Soil Respiration Components Research Articles

2010–2014年哀牢山亚热带常绿阔叶林土壤呼吸数据集

Subtropical forests, as the largest forest type in China, play an important role in regulating global climate change and maintaining atmospheric carbon balance. The carbon emitted by soil through respiration is the main contributor of atmospheric CO2 levels, so even slight changes in soil carbon pool can significantly affect the concentration of atmospheric CO2. Therefore, at present, the magnitude and dynamic change characteristics of soil carbon storage in subtropical forests are attached great importance to. Ailao Mountain in Yunan Province stands as a crucial region for the distribution of subtropical forests in China. This study used a multichannel automated chamber system to estimate soil respiration in a subtropical evergreen broad-leaved forest ecosystem of Ailao Mountain. Ailao Mountain Station for Subtropical Forest Ecosystem Studies is a national field station and a basic observation station of the Chinese Ecosystem Research Network. We gathered soil respiration data from the subtropical evergreen broad-leaved forest in Ailao Mountain from 2011 to 2014, including soil temperature 5cm (TS), soil moisture content 10cm (SWC) and soil respiration data (RS), organized at daily, monthly and annual scales. This dataset is of great significance in revealing the effects of climate change on soil ecological processes in subtropical evergreen broad-leaved forests. It can facilitate precise evaluation of soil organic carbon emissions and forest ecosystem management, and provide both empirical and theoretical basis for further research on the effects of global changes (e.g. climate warming) on soil respiration components, especially with a focus on soil organic carbon emissions.

Soil Respiration after Bark Beetle Infestation along a Vertical Transect in Mountain Spruce Forest

In recent decades, large-scale forest disturbances such as windthrow and bark beetle infestations have significantly impacted Earth’s carbon balance and forest ecosystems. This impact alters soil respiration (SR), along with decreased gross primary productivity. To investigate the impact of bark beetle (Ips typographus L.) infestations in mountain spruce forests on SR, we measured SR at sites infested by bark beetles and adjacent undisturbed stands in the Tatra National Park (Slovakia) during the vegetation period (May–September) in 2016–2017 five to six years after the initial bark beetle attack. The measurements were taken along an altitudinal gradient (1100–1400 m a.s.l.). The highest rates of SR were observed during the summer months in both years (from June to August). However, yearly SR from May to September at infested sites showed significantly higher rates than uninfested ones in both years. SR showed a decreasing pattern with elevation gain in 2016 at infested sites, but this pattern was not observed in 2017. This study provides important insights into the impact of bark beetle infestations on SR and emphasizes the need for further research on the long-term effects of forest disturbances on carbon cycling. It also underscores the importance of determining the effect of different components of SR on the changed environment due to bark beetle attacks on mountain spruce forests.

Acid rain reduced soil carbon emissions and increased the temperature sensitivity of soil respiration: A comprehensive meta-analysis

Soil respiration the second-largest carbon flux in terrestrial ecosystems, has been extensively studied across a wide range of biomes. Surprisingly, no consensus exist on how acid rain (AR) impacts the spatiotemporal pattern of soil respiration. Therefore, we conducted a meta-analysis using 318 soil respiration and 263 soil respiration temperature sensitivity (Q10) data points obtained from 48 studies to assess the impact of AR on soil respiration components and their Q10. The results showed that AR reduced soil total respiration (Rt) and soil autotrophic respiration (Ra) by 7.41 % and 20.75 %, respectively. As the H+ input increased, the response rates of Ra to AR (RR-Ra) and soil heterotrophic respiration (Rh) to AR (RR-Rh) decreased and increased, respectively. With increased AR duration, the RR-Ra increased, whereas the RR-Rh did not change. AR increased the Q10 of Rt (Rt-Q10) and Rh (Rh-Q10) by 1.92 % and 9.47 %, respectively, and decreased the Q10 of Ra (Ra-Q10) by 2.77 %. Increased mean annual temperature, mean annual precipitation, and initial soil organic carbon increased the response rate of Ra-Q10 to AR (RR-Ra-Q10) and decreased the response rate of Rh-Q10 to AR (RR-Rh-Q10). However, as the AR frequency and initial soil pH increased, both RR-Ra-Q10 and RR-Rh-Q10 also increased. In summary, AR decreased Rt but increased Q10, likely due to soil acidification (soil pH decreased by 7.84 %), reducing plant root biomass (decreased by 5.67 %) and soil microbial biomass (decreased by 5.67 %), changing microbial communities (increased fungi to bacteria ratio of 15.91 %), and regulated by climate, vegetation, soil and AR regimes. To the best of our knowledge, this is the first study to reveal the large-scale, varied response patterns of soil respiration components and their Q10 to AR. It highlights the importance of applying the reductionism theory in soil respiration research to enhance our understanding of soil carbon cycling processes with in the context of global climate change.

