Soil chronosequences, soil development, and soil evolution: a critical review

Chemistry and Ecology, 2010

Earth Surface Processes and Landforms, 2012

Applications of ergodic reasoning (or location for time substitution) aid efforts at environmental reconstruction and prediction, providing a useful tool to analyse and communicate stages of landscape evolution. Analysis of the historical range of behaviour and change that a river system has experienced can be used to interpret thresholds that have been breached, and underlying controls and/or triggers for adjustment and change. This information can be used to forecast future trajectories of adjustment and provide target conditions for management activities. This paper uses a case study from upper Wollombi Brook, New South Wales, Australia to demonstrate how ergodic reasoning can be used to assess river behaviour, change and responses to natural and human-disturbances. The 'river evolution diagram' developed by Brierley and Fryirs (Geomorphology and River Management: Applications of the River Styles Framework. Blackwell Publishing: Oxford, 2005) is presented as a means for depicting the range of behaviour and evolutionary variability of this river. These approaches can be readily applied in other systems. Implications for approaches to analysis of river evolution and management are outlined. Figure 4. Ergodic matrix of river evolution for Wollombi Brook. The sequence of changes is summarized in schematic timeslices from the work of Erskine (2008) and Erskine and Melville . Four representative sites within the four process zones were chosen to depict the main changes that have occurred since European settlement. The timing of transition in river type is also noted.

Nutrient Cycling in Agroecosystems, 2013

and N (0.4-4.8 mg L -1 ) were moderate or low with respect to possible consequence for human health and not responsible for eutrophication observed in Lake Victoria.

Quaternary Research, 2015

The terminal lake systems of central Australia are key sites for the reconstruction of late Quaternary paleoenvironments. Paleoshoreline deposits around these lakes reflect repeated lake filling episodes and such landforms have enabled the establishment of a luminescence-based chronology for filling events in previous studies. Here we present a detailed documentation of the morphology and chemistry of soils developed in four well-preserved beach ridges of late Pleistocene and mid-to-late Holocene age at Lake Callabonna to assess changes in dominant pedogenic processes. All soil profiles contain evidence for the incorporation of eolian-derived material, likely via the formation of desert pavements and vesicular horizons, and limited illuviation due to generally shallow wetting fronts. Even though soil properties in the four studied profiles also provide examples of parent material influence or site-specific processes related to the geomorphic setting, there is an overall trend of increasing enrichment of eolian-derived material since at least~33 ka. Compared to the Holocene profiles, the derived average accumulation rates for the late Pleistocene profiles are significantly lower and may suggest that soils record important regional changes in paleoenvironments and dust dynamics related to shifts in the Southern Hemisphere westerlies.

Biology and Fertility of Soils, 2014

Biology and Fertility of Soils, 2013

Recent studies with Andisols show that the carbon (C) stabilization capacity evolves with soil age relative to the evolution of the mineral phase. However, it is not clear how soil mineralogical changes during pedogenesis are related to the composition of soil organic matter (SOM) and 14 C activity as an indicator for the mean residence time of soil organic matter (SOM). In the present study, we analyzed the contribution of allophane and metal-SOM complexes to soil C stabilization. Soil organic matter was analyzed with solid-state 13 C nuclear magnetic resonance spectroscopy. Additionally, the soil was extracted with Na-pyrophosphate (Al p , Fe p) and oxalate (Al o , Si o , and Fe o). Results supported the hypothesis that allophane plays a key role for SOM stabilization in deep and oldest soil, while SOM stabilization by metal (Al and Fe) complexation is more important in the surface horizons and in younger soils. The metal/C p ratio (C p extracted in Na-pyrophosphate), soil pH, and radiocarbon age seemed to be important indicators for formation of SOM-metal complexes or allophane in top-and subsoils of Andisols. Changes in main mineral stabilization agents with soil age do not influence SOM composition. We suggest that the combination of several chemical parameters (Al p , Fe p and C p , metal/C p ratio, and pH) which change through soil age controls SOM stabilization.

