Changes in soil moisture predict soil carbon losses upon rewetting in a perennial semiarid steppe in SE Spain

Rey, Ana; Oyonarte, Cecilio; Morán‐López, Teresa; Raimundo, João; Pegoraro, E.

doi:10.1016/j.geoderma.2016.06.025

Cited by 74 publications

(50 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this regard, the ecosystems' functioning could be divided into three different phases. The first phase corresponded to the autumn months, when the first rainfall events after the dry summer (i.e., rain pulses) activated the soil microbiota, triggering respiratory CO 2 emissions as previously measured at the same experimental sites (López-Ballesteros et al, 2016;Rey et al, 2017). During this phase, maximum net CO 2 emission was observed at the natural site, which exceeded the biological net CO 2 flux observed at the degraded site (Fig.…”

Section: Discussionsupporting

confidence: 56%

“…Regarding the topographic, geologic and edaphic characteristics, both sites are located on an alluvial fan, where the main geological materials consist of quaternary conglomerates and Neogene-Quaternary sediments cemented by lime (caliche) (Rodríguez-Fernández et al, 2015) on slopes of 2-6 % , so no significant runoff occurs. Additionally, both sites present petrocalcic horizons.…”

Section: Experimental Site Descriptionmentioning

confidence: 99%

“…While BB has deeper and more fertile soils and higher vegetation cover, AMO shows thinner and poorer soils and has half of Balsa Blanca's vegetation cover. Therefore, in accordance with Rey et al (2011Rey et al ( , 2017, we considered that BB represents the natural site, currently being a representative ecosystem of the area, while AMO represents a degraded site with respect to BB. The stronger degradation effects observed in AMO (degraded site) compared to BB (natural site) are probably due to its proximity to populated areas.…”

Section: Experimental Site Descriptionmentioning

confidence: 99%

See 2 more Smart Citations

Can land degradation drive differences in the C exchange of two similar semiarid ecosystems?

et al. 2018

Self Cite

View full text Add to dashboard Cite

Abstract. Currently, drylands occupy more than one-third of the global terrestrial surface and are recognized as areas vulnerable to land degradation. The concept of land degradation stems from the loss of an ecosystem's biological productivity due to long-term loss of natural vegetation or depletion of soil nutrients. Drylands' key role in the global carbon (C) balance has been recently demonstrated, but the effects of land degradation on C sequestration by these ecosystems still need to be investigated. In the present study, we compared net C and water vapor fluxes, together with satellite, meteorological and vadose zone (CO 2 , water content and temperature) measurements, between two nearby (∼ 23 km) experimental sites representing "natural" (i.e., site of reference) and "degraded" grazed semiarid grasslands. We utilized data acquired over 6 years from two eddy covariance stations located in southeastern Spain with highly variable precipitation magnitude and distribution. Results show a striking difference in the annual C balances with an average net CO 2 exchange of 196 ± 40 (C release) and −23 ± 2 g C m −2 yr −1 (C fixation) for the degraded and natural sites, respectively. At the seasonal scale, differing patterns in net CO 2 fluxes were detected over both growing and dry seasons. As expected, during the growing seasons, greater net C uptake over longer periods was observed at the natural site. However, a much greater net C release, probably derived from subterranean ventilation, was measured at the degraded site during drought periods. After subtracting the nonbiological CO 2 flux from net CO 2 exchange, flux partitioning results point out that, during the 6 years of study, gross primary production, ecosystem respiration and water use efficiency were, on average, 9, 2 and 10 times higher, respectively, at the natural site versus the degraded site. We also tested differences in all monitored meteorological and soil variables and CO 2 at 1.50 m belowground was the variable showing the greatest intersite difference, with ∼ 1000 ppm higher at the degraded site. Thus, we believe that subterranean ventilation of this vadose zone CO 2 , previously observed at both sites, partly drives the differences in C dynamics between them, especially during the dry season. It may be due to enhanced subsoil-atmosphere interconnectivity at the degraded site.

show abstract

Section: Discussionsupporting

confidence: 56%

Section: Experimental Site Descriptionmentioning

confidence: 99%

Section: Experimental Site Descriptionmentioning

confidence: 99%

See 1 more Smart Citation

Can land degradation drive differences in the C exchange of two similar semiarid ecosystems?