Short-term warming-induced increase in non-microbial carbon emissions from semiarid abandoned farmland soils

Soil warming is expected to accelerate microbial carbon (C) degradation, increasing carbon dioxide (CO2) emissions. This process greatly contributes to global warming. To validate this positive feedback loop in semiarid restored ecosystems, we examined the effects of 2 years of open-top chamber warming on soil CO2 efflux (soil respiration) and microbial metabolic characteristics in abandoned farmland on the Chinese Loess Plateau. Soil warming of 1.3 °C above ambient at 10 cm depth significantly stimulated CO2 emissions by 40.5 %. Despite short-term warming alleviating the C (energy) limitation on microbial activity, no substantial differences in microbial C use efficiency or biomass turnover rate were noted compared to those in the control. Importantly, we found little evidence that warming altered the expression levels of carbohydrate metabolism genes annotated using the eggNOG, KEGG, and CAZy databases. All expressed genes targeting the degradation of diverse carbonaceous components were assigned to bacterial taxa unaffected by warming. Therefore, short-term warming stimulated soil CO2 emissions from non-microbial sources but did not drive the abandoned farmland in the reverse direction to a C source. Our findings highlight the importance of conducting long-term comparisons of microbial metabolic profiles and soil respiration components to elucidate the mechanisms underlying changes in C-cycling in ecosystems that have undergone restoration and experienced warming.

Effect of Changes in Throughfall on Soil Respiration in Global Forest Ecosystems: A Meta-Analysis

To date, there has been limited knowledge about how soil carbon dioxide (CO2) emissions from forest ecosystems at a global scale respond to the altered precipitation, and the key influencing mechanisms involved. Thirty-seven studies conducted under throughfall manipulation conditions in forest ecosystems around the globe were selected in this meta-analysis, with a total of 103 paired observations. Experimental categories such as climate types, forest types, soil texture, and the area size of changes in throughfall manipulation were included to qualify the responses of annual soil CO2 emissions to the altered throughfall. The responses of the annual soil CO2 emissions to the altered throughfall would be more sensitive in temperate forests than those in tropical and subtropical forests, probably due to the relatively long residence time of soil carbon (C) and the seasonal freeze–thaw events in temperate forests, as well as the relatively high concentration of non-structural carbohydrates in the belowground part of temperate terrestrial plants. A relatively large positive response of the soil CO2 emissions to the increased throughfall was observed in Mediterranean forests due to small precipitation during the growing season and mostly coarse-textured soils. Besides climate types, the sizes of the effect of the altered throughfall on the soil CO2 emissions (lnRCO2) varied with forest types and soil texture categories. Based on the regression analysis of the lnRCO2 values against the changes in throughfall, the annual soil CO2 emissions in forest ecosystems at a global scale would be increased by 6.9%, provided that the change in annual precipitation was increased by 10%. The results of structural equation modeling analysis indicate that fine root biomass and soil microbial biomass, along with the changes in annual precipitation, would substantially affect the altered throughfall-induced annual soil CO2 emissions in global forest ecosystems. The findings of this meta-analysis highlight that the measurement of soil respiration components, the priming effects of soil organic C decomposition, and C allocation between the aboveground and belowground parts of different tree species under the altered precipitation conditions, deserve more attention in the future.

