Rainfall pulse primarily drives litterfall respiration and its contribution to soil respiration in a young exotic pine plantation in subtropical China

Although litterfall respiration (RL) is a key process of soil carbon dynamics in forests, factors that drive RL and its contribution to soil respiration (RS) have not been sufficiently studied. Using a litter removal method, we researched RL and the ratio of RL:RS in a 20-year-old exotic slash pine ( Pinus elliottii Englem.) plantation in subtropical China. Soil temperature explained 67%, 78%, and 25% of variation in RS, mineral soil respiration (RS-L), and RL, respectively, but had little impact on RL:RS. To study influences besides temperature, measured RS and RS-L were normalized using the Arrhenius equation. Even though this subtropical plantation was characterized by a humid climate with abundant precipitation, a rainfall pulse induced increase in soil moisture primarily drove RL and its contribution to RS but depressed RS-L. The response of RL to rainfall and soil moisture was significantly more sensitive than that of RS-L. Furthermore, the effects of rainfall and soil moisture on RS, RL, and RL:RS were higher during the dry season (July–December) than during the wet season (January–June). In the context of climate change, RL and its contribution to RS are expected to decrease because of the predicted decrease in rainfall amount and frequency in subtropical regions.

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Precipitation frequency controls interannual variation of soil respiration by affecting soil moisture in a subtropical forest plantation

Canadian Journal of Forest Research ◽

10.1139/x11-105 ◽

2011 ◽

Vol 41 (9) ◽

pp. 1897-1906 ◽

Cited By ~ 36

Author(s):

Yidong Wang ◽

Qingkang Li ◽

Huimin Wang ◽

Xuefa Wen ◽

Fengting Yang ◽

...

Keyword(s):

Soil Moisture ◽

Soil Respiration ◽

Interannual Variation ◽

Pinus Elliottii ◽

Subtropical Forest ◽

Annual Rainfall ◽

Precipitation Pattern ◽

Humid Climate ◽

Precipitation Frequency ◽

Data Set

Despite the significance of interannual variation of soil respiration (RS) for understanding long-term soil carbon dynamics, factors that control the interannual variation of RS have not been sufficiently investigated. Interannual variation of RS was studied using a 6-year data set collected in a subtropical plantation dominated by an exotic species, slash pine (Pinus elliottii Engelm.), in China. The results showed that seasonal variation of RS was significantly affected by soil temperature and soil water content (SWC). RS in the dry season (July–October) was constrained by seasonal drought. Mean annual RS was estimated to be 736 ± 30 g C·m–2·year–1, with a range of 706–790 g C·m–2·year–1. Although this forest was characterized by a humid climate with high precipitation (1469 mm·year–1), the interannual variation of RS was attributed to the changes of annual mean SWC (R2 = 0.66, P = 0.03), which was affected by annual rainfall frequency (R2 = 0.80, P < 0.01) and not rainfall amount (P = 0.84). Consequently, precipitation pattern indirectly controlled the interannual variation of RS by affecting soil moisture in this subtropical forest. In the context of climate change, interannual variation of RS in subtropical ecosystems is expected to increase because of the predicted changes of precipitation regime.

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Measurements of soil respiration and simple models dependent on moisture and temperature for an Amazonian southwest tropical forest

Biogeosciences Discussions ◽

10.5194/bgd-6-6147-2009 ◽

2009 ◽

Vol 6 (3) ◽

pp. 6147-6177 ◽

Cited By ~ 1

Author(s):

F. B. Zanchi ◽

H. R. da Rocha ◽

H. C. de Freitas ◽

B. Kruijt ◽

M. J. Waterloo ◽

...

Keyword(s):

Soil Moisture ◽

Soil Respiration ◽

Soil Temperature ◽

Field Measurements ◽

Dry Season ◽

Wet Season ◽

Hourly Data ◽

Fresh Litter ◽

Favorable Conditions

Abstract. Soil respiration plays a significant role in the carbon cycle of Amazonian tropical forests, although in situ measurements have only been poorly reported and the dependence of soil moisture and soil temperature also weakly understood. This work investigates the temporal variability of soil respiration using field measurements, which also included soil moisture, soil temperature and litterfall, from April 2003 to January 2004, in a southwest Brazilian tropical rainforest near Ji-Paraná, Rondônia. The experimental design deployed five automatic (static, semi-opened) soil chambers connected to an infra-red CO2 gas analyzer. The mean half-hourly soil respiration showed a large scattering from 0.6 to 18.9 μmol CO2 m−2 s−1 and the average was 8.0±3.4 μmol CO2 m−2 s−1. Soil respiration varied seasonally, being lower in the dry season and higher in the wet season, which generally responded positively to the variation of soil moisture and temperature year round. The peak was reached in the dry-to-wet season transition (September), this coincided with increasing sunlight, evapotranspiration and ecosystem productivity. Litterfall processes contributed to meet very favorable conditions for biomass decomposition in early wet season, especially the fresh litter on the forest floor accumulated during the dry season. We attempted to fit three models with the data: the exponential Q10 model, the Reichstein model, and the log-soil moisture model. The models do not contradict the scattering of observations, but poorly explain the variance of the half-hourly data, which is improved when the lag-time days averaging is longer. The observations suggested an optimum range of soil moisture, between 0.115

