Study on Adsorption of Rare Earth Elements by Kaolinite

For better understanding the adsorption of rare earth elements (REEs) by clay minerals and its controlling factors, the experiments on adsorption of REEs in solutions with 1 g·L-1 kaolinite were performed at different conditions. The results are as follows: the REEs reach equilibrium in the adsorption-desorption process for 24; Langmuir′s adsorption curve is used for modeling the adsorption of REEs by kaolinite; a general trend is that the higher the contents of REEs are, the less obvious the fractionation is. Furthermore, there is significant effect of pH on the adsorption and fractionation of REEs by kaolinite, and the REEs distribution coefficient increases with increasing pH. When pH is nearly neutral, as reaches 7, heavy REEs are more adsorbed than light REEs.

Effect of Rare Earths on Fractionation and Transformation of Soil Available Nitrogen

The effect of rare earths (RE) on fractionation and transformation of available nitrogen in a yellow cinnamon soil was studied with soil cultivation. The results show that under the dry condition, when the extraneous RE are added to the soil, both concentrations of soil ammonium N and hydrolysable N increase, and the concentrations of soil nitric N decrease. The concentrations of soil available N increase with the increase of RE concentrations in soils when the RE concentrations are low, but it decreases with the increase of high RE concentrations in soils. The NOEC (no observed effect concentration) of the extraneous RE to available N in the soils is 443.8 mg·kg -1 . Under the inundated condition, low RE concentrations in soil has no significant effect on soil ammonium N and hydrolysable N. However, when the soil RE concentrations are high, both of them decrease with the increase of RE concentrations. The NOEC of the extraneous RE to soil ammonium N and hydrolysable N are 171.2 and 256.9 mg·kg -1 , respectively.

Effects of Lanthanum and Cerium on Acid Phosphatase Activities in Two Soils

To evaluate the security of using thulium, comparision between effects of La and those of Ce on acidic phosphatase activities in red soil and yellow soil in Zhejiang district was studied under conditions of ambient temperature and humidity. Results show that the acid phosphatase from different soil respondes to La and Ce differently. The activity of acid phosphatase in soil 1 declines with the increase of the concentration of La and Ce. The maximum inhibitory ratio of La and Ce reaches 69.8% and 71.0% respectively. But La and Ce have stimulative effect on the activity of acid phosphatase in soil 2. Under the effect of same concentration of the thulium, the acid phosphatase in two soils increases with the extending of culture time.

Temporal Stability of Apparent Soil Electrical Conductivity Measured by Electromagnetic Induction Techniques

Assessing and managing the spatial variability of hydropedological properties are important in environmental,agricultural,and geological sciences.The spatial variability of soil apparent electrical conductivity(ECa) measured by electromagnetic induction(EMI) techniques has been widely used to infer the spatial variability of hydrological and pedological properties.In this study,temporal stability analysis was conducted for measuring repeatedly soil ECa in an agricultural landscape in 2008.Such temporal stability was statistically compared with the soil moisture,terrain indices(slope,topographic wetness index(TWI),and profile curvature),and soil properties(particle size distribution,depth to bedrock,Mn mottle content,and soil type).Locations with great and temporally unstable soil ECa were also associated with great and unstable soil moisture,respectively.Soil ECa were greater and more unstable in the areas with great TWI(TWI > 8),gentle and concave slope(slope < 3%; profile curvature > 0.2).Soil ECa exponentially increased with depth to bedrock,and soil profile silt and Mn mottle contents(R2= 0.57),quadratically(R2 = 0.47),and linearly(R 2 = 0.47),respectively.Soil ECa was greater and more unstable in Gleysol and Nitosol soils,which were distributed in areas with low elevation(< 380 m),thick soil solum(> 3 m),and fluctuated water table(shallow in winter and spring but deep in summer and fall).In contrast,Acrisol,Luvisol,and Cambisol soils,which are distributed in the upper slope areas,had lower and more stable soil ECa.Through these observations,we concluded that the temporal stability of soil ECa can be used to interpret the spatial and temporal variability of these hydropedological properties.

Geochemical Characteristics of Rare Earth Elements in Sewage Discharge Channels of Tianjin

The geochemical features of rare earth elements (REEs) in the North and South sewage discharge channels of Tianjin were studied. The results show that concentrations of dissolved REEs in water of the sewage discharge channels are very low, while concentrations of Eu and heavy REEs are higher than those in natural rivers. Concentrations of REEs in unfiltered water are high and they mainly resided on suspended matter. Distribution patterns of the dissolved and suspended light REEs vary reversely with the atomic number. Concentrations of REEs in the sediments and suspended matter are lower than those in natural rivers, and concentrations of REEs in the suspended matter are much lower than those in the sediments. Distribution patterns of REEs in sediments and suspended matter were similar with light REE enrichment and positive Eu-anomaly. This distribution pattern is different from those of natural rivers. The differences may cause by the large amount of organic pollutants in sewage.