Effects of Short-Term Nitrogen and Phosphorus Addition on Soil Respiration Components in a Subalpine Grassland of Qilian Mountains

In order to investigate the effects of short-term nitrogen and phosphorus addition on soil respiration and its components in a subalpine grassland located on the Qilian Mountains, a random block design of nitrogen[10 g·(m2·a)-1, N], phosphorus[5 g·(m2·a)-1, P], nitrogen and phosphorus addition[10 g·(m2·a)-1N and 5 g·(m2·a)-1P, NP], the control (CK), and complete control (CK') was conducted from June to August 2019, and total soil respiration and its component respiration rates were measured. The results showed that nitrogen addition reduced soil total respiration and heterotrophic respiration rates at a lower rate than P addition[-16.71% vs. -19.20%; -4.41% vs. -13.05%], but the rate of decrease in autotrophic respiration was higher than that of P addition (-25.03% vs. -23.36%); N and P mixed application had no significant effect on soil total respiration rate. The total soil respiration rate and its components were significantly exponentially correlated with soil temperature, and the temperature sensitivity of soil respiration rate was decreased by nitrogen addition (Q10:-5.64%-0.00%). P increased Q10 (3.38%-6.98%), and N and P reduced autotrophic respiration rate but increased heterotrophic respiration rate Q10 (16.86%) and decreased total soil respiration rate Q10 (-2.63%- -2.02%). Soil pH, soil total nitrogen, and root phosphorus content were significantly correlated with autotrophic respiration rate (P<0.05) but not with heterotrophic respiration rate, and root nitrogen content was significantly negatively correlated with heterotrophic respiration rate (P<0.05). In general, autotrophic respiration rate was more sensitive to N addition, whereas heterotrophic respiration rate was more sensitive to P addition. Both N and P addition significantly reduced soil total respiration rate, whereas N and P mixture did not significantly affect soil total respiration rate. These results can provide a scientific basis for the accurate assessment of soil carbon emission in subalpine grassland.

Moso bamboo expansion decreased soil heterotrophic respiration but increased arbuscular mycorrhizal mycelial respiration in a subtropical broadleaved forest

Moso bamboo (Phyllostachys Pubescens) expansion into adjacent forests has been widely reported to affect plant diversity and its association with mycorrhizal fungi in subtropical China, which will likely have significant impacts on soil respiration. However, there is still limited information on how Moso bamboo expansion changes soil respiration components and their linkage with microbial community composition and activity. Based on a mesh exclusion method, soil respirations derived from roots, arbuscular mycorrhizal (AM) mycelium, and free-living microbes were investigated in a pure Moso bamboo forest (expanded), an adjacent broadleaved forest (non-expanded), and a mixed bamboo-broadleaved forest (expanding). Our results showed that bamboo expansion decreased the cumulative CO2 effluxes from total soil respiration, root respiration and soil heterotrophic respiration (by 19.01%, 30.34%, and 29.92% on average), whereas increased those from AM mycelium (by 78.67% in comparison with the broadleaved forests). Bamboo expansion significantly decreased soil organic carbon (C) content, bacterial and fungal abundances, and enzyme activities involved in C, N and P cycling whereas enhanced the interactive relationships among bacterial communities. In contrast, the ingrowth of AM mycelium increased the activities of β-glucosidase and N-acetyl-β-glucosaminidase and decreased the interactive relationships among bacterial communities. Changes in soil heterotrophic respiration and AM mycelium respiration had positive correlations with soil enzyme activities and fungal abundances. In summary, our findings suggest that bamboo expansion decreased soil heterotrophic respiration by decreasing soil microbial activity but increased the contribution of AM mycelial respiration to soil C efflux, which may potentially increase soil C loss from AM mycelial pathway.

Intensive grassland management disrupts below-ground multi-trophic resource transfer in response to drought

Modification of soil food webs by land management may alter the response of ecosystem processes to climate extremes, but empirical support is limited and the mechanisms involved remain unclear. Here we quantify how grassland management modifies the transfer of recent photosynthates and soil nitrogen through plants and soil food webs during a post-drought period in a controlled field experiment, using in situ 13C and 15N pulse-labelling in intensively and extensively managed fields. We show that intensive management decrease plant carbon (C) capture and its transfer through components of food webs and soil respiration compared to extensive management. We observe a legacy effect of drought on C transfer pathways mainly in intensively managed grasslands, by increasing plant C assimilation and 13C released as soil CO2 efflux but decreasing its transfer to roots, bacteria and Collembola. Our work provides insight into the interactive effects of grassland management and drought on C transfer pathways, and highlights that capture and rapid transfer of photosynthates through multi-trophic networks are key for maintaining grassland resistance to drought.

