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Schematic diagram of experimental plot layout. Organic matter treatments: both litter removal and root trenching (LRRT), only litter removal (LR), control (CK), only root trenching (RT), and litter addition (LA).
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Alteration in the amount of soil organic matter input can have profound effect on carbon dynamics in forest soils. The objective of our research was to determine the response in soil respiration to above- and belowground organic matter manipulation in a Chinese pine (Pinus tabulaeformis) plantation. Five organic matter treatments were applied durin...
Context in source publication
Context 1
... the end of May 2010, fifteen 1×1 m subplots were randomly established in each plot for soil respiration measurements. The schematic diagram of the experimental plot layout is shown in Fig 1. The subplots were subjected to five organic matter treatments: (1) both litter removal and root trenching (LRRT for short), (2) only litter removal (LR), (3) control (CK), (4) only root trenching (RT), (5) litter addition (LA). ...
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Citations
... Thus, soil moisture controls the CO 2 flux during these months. Previous studies have reported that soil moisture and temperature affect rates of seasonal soil respiration (Carbonell-Bojollo et al., 2019;Cui et al., 2020;Davidson et al., 2000;Fan et al., 2015;Guntiñas et al., 2013;Sheng et al., 2010). Here, we observed an exponential relationship between soil temperature and soil respiration in both plot types, and a quadratic relationship between soil moisture and soil respiration in SB plots. ...
... Therefore, understanding the impacts of climate change on N is important because of its role in changing the patterns of R T in forest ecosystems. As a biological process, R T is closely associated with plant growth and the supply of photosynthetic substrates (Fan et al., 2015). R T and its fractions are a measurement of soil microbial activity, and the soil microbes can regulate N cycling in the soil (Sanyal et al., 2021). ...
Soil respiration, the second largest CO2 flux in terrestrial ecosystems, involves the microbial respiration of litter from aboveground sources, belowground litter and root respiration, from rhizodeposition. In the subtropical forests of the Ailao Mountain, a chamber with automated CO2 efflux was set up with two treatments: a control treatment with litterfall to measure the total soil respiration (RT) and a litter removal treatment to measure aboveground litterfall respiration (RL). This study aimed to examine the responses of RL to unexpected heavy snowfall events and soil temperature (ST), soil moisture (SM), rainfall (RF), total litterfall (TL), litter water content (LWC), nitrate nitrogen (NO3⁻-N), and ammonium nitrogen (NH4⁺-N). The period of the study was divided into two: before the heavy snowfall event (BS) and during and after the heavy snowfall event (AS). The rate of RL was slightly decreased in AS (1.18 ± 0.03 μmol CO2 m⁻² s⁻¹) compared with that in BS (1.19 ± 0.02 μmol CO2 m⁻² s⁻¹). The relationships between RL and ST, SM, RF, and LWC, respectively, were all statistically significant (p < 0.05) in both periods. However, the relationships between RL and TL and NH4⁺-N, respectively, were not statistically significant for either period. The relationship between RL and NO3⁻-N was statistically significant for AS but not for BS. The relationship between RL and RF was statistically significant from 2011 to 2018. The temperature dependence of soil respiration was higher in BS than in AS, and the effect of litter removal was 2.55 % and 2.32 % for AS and BS respectively. The results indicate that current global terrestrial models underestimate RL trends for the feedback of global climate change in subtropical forests.
... Thus, soil moisture controls the CO 2 flux during these months. Previous studies have reported that soil moisture and temperature affect rates of seasonal soil respiration (Carbonell-Bojollo et al., 2019;Cui et al., 2020;Davidson et al., 2000;Fan et al., 2015;Guntiñas et al., 2013;Sheng et al., 2010). Here, we observed an exponential relationship between soil temperature and soil respiration in both plot types, and a quadratic relationship between soil moisture and soil respiration in SB plots. ...