Biogeosciences, 2009

Nutrients and trace metals in river-floodplain systems may originate from anthropogenic activities and/or geogenic sources. Here, we analyze a soil chronosequence (2 to approximately 600 years) on a floodplain at the Danube River (Austria) to quantify the rates of P and Cu redistribution among biogeochemical pools during early soil formation under temperate continental climate. While bulk and clay mineralogy remained unchanged over the studied age gradient, we found considerable (mostly non-linear) redistribution of P and Cu among biogeochemical pools. The calcium-associated P and Cu fractions decreased rapidly during the initial decades of soil formation. The dissolution of calcium-associated P was mirrored by marked accumulation of organic P. Copper incorporated within resistant minerals showed a relative enrichment with soil age. The mean dissolution rates of calcium-associated (primary mineral) P decreased exponentially with increasing soil age from ∼1.6 g m −2 yr −1 over ∼15 years to ∼0.04 g m −2 yr −1 over ∼550 years, and were almost an order of magnitude higher than rates reported for tropical environments. Our study demonstrates that on riverine floodplains, rapid biogeochemical transformations can occur within the first centuries of soil formation under temperate climatic conditions.

Frontiers in Environmental Science

Recent modeling and comparison with field results showed that soil formation by chemical weathering, either from bedrock or unconsolidated material, is limited largely by solute transport. Chemical weathering rates are proportional to solute velocities. Nonreactive solute transport described by non-Gaussian transport theory appears compatible with soil formation rates. This change in understanding opens new possibilities for predicting soil production and depth across orders of magnitude of time scales. Percolation theory for modeling the evolution of soil depth and production was applied to new and published data for alpine and Mediterranean soils. The first goal was to check whether the empirical data conform to the theory. Secondly we analyzed discrepancies between theory and observation to find out if the theory is incomplete, if modifications of existing experimental procedures are needed and what parameters might be estimated improperly. Not all input parameters required for current theoretical formulations (particle size, erosion, and infiltration rates) are collected routinely in the field; thus, theory must address how to find these quantities from existing climate and soil data repositories, which implicitly introduces some uncertainties. Existing results for soil texture, typically reported at relevant field sites, had to be transformed to results for a median particle size, d 50 , a specific theoretical input parameter. The modeling tracked reasonably well the evolution of the alpine and Mediterranean soils. For the Alpine sites we found, however, that we consistently overestimated soil depths by ∼45%. Particularly during early soil formation, chemical weathering is more severely limited by reaction kinetics than by solute transport. The kinetic limitation of mineral weathering can affect the system until 1 kyr to a maximum of 10 kyr of soil evolution. Thereafter, solute transport seems dominant. The trend and scatter of soil depth evolution is well captured, particularly for Mediterranean soils. We assume that some neglected processes, such as bioturbation, tree throw, and land use change contributed to local reorganization of the soil and thus to some differences to the model. Nonetheless, the model is able to generate soil depth and confirms decreasing production rates with age. A steady state for soils is not reached before about 100 kyr to 1 Myr

Ecological Processes

Introduction: Primary succession on glacial forelands is increasingly relevant as rapid glacial retreat is exposing growing land areas to plant colonization. We investigated temporal trends, controls, and outcomes in floral succession on a subarctic glacial foreland. Specifically, we examined changes in community composition (mosses, low shrubs, forbs, trees, and graminoids) over long-term (decadal) and short-term (< 10 years) scales and attempted to identify the underlying processes responsible for the observed successional patterns. Methods: The study area was the foreland of the Skaftafellsjӧkull, located in Vatnajӧkull National Park near the south coast of Iceland. We established nine transect lines at varying distances from the ice front representing surfaces of age ranging from less than one decade to over 100 years. Each transect consisted of five measurement stations of 1 m 2 where we measured vegetative cover (VC), species richness (SR), and species density (SD) and calculated species evenness (SE). Measurements were made initially in 2007 and repeated at the same geographic coordinates in 2014. Results: VC increased with distance from the ice front from 16% to over 90%. SR and SD increased from the youngest pioneer community through a mid-successional stage corresponding to an age of over 60 but less than 100 years. Increased VC but declining SR, SD, and SE characterized the oldest (over 100 years) bryophyte-dominated surfaces. Species turnover, which involved forbs almost exclusively, increased moderately from early through midsuccessional sites and declined on older sites. Comparison of the measurements made in 2014 to those made in 2007 demonstrates increased SR at mid-successional sites while SD remained relatively constant. Conclusion: At a small scale, colonization is controlled by local factors such as microtopography and aspect, particularly in proximity to the glacier. At the landscape level, changes in VC and community structure are controlled by time and nutrient availability. Low nutrient levels and limited site availability favor bryophyte dominance on the oldest surfaces. The greatest community-level changes observed over the 7-year interval were increases in surface cover by mosses and low shrubs, particularly in mid-successional and older sites. These changes suggest that the community on the oldest surfaces has not yet reached equilibrium.

