scholarly journals Vegetation and elevation influence the timing and magnitude of soil CO<sub>2</sub> efflux in a humid, topographically complex watershed

2015 ◽  
Vol 12 (10) ◽  
pp. 2975-2994 ◽  
Author(s):  
J. W. Atkins ◽  
H. E. Epstein ◽  
D. L. Welsch
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Soil Water ◽  
Forest Canopy ◽  
Biogeochemical Cycles ◽  
Landscape Position ◽  
Temperature Threshold ◽  
Co2 Efflux ◽  
High Soil Moisture ◽  
Vegetation Heterogeneity

Abstract. In topographically complex watersheds, landscape position and vegetation heterogeneity can alter the soil water regime through both lateral and vertical redistribution, respectively. These alterations of soil moisture may have significant impacts on the spatial heterogeneity of biogeochemical cycles throughout the watershed. To evaluate how landscape position and vegetation heterogeneity affect soil CO2 efflux (FSOIL), we conducted observations across the Weimer Run watershed (373 ha), located near Davis, West Virginia, for three growing seasons with varying precipitation. An apparent soil temperature threshold of 11 °C for FSOIL at 12 cm depth was observed in our data, where FSOIL rates greatly increase in variance above this threshold. We therefore focus our analyses of FSOIL on instances in which soil temperature values were above this threshold. Vegetation had the greatest effect on FSOIL rates, with plots beneath shrubs at all elevations, for all years, showing the greatest mean rates of FSOIL (6.07 μmol CO2 m−2 s−1) compared to plots beneath closed-forest canopy (4.69 μmol CO2 m−2 s−1) and plots located in open, forest gap (4.09 μmol CO2 m−2 s−1) plots. During periods of high soil moisture, we find that CO2 efflux rates are constrained, and that maximum efflux rates occur during periods of average to below-average soil water availability. While vegetation was the variable most related to FSOIL, there is also strong interannual variability in fluxes determined by the interaction of annual precipitation and topography. These findings add to the current theoretical constructs related to the interactions of moisture and vegetation in biogeochemical cycles within topographically complex watersheds.

scholarly journals Vegetation heterogeneity and landscape position exert strong controls on soil CO<sub>2</sub> efflux in a moist, Appalachian watershed

2014 ◽  
Vol 11 (12) ◽  
pp. 17631-17673 ◽  
Author(s):  
J. W. Atkins ◽  
H. E. Epstein ◽  
D. L. Welsch
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Biogeochemical Cycles ◽  
Soil Co2 Efflux ◽  
Landscape Position ◽  
Temperature Threshold ◽  
Valuable Insight ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Vegetation Heterogeneity

Abstract. In topographically complex watersheds, landscape position and vegetation heterogeneity can alter the soil water regime through both lateral and vertical redistribution, respectively. These alterations of soil moisture may have significant impacts on the spatial heterogeneity of biogeochemical cycles throughout the watershed. To evaluate how landscape position and vegetation heterogeneity affect soil CO2 efflux (FSOIL) we conducted observations across the Weimer Run watershed (373 ha), located near Davis, West Virginia, for three growing seasons with varying precipitation (2010 – 1042 mm; 2011 – 1739 mm; 2012 – 1244 mm; precipitation data from BDKW2 station, MesoWest, University of Utah). An apparent soil temperature threshold of 11 °C at 12 cm depth on FSOIL was observed in our data – where FSOIL rates greatly increase in variance above this threshold. For analysis, FSOIL values above this threshold were isolated and examined. Differences in FSOIL among years were apparent by elevation (F4,633 = 3.17; p = 0.013) and by vegetation cover (F4, 633 = 2.96; p = 0.019). For the Weimer Run watershed, vegetation exerts the major control on soil CO2 efflux (FSOIL), with the plots beneath shrubs at all elevations for all years showing the greatest mean rates of FSOIL (6.07 μmol CO2 m-2 s-1) compared to plots beneath closed-forest canopy (4.69 μmol CO2 m-2 s-1) and plots located in open, forest gaps (4.09 μmol CO2 m-2 s-1) plots. During periods of high soil moisture, we find that CO2 efflux rates are constrained and that maximum efflux rates in this system occur during periods of average to below average soil water availability. These findings offer valuable insight into the processes occurring within these topographically complex, temperate and humid systems, and the interactions of abiotic and biotic factors mediating biogeochemical cycles. With possible changing rainfall patterns as predicted by climate models, it is important to understand the couplings between water and carbon cycling at the watershed and landscape scales, and their potential dynamics under global change scenarios.

scholarly journals Constraint of soil moisture on CO<sub>2</sub> efflux from tundra lichen, moss, and tussock in Council, Alaska, using a hierarchical Bayesian model