The temporal dynamics of soil respiration change in response to different land management practices are not well documented. This study investigated the effects of soil bunds on the monthly and diurnal dynamics of soil respiration rates in the highlands of the Upper Blue Nile basin in Ethiopia. Six plots (with and without soil bunds, three replicates) were used for measurement of seasonal soil respiration, and 18 plots were used for measurement of diurnal soil respiration. We collected seasonal variation data on a monthly basis from September 2020 to August 2021. Diurnal soil respiration data were collected four times daily (5 a.m., 11 a.m., 5 p.m., and 11 p.m.) for 2 weeks from 16 to 29 September 2021. A Wilcoxon signed-rank test showed that seasonal soil respiration rates differed significantly (p < 0.05) between soil bund and control plots in all seasons. In plots with soil bunds, seasonal soil respiration rates were lowest in February (1.89 ± 0.3 µmol CO2 m–2 s–1, mean ± SE) and highest in October (14.54 ± 0.5 µmol CO2 m–2 s–1). The diurnal soil respiration rate was significantly (p < 0.05) higher at 11 a.m. than at other times, and was lowest at 5 a.m. Seasonal variation in soil respiration was influenced by soil temperature negatively and moisture positively. Diurnal soil respiration was significantly affected by soil temperature but not by soil moisture. Further study is required to explore how differences in soil microorganisms between different land management practices affect soil respiration rates.
... Thus, soil moisture controls the CO 2 flux during these months. Previous studies have reported that soil moisture and temperature affect rates of seasonal soil respiration (Carbonell-Bojollo et al., 2019;Cui et al., 2020;Davidson et al., 2000;Fan et al., 2015;Guntiñas et al., 2013;Sheng et al., 2010). Here, we observed an exponential relationship between soil temperature and soil respiration in both plot types, and a quadratic relationship between soil moisture and soil respiration in SB plots. ...
The temporal dynamics of soil respiration change in response to different land management practices is not well documented. This study investigated the effects of soil bunds on the monthly and diurnal dynamics of soil respiration rates in the highlands of the Upper Blue Nile basin in Ethiopia. Six plots (with and without soil bunds, three replicates) were used for measurement of seasonal soil respiration, and eighteen plots were used for measurement of diurnal soil respiration. We collected seasonal variation data on a monthly basis from September 2020 to August 2021. Diurnal soil respiration data were collected four times daily (5 a.m., 11 a.m., 5 p.m., and 11 p.m.) for two weeks from 16–29 September 2021. A Wilcoxon signed-rank test showed that seasonal soil respiration rates differed significantly ( p < 0.05) between plots with and without soil bunds in all seasons. In plots with soil bunds, seasonal soil respiration rates were lowest in February (1.89 ± 0.3 µmol CO 2 m − 2 s − 1 , mean ± SE) and highest in October (14.54 ± 0.5 µmol CO 2 m − 2 s − 1 ). Diurnal soil respiration rate was significantly ( p < 0.05) higher at 11 a.m. than at other times, and was lowest at 5 a.m. Both soil temperature and moisture significantly affected seasonal variation in soil respiration. Diurnal variation in soil respiration was significantly affected by soil temperature but not by soil moisture. Further study is required to explore how differences in soil microorganisms between different land management practices affect soil respiration rates.
... Zou et al. (2018) and Rustad et al. (2001) also observed increases in soil CO 2 emissions following warming and precipitation in numerous regions. As we know, nitrogen availability can be utilised by soil respiration and fertiliser as major factors affecting soil respiration in farmland, directly by influencing root and microbial activities and indirectly by influencing physical and chemical soil properties (Ding et al. 2007;Huang et al. 2012;Fan et al. 2015;Gong et al. 2015). Therefore, it can be reasonably assumed that N fertilisation may impact CO 2 emissions by affecting these factors. ...