Regional Environmental Change, 2016

Recent studies suggest that carbon (C) is stored in the topsoil of pastures established after deforestation. However, little is known about the long-term capacity of tropical pastures to sequester C in different soil layers after deforestation. Deep soil layers are generally not taken into consideration or are underestimated when C storage is calculated. Here we show that in French Guiana, the C stored in the deep soil layers contributes significantly to C stocks down to a depth of 100 cm, and that C is sequestered in recalcitrant soil organic matter in the soil below a depth of 20 cm. The contribution of the 50-100 cm soil layer increased from 22% to 31% with the age of the pasture. We show that long-term C sequestration in C4 tropical pastures is linked to the development of C3 species (legumes and shrubs), which increase both inputs of N into the ecosystem and the C:N ratio of soil organic matter. The deep soil under old pastures contained more C3 carbon than the native forest. If C sequestration in the deep soil is taken into account, our results suggest that the soil C stock in pastures in Amazonia would be higher with sustainable pasture management, in particular by promoting the development of legumes already in place and by introducing new Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation species.

Global Change Biology, 2016

Amazonian forests continuously accumulate carbon (C) in biomass and in soil, representing a carbon sink of 0.42-0.65 GtC yr-1. In recent decades, more than 15% of Amazonian forests have been converted into pastures, resulting in net C emissions (~200 tC ha-1) due to biomass burning and litter mineralization in the first years after deforestation. However, little is known about the capacity of tropical pastures to restore a forest C sink. Our data suggest that 24-year-old permanent tropical pastures in French Amazonia can partly restore the C storage observed in native forest. A unique combination of a large chronosequence study and eddy covariance measurements showed that pastures stored between-1.27 ± 0.37 and-5.31 ± 2.08 tC ha-1 yr-1 while the nearby native forest stored-3.31 ± 0.44 tC ha-1 yr-1. This carbon is mainly sequestered in the humus of deep soil layers (20-100 cm), whereas no C storage was observed in the 0-20 cm layer. C storage in C4 tropical pasture is associated with the installation and development of C3 species, which increase either the input of N to the ecosystem or the C:N ratio of soil organic matter. Efforts to curb deforestation remain an obvious priority to preserve forest C stocks and biodiversity. However, our results show that if sustainable management is applied in tropical pastures coming from deforestation (avoiding fires and overgrazing, using a grazing rotation plan and a mixture of C3 and C4 species), they can ensure a continuous C storage, thereby adding to the current C sink of Amazonian forests.

Journal of Ecology, 2017

1. During soil development, bacteria and fungi can be differentially affected by changes in soil biogeochemistry. Since the chemistry of parent material affects soil pH, nutrient availability, and indirectly litter quality, we hypothesize that parent material has an important influence on microbial community patterns during long-term soil development. 2. In this paper, we tested for the effect of parent material, as well as, soil and litter properties upon microbial community patterns in three c. 20 000-year-old semi-arid chronosequences developed on sedimentary and volcanic (i.e. Andesitic and Dacitic) soils in the Dry Puna of Bolivia. We evaluated microbial patterns by analysing the terminal restriction fragment length polymorphism from amplified bacterial 16S rRNA genes, and the fungal internal transcribed spacer region, and quantitative real-time polymerase chain reaction. 3. Soil and litter characteristics differed significantly between the Sedimentary and volcanic chronosequences. In particular, soil pH was alkaline in all stages of the Sedimentary chronosequence; whereas it changed from alkaline to near neutral across stages in both volcanic chronosequences. Composition of bacterial communities changed across volcanic chronosequences, and this change was associated with a reduction in soil pH and increases in litter quality, whereas no differences were found in the Sedimentary chronosequence. Fungal community composition, in contrast, did not change across any chronosequence. 4. Relative microbial abundance, expressed as the fungal:bacterial ratio, declined across stages of the Sedimentary chronosequence in association with decreases in TC and TP, whereas in the Andesitic chronosequence decreases in fungal:bacterial ratios were related with increases in litter quality and declines in soil pH. 5. Synthesis. Our results show the importance of parent material in affecting bacterial and fungal communities during soil development. Further, in semi-arid chronosequences, fungal:bacterial ratios tend to decline given that soil pH in young soils is rather alkaline. Our results also are consistent with the general framework that highlights the importance of above-ground (i.e. litter quality) and below-ground (i.e. soil properties) in affecting microbial relative abundance and community composition during soil development.

