Land use conversion influences soil respiration across a desert-oasis ecoregion in Northwest China, with consideration of cold season CO2 efflux and its significance

Abstract. The current understanding of the responses of soil respiration (Rs) to soil temperature (Ts) and soil moisture is limited for desert ecosystems. Soil CO2 efflux from a desert shrub ecosystem was measured continuously with automated chambers in Ningxia, northwest China, from June to October 2012. The diurnal responses of Rs to Ts were affected by soil moisture. The diel variation in Rs was strongly related to Ts at 10 cm depth under moderate and high volumetric soil water content (VWC), unlike under low VWC. Ts typically lagged Rs by 3–4 h. However, the lag time varied in relation to VWC, showing increased lag times under low VWC. Over the seasonal cycle, daily mean Rs was correlated positively with Ts, if VWC was higher than 0.08 m3 m−3. Under lower VWC, it became decoupled from Ts. The annual temperature sensitivity of Rs (Q10) was 1.5. The short-term sensitivity of Rs to Ts varied significantly over the seasonal cycle, and correlated negatively with Ts and positively with VWC. Our results highlight the biological causes of diel hysteresis between Rs and Ts, and that the response of Rs to soil moisture may result in negative feedback to climate warming in desert ecosystems. Thus, global carbon cycle models should account the interactive effects of Ts and VWC on Rs in desert ecosystems.

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Seasonal variations in soil respiration and temperature sensitivity under three land-use types in hilly areas of the Sichuan Basin

Soil Research ◽

10.1071/sr07223 ◽

2008 ◽

Vol 46 (8) ◽

pp. 727 ◽

Cited By ~ 20

Author(s):

XiaoGuo Wang ◽

Bo Zhu ◽

MeiRong Gao ◽

YanQiang Wang ◽

XunHua Zheng

Keyword(s):

Land Use ◽

Soil Moisture ◽

Soil Respiration ◽

Soil Temperature ◽

Co2 Efflux ◽

Forest Plantation ◽

Soil Co2 ◽

Q10 Value ◽

Land Use Types ◽

The Relationship

CO2 emissions from soils were measured under 3 land-use types at the adjacent plots of forest plantation, grassland, and cropland from January 2005 to December 2006. Mean soil CO2 efflux rates measured during the 2-year study varied from 59 to 527 mg CO2/m2.h in forest plantation, 37 to 498 mg CO2/m2.h in grassland, and 32 to 397 mg CO2/m2.h in cropland. Soil respiration in the 3 types of land-use showed a similar seasonal pattern in variation during both years, in which the single-peaked curve occurred in early summer and the minimum in winter. In particular, the date of maximum soil CO2 efflux rate in cropland occurred about 30 days earlier than in forest and grassland in both 2005 and 2006. The relationship of soil respiration rate (R) with soil temperature (T ) and soil moisture (W ) fitted well to the equation R = β0eβ1TW β2 (a, b, c were constants) than other univariate models which consider soil water content or soil temperature alone. Soil temperature and soil moisture together explained 69–92% of the temporal variation in soil respiration in the 3 land-use types. Temperature sensitivity of soil respiration (Q10) was affected positively by soil moisture of top 0.1 m layer and negatively by soil temperature at 0.05 m depth. The relationship between Q10 values and soil temperature (T ) or soil moisture (W ) indicated that a 1°C increase in soil temperature at 0.05 m depth will reduce the Q10 value by 0.07, 0.05, and 0.06 in forest, grassland, and cropland, respectively. Similarly, a 1% decrease in soil moisture of the top 0.1 m layer will reduce the Q10 value by 0.10, 0.09, and 0.11 in forest, grassland, and cropland.

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Interdependencies between temperature and moisture sensitivities of CO<sub>2</sub> emissions in European land ecosystems

Biogeosciences ◽

10.5194/bg-12-5981-2015 ◽

2015 ◽

Vol 12 (20) ◽

pp. 5981-5993 ◽

Cited By ~ 13

Author(s):

C. Gritsch ◽

M. Zimmermann ◽

S. Zechmeister-Boltenstern

Keyword(s):