2014 ◽  
Vol 11 (19) ◽  
pp. 5567-5579 ◽  
Author(s):  
Y. Kim ◽  
K. Nishina ◽  
N. Chae ◽  
S. J. Park ◽  
Y. J. Yoon ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Environmental Factors ◽  
Soil Temperature ◽  
Co2 Emission ◽  
Emission Rate ◽  
Growing Season ◽  
The Arctic ◽  
Co2 Efflux ◽  
Growing Seasons ◽  
Tundra Ecosystem

Abstract. The tundra ecosystem is quite vulnerable to drastic climate change in the Arctic, and the quantification of carbon dynamics is of significant importance regarding thawing permafrost, changes to the snow-covered period and snow and shrub community extent, and the decline of sea ice in the Arctic. Here, CO2 efflux measurements using a manual chamber system within a 40 m × 40 m (5 m interval; 81 total points) plot were conducted within dominant tundra vegetation on the Seward Peninsula of Alaska, during the growing seasons of 2011 and 2012, for the assessment of driving parameters of CO2 efflux. We applied a hierarchical Bayesian (HB) model – a function of soil temperature, soil moisture, vegetation type, and thaw depth – to quantify the effects of environmental factors on CO2 efflux and to estimate growing season CO2 emissions. Our results showed that average CO2 efflux in 2011 was 1.4 times higher than in 2012, resulting from the distinct difference in soil moisture between the 2 years. Tussock-dominated CO2 efflux is 1.4 to 2.3 times higher than those measured in lichen and moss communities, revealing tussock as a significant CO2 source in the Arctic, with a wide area distribution on the circumpolar scale. CO2 efflux followed soil temperature nearly exponentially from both the observed data and the posterior medians of the HB model. This reveals that soil temperature regulates the seasonal variation of CO2 efflux and that soil moisture contributes to the interannual variation of CO2 efflux for the two growing seasons in question. Obvious changes in soil moisture during the growing seasons of 2011 and 2012 resulted in an explicit difference between CO2 effluxes – 742 and 539 g CO2 m−2 period−1 for 2011 and 2012, respectively, suggesting the 2012 CO2 emission rate was reduced to 27% (95% credible interval: 17–36%) of the 2011 emission, due to higher soil moisture from severe rain. The estimated growing season CO2 emission rate ranged from 0.86 Mg CO2 in 2012 to 1.20 Mg CO2 in 2011 within a 40 m × 40 m plot, corresponding to 86 and 80% of annual CO2 emission rates within the western Alaska tundra ecosystem, estimated from the temperature dependence of CO2 efflux. Therefore, this HB model can be readily applied to observed CO2 efflux, as it demands only four environmental factors and can also be effective for quantitatively assessing the driving parameters of CO2 efflux.

scholarly journals Significance of soil respiration from biological activity in the degradation processes of different types of organic matter

2020 ◽  
Vol 1 (2) ◽  
pp. 171-179
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Temperature Sensitivity ◽  
Soil Co2 Efflux ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Total Soil

Soil respiration is a major component of global carbon cycle. Therefore, it is crucial to understand the environmental controls on soil respiration for evaluating potential response of ecosystems to climate change. In a temperate deciduous forest (located in Northern-Hungary) we added or removed aboveground and belowground litter to determine total soil respiration. We investigated the relationship between total soil CO2 efflux, soil moisture, and soil temperature. Soil CO2 efflux was measured at each plot using soda-lime method. Temperature sensitivity of soil respiration (Q10) was monitored via measuring soil temperature on an hourly basis, while soil moisture was determined monthly. Soil respiration increased in control plots from the second year after implementing the treatment, but results showed fluctuations from one year to another. The effect of doubled litter was less significant than the effect of removal. Removed litter and root inputs caused substantial decrease in soil respiration. We found that temperature was more influential in the control of soil respiration than soil moisture. In plots with no litter Q10 varied in the largest interval. For treatment with doubled litter layer, temperature sensitivity of CO2 efflux did not change considerably. The effect of increasing soil temperature is more conspicuous to soil respiration in litter removal treatments since lack of litter causes greater irradiation. When exclusively leaf litter was considered, the effect of temperature on soil respiration was lower in treatments with added litter than with removed litter. Our results reveal that soil life is impacted by the absence of organic matter, rather than by an excess of organic matter. Results of CO2 emission from soils with different organic matter content can contribute to sustainable land use, considering the changed climatic factors caused by global climate change.

scholarly journals Spatially variable soil water repellency enhances soil respiration rates (CO<sub>2</sub> efflux)

2017 ◽  
Author(s):  
Emilia Urbanek ◽  
Stefan H. Doerr
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Water ◽  
Water Distribution ◽  
Preferential Flow ◽  
Water Repellency ◽  
Water Repellent ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Soil Water Repellency