Over the last century, anthropogenic greenhouse-gas (GHG) emissions have changed the global climate, and agriculture plays an important role in the global flux of GHG. Agricultural management practices, such as split N applications and the use of controlled-release fertilisers have significantly increased the crop yield and N-use efficiency by balancing the N demand of crops and the N availability of soils. However, the impacts of these practices on GHG emissions (in particular in wheat–peanut relay intercropping systems) have not been evaluated in detail. In this study, a common compound fertiliser and a controlled release compound fertiliser (CRF) were used the day prior to sowing, at the jointing stage of wheat and at the peanut anthesis stage in ratios of 50-50-0% (JCF100), 35-35-30% (JCF70) and 35-35-30% (JCRF70), with a control treatment of 0 kg ha−1. The findings demonstrated that treatment JCF70 achieved increases in yields of 9.7% and 14.6% for wheat grain and peanut pod, respectively, compared to treatment JCF100; however, this treatment also significantly increased soil emissions of CO2 and N2O. In addition, cumulative emissions of CO2 and N2O were higher in the peanut growing season by 74.4 and 31.7%, respectively, than in the wheat growing season owing to the relatively higher soil temperature during the former season. Fertilisation combined with irrigation, was found to be the main cause of GHG emissions. Under the same fertiliser rate and N-management style, JCRF70 further increased the yield of peanut pods and the total combined yield of peanut and wheat by 10.3% and 8.9%, respectively, compared to treatment JCF70. The cumulative CO2 and N2O emissions in treatment JCRF70 were 20.4–45.4% less than those in treatment JCF70. The total global warming potentials of CO2 and N2O were lowest in treatment JCRF70 owing to it providing the highest grain yield. Therefore, N application with three splits, together with the use of a slow-release fertiliser, may be a simple and effective approach to enhance the grain yield whilst reducing the GHG emissions.
... Therefore, understanding the impacts of climate change on N is important because of its role in changing the patterns of R T in forest ecosystems. As a biological process, R T is closely associated with plant growth and the supply of photosynthetic substrates (Fan et al., 2015). R T and its fractions are a measurement of soil microbial activity, and the soil microbes can regulate N cycling in the soil (Sanyal et al., 2021). ...
... Recent studies showed that variations in aboveground and belowground production of plant litter may increase or decrease Rs due to the different qualities and/or quantities of the litter (Yi et al., 2007;Wang et al., 2013;Fan et al., 2015;Wang et al., 2017;Chen and Chen, 2018). The contribution of R A to Rs was found to vary considerably and to depend on the quantity of fine root biomass and forest types. ...
... Plant traits such as litterfall and root chemical composition could affect their contribution to Rs because they affect decomposition rates by altering the microbial biomass, microbial activity, and microbial community composition (Wang et al., 2013. The chemical composition of roots and litterfall varies widely among tree species in highly diverse subtropical forests (Fan et al., 2015;Ni et al., 2021). Arbuscular mycorrhiza and ectomycorrhiza plants dominate in most natural and anthropogenic ecosystems, and they differ in belowground C allocation, the capacity of organic nutrient acquisition, and therefore play an important role in the forest C cycling and nutrient acquisition (Tedersoo and Bahram, 2019). ...
Soil respiration (RS) is the largest terrestrial carbon (C) flux to the atmosphere, and it can be influenced by changing input of plant C from above- and/or below ground. Especially in tropical and sub-tropical ecosystems, the contributions of litter respiration (RL), autotrophic respiration (RA) and mineral soil respiration (RM) are still poorly understood. In the present study, RS was measured under untreated control (CT), root exclusion (NR), litterfall exclusion (NL), and combined litterfall and root exclusion (NRNL) in a subtropical Cunninghamia lanceolata plantation and a secondary Castanopsis carlesii forest for three years. In addition, litter input, litter and soil chemistry, and microbial biomass and community structure (PLFAs) were assessed. RS was significantly higher in the C. carlesii forest than in the coniferous C. lanceolata forest. RL and RA were significantly higher in the C. carlesii forest than in the C. lanceolata forest, while there was no significant difference in RM. RM, RA, and RL contributed 55%, 29%, and 16% to RS under C. lanceolata, and 39%, 32%, and 29% under C. carlesii, respectively. Above ground litter input and microbial biomass were lower in the coniferous C. lanceolata forest. Soil microbial biomass was significantly lower in NL, NR and NRNL in both forests. NL had most pronounced effects on the microbial community composition in the C. carlesii soil, whereas NR and NRNL affected the community composition in C. lanceolata soil. Overall, the unexpectedly small and only insignificant additive effects of litter exclusion and root exclusion in the combined treatment (NRNL) suggest that yet unresolved interactions had accelerated the decomposition of mineral soil organic matter and RM under this lowest plant C-input scenario. Hence, in the case that above and below ground plant C inputs change simultaneously, effects on RS and its components might be more complex than suggested by single-C-source manipulation studies.
