Soil type regulates the divergent loss characteristics of sediment associated carbon and nitrogen in different size classes during rainfall erosion on cultivated lands.

Sediment associated carbon and nitrogen loss under rainfall, an important cause of soil quality degradation and water eutrophication, strongly depends on the intrinsic properties of original soil types. Relative to total loss, the transport behaviors of organic carbon and nitrogen among sediment size classes and response to soil types remain poorly understood. The concentrations of organic carbon (OC) and total nitrogen (TN) in different sediment size classes (>1, 0.

Significant loss of soil inorganic carbon at the continental scale.

Widespread soil acidification due to atmospheric acid deposition and agricultural fertilization may greatly accelerate soil carbonate dissolution and CO release. However, to date, few studies have addressed these processes. Here, we use meta-analysis and nationwide-survey datasets to investigate changes in soil inorganic carbon (SIC) stocks in China.

Temporal and Spatial Heterogeneity of Soil Erosion and a Quantitative Analysis of Its Determinants in the Three Gorges Reservoir Area, China.

As the most typical ecologically fragile area in South China, the Three Gorges Reservoir Area (TGRA) suffers from water and soil loss, which has threatened the local ecological environment. Understanding the spatial heterogeneity of soil erosion and exploring its determinants are of great significance in preventing soil erosion and maintaining ecological sustainability in the TGRA. This study investigates the spatial heterogeneity of soil erosion and quantitatively identifies the determinants in the TGRA based on the Chinese Soil Loss Equation (CSLE) and geographical detector method.

Effect of soil moisture on soil disintegration characteristics of different weathering profiles of collapsing gully in the hilly granitic region, South China.

Collapsing gully erosion is the main important and specific soil erosion type in the red soil region of tropical and subtropical South China. Knowledge of the soil disintegration characteristics within different weathering profiles (surface layer, red soil layer, sandy soil layer and detritus layer) and its relationships with soil particle size distribution and soil properties is important in understanding the mechanism of the forming process and development of the collapsing gully. In this paper, we conducted an experiment on four collapsing gullies located four counties (Tongcheng County, Gan County, Anxi County and Wuhua County) in the hilly granitic region of southern China.

Controlling factors of soil selenium distribution in a watershed in Se-enriched and longevity region of South China.

Selenium (Se) is an essential nutritional element for human beings. Many studies have been conducted on concentration and distribution patterns of soil Se in low Se, Se-enriched, and selenosis areas; however, soil Se has not been systematically studied in a watershed, especially in Se-enriched longevity region and karst area in South China. This study is carried out to explore the controlling factors of Se-enriched soils in Baishou river tributary watershed, where soils are Se-enriched, and local people have the phenomenon of longevity.

The effects of rainfall regimes and terracing on runoff and erosion in the Three Gorges area, China.

Changes in natural rainfall regimes have taken place and are expected to become more pronounced in future decades. These changes are also likely to be accompanied by changes in crop management practices. The main purpose of this study was to analyze runoff and soil loss in relation to rainfall regimes and terracing in the Three Gorges area, China.

Effects of soil type and rainfall intensity on sheet erosion processes and sediment characteristics along the climatic gradient in central-south China.

Soil erosion poses a major threat to the sustainability of natural ecosystems. The main objective of this study was to investigate the effects of soil type and rainfall intensity on sheet erosion processes (hydrological, erosional processes and sediment characteristics) from temperate to tropical climate. Field plot experiments were conducted under pre-wetted bare fallow condition for five soil types (two Luvisols, an Alisol, an Acrisol and a Ferralsol) with heavy textures (silty clay loam, silty clay and clay) derived separately from loess deposits, quaternary red clays and basalt in central-south China.

Fractal features of soil particle size distribution under different land-use patterns in the alluvial fans of collapsing gullies in the hilly granitic region of southern China.

Collapsing gullies are among the most severe soil erosion problems in the tropical and subtropical areas of southern China. However, few studies have examined the relationship of soil particle size distribution (PSD) changes with land-use patterns in the alluvial fans of collapsing gullies. Recently, the fractal method has been applied to estimate soil structure and has proven to be an effective tool in analyzing soil properties and their relationships with other eco-environmental factors.