Carbon Dioxide ◽

Land Use ◽

Soil Respiration ◽

Co2 Emissions ◽

Temperature Sensitivity ◽

Positive Relationship ◽

Co2 Efflux ◽

Moisture Contents ◽

Laboratory Incubation ◽

Land Use Types

Abstract. Soil respiration is one of the largest terrestrial fluxes of carbon dioxide (CO2) to the atmosphere. Hence, small changes in soil respiration rates could have large effects on atmospheric CO2. In order to assess CO2 emissions from diverse European soils with different land-use types and climate (soil moisture and temperature), we conducted a laboratory incubation experiment. Emission measurements of CO2 under controlled conditions were conducted using soil monoliths of nine sites from a European flux network (ÉCLAIRE). The sites are located all over Europe – from the United Kingdom in the west to Ukraine in the east, and from Italy in the south to Finland in the north – and can be separated according to four land-use types (forests, grasslands, arable lands and one peatland). Intact soil cores were incubated in the laboratory in a two-way factorial design, with temperature (5, 10, 15, 20 and 25 °C) and water-filled pore space (WFPS; 5, 20, 40, 60 and 80 %) as the independent variables, while CO2 flux was the response variable. The latter was measured with an automated laboratory incubation measurement system. Land use generally had a substantial influence on carbon dioxide fluxes, with the order of CO2 emission rates of the different land-use types being grassland > peatland > forest/arable land (P < 0.001). CO2 efflux responded strongly to varying temperature and moisture content with optimum moisture contents for CO2 emissions between 40 and 70 % WFPS and a positive relationship between CO2 emissions and temperature. The relationship between temperature and CO2 emissions could be well described by a Gaussian model. Q10 values ranged between 0.86 and 10.85 and were negatively related to temperature for most of the moisture contents and sites investigated. At higher temperatures the effect of water and temperature on Q10 was very low. In addition, under cold temperatures Q10 varied with moisture contents, indicating a stronger prospective effect of rain events in cold areas on temperature sensitivity. At both coniferous forest sites we found a strong increase in the temperature sensitivity at a moisture range between 20 and 40 % WFPS. We developed a new approach to calculate moisture sensitivity (MS) of CO2 efflux. MS was calculated as the slope of a polynomial function of second degree. Moisture sensitivities were highest under dry and wet conditions. In addition we found a positive relationship between MS of CO2 efflux and temperature for both arable lands.

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Soil respiration and carbon loss relationship with temperature and land use conversion in freeze–thaw agricultural area

The Science of The Total Environment ◽

10.1016/j.scitotenv.2015.06.109 ◽

2015 ◽

Vol 533 ◽

pp. 215-222 ◽

Cited By ~ 12

Author(s):

Wei Ouyang ◽

Xuehui Lai ◽

Xia Li ◽

Heying Liu ◽

Chunye Lin ◽

...

Keyword(s):

Land Use ◽

Soil Respiration ◽

Agricultural Area ◽

Carbon Loss ◽

Land Use Conversion ◽

Freeze Thaw

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Effects of land use on soil C02 flux in the Paramo de Guerrero, Colombia

Agronomía Colombiana ◽

10.15446/agron.colomb.v34n3.58791 ◽

2016 ◽

Vol 34 (3) ◽

pp. 364-373 ◽

Cited By ~ 3

Author(s):

Diego Peña-Quemba ◽

Yolanda Rubiano-Sanabria ◽

Diego Riveros-Iregui

Keyword(s):

Land Use ◽

Soil Respiration ◽

Molecular Diffusion ◽

Carbon Sink ◽

Potato Crop ◽

Co2 Flux ◽

Co2 Efflux ◽

Tillage Practices ◽

Atmo Sphere ◽

Effects Of Land Use

The Andean paramo is an important global carbon sink and has a fundamental ecological function of capture, regulation and supply of water resources. The soil CO2 efflux is a natural process through which the carbon is released into the atmo sphere by molecular diffusion. The aim of this study was to establish the effect of different land use and soil managements practices over CO2 efflux in the Paramo de Guerrero, using the soil respiration chamber technique. We evaluated five differ ent land covers present in the Paramo de Guerrero (paramo vegetation, pasture, two tillage cover and potato crop). Our results show that soil respiration was lower in the paramo (0.42 g CO2 m-2 h-1) than in the others land uses, probably due to the higher moisture content (57.1% on average). The tillage practices showed a primary physical effect, continued by the increase of the velocity of biological and chemical processes drived by soil microorganisms, such as microbial respiration and organic matter mineralization. This study demostrates that moisture and soil temperature were not the main drivers of CO2 flux in the conditions of the Paramo de Guerrero, but the agricultural management and the land use affect differentially the accumulation and release dynamics of soil organic carbon to the atmosphere.