Intensive management enhances mycorrhizal respiration but decreases free-living microbial respiration by affecting microbial abundance and community structure in Moso bamboo forest soils

Intensive management is known to markedly alter soil carbon (C) storage and turnover in Moso bamboo forests compared to extensive treatment regimes. However, the effect of intensive management on soil respiration (R S ) components is still unclear. This study aimed to evaluate the changes in different R S components (root, mycorrhiza, and microbes) in Moso bamboo forests under extensive and intensive management practices. A one-year in-situ microcosm experiment was carried out to quantify the R S components in Moso bamboo forests under the two management approaches using mesh screens of varying sizes. The result showed that total R S and its components exhibited similar seasonal variability between the two groups. Compared to extensive management, intensive management significantly increased cumulative respiration from mycorrhizal fungi by 36.73% while decreasing cumulative respiration from free-living soil microbes by 8.97%. Moreover, the abundance of arbuscular mycorrhizal fungi (AMF) increased by 43.38%. In contrast, bacterial and fungal abundance decreased by 21.65% and 33.30% under intensive management. Both management practices significantly changed the bacterial community composition, which could be mainly explained by soil pH and available K. Mycorrhizal fungi and intensive management affected the co-occurrence interrelationships between bacterial members. Structural equation modeling indicated that intensive management changed the cumulative soil respiration via elevating AMF abundance and lowering bacterial abundance. We conclude that intensive management reduced the microbial respiration-derived C loss and increased the mycorrhizal respiration-derived C loss.

Ecosystem photosynthesis depends on increased water availability to enhance carbon assimilation in semiarid desert steppe in northern China

The amount and intensity of precipitation may have important effects on plant growth and ecosystem carbon exchange in semiarid desert steppes; further understanding of how the dryland carbon cycle responds to changes in precipitation and its underlying mechanisms is necessary for an accurate understanding of the global carbon cycle. A field experiment was conducted in a semiarid desert steppe in Ningxia, China, to clarify the response patterns of ecosystem carbon fluxes along five levels of precipitation gradients (Simulating the natural precipitation percentages of 33 % (−33 %, 84 mm), 66 % (−66 %, 167 mm), 100 % (CK, 253 mm), 133 % (+33 %, 336 mm) and 166 % (+66 %, 420 mm) by rain shelters and sprinklers; CK is natural precipitation). The result showed that the trends of net ecosystem CO 2 exchange (NEE) and gross ecosystem photosynthesis (GEP) were consistent and those of ecosystem respiration (ER) and Soil respiration (SR) and autotrophic (Ra) and heterotrophic (Rh) components of SR were also consistent. NEE, ER, GEP and SR all reached their highest values in August. Changes in precipitation significantly affected ecosystem carbon fluxes, with NEE, ER and SR decreasing with decreasing precipitation and NEE, ER and GEP increasing with increasing precipitation. Soil respiration was more sensitive to the decreased precipitation treatment. During the growing season, NEE, ER, GEP, and SR were significantly positively correlated with precipitation, soil moisture (SM) and aboveground biomass (AGB). With the increase of precipitation variability, the promotion effect of increasing precipitation on GEP will exceed the promotion effect on ER, causing changes in carbon exchange and carbon sinks. Photosynthesis and respiration appeared tightly coupled, indicating that photosynthetic products regulate above- and belowground carbon cycling in semiarid steppe. Our study highlights the importance of water availability in carbon exchange processes in semiarid desert steppe of northern China. Decreased precipitation can lead to significant changes in SM and AGB, with negative impacts on GEP and SR, resulting in uncertainty in regional carbon sequestration. These findings will help us understand the vulnerability of semiarid steppe ecosystems under the influence of future precipitation changes and aim to provide a scientific reference for ecological management and restoration of semiarid desert steppes. • Effect of precipitation changes on above- and below-ground carbon fluxes was studied. • Increased precipitation promotes GEP more than ER, leading to carbon sinks. • Soil respiration was more sensitive to the decreased precipitation treatment. • There is a strong coupling between photosynthesis and soil respiration.