[Oxidation Process of Dissolvable Sulfide by Manganite and Its Influencing Factors].

As one of the manganese oxides, which are easily generated and widely distributed in supergene environment, manganite participates in the oxidation of dissolvable sulfide (S²⁻), and affects the migration, transformation, and the fate of sulfides. In the present work, the redox mechanism was studied by determining the intermediates, and the influence of initial pH and oxygen atmosphere on the processes were studied. The chemical composition, crystal structures and micromorphologies were characterized by XRD, FTIR and TEM.

Variation of Soil Aggregation along the Weathering Gradient: Comparison of Grain Size Distribution under Different Disruptive Forces.

The formation and stabilization of soil aggregates play a key role in soil functions. To date, few studies have been performed on the variation of soil aggregation with increasing soil weathering degree. Here, soil aggregation and its influencing factors along the weathering gradient were investigated.

Interaction mechanisms and kinetics of ferrous ion and hexagonal birnessite in aqueous systems.

Background: In soils and sediments, manganese oxides and oxygen usually participate in the oxidation of ferrous ions. There is limited information concerning the interaction process and mechanisms of ferrous ions and manganese oxides. The influence of air (oxygen) on reaction process and kinetics has been seldom studied.

Assessing regional environmental quality by integrated use of remote sensing, GIS, and spatial multi-criteria evaluation for prioritization of environmental restoration.

This study was an attempt to analyse the regional environmental quality with the application of remote sensing, geographical information system, and spatial multiple criteria decision analysis and, to project a quantitative method applicable to identify the status of the regional environment of the study area. Using spatial multi-criteria evaluation (SMCE) approach with expert knowledge in this study, an integrated regional environmental quality index (REQI) was computed and classified into five levels of regional environment quality viz. worse, poor, moderate, good, and very good.

Effects of vegetation on runoff generation, sediment yield and soil shear strength on road-side slopes under a simulation rainfall test in the Three Gorges Reservoir Area, China.

Vegetation recolonization has often been used to control roadside slope erosion, and in this paper, four restoration models - Natural Restoration, Grass, Grass & Shrub, Sodded Strip - were chosen to recolonize the plants on a newly built unpaved roadside slope in the Three Gorges Reservoir Area. After eight months growth, eight rainfall simulations (intensity of 90 mm h(-1) for 60 min) and in-situ soil shear strength test were then carried out to identify the impacts of vegetation on roadside slope erosion and soil shear strength. The erosion on cutslopes was higher than that on fillslopes.

[Effects of different vegetation protection measures on erosion prevention of unpaved roadside slopes in Three Gorges Reservoir Area].

One of the main impacts of road construction is the creation of bare and steep slopes when lack of vegetation protection, which usually generates serious soil loss, a major erosion source in mountainous areas. In this study, six treatments including planting grass (GRA), grass and bush (GBC), building terrace combined with grass and bush (TGB), planting sod strip (SS), building sloping farmland (SFL), and building sloping farmland combined with grass (SFLG) were installed on the newly constructed unpaved roadside slopes in Three Gorges Reservoir Area to investigate the effects of these measures on the erosion prevention of the unpaved roadside slopes under natural rainfall. Among the six treatments, GBC had the best effect, which had the quickest revegetation rate (the mean vegetation coverage increased from 20.

The effects of land use change on environmental quality in the red soil hilly region, China: a case study in Xianning County.

Land use and land cover change is gaining recognition as a key driver of environmental change. Rapid change of land use has occurred in the red soil hilly region of southeast China in the past three decades due to rural land reform, population pressure and rapid economic growth. In this paper, land use change and its impacts on environmental quality of Xianning County were investigated using technologies of remote sensing (RS), geographic information systems (GIS), and spatial principal components analysis (SPCA).

[Dynamic changes of forest vegetation coverage in letianxi basin of Three Gorges Reservoir Area: a study based on multi-source data].

Based on the multi-temporal and multi-source sensor images of 1987-2005, the dynamic changes of forest vegetation coverage in Letianxi basin of Three Gorges Reservoir Area were investigated by the methods of color balancing, image fusion, and radiometric normalization. The results showed that in 1987-2005, the forest area in the basin increased from 265.82 km2 to 346.