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Interdependencies between temperature and moisture sensitivities of CO<sub>2</sub> emissions in European land ecosystems

Biogeosciences Discussions ◽

10.5194/bgd-12-4433-2015 ◽

2015 ◽

Vol 12 (6) ◽

pp. 4433-4464 ◽

Cited By ~ 1

Author(s):

C. Gritsch ◽

M. Zimmermann ◽

S. Zechmeister-Boltenstern

Keyword(s):

Carbon Dioxide ◽

Land Use ◽

Soil Moisture ◽

Soil Respiration ◽

Co2 Emissions ◽

Temperature Sensitivity ◽

Positive Relationship ◽

Co2 Efflux ◽

Land Uses ◽

Moisture Contents

Abstract. Soil respiration is one of the largest terrestrial fluxes of carbon dioxide (CO2) to the atmosphere. Hence, small changes in soil respiration rates could have large effects on atmospheric CO2. In order to assess CO2 emissions from diverse European soils under different land-use and climate (soil moisture and temperature) we conducted a laboratory incubation experiment. Emission measurements of carbon dioxide under controlled conditions were conducted using soil monoliths of nine sites from the ÉCLAIRE flux network. Sites are located all over Europe; from the UK in the west to the Ukraine in the east; Italy in the south to Finland in the north and can be separated according to four land-uses (forests, grasslands, arable lands and one peatland). Intact soil cores were incubated in the laboratory at the temperatures 5, 10, 15, 20, and 25 °C in a two factorial design of five soil moisture levels (5, 20, 40, 60, 80 (100)% water filled pore space, WFPS), before analysed for CO2 fluxes with an automated laboratory incubation measurement system. Land-use generally had a substantial influence on carbon dioxide fluxes, with the order of CO2 emission rates of the different land-uses being grassland > peatland > forest/arable land (P < 0.001). CO2 efflux responded strongly to varying temperature and moisture content with optimum moisture contents for CO2 emissions between 40–70% WFPS and a positive relationship between CO2 emissions and temperature. The relationship between temperature and CO2 emissions could be well described by a Gaussian model. Q10 values ranged between 0.86–10.85 and were negatively related to temperature for most of the moisture contents and sites investigated. At higher temperatures the effect of water and temperature on Q10 was very low. In addition under cold temperatures Q10 varied with moisture contents indicating a stronger prospective effect of rain events in cold areas on temperature sensitivity. We found at both coniferous forest sites a strong increase of the temperature sensitivity at a moisture range between 20–40% WFPS. In our study moisture sensitivity (MS) of CO2 efflux was calculated as the slope of a polynomial function of second degree. Moisture sensitivities were highest under dry and wet conditions. In addition we found a positive relationship between MS of CO2 efflux and temperature for both arable lands.

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Historic and Simulated Desert-Oasis Ecotone Changes in the Arid Tarim River Basin, China

Remote Sensing ◽

10.3390/rs13040647 ◽

2021 ◽

Vol 13 (4) ◽

pp. 647

Author(s):

Fan Sun ◽

Yi Wang ◽

Yaning Chen ◽

Yupeng Li ◽

Qifei Zhang ◽

...

Keyword(s):

Land Use ◽

Land Use Change ◽

Markov Model ◽

River Basin ◽

Arable Land ◽

Current Trend ◽

Ecological Crisis ◽

Tarim River ◽

Tarim River Basin ◽

Desert Oasis

The desert-oasis ecotone, as a crucial natural barrier, maintains the stability of oasis agricultural production and protects oasis habitat security. This paper investigates the dynamic evolution of the desert-oasis ecotone in the Tarim River Basin and predicts the near-future land-use change in the desert-oasis ecotone using the cellular automata–Markov (CA-Markov) model. Results indicate that the overall area of the desert-oasis ecotone shows a shrinking trend (from 67,642 km2 in 1990 to 46,613 km2 in 2015) and the land-use change within the desert-oasis ecotone is mainly manifested by the conversion of a large amount of forest and grass area into arable land. The increasing demand for arable land for groundwater has led to a decline in the groundwater level, which is an important reason for the habitat deterioration in the desert-oasis ecotone. The rising temperature and drought have further exacerbated this trend. Assuming the current trend in development without intervention, the CA-Markov model predicts that by 2030, there will be an additional 1566 km2 of arable land and a reduction of 1151 km2 in forested area and grassland within the desert-oasis ecotone, which will inevitably further weaken the ecological barrier role of the desert-oasis ecotone and trigger a growing ecological crisis.

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