Contribution of the Root Component to Soil Respiration in Oriental Beech Stands in Artvin, Turkey

Abstract Autotrophic (root) and heterotrophic respiration components respond differently to environmental variables, and each component behaves differently at different time scales, so it is necessary to partition total soil respiration into its components. The aims of this study were determine soil respiration and its root and heterotrophic components in beech stands, examine the relationship between respiration and biogeochemical factors, and assess seasonal variation in soil respiration. Trenching was applied to separate soil respiration components 6 months before measurements. Monthly soil respiration, temperature and moisture measurements, and seasonal soil and root sampling were carried out in Oriental beech (Fagus orientalis L.) stands located in Artvin Saçinka, Turkey from April 2018 to November 2018 and also (except soil sampling) from May 2019 to November 2019. The average contribution of root respiration and heterotrophic respiration to total soil respiration were 58.8% and 41.2%, respectively. Carbon and nitrogen dynamics explained variations of soil respiration with significant models. This study indicates that soil respiration and its components are associated with biogeochemical factors as well as environmental climatic conditions, and each component of respiration responds differently to changes in them.

Responses of soil respiration and microbial community structure to fertilizer and irrigation regimes over 2 years in temperate vineyards in North China

Fertilizer and irrigation regimes can profoundly affect soil carbon (C) emissions, which influence soil organic carbon (SOC) storage. However, information regarding the effects of fertilizer and irrigation management on the components of soil respiration (Rs) and the underlying microbial community characteristics in vineyard ecosystems remains limited. Therefore, a 2-year field experiment was conducted in a wine-grape vineyard (WGV) and a table-grape vineyard (TGV). Each vineyard included two fertilizer and irrigation regimes: farmers' practice (FP) and recommended practice (RP). The trenching method was employed to separate Rs into heterotrophic respiration (Rh) and autotrophic respiration (Ra). Additionally, the SOC storage and soil microbial community structure at 0–20 cm soil depth were determined after the 2-year experiment. The results showed that the fertilizer and irrigation regimes caused no effect on Ra. Compared with the FP treatment in WGV and TGV, the RP treatment significantly (P < 0.05) decreased the average daily Rh by 15.13 % and 17.11 %, which contributed to the annual Rs values at the whole-vineyard scale decreased by 8.93 % and 11.78 %, respectively. Besides, compared with the initial value, the SOC storage under RP treatment were effectively increased by 6.39 % and 6.33 % in WGV and TGV, respectively. Low annual total Rh was partially ascribed to the significant (P < 0.05) decline in Proteobacteria and Bacteroidetes relative abundance, thus reducing the decomposition rate of SOC. Compared with WGV, the fertilizer and water input was higher in the TGV, which resulted in the annual total Rs and Rh values at the whole-vineyard scale was increased by 11.53 % and 15.74 %, respectively, while the annual total Ra was decreased by 18.83 % due to the lower grapevine density and more frequent summer pruning. Overall, RP treatment was found to be a suitable strategy for reducing soil C emissions and benefiting SOC storage in vineyards around North China.

Heterotrophic respiration and its proportion to total soil respiration decrease with warming but increase with clipping

Revealing how heterotrophic respiration (Rh) and its contribution to soil respiration (Rs, Rh/Rs ratio) respond to climate warming and land-use change is crucial for advancing our understanding of the feedback between the terrestrial carbon (C) cycle and future climate changes. Here we conducted a 7-year manipulation experiment by warming and clipping to explore their impacts on Rh and Rh/Rs ratio in an alpine meadow on the Qinghai-Tibet Plateau. Infrared heaters were used to simulate climate warming and clipping was applied to mimic yearly hay or biofuel harvest. We found that, on average, warming significantly decreased Rh/Rs ratio by 5.5%, which was attributed to the little change in Rh and increased autotrophic respiration (Ra, 18.3%) under warming. In contrast, clipping significantly increased Rh/Rs ratio by 8.1%, which was mainly due to the clipping-induced increase in Rh (22.6%) and decrease in Ra (3.9%). Warming or clipping-induced changes in Rh and the Rh/Rs ratio were mainly controlled by the microbial metabolic quotient, microbial biomass C and nitrogen, soil moisture, and soil temperature. Moreover, warming and clipping both increased Rs by 13.2% and 15.5%, respectively, over the study period. Our study highlights the differential responses of the two soil respiration components to warming and clipping, and suggests that climate warming does not necessarily increase Rh but clipping largely stimulates Rh, which may accelerate the turnover and losses of soil C in this alpine meadow. Hence, quantifying how Rh and the Rh/Rs ratio respond to global changes has large implications for better predicting the future ecosystem C cycle and its feedback to climate system in ecosystem models.