... Changes in plant litter inputs can influence both the decomposition and formation of SOC and ultimately have intense influences on SOC dynamics by regulating plant residue addition. The increased coarse-sized SOC caused by litter addition will rapidly deplete and stimulate C decomposition in fine-sized fractions, which ultimately induces higher SOC decomposition (Fan et al. 2015;Leitner et al. 2016). The l3 C abundance of SOC corresponds closely to the l3 C abundance of the plant material from which it is derived and to the decomposition degree of organic materials, and newly formed plant residues often result in relatively 13 C-depleted signals (Gregorich et al. 1995). ...
... SOC decomposition represented by CO 2 respiration rate was significantly affected by litter addition, while the SOC respiration rate was influenced by understory removal. An increase in CO 2 respiration following litter addition has been frequently reported (Fan et al. 2015;Fang et al. 2015;Leff et al. 2012), while the flux did not differ when expressed per unit SOC in our research. This suggests that the decomposability of the SOC did not significantly change and that the increase in flux was proportional to the increase in SOC. ...
AimsAboveground litter inputs have been modified by global changes in plantation forests, where understory management is also prevalent, which may alter soil fertility and stand productivity. This study aimed to quantify the specific roles of litter and understory in affecting soil carbon (C) and nitrogen (N) dynamics.MethodsA field experiment was established with four treatments, namely, litter addition (LA), understory removal (UR), litter addition and understory removal (LA + UR), and a control, in a subtropical Cunninghamia lanceolata plantation. Topsoil δ13C, organic C concentration, storage and decomposition, mineral N, N mineralization, and C and N hydrolase activities were analyzed.ResultsLitter addition significantly increased soil organic C, macro-particulate organic C (macro-POC) and mineral N at a 0–5 cm depth, but decreased δ13Cmacro-POC at 0–5 cm and 5–10 cm depths. Understory removal significantly increased soil NH4+-N, the rates of nitrification and net N mineralization as well as the soil organic C respiration rate at the two depths, while it decreased the C storage in bulk soil, especially in mineral protected pools. The activities of β-glucosidase and β-N-acetylglucosaminidase increased with litter addition and understory removal, respectively.Conclusions
Litter addition tends to improve soil C quantity and quality due to fresh organic C inputs, while understory removal helps increase the N supply via the acceleration of N mineralization and the absence of understory plant uptake.
... Farming practices influence soil respiration by altering both autotrophic and heterotrophic respiration. These changes may have positive or negative influence on soil C sequestration and climate change (Gomez-Casanovas et al. 2012;Fan et al. 2015). The influence of farming practices on soil respiration must be quantified in order to estimate soil C emission from farmland. ...
... Photosynthesis is an important component of the global C cycle. Photosynthesis is strongly influenced by both anthropogenic activities and climatic factors Fan et al. 2015). The fixation of atmospheric CO 2 by plants sequesters organic C in above and below ground biomass. ...
... Therefore, manure application to farmland not only makes use of an important agricultural resource but also promotes integration between the crop and livestock industry. Although many researchers have studied the effect of farming practices on C cycling in farmland (Ding et al. 2007;Fan et al. 2015), information is still limited on the systematic study of the C cycle under long-term current farming practices, particularly in grey desert soil in arid regions of Northwest China. The goal of this field experiment was to assess the C cycle in a cotton field in arid Northwest China after six years of different residue management and fertilization practices. ...