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Measurements of CO2 exchange over a woodland savanna (Cerrado Sensu stricto) in southeast Brasil

Biota Neotropica ◽

10.1590/s1676-06032002000100009 ◽

2002 ◽

Vol 2 (1) ◽

pp. 1-11 ◽

Cited By ~ 43

Author(s):

Humberto R. da Rocha ◽

Helber C. Freitas ◽

Rafael Rosolem ◽

Robinson I.N. Juárez ◽

Rafael N. Tannus ◽

...

Keyword(s):

Soil Moisture ◽

Soil Respiration ◽

Climatic Variability ◽

Co2 Flux ◽

Moisture Stress ◽

Sensu Stricto ◽

Dry Season ◽

Eddy Correlation ◽

Wet Season ◽

Data Set

The technique of eddy correlation was used to measure the net ecosystem exchange over a woodland savanna (Cerrado Sensu stricto) site (Gleba Pé de Gigante) in southeast Brazil. The data set included measurements of climatological variables and soil respiration using static soil chambers. Data were collected during the period from 10 October 2000 to 30 March 2002. Measured soil respiration showed average values of 4.8 molCO2 m-2s-1 year round. Its seasonal differences varied from 2 to 8 molCO2 m-2s-1 (Q10 = 4.9) during the dry (April to August) and wet season, respectively, and was concurrent with soil temperature and moisture variability. The net ecosystem CO2 flux (NEE) variability is controlled by solar radiation, temperature and air humidity on diel course. Seasonally, soil moisture plays a strong role by inducing litterfall, reducing canopy photosynthetic activity and soil respiration. The net sign of NEE is negative (sink) in the wet season and early dry season, with rates around -25 kgC ha-1day-1, and values as low as 40 kgC ha-1day-1. NEE was positive (source) during most of the dry season, and changed into negative at the onset of rainy season. At critical times of soil moisture stress during the late dry season, the ecosystem experienced photosynthesis during daytime, although the net sign is positive (emission). Concurrent with dry season, the values appeared progressively positive from 5 to as much as 50 kgC ha-1day-1. The annual NEE sum appeared to be nearly in balance, or more exactly a small sink, equal to 0.1 0.3 tC ha-1yr-1, which we regard possibly as a realistic one, giving the constraining conditions imposed to the turbulent flux calculation, and favourable hypothesis of succession stages, climatic variability and CO2 fertilization.

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Responses of Soil Respiration to Precipitation Changes in Mongolian Pine Plantation at Horqin Sandy Lands in Northeast China

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.518-523.4545 ◽

2012 ◽

Vol 518-523 ◽

pp. 4545-4551 ◽

Cited By ~ 1

Author(s):

Zhi Ping Fan ◽

Xue Kai Sun ◽

Fa Yun Li ◽

Qiong Wang

Keyword(s):

Soil Moisture ◽

Soil Respiration ◽

Soil Temperature ◽

Terrestrial Ecosystems ◽

Semiarid Region ◽

Precipitation Pattern ◽

Pine Plantation ◽

Water Addition ◽

Soil Temperatures ◽

Precipitation Changes

Soil respiration as a major flux in the global carbon cycle plays an important role in regulating soil carbon pools. Global climatic changes including warming and a changing precipitation pattern could have a profound impact on soil respiration of terrestrial ecosystems, especially in arid and semiarid region where water is limited. We conducted a field experiment to simulate precipitation changes in a Mongolian pine plantation at Horqin sandy lands. The results indicated that, soil respiration was significantly affected by reduced rainfall treatment and water addition treatment in 9 experiment plots. Soil respiration rates in the water addition treatment plots increased about 40.7% to 166.4% and decreased about 34.0% to 70.0% in the reduced rainfall treatment plots. A model of the relationships between soil respiration and moisture with temperature was obtained by an empirical equation. Through operating the model, it was indicated that the highest soil respiration rate occurred at high soil water contents and intermediate soil temperatures in 9 plots. In the combined responses of soil respiration to soil temperature and soil moisture, soil temperature as a single independent variable explained only 29.9% of variance in soil respiration, and soil moisture was 71.3% of variance in soil respiration. It was concluded from our results that precipitation compared with soil temperature dominated more significantly the variability of ecosystem soil respiration in semiarid sandy lands.