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…These findings are consistent with those of Liu, Fox, and Xu (), who also observed a rapid increase in CO 2 efflux immediately, (i.e., the first day), after the water addition into soil samples (which were ground and sieved), followed by a gradual decline. This effect is described as the Birch effect (Birch, ; Rey, Oyonarte, Morán‐López, Raimundo, & Pegoraro, ; P. A. Smith et al, ). In cases of the soil samples with the best developed soil structure (transect summit—B1 [see Section 3.3] and loess sample [L]), the initial fast increase of NCER turned into a gradual decrease of the observed NCER with increasing amount of water infiltrating into the soil sample.…”

Section: Resultsmentioning

confidence: 99%

“…Birch effect(Birch, 1958;Rey, Oyonarte, Morán-López, Raimundo, & Pegoraro, 2017;P. A. Smith et al, 2017).…”

mentioning

confidence: 99%

Influence of soil–water content on CO₂ efflux within the elevation transect heavily impacted by erosion

et al. 2018

View full text Add to dashboard Cite

This study focused on the effects of organic carbon contents and soil hydraulic conditions on CO2 efflux. Samples were collected at 5 positions (summit, shoulder, backslope, footslope, and toeslope) of the elevation transect affected by erosion and the parent material (loess). Initially, air‐dried soil samples were placed on top of a clay tank, and the samples were wetted by capillary rise to soil saturation, and soil CO2 efflux was measured. Numerical inversions of the measured cumulative capillary rise and evaporation data using the HYDRUS‐1D program were applied to simulate the water regime in the columns and estimate the soil hydraulic parameters. In all cases, the net CO2 efflux (NCER) rapidly increased at the beginning of the wetting. NCER decreased with increasing soil–water content (summit, shoulder, backslope, and loess) or remained relatively stable (footslope and toeslope). The average soil–water content values at the maximal values of NCER (maxNCER) for the summit, shoulder, and footslope were similar. Lower average soil–water contents at maxNCER were simulated for the backslope, toeslope, and loess, which were attributed to the high contents of loess substrate in topsoil samples. The maxNCER measured on topsoils were closely related to the organic carbon contents (R = 0.94) and the maxNCER obtained on all samples correlated with the parameters αRES (R = 0.856) and nRES (R = −0.876) of the soil–water retention curves and saturated hydraulic conductivity (R = 0.856).

show abstract

Pedotransfer Functions in Earth System Science: Challenges and Perspectives

Looy

Bouma

Herbst

et al. 2017

Reviews of Geophysics

368

297

View full text Add to dashboard Cite

Soil, through its various functions, plays a vital role in the Earth's ecosystems and provides multiple ecosystem services to humanity. Pedotransfer functions (PTFs) are simple to complex knowledge rules that relate available soil information to soil properties and variables that are needed to parameterize soil processes. In this paper, we review the existing PTFs and document the new generation of PTFs developed in the different disciplines of Earth system science. To meet the methodological challenges for a successful application in Earth system modeling, we emphasize that PTF development has to go hand in hand with suitable extrapolation and upscaling techniques such that the PTFs correctly represent the spatial heterogeneity of soils. PTFs should encompass the variability of the estimated soil property or process, in such a way that the estimation of parameters allows for validation and can also confidently provide for extrapolation and upscaling purposes capturing the spatial variation in soils. Most actively pursued recent developments are related to parameterizations of solute transport, heat exchange, soil respiration, and organic carbon content, root density, and vegetation water uptake. Further challenges are to be addressed in parameterization of soil erosivity and land use change impacts at multiple scales. We argue that a comprehensive set of PTFs can be applied throughout a wide range of disciplines of Earth system science, with emphasis on land surface models. Novel sensing techniques provide a true breakthrough for this, yet further improvements are necessary for methods to deal with uncertainty and to validate applications at global scale.

show abstract

Changes in soil moisture predict soil carbon losses upon rewetting in a perennial semiarid steppe in SE Spain

Cited by 74 publications

References 55 publications

Can land degradation drive differences in the C exchange of two similar semiarid ecosystems?

Can land degradation drive differences in the C exchange of two similar semiarid ecosystems?

Influence of soil–water content on CO₂ efflux within the elevation transect heavily impacted by erosion

Pedotransfer Functions in Earth System Science: Challenges and Perspectives

Contact Info

Product

Resources

About

Changes in soil moisture predict soil carbon losses upon rewetting in a perennial semiarid steppe in SE Spain

Cited by 74 publications

References 55 publications

Can land degradation drive differences in the C exchange of two similar semiarid ecosystems?

Can land degradation drive differences in the C exchange of two similar semiarid ecosystems?

Influence of soil–water content on CO2 efflux within the elevation transect heavily impacted by erosion

Pedotransfer Functions in Earth System Science: Challenges and Perspectives

Contact Info

Product

Resources

About

Influence of soil–water content on CO₂ efflux within the elevation transect heavily impacted by erosion