Reclamation enhances the ratio of soil to ecosystem respiration under warming in an alpine meadow
Zheng LiLiang YanYong ZhangGuozheng HuShicheng HeJun YanYouxia WangWendong XieHasbagan GanjurjavQingzhu Gao
0
Citation
46
Reference
10
Related Paper
Abstract:
The construction of cultivated grasslands can increase grass production but also pose a threat to soil carbon storage, and it still remains unclear how construction of cultivated grasslands affects the components of ecosystem respiration (ER) toward a warming climate. Therefore, we conducted a 5-year (2012 to 2016) manipulative warming experiment in an alpine meadow and a cultivated grassland on the Qinghai–Xizang Plateau to explore the separate and interactive effects of warming and reclamation on soil respiration (SR), crop respiration (CR), ER, and the ratio of SR to ER (SR/ER). The plant height, coverage, aboveground production, SR, ER, CR, and SR/ER were measured. We found that warming increased the 5-year mean SR by 61.1% and 63.4% in the alpine meadow and the cultivated grassland, respectively. The 5-year mean SR/ER was increased by warming for the alpine meadow (38.7%) and the cultivated grassland (38.0%). Under warming, reclamation increased the 5-year mean SR/ER by 15.0%. Reclamation increased the sensitivity of SR and CR to warming, resulting in the increase in SR/ER under warming in the cultivated grassland. Overall, our results indicated that reclamation can increase the contribution of SR to the ecosystem carbon emission under warming and is detrimental to the storage of soil carbon in the alpine meadow especially toward a warming climate. Therefore, despite the increase in production by the construction of cultivated grasslands, the increase in carbon emission under warming by reclamation should attract attention.Keywords:
Ecosystem respiration
Soil respiration
The understanding on the contribution of root respiration to total soil respiration is still very limited, especially for sugarcane. In this study, trenching experiments in sugarcane plantations were conducted to separate and investigate soil respiration for this crop. The measurements were performed for the whole growing period of 344 days to quantify root respiration. The obtained monitoring data showed that the respiration rate is increasing with the age of the plant, accounting for up to 29% of the total soil respiration before harvesting. The root to soil respiration ratio increased rapidly during the young seedling stage, i.e. first five months, then declined and finally got stabilized during yield formation and ripening respectively. In addition, the results from the measurements confirmed that soil respiration was positively correl moisture content. Keywords—Soil respiration, root respiration, experiment, sugarcane.
Soil respiration
Respiration rate
Cite
Citations (1)
Soil respiration includes root respiration and microbial respiration. Effects of nitrogen addition on root respiration and microbial respiration may be quite different. We examined the effects of N-addition on the releasing of soil CO2 and the responses of root respiration and microbial respiration in a Keerqin sandy grassland, Northeast China. Results showed that both soil respiration and microbial respiration firstly rose then declined during the growing season (May to October). Microbial respiration was the main contributor of soil respiration, accounting for 82.6%. Contribution rate of root respiration altered with months, peaking in May (49.4%) and August (41.9%), with an average contribution rate of 17.4% during the growing season. Root respiration (with a decrease of 17.7%) was more sensitive to N-addition compared with microbial respiration (with a decrease of 3.9%) at 10 ℃. N-addition increased Q10 values of soil respiration and microbial respiration, and enhanced their sensitivity to soil water content variation.土壤呼吸可以细化为根系呼吸和微生物呼吸,二者对氮添加的响应有所不同.本文以科尔沁沙质草地为研究对象,探讨氮添加对土壤CO2排放的影响,并细化为微生物呼吸和根系呼吸的响应特征.结果表明: 在观测期(5—10月),土壤呼吸、微生物呼吸月动态均呈先升高后降低的趋势;微生物呼吸是土壤呼吸的主要贡献者,占82.6%;观测期内根系呼吸贡献率随月份而变化,根系呼吸贡献率两个峰值分别出现在5月(占49.4%)和8月(占41.9%),6个月的平均贡献率为17.4%;在10 ℃条件下,根系呼吸较微生物呼吸对氮添加的响应更为敏感,微生物呼吸速率在氮添加后降低了3.9%,而根系呼吸降低了17.7%;氮添加提高了土壤呼吸、微生物呼吸温度敏感性Q10值,也提高了二者对土壤水分变化的敏感程度.
