Quantitative paleoenvironmental and paleoclimatic reconstruction using paleosols

Baseflow is the portion of streamflow that is sustained between precipitation events, fed to stream channels by delayed (usually subsurface) pathways. Understanding baseflow processes is critical t...

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Effects of watershed topography, soils, land use, and climate on baseflow hydrology in humid regions: A review

A comprehensive 30x30 arc-second resolution gridded soil characteristics data set of China has been developed for use in the land surface modeling. It includes physical and chemical attributes of soils derived from 8979 soil profiles and the Soil Map of China (1:1,000,000). We used the polygon linkage method to derive the spatial distribution of soil properties. The profile attribute database and soil map are linked under the framework of the Genetic Soil Classification of China which avoids uncertainty in taxon referencing. Quality control information (i.e., sample size, soil classification level, linkage level, search radius and texture) is included to provide confidence information for the derived soil parameters. The data set includes 28 attributes for 8 vertical layers at the spatial resolution of 30x30 arc-seconds. Based on this data set, the estimated storage of soil organic carbon in the upper 1 m of soil is 72.5 Pg, total N is 6.6 Pg, total P is 4.5 Pg, total K is 169.9 Pg, alkali-hydrolysable N is 0.55 Pg, available P is 0.03 Pg, and available K is 0.61 Pg. These estimates are reasonable compared with previous studies. The distributions of soil properties are consistent with common knowledge of Chinese soil scientists and the spatial variations over large areas are well represented. The data set can be incorporated into land models to better represent the role of soils in hydrological and biogeochemical cycles in China.

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A China data set of soil properties for land surface modeling

Breaking ground: Pedological, geological, and ecological implications of soil bioturbation

. The Critical Zone (CZ) is a holistic framework for integrated studies of water with soil, rock, air, and biotic resources in the near-surface terrestrial environment. This most heterogeneous and complex region of the Earth ranges from the vegetation top to the aquifer bottom, with a highly variable thickness globally and a yet-to-be clearly defined lower boundary of active water cycle. Interfaces among different compartments in the CZ are critical, which provide fertile ground for interdisciplinary research. The reconciliation of coupled geological and biological cycles (vastly different in space and time scales) is essential to understanding the complexity and evolution of the CZ. Irreversible evolution, coupled cycling, interactive layers, and hierarchical heterogeneity are the characteristics of the CZ, suggesting that forcing, coupling, interfacing, and scaling are grand challenges for advancing CZ science. Hydropedology – the science of the behaviour and distribution of soil-water interactions in contact with mineral and biological materials in the CZ – is an important contributor to CZ study. The pedosphere is the foundation of the CZ, which represents a geomembrance across which water and solutes, as well as energy, gases, solids, and organisms are actively exchanged with the atmosphere, biosphere, hydrosphere, and lithosphere, thereby creating a life-sustaining environment. Hydropedology emphasizes in situ soils in the landscape setting, where distinct pedogenic features and soil-landscape relationships are essential to understanding interactive pedologic and hydrologic processes. Both CZ science and hydropedology embrace an evolutionary and holistic worldview, which offers stimulating opportunities through steps such as integrated systems approach, evolutionary mapping-monitoring-modeling framework, and fostering a global alliance. Our capability to predict the behaviour and evolution of the CZ in response to changing environment can be significantly improved if cross-site scientific comparisons, evolutionary treatment of organized complex systems, and deeper insights into the CZ can be made.

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Earth's Critical Zone and hydropedology: concepts, characteristics, and advances

Part I. The Building Blocks of Soils: 1. Introduction 2. Basic concepts: soil morphology 3. Basic concepts: soil horizonation... the alphabet of soils 4. Basic concepts: soil mineralogy 5. Basic concepts: soil chemistry 6. Basic concepts: soil physics 7. Basic concepts: soil organisms 8. Soil classification and mapping 9. Weathering Part II. Soil Genesis: From Parent Material to Soil: 10. Soil parent materials 11. Pedoturbation 12. Models and concepts of soil formation 13. Soil genesis and profile differentiation Part III. Soil Geomorphology: 14. Soil geomorphology and hydrology 15. Soil development and surface exposure dating 16. Soils, paleosols, and paleoenvironmental reconstruction 17. Conclusions.

Soils : genesis and geomorphology

This study was carried out under laboratory conditions, from October 1995 to January 1996, in order to evaluate the influence of liming and phosphorus (P) application on nitrogen (N) and sulfur (S) mineralization in seven Brazilian (0-20 cm) soils with a wide variability in chemical and physical properties.Soilsamples,beforefertilizationwithP(KH 2PO4),were pre-incubated during seven days with CaCO3, and incubated again for another 70 days. The content of mineralized N (NH4+ and NO3-) and S (SO42-) were measured every other week, in aerobic conditions. Transformation of N and S showed different mineralization patterns from each other, with mineral N levels undergoing much greater variation than sulfate levels. Mineralized N amounts were not affected by soil acidity, although liming accelerated N mineralization in Humic Gley and Red-Yellow Latosol (colected in Rio de Janeiro) soils. Liming the soils to a pH around 6.0 resulted in increased net S mineralization in Low Humic Gley and Red-Yellow Latosol (colected in Rio de Janeiro) soils. Addition of superphosphate did not influence N and S mineralization processes. The greater prevalence of nitrate and sulphate in some of the limed soils suggests that the criterion used to choose time of lime application needs to be changed.

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Mineralização de nitrogênio e enxofre em solos brasileiros sob influência da calagem e fósforo

The influence of parent materials on soil properties has long been recognized. Early pedologists and soil geographers based their concepts of soils largely on its presumed parent material. Later, parent material was viewed simply as a factor that influences soil development – an influence that diminishes in importance with time. No one disputes the fact that geologic controls and factors are important to a complete understanding of soil development and soil patterns (Fig. 8.1). Parent material is the framework for the developing soil profile. In fact, the more holistically one examines a soil, including not just the upper 2 m or simply the solum, but also the many deep horizons, the more important parent material seems. One goal of soil geomorphology is to identify the types and origins of a soil's parent material; any study of soil genesis must ascertain what the parent material of the soil is. Information on parent material is paramount to the study of soils, especially soils on Pleistocene or younger surfaces (Roy et al . 1967, Schaetzl et al . 2000). Many times, the role of the soil geomorphologist is to produce a surficial geology map from a soils map. From this surficial sediment map comes a better understanding of the sedimentological and surficial processes that were operative in the past. This exercise may be relatively easy for young soils on young landscapes, but it is an extreme challenge on older landscapes. Conversely, one almost cannot make a soil survey without detailed information about surficial geology, illustrating the interrelatedness of soils and parent materials in almost all landscapes.

Sharon Anderson

Papers

Soils : genesis and geomorphology

Mineralização de nitrogênio e enxofre em solos brasileiros sob influência da calagem e fósforo

Soils: Soil parent materials

Soils: Soil genesis and profile differentiation

Soils, paleosols and paleoenvironmental reconstruction