Understanding the influence of farming practices on carbon (C) cycling is important for maintaining soil quality and mitigating climate change, especially in arid regions where soil infertility, water deficiency, and climate change had significantly influenced on agroecosystem. A field experiment was set up in 2009 to examine the influence of residue management and fertilizer application on the C cycle in a cotton field in the Xinjiang Uygur Autonomous Region of Northwest China. The study included two residue management practices (residue incorporation (S) and residue removal (NS)) and four fertilizer treatments (no fertilizer (CK), organic manure (OM), chemical fertilizer (NPK), chemical fertilizer plus organic manure (NPK+OM)). Soil organic carbon (SOC) and some of its labile fractions, soil CO 2 flux, and canopy apparent photosynthesis were measured during the cotton growing seasons in 2015 and 2016. The results showed that SOC, labile SOC fractions, canopy apparent photosynthesis, and soil CO 2 emission were significantly greater in S+NPK+OM (residue incorporation+chemical fertilizer) than in the other treatments. Analysis of all data showed that canopy apparent photosynthesis and soil CO 2 emission increased as SOC increased. The S+OM (residue incorporation+organic manure) and S+NPK+OM treatments were greater for soil C sequestration, whereas the other treatments resulted in soil C loss. The S+NPK treatment is currently the standard management practice in Xinjiang. The results of this study indicate that S+NPK cannot offset soil C losses due to organic matter decomposition and autotrophic respiration. Residue return combined with NPK fertilizer and organic manure application is the preferred strategy in arid regions for increasing soil C sequestration.
... However, there is no consistent conclusion on contributions of them to soil CO 2 efflux. For example, Rey et al. (2002) reported that root respiration (belowground autotrophic respiration, R BA ) contributed to 55% of R Soil in a coppiced oak forest, but this contribution was only 17.6% in a Pinus tabulaeformis plantation (Fan et al. 2015), and some studies found that the contributions of aboveground leaf litter decomposition (R AL ) and R BA to R Soil were similar in a subtropical coniferous forest (Wang et al. 2013). This inconsistency may stem from considerable differences in quantity of leaf litter and roots under various forest types (Allison and Vitousek 2004;Li et al. 2004;Wang et al. 2007). ...
Aims
Changing quantity and quality of plant C input to soils under global change influences soil C cycling in terrestrial ecosystems. However, how soil CO2 emission responds to changes in C input remains poorly understood.
Methods
A detritus input and removal experiment was conducted in a subtropical forest (Cunninghamia lanceolata) to investigate how aboveground and belowground litters affect soil respiration (RSoil). In this experiment, four treatments with three replicates were included, as follows: control (CK), litter removal (NL), root trenching (NR), and no C-input (i.e. litter removal combined with root trenching, NI). RSoil was measured for 4 years from 2011 to 2014.
Results
The mean annual CO2 effluxes in the NL, NR, and NI plots were lower (23.4%, 24.9%, and 38.8%, respectively) than those in the CK plots, suggesting that decreasing C input significantly decreased RSoil. Soil heterotrophic respiration (soil organic matter decomposed by microorganisms) accounted for 52.1% of RSoil, and aboveground recent litter decomposition and belowground autotrophic respiration (live roots and associated microorganism) contributed to 23.7% and 24.2% of RSoil, respectively. RSoil was significantly and positively correlated with soil temperature, but negatively correlated with volumetric soil moisture. The variation in RSoil was more explained by soil temperature than soil moisture, and the responses of RSoil to soil temperature and moisture were altered by C input manipulation. Annual RSoil rate was strongly and negatively related to the Gram-positive bacteria concentration and the ratio of Gram-positive to -negative bacteria.
Conclusion
This study highlighted that aboveground recent leaf litter and belowground live roots and associated microbes had similar contributions to RSoil, and soil temperature and Gram-positive bacteria were the dominant factors controlling RSoil in a subtropical forest.