Q10
Soil respiration
Respiration rate
Growing season
Cite
Citations (4)
Field experiment was carried out in the spring of 2008 in order to investigate the effects of increased UV-B radiation on the temperature sensitivity of wheat plant respiration and soil respiration from elongation to flowering periods. Static chamber-gas chromatography method was used to measure ecosystem respiration and soil respiration under 20% UV-B radiation increase and control. Environmental factors such as temperature and moisture were also measured. Results indicated that supplemental UV-B radiation inhibited the ecosystem respiration and soil respiration from wheat elongation to flowering periods, and the inhibition effect was more obvious for soil respiration than for ecosystem respiration. Ecosystem respiration rates, on daily average, were 9%, 9%, 3%, 16% and 30% higher for control than for UV-B treatment forthe five measurement days, while soil respiration rates were 99%, 93%, 106%, 38% and 10% higher for control than for UV-B treatment. The Q10s (temperature sensitivity coefficients) for plant respiration under control and UV-B treatments were 1.79 and 1.59, respectively, while the Q10s for soil respiration were 1.38 and 1.76, respectively. The Q10s for ecosystem respiration were 1.65 and 1.63 under CK and UV-B treatments, respectively. Supplemental UV-B radiation caused a lower Q10 for plant respiration and a higher Q10 for soil respiration, although no significant effect of supplemental UV-B radiation on the Q10 for ecosystem respiration was found.
Q10
Soil respiration
Respiration rate
UV-B Radiation
Climate Change
Cite
Citations (0)
We measured ecosystem CO2 fluxes for an alpine shrubland on the north-eastern Tibetan Plateau, Qinghai, China. The study is to understand (1) the seasonal variation of CO2 flux and (2) how environmental factors affect the seasonality of CO2 exchange in the alpine ecosystem. Daytime ecosystem respiration was extrapolated from the relationship between temperature and nighttime CO2 fluxes under high turbulent conditions.Seasonal patterns of gross ecosystem production, ecosystem respiration and net ecosystem CO2 exchange followed highly the seasonal change of aboveground biomass in the alpine shrubland. The net ecosystem CO2 exchange was mainly controlled by the variation of photosynthetic photon flux density, while the ecosystem respiration was closely correlated to the soil temperature at 5-cm depth. Integrated values of gross ecosystem production, ecosystem respiration and net ecosystem CO2 exchange for the period from November 1, 2002 to October 31 2003 were estimated to be 1418, 1155 and 222 g CO2 m(-2) yr(-1), respectively.
Shrubland
Ecosystem respiration
Seasonality
Cite
Citations (0)
Soil respiration includes three biological processes: soil microbes respiration,roots respiration and soil fauna respiration.Different process have different C source,thus the three biological processes have different contribution to the total soil respiration.Separating these three biological processes is difficult and important for soil research,only understanding the proportion of every process in total soil respiration,can master the essence of soil respiration,the distribution and the efflux of C.Through the survey of the publications over the worlds,the theory,the effect mechanism and the advances of three biological processes of soil respiration were compared and reviewed,then bring forward the approaches that separate the three biological processes.For the measurement of soil fauna respiration,this paper lists the relevant research specially.
Soil respiration
Cite
Citations (1)
Plant root activities and measuring methods play a key role in the study of soil respiration in the terrestrial ecosystem carbon cycle. This study was used to study the effect of plant roots and measuring methods on soil respiration rate, determined by both dynamic chamber-IRGA and static chamber-GC methods, in the wheat field. At the same time, the difference of two methods for measuring soil respiration was compared, too. The results showed that, soil respiration rates were significantly higher in the treatment with roots than root-free treatment. Under the treatment influenced by roots, soil respiration rate measured by static chamber–GC method was higher than by dynamic chamber-IRGA method. However, that determined by dynamic chamber-IRGA method was higher than by static chamber–GC method under the root-free treatment. While there was the significant difference between soil respiration rates determined by two methods, the significant liner relative was found between methods, through which the soil respiration rates measured by two methods could be converted each other.