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Effects of precipitation on soil respiration and its temperature/moisture sensitivity in three subtropical forests in Southern China

Biogeosciences Discussions ◽

10.5194/bgd-9-15667-2012 ◽

2012 ◽

Vol 9 (11) ◽

pp. 15667-15698

Author(s):

H. Jiang ◽

Q. Deng ◽

G. Zhou ◽

D. Hui ◽

D. Zhang ◽

...

Keyword(s):

Soil Moisture ◽

Soil Respiration ◽

Temperature Sensitivity ◽

Southern China ◽

Dry Season ◽

Wet Season ◽

Moisture Sensitivity ◽

Masson Pine ◽

Subtropical Forests ◽

Extreme Flood

Abstract. Both long-term observation data and model simulations suggest an increasing chance of serious drought in the dry season and extreme flood in the wet season in Southern China, yet little is known about how changes in precipitation pattern will affect soil respiration in the region. We conducted a field experiment to study the responses of soil respiration to precipitation manipulations – precipitation exclusion to mimic drought, double precipitation to simulate flood, and ambient precipitation (Abbr. EP, DP and AP, respectively) – in three subtropical forests in Southern China. The three forests include Masson pine forest (PF), coniferous and broadleaved mixed forest (MF) and monsoon evergreen broadleaved forest (BF). Our observations showed that altered precipitation can strongly influence soil respiration, not only through the well-known direct effects of soil moisture, but also by modification on both moisture and temperature sensitivity of soil respiration. In the dry season, soil respiration and its temperature sensitivity in the three forests showed rising trends with precipitation increase, and its moisture sensitivity showed an opposite trend. In the wet season, the EP treatment also decreased soil respiration and its temperature sensitivity, and enhanced moisture sensitivity in all three forests. Soil respiration under the DP treatment increased significantly in the PF only, and no significant change was found for either moisture or temperature sensitivity. However, the DP treatment in the MF and BF reduced temperature sensitivity significantly. Our results indicated that soil respiration would decrease in the three subtropical forests if soil moisture continues to decrease in the future. More rainfall in the wet season could have limited effect on the response of soil respiration to the rising of temperature in the BF and MF.

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Responses of soil respiration and its temperature/moisture sensitivity to precipitation in three subtropical forests in southern China

Biogeosciences ◽

10.5194/bg-10-3963-2013 ◽

2013 ◽

Vol 10 (6) ◽

pp. 3963-3982 ◽

Cited By ~ 42

Author(s):

H. Jiang ◽

Q. Deng ◽

G. Zhou ◽

D. Hui ◽

D. Zhang ◽

...

Keyword(s):

Soil Moisture ◽

Soil Respiration ◽

Temperature Sensitivity ◽

Soil Microbial Biomass ◽

Fine Root ◽

Southern China ◽

Wet Season ◽

Moisture Sensitivity ◽

Soil Microbial ◽

Forest Sites

Abstract. Both long-term observation data and model simulations suggest an increasing chance of serious drought in the dry season and extreme flood in the wet season in southern China, yet little is known about how changes in precipitation pattern will affect soil respiration in the region. We conducted a field experiment to study the responses of soil respiration to precipitation manipulations – precipitation exclusion to mimic drought, double precipitation to simulate flood, and ambient precipitation as control (abbr. EP, DP and AP, respectively) – in three subtropical forests in southern China. The three forest sites include Masson pine forest (PF), coniferous and broad-leaved mixed forest (MF) and monsoon evergreen broad-leaved forest (BF). Our observations showed that altered precipitation strongly influenced soil respiration, not only through the well-known direct effects of soil moisture on plant and microbial activities, but also by modification of both moisture and temperature sensitivity of soil respiration. In the dry season, soil respiration and its temperature sensitivity, as well as fine root and soil microbial biomass, showed rising trends with precipitation increases in the three forest sites. Contrarily, the moisture sensitivity of soil respiration decreased with precipitation increases. In the wet season, different treatments showed different effects in three forest sites. The EP treatment decreased fine root biomass, soil microbial biomass, soil respiration and its temperature sensitivity, but enhanced soil moisture sensitivity in all three forest sites. The DP treatment significantly increased soil respiration, fine root and soil microbial biomass in the PF only, and no significant change was found for the soil temperature sensitivity. However, the DP treatment in the MF and BF reduced soil temperature sensitivity significantly in the wet season. Our results indicated that soil respiration would decrease in the three subtropical forests if soil moisture continues to decrease in the future. More rainfall in the wet season could have limited effect on the response of soil respiration to the rising of temperature in the BF and MF.

