil organic carbon sink in forest ecosystems, especially in high-altitude areas.

Controls and Variability of Soil Respiration Temperature Sensitivity Across China

Controls and Variability of Soil Respiration Temperature Sensitivity Across China

Past climate conditions predict the influence of nitrogen enrichment on the temperature sensitivity of soil respiration

The response of soil carbon release to global warming is largely determined by the temperature sensitivity of soil respiration, yet how this relationship will be affected by increasing atmospheric nitrogen deposition is unclear. Here, we present a global synthesis of 686 observations from 168 field studies to investigate the relationship between nitrogen enrichment and the temperature sensitivity of soil respiration. We find that the temperature sensitivity of total and heterotrophic soil respiration increased with latitude. In addition, for total and autotrophic respiration, the temperature sensitivity responded more strongly to nitrogen enrichment with increasing latitude. Temperature and precipitation during the Last Glacial Maximum were better predictors of how the temperature sensitivity of soil respiration responds to nitrogen enrichment than contemporary climate variables. The tentative legacy effects of paleoclimate variables regulate the response through shaping soil organic carbon and nitrogen content. We suggest that careful consideration of past climate conditions is necessary when projecting soil carbon dynamics under future global change.

Equilibrium in soil respiration across a climosequence indicates its resilience to climate change in a glaciated valley, western Himalaya

Soil respiration (SR), a natural phenomenon, emits ten times more CO2 from land than anthropogenic sources. It is predicted that climate warming would increase SR in most ecosystems and give rise to positive feedback. However, there are uncertainties associated with this prediction primarily due to variability in the relationship of SR with its two significant drivers, soil temperature and moisture. Accounting for the variabilities, we use a climosequence in Himalaya with a temperature gradient of ~ 2.1 °C to understand the variations in the response of SR and its temperature sensitivity to climate change. Results indicate an equilibrium in SR ranging from 1.92 to 2.42 µmol m−2 s−1 across an elevation gradient (3300–3900 m) despite its increased sensitivity to temperature (Q10) from 0.47 to 4.97. Additionally, moisture reduction towards lower elevation weakens the temperature-SR relationship. Finally, soil organic carbon shows similarities at all the elevations, indicating a net-zero CO2 flux across the climosequence. The findings suggest that as the climate warms in this region, the temperature sensitivity of SR reduces drastically due to moisture reduction, limiting any change in SR and soil organic carbon to rising temperature. We introduce an equilibrium mechanism in this study which indicates the resilient nature of SR to climate change and will aid in enhancing the accuracy of climate change impact projections.

Characteristics of Soil Respiration and Its Components of a Mixed Dipterocarp Forest in China

Background: Although numerous studies have been carried out in recent decades, soil respiration remains one of the less understood elements in global carbon budget research. Tropical forests store a considerable amount of carbon, and a well-established knowledge of the patterns, components, and controls of soil respiration in these forests will be crucial in global change research. Methods: Soil respiration was separated into two components using the trenching method. Each component was measured at multiple temporal scales and in different microhabitats. A commercial soil efflux system (Li8100/8150) was used to accomplish soil respiration monitoring. Four commonly used models were compared that described the temperature dependence of soil heterotrophic respiration using nonlinear statistics. Results and Conclusions: Trenching has a limited effect on soil temperature but considerably affects soil water content due to the exclusion of water loss via tree transpiration. Soil respiration decreased gradually from 8 to 4 μmol·m−2·s−1 6 days after trenching. Soil autotrophic (Ra) and heterotrophic respiration (Rh) have contrasting diel patterns and different responses to temperature. Rh was negatively correlated with temperature but positively correlated with relative humidity. Both Ra and Rh varied dramatically among microhabitats. The Q10 value of Rh derived using the Q10 model was 2.54. The Kirschbaum–O’Connell model, which implied a strong decrease of Q10 with temperature, worked best in describing temperature dependence of Rh. Heterotrophic respiration accounted for nearly half of the total soil efflux. We found an unexpected diurnal pattern in soil heterotrophic respiration which might be related to diurnal moisture dynamics. Temperature, but not soil moisture, was the major controller of seasonal variation of soil respiration in both autotrophic and heterotrophic components. From a statistical perspective, the best model to describe the temperature sensitivity of soil respiration was the Kirschbaum–O’Connell model. Soil respiration varied strongly among the microhabitats and played a crucial role in stand-level ecosystem carbon balance assessment.

Plant community composition alters moisture and temperature sensitivity of soil respiration in semi-arid shrubland.

Soil respiration (Rs) is the second largest carbon (C) flux to the atmosphere and our understanding of how Rs and its components shift with plant-community composition remains an important question. We used high-frequency soil respiration measurements and root exclusion to evaluate how Rs, autotrophic respiration (Ra) and heterotrophic respiration (Rh) vary between a semi-arid perennial shrub community and annual invasive community. Over two growing seasons, total Rs was 40% higher under annual vegetation compared to shrubs. Partitioning revealed consistently higher Ra under annual vegetation which accounted for most of the difference in Rs. Under annual vegetation, Ra increased soon after the first rain events and remained high despite cooling temperatures while shrub Ra increased only when soil temperature began to warm up. The Rh rates were similar between vegetation types when daily soil temperatures were lower than 20°C. As soil temperatures increased and soil moisture dropped below 10%, Rh was consistently higher under annual vegetation than shrubs. Seasonal dynamics of Rs and Rh were best modeled with an interaction term between soil moisture and temperature with significantly different model parameters for each vegetation type. Differences in the timing and magnitude of Rs and Ra between vegetation types are consistent with phenological differences between shrubs and annuals. Under annuals, larger Rh at high temperatures suggests that expansion of annual vegetation and future hotter and drier conditions could lead to greater C losses from this semi-arid shrub system.