Abstract. Soil CO2 emissions are strongly dependent on water distribution in soil pores, which in turn can be affected by soil water repellency (SWR; hydrophobicity). SWR restricts infiltration and movement of water, affecting soil hydrology as well as biological and chemical processes. Effects of SWR on soil carbon dynamics and specifically on soil respiration (CO2 efflux) have been studied in a few laboratory experiments but they remain poorly understood. Existing studies suggest that soil respiration is reduced in water repellent soils, but the responses of soil CO2 efflux to varying water distribution created by SWR are not yet known. Here we report on the first field-based study that tests whether soil water repellency indeed reduces soil respiration, based on in situ field measurements carried out over three consecutive years at a grassland and pine forest site under the humid temperate climate of the UK. CO2 efflux was reduced on occasions when soil exhibited consistently high SWR and low soil moisture following long dry spells. However, the highest respiration rates occurred not when SWR was absent, but when SWR, and thus soil moisture, was spatially patchy, a pattern observed for the majority of the measurement period. This somewhat surprising phenomenon can be explained by SWR-induced preferential flow, directing water and nutrients to microorganisms decomposing organic matter concentrated in hot spots near preferential flow paths. Water repellent zones provide air-filled pathways through the soil, which facilitate soil-atmosphere O2 and CO2 exchanges. This study demonstrates that SWR have contrasting effects on CO2 fluxes and, when spatially-variable, can enhance CO2 efflux. Spatial variability in SWR and associated soil moisture distribution needs to be considered when evaluating the effects of SWR on soil carbon dynamics under current and predicted future climatic conditions.

scholarly journals Soil Moisture Sensor Test with Mississippi Delta Soils

2019 ◽  
Vol 62 (2) ◽  
pp. 363-370
Author(s):  
Ruixiu Sui ◽  
Horace C. Pringle ◽  
Edward M. Barnes
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Measurement Accuracy ◽  
Mississippi Delta ◽  
Soil Water Potential ◽  
Gravimetric Method ◽  
Irrigation Scheduling

Abstract. One of the methods for irrigation scheduling is to use sensors to measure the soil moisture level in the plant root zone and apply water if there is a water shortage for the plants. The measurement accuracy and reliability of the soil moisture sensors are critical for sensor-based irrigation management. This study evaluated the measurement accuracy and repeatability of the EC-5 and 5TM soil volumetric water content (SVWC) sensors, the MPS-2 and 200SS soil water potential (SWP) sensors, and the 200TS soil temperature sensor. Six 183 cm × 183 cm × 71 cm wooden compartments were built inside a greenhouse, and each compartment was filled with one type of soil from the Mississippi Delta. A total of 66 sensors with 18 data loggers were installed in the soil compartments to measure SVWC, SWP, and soil temperature. Soil samples were periodically collected from the compartments to determine SVWC using the gravimetric method. SVWC measured by the sensors was compared with that determined by the gravimetric method. The SVWC readings from the sensors had a linear regression relationship with the gravimetric SVWC (r2 = 0.82). This relationship was used to calibrate the sensor readings. The SVWC and SWP sensors could detect the general trend of soil moisture changes. However, their measurements varied significantly among the sensors. To obtain accurate absolute soil moisture measurements, the sensors require individual and soil-specific calibration. The 5TM, MPS-2, and 200TS sensors performed well in soil temperature measurement tests. Individual temperature readings from these sensors were very close to the mean of all sensor readings. Keywords: Irrigation, Sensors, Soil types, Soil water content, Soil water potential.

VARIATION OF SUNFLOWER GROWTH, SOIL MOISTURE AND SOIL TEMPERATURE IN RELATION TO PLANTING PATTERNS AT A HIGH LATITUDE SITE

2001 ◽  
Vol 49 (3) ◽  
pp. 273-282 ◽  
Author(s):  
M. Long ◽  
H. Eiszner
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Soil Water ◽  
High Latitude ◽  
Dry Matter ◽  
Field Experiments ◽  
Hyperbolic Model ◽  
Row Spacing ◽  
Dry Matter Accumulation ◽  
Deep Soil

HALLE-WITTENBERG, HALLE(SAALE), GERMANY Received: 13 June, 2001; accepted: 6 August, 2001 Field experiments were conducted at a high latitude site for sunflower (Helianthus annuus L.) production in central Germany (51 o 24' N, 11 o 53' E) in 1996, 1997 and 1998. The responses of sunflower development to various planting patterns differed in the duration from emergence to the middle of the linear growth period as calculated via a tangent hyperbolic model F(t)=(. +ß)×tanh[. ×(t–.)]. Final dry matter accumulation showed few differences among the planting patterns: 12 plants m –2 at 50 cm row spacing at 75 cm row spacing (RS2PD2) and 4 plants m –2 at 100 cm row spacing (RS3PD1). The actual and simulated values for final dry matter were close to 1200 g m –2 . The responses of soil moisture and temperature to planting patterns changed from the upper to the deep soil layers. In a normal year, e.g. 1997, the soil water to 150 cm depth was sufficient for sunflower growth. In a drought year, e.g. 1998, soil water deeper than 150 cm was used by sunflower crops. The soil temperature was mostly lower in RS1PD3 and RS2PD2 than in RS3PD1, particularly in the upper soil, at depths of 5 and 20 cm. The most important factor defining the responses of soil moisture and temperature to planting patterns seems to be the amount of radiation penetrating the ground, which may depend on latitude, wind and row orientation.