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Soil respiration in a tropical montane grassland ecosystem is largely heterotroph-driven and increases under simulated warming

10.1101/501155 ◽

2018 ◽

Author(s):

Yadugiri V Tiruvaimozhi ◽

Mahesh Sankaran

Keyword(s):

Soil Moisture ◽

Soil Respiration ◽

Arbuscular Mycorrhizal ◽

Grassland Ecosystem ◽

Ambient Conditions ◽

Wet Season ◽

Soil C ◽

High Soil Moisture ◽

Tightly Coupled ◽

Set Up

Soil respiration, a major source of atmospheric carbon (C), can feed into climate warming, which in turn can amplify soil CO2 efflux by affecting root, arbuscular mycorrhizal fungal (AMF) and other heterotrophic respiration. Although tropical ecosystems contribute >60% of the global soil CO2 efflux, there is currently a dearth of data on tropical soil respiration responses to temperature rise. We set up a simulated warming and soil respiration partitioning experiment in tropical montane grasslands in the Western Ghats in southern India, to (a) evaluate soil respiration responses to warming, (b) assess the relative contributions of autotrophic and heterotrophic components to soil respiration, and (c) assess the roles of soil temperature and soil moisture in influencing soil respiration in this system. Our results show that soil respiration was tightly coupled with soil moisture availability, with CO2 efflux levels peaking during the wet season. Soil warming by ~1.4 °C nearly doubled soil respiration from ~0.64 g CO2 m-2 hr-1 on average under ambient conditions to ~1.17 g CO2 m-2 hr-1 under warmed conditions. However, warming effects on soil CO2 efflux were contingent on water availability, with greater relative increases in soil respiration observed under conditions of low, compared to high, soil moisture. Hetrotrophs contributed to the majority of soil CO2 efflux, with respiration remaining unchanged when roots and/or AMF hyphae were excluded. Overall, our results indicate that future warming is likely to substantially increase the largely heterotroph-driven soil C fluxes in this tropical montane grassland ecosystem.

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Potential Soil Respiration in Forest Soil according to Soil Temperature and Soil Moisture Change

Korean Journal of Nature Conservation ◽

10.30960/kjnc.2009.7.4.191 ◽

2009 ◽

Vol 7 (4) ◽

pp. 191-201

Author(s):

Eunhye LEE ◽

Jaeseok LEE

Keyword(s):

Soil Moisture ◽

Soil Respiration ◽

Soil Temperature ◽

Forest Soil ◽

Moisture Change

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Silvicultural treatments, microclimatic conditions and seedling response in Southern Interior clearcuts

Canadian Journal of Soil Science ◽

10.4141/s97-042 ◽

1998 ◽

Vol 78 (1) ◽

pp. 115-126 ◽

Cited By ~ 39

Author(s):

R. L. Fleming ◽

T. A. Black ◽

R. S. Adams ◽

R. J. Stathers

Keyword(s):

Soil Moisture ◽

Seedling Establishment ◽

Initial Period ◽

Mineral Soil ◽

Soil Disturbance ◽

Near Surface ◽

Lower Elevation ◽

Organic Horizons ◽

Soil Temperatures ◽

Microclimatic Conditions

Post-harvest levels of soil disturbance and vegetation regrowth strongly influence microclimate conditions, and this has important implications for seedling establishment. We examined the effects of blading (scalping), soil loosening (ripping) and vegetation control (herbicide), as well as no soil disturbance, on growing season microclimates and 3-yr seedling response on two grass-dominated clearcuts at different elevations in the Southern Interior of British Columbia. Warmer soil temperatures were obtained by removing surface organic horizons. Ripping produced somewhat higher soil temperatures than scalping at the drier, lower-elevation site, but slightly reduced soil temperatures at the wetter, higher-elevation site. Near-surface air temperatures were more extreme (higher daily maximums and lower daily minimums) over the control than over exposed mineral soil. Root zone soil moisture deficits largely reflected transpiration by competing vegetation; vegetation removal was effective in improving soil moisture availability at the lower elevation site, but unnecessary from this perspective at the higher elevation site. The exposed mineral surfaces self-mulched and conserved soil moisture after an initial period of high evaporation. Ripping and scalping resulted in somewhat lower near-surface available soil water storage capacities. Seedling establishment on both clearcuts was better following treatments which removed vegetation and surface organic horizons and thus enhanced microclimatic conditions, despite reducing nutrient supply. Such treatments may, however, compromise subsequent stand development through negative impacts on site nutrition. Temporal changes in the relative importance of different physical (microclimate) and chemical (soil nutrition) properties to soil processes and plant growth need to be considered when evaluating site productivity. Key words: Microclimate, soil temperature, air temperature, soil moisture, clearcut, seedling establishment

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