Soil respiration
Respiration rate
Cite
Citations (1)
Ecosystem respiration
Terrestrial ecosystem
Cite
Citations (37)
Soil respiration in a typical wheat cropland was measured from April to June,2011 to understand the diel variations of the total soil respiration, heterotrophic respiration, autotrophic respiration,and their corresponding controlling factors in wheat croplands in the North China Plain.The root exclusion method was used to measure total soil respiration,heterotrophic respiration and autotrophic respiration.The results showed that the total soil respiration and the heterotrophic respiration both had single peaks at around 14:00, while the autotrophic respiration did not have apparent diel characteristics.The ratio of autotrophic respiration to the total soil respiration varied little throughout the day but varied some during different growth stages.The heterotrophic respiration was more closely related to the air temperature than to the soil temperature. In addition, the heterotrophic respiration was negatively correlated to the relative humidity. The autotrophic respiration was dependent on the gross primary production with a time lag.In summary,the diel variations of soil respiration in a field were mainly dependent on the air temperature,relative humidity and photosynthesis rate.
Diel vertical migration
Soil respiration
Autotroph
Cite
Citations (0)
The alpine meadow ecosystem on the Qinghai-Tibetan Plateau is characterized by low temperatures because of its high elevation. The low-temperature environment may limit both ecosystem photosynthetic CO2 uptake and ecosystem respiration, and thus affect the net ecosystem CO2 exchange (NEE). We clarified the low-temperature constraint on photosynthesis and respiration in an alpine meadow ecosystem on the northern edge of the plateau using flux measurements obtained by the eddy covariance technique in two growing seasons. When we compared NEE during the two periods, during which the leaf area index and other environmental parameters were similar but the mean temperature differed, we found that NEE from 9 August to 10 September 2001, when the average temperature was low, was greater than that during the same period in 2002, when the average temperature was high, but the ecosystem gross primary production was similar during the two periods. Further analysis showed that ecosystem respiration was significantly higher in 2002 than in 2001 during the study period, as estimated from the relationship between temperature and nighttime ecosystem respiration. The results suggest that low temperature controlled the NEE mainly through its influence on ecosystem respiration. The annual NEE, estimated from 15 January 2002 to 14 January 2003, was about 290 g CO2 m(-2) year(-1). The optimum temperature for ecosystem NEE under light-saturated conditions was estimated to be around 15 degrees C.
Ecosystem respiration
Growing season
Cite
Citations (4)
Terrestrial ecosystems have strong feedback to atmospheric CO2 concentration and climate change. However, the long-term whole life cycle dynamics of ecosystem carbon (C) fluxes and overall balance in some ecosystem types, such as heathland ecosystems, have not been thoroughly explored. We studied the changes in ecosystem CO2 flux components and overall C balance over a full ecosystem lifecycle in stands of Calluna vulgaris (L.) Hull by using a chronosequence of 0, 12, 19 and 28 years after vegetation cutting. Overall, the ecosystem C balance was highly nonlinear over time and exhibited a sinusoidal-like curvature of C sink/source change over the three-decade timescale. After cutting, plant-related C flux components of gross photosynthesis (PG), aboveground autotrophic respiration (Raa) and belowground autotrophic respiration (Rba) were higher at the young age (12 years) than at middle (19 years) and old (28 years) ages. The young ecosystem was a C sink (12 years: -0.374 kg C m-2 year-1) while it became a C source with aging (19 years: 0.218 kg C m-2 year-1) and when dying (28 years: 0.089 kg C m-2 year-1). The post-cutting C compensation point was observed after four years, while the cumulative C loss in the period after cutting had been compensated by an equal amount of C uptake after seven years. Annual ecosystem C payback from the ecosystem to the atmosphere started after 16 years. This information may be used directly for optimizing vegetation management practices for maximal ecosystem C uptake capacity. Our study highlights that whole life cycle observational data of changes in C fluxes and balance in ecosystems are important and the ecosystem model needs to take the successional stage and vegetation age into account when projecting component C fluxes, ecosystem C balance, and overall feedback to climate change.
Ecosystem respiration
Chronosequence
Terrestrial ecosystem
Carbon sink
Calluna
Cite
Citations (2)