Eurasian Soil Science, 2016

Geoarchaeological m ethods were used to study chronosequences of surface soils in the steppe zone and to trace soil evolution during the Late Holocene in northwestern Crimea. It was found that the m orpholog ical and functional "m aturity" of the humus horizons in steppe chernozems of the Late Holocene was reached in about 1600-1800 yrs. After this, their development decelerated irreversibly. The maximum concentration of trace elements accumulated in these horizons in the course of pedogenesis was reached in 1400 yrs. A new m ethod of pedogenetic chronology based on the model chronofunction of the development o f irreversible results of pedogenesis over time is suggested. Original pedochronological data and growth functions-the most suitable m odels for simulating pedogenesis over the past three thousand years-suggest that the development of m orphological features of soil as an organomineral natural body follows growth patterns established for biolog ical systems.

Arctic, Antarctic, and Alpine Research, 2019

The tree-ring stable carbon and oxygen isotope chronologies from two forest sites located in the Forni Glacier forefield (Italy)-one along the glacier stream (GL) and the other toward the valley slope (SL)-were analyzed with the aim of disentangling the precipitation and glacier meltwater inputs in source water δ 18 O, as reflected by the tree-ring cellulose δ 18 O. The cellulose δ 18 O from the GL trees has a negative correlation with winter and summer temperatures, whereas the cellulose δ 18 O from the SL trees has a positive correlation with precipitation δ 18 O. The isotopic signature of the source water at the GL site is also influenced by waters of glacial origin, as confirmed by the 18 O-depleted glacier meltwater inputs (GMWI_δ 18 O) estimated by means of an isotope model. The GMWI_δ 18 O values are consistent with the mean difference measured between the δ 18 O in the glacier stream and in the precipitation and the winter and summer temperature explains up to 37 percent of the GMWI_δ 18 O variance. Our results show an increasing influence of glacier meltwater throughout the past decade for the GL site. Our analysis opens new opportunities to reconstruct changes in water regimes of the glacier streams by means of the tree-ring cellulose δ 18 O.

Landscape Ecology, 2012

To understand the overwhelming species richness in soil the focus of attention has traditionally been on local soil conditions, such as physical and chemical characteristics. Regional factors like landscape history have been largely ignored. The aim of our study was to assess the importance of geological site age and local site conditions on oribatid mite species richness in undisturbed forest soils. We wanted to evaluate the processes underlying spatial changes in oribatid species richness at the regional level. We selected 41 sites across the Netherlands with different forest types, located on soils with varying levels of humidity and nutrient richness. The selected sites formed a clear spatiotemporal gradient in geological site age, ranging from Holocene sites along the west coast and rivers towards Pleistocene sites in the east of the country. Five samples were collected at each site. Oribatid mites were counted and identified to the species level. In total 145 oribatid mite species were recorded. We observed that oribatid mite species richness across sites was positively affected by site age. Soil nutrient status, water availability, soil type, or forest vegetation type had rather a local modulating effect on soil mite diversity. The increase in species diversity with geological site age was mainly due to an increase in sexually-reproducing species, with an apparent high competitive ability, but lower reproduction rate. Our results suggest that spatial patterns of soil animal community diversity and composition can be significantly determined by geologic age at the regional level. Keywords Oribatida Á Acari Á Geological age Á Soil fauna diversity Á Spatial distribution Á Landscape Á Mite Á Forest vegetation type Á Soil type Electronic supplementary material The online version of this article (