Carbon Dynamics in Rewetted Tropical Peat Swamp Forests

Degraded and drained peat swamp forests (PSFs) are major sources of carbon emissions in the forestry sector. Rewetting interventions aim to reduce carbon loss and to enhance the carbon stock. However, studies of rewetting interventions in tropical PSFs are still limited. This study examined the effect of rewetting interventions on carbon dynamics at a rewetted site and an undrained site. We measured aboveground carbon (AGC), belowground carbon (BGC), litterfall, heterotrophic components of soil respiration (Rh), methane emissions (CH4), and dissolved organic carbon (DOC) concentration at both sites. We found that the total carbon stock at the rewetted site was slightly lower than at the undrained site (1886.73 ± 87.69 and 2106.23 ± 214.33 Mg C ha−1, respectively). The soil organic carbon (SOC) was 1685 ± 61 Mg C ha−1 and 1912 ± 190 Mg C ha−1 at the rewetted and undrained sites, respectively, and the carbon from litterfall was 4.68 ± 0.30 and 3.92 ± 0.34 Mg C ha−1 year−1, respectively. The annual average Rh was 4.06 ± 0.02 Mg C ha−1 year−1 at the rewetted site and was 3.96 ± 0.16 Mg C ha−1 year−1 at the undrained site. In contrast, the annual average CH4 emissions were −0.0015 ± 0.00 Mg C ha−1 year−1 at the rewetted site and 0.056 ± 0.000 Mg C ha−1 year−1 at the undrained site. In the rewetted condition, carbon from litter may become stable over a longer period. Consequently, carbon loss and gain mainly depend on the magnitude of peat decomposition (Rh) and CH4 emissions.

Heterotrophic and rhizospheric respiration in coniferous forest soils along a latitudinal gradient

Northern forest soils are a major carbon (C) reservoir of global importance. To estimate how the C balance in these soils will change, the roles of tree roots and soil microbes in C balance should first be decoupled. This study determined how the activity of heterotrophs and tree roots together with root-associated microbes in the rhizosphere varies in coniferous forest soils in boreal, hemiboreal, and temperate climates along a latitudinal gradient using a trenching approach. We created experimental plots without living tree roots, measured soil respiration (CO2 efflux) from these and from unmanipulated plots using the chamber technique, and partitioned the efflux into root-rhizosphere (RR) and heterotrophic (RH) respiration. The share of RR in ecosystem gross primary production (GPP) decreased from north to south in the Scots pine (Pinus sylvestris L.) and the Norway spruce (Picea abies (L.) Karst.) forests, with the exception of a mixed site, where the share of RR in GPP varied strongly between the years. RR per ground area and per root biomass were mainly independent of climate within the gradient. RH per ground area increased from north to south with temperature, while RH per soil C did not change with temperature. Soil moisture did not significantly affect the respiration components in the northernmost site, whereas soil moisture was positively connected with RH and negatively with RR in other Scots pine sites and positively connected with RR in pure Norway spruce stands. The dynamic ecosystem model LPJ-GUESS was able to capture the seasonal dynamics of RH and RR at the sites, but overall accuracy varied markedly between the sites, as the model underestimated RH in the southern site and RR elsewhere. Our study provides knowledge about the nature of soil respiration components. The valuable insights can be used in more accurate land-ecosystem modelling of forest ecosystems.