scholarly journals Soil CO2 efflux in a beech forest: dependence on soil temperature and soil water content

1999 ◽  
Vol 56 (3) ◽  
pp. 221-226 ◽  
Author(s):  
Daniel Epron ◽  
Lætitia Farque ◽  
Éric Lucot ◽  
Pierre-Marie Badot
Keyword(s):  
Soil Temperature ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Beech Forest ◽  
Soil Co2 Efflux ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Forest Dependence

scholarly journals PERANAN EKOLOGI DUSUNG DAN NON DUSUNG DAN KONTRIBUSINYA PADA KONSERVASI LINGKUNGAN DI DESA URENG KECAMATAN LEIHITU KABUPATEN MALUKU TENGAH

2018 ◽  
Vol 2 (1) ◽  
pp. 28-48
Author(s):  
Napsiah Heluth ◽  
J. Matinahoru ◽  
Fransina Latumahina
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Air Temperature ◽  
Organic Content ◽  
Environmental Conservation ◽  
Soil Macrofauna ◽  
Organic C

The research study aims to determine the ecological conditions of dusung and non dusung, and the role of the contribution to environmental conservation in Ureng Village. The research method used was purposive sampling with observation parameters were microclimate (CO2 content, air temperature, humidity), vegetation conditions and soil conditions (soil temperature, soil moisture, soil pH, soil moisture content, soil macrofauna and organic C) . The results of  Paired of each parameter measured mostly show a smaller calculated t value compared to the t0.05 table value (1.8595) which means that the parameter is not a real difference, ie for the air humidity, t count = 0.27,; soil pH, t count = 0.6; soil macrofauna, t count = -0.66 and vegetation, t count = 1.01. As for the parameters of CO2; air temperature, soil temperature, , soil water content and organic C, t value of CO2 gives the value t count = - 16.06; air temperature = -5.11; soil temperature = -3.62; soil moisture, t count = 2,16; soil water content = 8.47, and C-Organic = 8.53; t count value which is greater than t table value which shows that there is a significant difference between CO2, air temperature, soil temperature, soil moisture, soil water content and C-Organic content in the dusung area which is greater than in the non-dusung area. From the results of the analysis it is known that dusung has a better role in environmental conservation when compared to non dusung which is indicated by the value of CO2 air temperature, soil temperature, soil moisture, soil water content and C-organic content.

scholarly journals How do Soil Moisture and Vegetation Covers Influence Soil Temperature in Drylands of Mediterranean Regions?

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1747 ◽  
Author(s):  
Javier Lozano-Parra ◽  
Manuel Pulido ◽  
Carlos Lozano-Fondón ◽  
Susanne Schnabel
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Vegetation Cover ◽  
Daily Maximum ◽  
Local Climate ◽  
Tree Canopies ◽  
Soil Temperatures

Interactions between land and atmosphere directly influence hydrometeorological processes and, therefore, the local climate. However, because of heterogeneity of vegetation covers these feedbacks can change over small areas, becoming more complex. This study aims to define how the interactions between soil moisture and vegetation covers influence soil temperatures in very water-limited environments. In order to do that, soil water content and soil temperature were continuously monitored with a frequency of 30 min over two and half hydrological years, using capacitance and temperature sensors that were located in open grasslands and below tree canopies. The study was carried out on three study areas located in drylands of Mediterranean climate. Results highlighted the importance of soil moisture and vegetation cover in modifying soil temperatures. During daytime and with low soil moisture conditions, daily maximum soil temperatures were, on average, 7.1 °C lower below tree canopies than in the air, whereas they were 4.2 °C higher in grasslands than in the air. As soil wetness decreased, soil temperature increased, although this effect was significantly weaker below tree canopies than in grasslands. Both high soil water content and the effect of shading were reflected in a decrease of maximum soil temperatures and of their daily amplitudes. Statistical analysis emphasized the influence of soil temperature on soil water reduction, regardless of vegetation cover. If soil moisture deficits become more frequent due to climate change, variations in soil temperature could increase, affecting hydrometeorological processes and local climate.

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

Soil Research ◽  
2008 ◽  
Vol 46 (8) ◽  
pp. 727 ◽  
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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