Biogeochemical Cycle and Residue of Extraneous Rare Earth Elements in Agricultural Ecosystem

Four groups of field experiments including foliage dressing with a regular amount of rare earth elements (REEs), soil dressing with a regular amount of REEs, soil dressing with a triple regular amount of REEs and the control were carried out in Panggezhuang Village, Daxing County, Beijing, where REE fertilizers are widely applied. The input and output fluxes of all kinds of REEs in the soil and plant system were measured using ICP-MS. The results show that the total amount of REEs carried by rain, snow, irrigation water, composite fertilizer and dust is at a very low level in the control field, which is only about 19.3 g·nm^(-1) per year. The amounts of REE input in the fields with application of extraneous REEs are much higher than that under control. The total amounts of REE input in the fields with foliage dressing and soil dressing are 9.7 and 106 times higher than that under control, respectively. However, the total outputs of REEs via wheat and infiltrated water are quite similar among the four experimental fields. Uptake of wheat is the main way of output and concentrations of REEs in different organs follow a descending order of roots>leaves>stems>crusts>seeds. Based on calculation, the amount of REE output is slightly higher than that of input in the control field, which implies that it is hard for REEs to accumulate in the soils without application of REE fertilizers. In the fields with the application of extraneous REEs, the amount of REEs in soils can increase with the increasing input of REEs. If REE-fertilizers are applied regularly via soil dressing with the ordinary amount, the concentrations of REEs in the surface soils may double in 159 years. The speed of REE accumulation with foliage dressing is much lower than that with soil dressing, and it needs 2008 years to double the concentrations of REEs in surface soils.

Summary of Experience from the Long-Term Pedological Research on the Banks and Slopes of Lake Most

This paper briefly assesses the conclusions from the long-term research of soil properties of the banks and shore of Lake Most. This paper mainly deals with the long-term development of the soil parameters of the anthropogenic soil profile and, to a lesser extent, the assessment of soil habitats with a typical flora. The experience gained will aid in the planning of further hydrological reclamation.

Soils of Fildes Peninsula,King George Island,the maritime Antarctic:Part^->.Formation processesand pedogenetic particu-larities

Based on the data obtained from tens of the investigated soil profiles scattered over the Fildes Peninsula, King George Island, the maritime Antarctic, the soil forming processes were discussed. It was concluded that on the weathering crusts resulted from various physical courses, the strong freeze thaw action within regolith, significant organic matter accumulation, evident leaching and illuviation, as well as initial argillification dominated the formation and development of the soils on the Fildes Peninsula. Furthermore, this study indicated that the juvenility of genesis, poor profile expression, variation in column thickness, etc. characterized the pedogenetic features of the soils of the Fildes Peninsula.

Soil Mapping of a Small Watershed in a Brazilian Savanna Biome: A Semi-Automatic Approach

The objective of this work is to propose a semi-automatic methodology for the creation of a semidetailed to detailed watershed’s soil map. This methodological proposal is based on the traditional method (field work and photo interpretation) and on morphometric variables analysis, using data originated from the Digital Elevation Model (DEM) of the Shuttle Radar Topography Mission (SRTM) program. The steps taken through this methodological proposal were the identification of the hydromorphic areas boundaries through interpretation of aerial orthophotographs;the compartmentalization of the relief through color composition techniques using the morphometric variables—slope, altimetry and horizontal curvature;the development of a pedological database based on data gathered in the field;the elaboration of a preliminary soil map based on the compartmentalized relief and on the dataset of the soils sampled in the field;the elaboration and adjustment of the final soil map according to the interpretation of aerial photographs and also the physical and chemical analyses of the soils. This semi-automatic methodology demonstrated improved efficiency in defining the soil units, reducing operation time and subjectivity of the process, thereby contributing to the systematization of soil mapping at watershed level in scale 1:50,000, as well as, promoting better knowledge between the relation of the geomorphic and soil variables in the Brazilian Savanna Cerrado.

Clay Sorbents in the Area of the Most and Sokolov Basins as a Possible Use in Agriculture Reclamations

This paper is devoted to the possibilities of the reclamation use of claystone sorbents of the Most and Sokolov basins. The properties of phytotoxic areas suitable for the application of sorbents, the locality, and parameters of the main clay sorbents of both brown coal basins are briefly summarized in the paper. Clay sorbents are suitable for the reclamation of phytotoxic surfaces contaminated by coal. This paper provides a brief evaluation of the properties of the claystone sorbents of the North Bohemian and Sokolov basins. In the region of the North Bohemian brown coal basin, potential sorbents can be used for the reclamation works.

Micromorphological description of vernacular cob process and comparison with rammed earth

Past builders have developed very low-embodied energy construction techniques optimizing the use of local building materials.These techniques are a source of inspiration for modern sustainable building.Unfortunately,this know-how was orally transmitted and was lost as earth construction fell into disuse during the 20th century in European countries.The absence of written documents makes necessary to use an archaeological approach in order to rediscover these construction strategies.Micromorphological analysis of thin sections collacted in earth building walls was used for the first time to describe cob construction technique and highlighted several typical pedofeatures allowing to clearly identifying this process.Finally,a first comparison of the cob and rammed earth micromorphological features permitted to identify two key factors to distinguish these two techniques,the manufacturing state(solid or plastic)and the organization of the material in the wall.