Influence of rhizosphere activity on litter decomposition in subtropical forest: implications of estimating soil organic matter contributions to soil respiration

AbstractLitter decomposition plays an important role in the carbon cycle and is affected by many factors in forest ecosystems. This study aimed to quantify the rhizosphere priming effect on litter decomposition in subtropical forest southwestern China. A litter decomposition experiment including control and trenching treatments was conducted using the litter bag method, and the litter decomposition rate was calculated by litter dry mass loss. Trenching did not change soil temperature, but increased the soil water content by 14.5%. In this study, the interaction of soil temperature and soil water content controlled the litter decomposition rate, and explained 87.4 and 85.5% of the variation in litter decomposition in the control and trenching treatments, respectively. Considering changes in soil environmental factors due to trenching, the litter decomposition rates were corrected by regression models. After correction, the litter decomposition rates of the control and trenching treatments were 32.47 ± 3.15 and 25.71 ± 2.72% year–1, respectively, in the 2-year period. Rhizosphere activity significantly primed litter decomposition by 26.3%. Our study suggested a priming effect of rhizosphere activity on litter decomposition in the subtropical forest. Combining previous interaction effect results, we estimated the contributions of total soil organic matter (SOM) decomposition, total litter decomposition, and root respiration to soil respiration in the subtropical forest, and our new method of estimating the components of soil respiration provided basic theory for SOM decomposition research.

Differential linkages between soil respiration components and microbial community structures under long-term forest conversion

Differential linkages between soil respiration components and microbial community structures under long-term forest conversion

川中丘陵区冬水田种植模式转旱作土壤呼吸组分特征及碳平衡

PDF HTML阅读 XML下载 导出引用 引用提醒 川中丘陵区冬水田种植模式转旱作土壤呼吸组分特征及碳平衡 DOI: 10.5846/stxb202105281410 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: “十三五”国家重点研发计划"粮食丰产科技创新"专项项目(2017YFD0301702) Carbon balance and characteristics of soil respiration components during the transition from paddy field to upland in the hilly region of central Sichuan Author: Affiliation: 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:冬水田-水稻是川中丘陵区传统的稻田种植模式,冬水田种植模式转变是实现多熟种植及机械化的重要途径。为探究冬水田-水稻种植模式转旱作过程中作物季及休闲期土壤呼吸速率及其组分构成,试验设置冬水田-水稻转旱作(FTD)、冬水田-水稻(FR)和冬闲田-玉米(FM)3种不同种植模式,采用根排除法和静态明箱-气相色谱法原位取样测定作物季及季后休闲期土壤呼吸及其组分,并通过测算净生态系统生产力(NEP)进而判断冬水田-水稻转旱作过程的农田系统碳汇强度。结果表明:(1)FTD显著提高了土壤总呼吸速率及其自养和异养呼吸速率,从而提高了其累积排放量(P<0.05)。与FR相比,FTD的土壤总呼吸及其自养和异养呼吸的累积排放量分别提高了13.14倍、11.32倍和15.56倍(P<0.05);与FM相比,FTD的土壤总呼吸及其自养和异养呼吸的累积排放量分别提高了70.56%、40.83%和115.47%(P<0.05)。(2)与FR和FM相比,FTD均降低了土壤呼吸及其组分的温度敏感性(Q10),且土壤总呼吸的温度敏感性介于异养呼吸和自养呼吸之间。(3)FR,FM和FTD的净生态系统生产力(NEP)均为正值,其数值分别为7911.66 kg/hm2,5667.89 kg/hm2和1583.46 kg/hm2,均表现为大气CO2的碳汇,但与FR与FM相比,FTD显著降低了其净生态系统生产力,呈现出较弱的碳汇。 Abstract:Winter paddy field-rice is a traditional rice planting pattern in the hilly areas of central Sichuan Province. The transformation of winter paddy field-rice planting pattern is an important measure to promote multi-cropping and mechanized cropping production. To investigate the soil respiration rate and its composition during crop season and fallow period during the transition from winter paddy field-rice to upland cropping (FTD), three different cropping patterns were set up in this experiment, including paddy field-rice to upland cropping (FTD), paddy field-rice (FR), and fallow field-corn (FM). Root removal method and static chamber gas chromatography were used to determine soil respiration and its components in crop season and fallow period after crop was harvested. The intensity of farmland carbon sink of FTD was evaluated by calculating net ecosystem productivity (NEP). The results showed that: (1) the total soil respiration rate, autotrophic respiration rate and heterotrophic respiration rate significantly increased in FTD than FR and FM (P<0.05). Compared with FR, the cumulative emissions amount of total soil respiration, autotrophic and heterotrophic respiration increased by 13.14 times, 11.32 times, and 15.56 times, respectively (P<0.05); Compared with FM, the cumulative emissions amount of the total soil respiration, autotrophic and heterotrophic respiration increased by 70.56%, 40.83% and 115.47%, respectively (P<0.05). (2) The respiration temperature sensitivity (Q10) value of total soil respiration, autotrophic respiration and heterotrophic respiration decreased in FTD than FR and FM. Meanwhile Q10 value of total soil respiration was between heterotrophic respiration Q10 value and autotrophic respiration Q10 value. (3) The NEP of FR, FM and FTD were positive, and their values were 7911.66 kg/hm2, 5667.89 kg/hm2 and 1583.46 kg/hm2, respectively. The three plant patterns were all the carbon sink of atmospheric CO2. Whereas, because the NEP in FTD was significantly lower than FR and FM, it only showed a weak carbon sink in FTD than that in FR and FM. 参考文献 相似文献 引证文献