Global patterns of geo-ecological controls on the response of soil respiration to warming

While soil respiration is known to be controlled by a range of biotic and abiotic factors, its temperature sensitivity in global models is largely related to climate parameters. Here, we show that temperature sensitivity of soil respiration is primarily controlled by interacting soil properties and only secondarily by vegetation traits and plant growth conditions. Temperature was not identified as a primary driver for the response of soil respiration to warming. In contrast, the nonlinearity and large spatial variability of identified controls stress the importance of the interplay among soil, vegetation and climate parameters in controlling warming responses. Global models might predict current soil respiration but not future rates because they neglect the controls exerted by soil development. To accurately predict the response of soil respiration to warming at the global scale, more observational studies across pedogenetically diverse soils are needed rather than focusing on the isolated effect of warming alone. Understanding the temperature sensitivity of soil respiration is critical to determining soil carbon dynamics under climate change. Spatial heterogeneity in controls highlights the importance of interactions between vegetation, soil and climate in driving the response of respiration to warming.

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

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.

Effects of Amendments on Physicochemical Properties and Respiration Rate of Soil from the Arid Region of Northwest China

In arid regions, decreased soil fertility has adversely affected agricultural sustainability. The effects of different amendments in alleviating these issues and increasing soil fertility remain unclear. Herein, a two-year field experiment was conducted to evaluate the properties of grey desert soil and soil respiration (SR) dynamics under six different treatment groups: biochar (BC), leonardite (LD), anionic polyacrylamide (PAM−), cationic polyacrylamide (PAM+) powder, anionic polyacrylamide solution in water (PAM−W), and control (CK). We observed that the BC and LD amendments significantly altered soil pH, organic matter, available nitrogen, available phosphorus, cation exchange capacity, and SR. PAM amendment increased the SR as compared to the control, except in autumn, but PAM did not affect the soil properties. SR under different amendments showed strong seasonal patterns, the highest and lowest SR rates were observed in June and January, respectively. Amendments and seasonal dynamics significantly affected SR, but no interaction was observed between these factors. Temporal variation of SR was substantially influenced by soil temperature at 15 cm of soil depth. Temperature sensitivity of SR (Q10) increased with soil depth and decreased with amendment addition. SR was significantly affected by soil temperature, moisture, air temperature, and their interactions. The outcomes of this study suggested that the BC and LD amendments improved soil fertility and negated the net carbon accumulation by increasing the SR and Q10 in arid agriculture soil.

To till or not to till in a temperate ecosystem? Implications for climate change mitigation

The management of agricultural soils affect the composition and scale of their greenhouse gas (GHG) emissions. There is conflicting evidence on the effect of zero-tillage on carbon storage and GHG emissions. Here we assess the effects of zero-tillage over a range of time frames (1–15 years) on carbon storage and GHG release and their controls in the UK Net global warming potential was 30% lower under zero-tillage systems, due to lower carbon dioxide fluxes, with the greatest impacts after longer periods of zero-tillage management. Simultaneously, in zero-tillage systems, soil carbon stocks and the proportion of sequestered recalcitrant carbon increased while the temperature sensitivity of soil respiration decreased with time, compared to conventionally soils. We conclude that zero-tillage could play a crucial role in both reducing GHG emissions and at the same time increase soil carbon sequestration, therefore contributing to mitigate against climate change. Our findings are particularly important in the context of designing new policies (for example the Environmental Land Management Schemes in the UK) that ensure the sustainability of agricultural production in a changing climate.

Sea-level rise enhances carbon accumulation in United States tidal wetlands

Sea-level rise enhances carbon accumulation in United States tidal wetlands

Simulated acid rain offset a warming-induced increase in soil respiration but did not impact the temperature sensitivity of soil respiration in a cropland

Investigating the effects of warming and simulated acid rain on soil respiration and its temperature sensitivity is crucial in predicting the potential responses of soil C cycles to future climate warming. A three-year field experiment with six treatments (CK, WA, CK-4.0, WA-4.0, CK-2.0 and WA-2.0) of warming (coded as WA) and three simulated acid rain levels (coded as CK, pH 4.0 and pH 2.0) was performed in an annual winter wheat–soybean cropland to study the comprehensive effects of warming and simulated acid rain on soil respiration and its temperature sensitivity. The results indicated that warming significantly (P < 0.001) increased soil respiration under no (CK) or low acid rain application (pH 4.0), while the warming effects on soil respiration were not significant under intensive acid rain conditions (pH 2.0). The annual mean soil respiration was 2.79 ± 0.02, 3.02 ± 0.01, 2.58 ± 0.07, 2.79 ± 0.03, 2.54 ± 0.04 and 2.50 ± 0.03 μmol m−2 s−1 in the CK, WA, CK-4.0, WA-4.0, CK-2.0 and WA-2.0 plots, respectively. Warming induced an 8.0% increase in soil respiration compared with the CK. Intensive simulated acid rain (pH 2.0) offset the warming effects on soil respiration. A total of 36.9–55.5% of the seasonal variation in soil respiration was explained by soil temperature, while the moisture effects on soil respiration were not significant (P > 0.05). Warming induced a significant (P < 0.001) decrease in the temperature sensitivity (Q10) of soil respiration. Simulated acid rain did not significantly (P > 0.05) impact the Q10 of soil respiration.