Comparing an exponential respiration model to alternative models for soil respiration components in a Canadian wildfire chronosequence (FireResp v1.0)

Abstract. Forest fires modify soil organic carbon and suppress soil respiration for many decades after the initial disturbance. The associated changes in soil autotrophic and heterotrophic respiration from the time of the forest fire, however, are less well characterized. The FireResp model predicts soil autotrophic and heterotrophic respiration parameterized with a novel dataset across a fire chronosequence in the Yukon and Northwest Territories of Canada. The dataset consisted of soil incubation experiments and field measurements of soil respiration and soil carbon stocks. The FireResp model contains submodels that consider a Q10 (exponential) model of respiration compared to models of heterotrophic respiration using Michaelis–Menten kinetics parameterized with soil microbial carbon. For model evaluation we applied the Akaike information criterion and compared predicted patterns in components of soil respiration across the chronosequence. Parameters estimated with data from the 5 cm soil depth had better model–data comparisons than parameters estimated with data from the 10 cm soil depth. The model–data fit was improved by including parameters estimated from soil incubation experiments. Models that incorporated microbial carbon with Michaelis–Menten kinetics reproduced patterns in autotrophic and heterotrophic soil respiration components across the chronosequence. Autotrophic respiration was associated with aboveground tree biomass at more recently burned sites, but this association was less robust at older sites in the chronosequence. Our results provide support for more structured soil respiration models than standard Q10 exponential models.

Monsoon-phase regulates the decoupling of auto- and heterotrophic respiration by mediating soil nutrient availability and root biomass in tropical grassland

Soil respiration is considered as one of the most sensitive parameters regulated by the interplay of different soil biophysical parameters, ground cover and climatic conditions. As per the global predictions, monsoon variability in South Asian countries can affect various soil processes. However, studies exploring the interactive role of vegetation and precipitation conditions on soil respiration and its components (viz., auto- and heterotrophic) are lacking. A mini-trenching method was performed to explore the alterations in auto- and heterotrophic components of soil respiration as well as their regulatory variables in grassland vegetation under different summer monsoonal phases. Three vegetation densities (viz. low, medium and high) based on herbaceous cover, and three monsoon phases (viz. onset, active and end) of the tropical summer monsoon were considered. The findings revealed that heterotrophic respiration was the major contributor to the total soil respiration under medium- and high-density vegetation with percent contribution of 62–80% and 53–88% respectively. Contrastingly, autotrophic respiration was the major contributor (54–56%) to soil respiration in low-density vegetation during active- and monsoon-end phases. Amongst the three monsoon phases, variation in soil respiration components was most pronounced during the active-monsoon phase. Structural Equation Modelling results revealed microbial biomass and root biomass as key regulators of auto- and heterotrophic respiration. Remarkably, a partitioning of root biomass parallel to the soil respiration was observed during monsoon-end phase where coarse root biomass and fine root biomass emerged as regulators of auto- and heterotrophic respiration, respectively. Moreover, for monsoon-onset and -end phases, a completely different set of variables involved in regulation of soil respiration components were identified. Our results revealed that the monsoon-phase mediates the root and nutrient dynamics which led to the differential decoupling of the components of soil respiration. Thus, inclusion of (below)-ground cover and monsoon-phase wise variation in soil biophysical parameters in the global biogeochemical models would be more helpful for better prediction of carbon balance in different ecosystems.