scholarly journals Problem hydromorphic soils in north-east Thailand. 2. Physical and chemical aspects, mineralogy and genesis.

1977 ◽  
Vol 25 (3) ◽  
pp. 170-181
Author(s):  
R. Brinkman

The Roi Et soil, which occurs on the extensive seasonally wet low terrace, is a silt loam with low clay contents in the surface horizon; the clay content increases with depth. The soil is seasonally water-saturated and seasonally dry, has considerable porosity, but has a dense ploughpan at a depth of about 0.2 m and a dense substratum below 1.4 m. The soil is strongly acid with a low base saturation and a very low cation exchange capacity. The silt and sand are 98% quartz. Disordered kaolinite is the main clay mineral. About a fifth of the clay fraction is soil chlorite - a strongly Al-interlayered vermiculite in the upper horizons but partially Al-interlayered in the substratum. The interlayers contain a small amount of ferrous iron. The quartz contents in the clay fractions range from one tenth in most of the profile to about three tenths in the surface horizon, with a corresponding decrease in kaolinite. The kaolinite in the upper horizons shows signs of dissolution. These data are in accordance with hypothetical clay eluviation-illuviation and long-continued Fe redistribution and ferrolysis, the ferrolysis involving clay alteration and dissolution under conditions of alternating reduction and oxidation of Fe. (Abstract retrieved from CAB Abstracts by CABI’s permission)

2021 ◽  
Vol 17 (AAEBSSD) ◽  
pp. 147-149
Author(s):  
P.N. Tripathi ◽  
U.S. Mishra ◽  
Pawan Sirothia ◽  
R.P. Singh

Three representative soil pedonsof northern hills of Chhattisgarh, M.P were morphologically studied, characterized and classified. The soils are very deep, colour ranges from brown (10YR5/3) to dark brown (10YR3/3) and very dark greyish brown (10YR3/2) in different horizons. Fe and calcretes are observed in sub surface horizons. The texture in surface soils varied from clay loam to clay while in pedon 2, the texture was observed sandy clay loam throughout the profile. The soils are calcareous and pH ranged from 7.0 to 7.5. The organic carbon content in these soils were (4.4 g kg-1), low to medium (6.1 g kg-1) in surface and decreased with depth. Cation exchange capacity (CEC) were found high in horizons where clay content was more. Based on morphological, physical and chemical properties P1 and P3 were classified as VerticHaplustalfs and pedon (P2) was placed under Typic Haplustepts.


1991 ◽  
Vol 116 (2) ◽  
pp. 275-279 ◽  
Author(s):  
E. P. Papanicolaou ◽  
C. G. Apostolakis ◽  
V. Skarlou ◽  
C. Nobeli ◽  
P. Kritidis

SUMMARYPlant:soil ratios (CRs) of 85Sr concentration were studied in wheat, lucerne, lettuce, radish, string bean (Phaseolus vulgaris), and cucumber grown in pots in eight Greek soil types in a glasshouse pot experiment in 1989.The CRs of the crops and of the plant parts studied differed according to soil type. They ranged from 0·034–1·39 for wheat grains to 7·6–36·5 for cucumber stems and leaves. The CRs of the edible parts were much lower than those of the other plant material.The correlation between CRs and clay content was negative and, in most cases, significant (P = 0·05–0·01) or highly significant (P < 0·01). The negative correlation improved (higher absolute value of r, lower variability) if clay plus silt content or cation exchange capacity was used instead of clay content.The correlation between CRs and soil properties was greatest for soil pH (r = –0·89) and decreased in the order: pH > total clay plus silt ≃ cation exchange capacity > total clay.


1992 ◽  
Vol 25 (11) ◽  
pp. 41-48 ◽  
Author(s):  
Y. Shimizu ◽  
S. Yamazaki ◽  
Y. Terashima

The sorption of pentachlorophenol (PCP, pKa’ = 4.75) onto natural solids from aqueous phase was investigated by batch sorption experiments. The experimental aqueous phase was prepared for set values of pH (2 to 12) and ionic strength (0.1 M). Experimental results indicated that the sorption decreased with increasing pH over the entire pH range tested. A simple mathematical model, based on the hypotheses that the sorption coefficients of non-ionized and ionized species are different and the pH has only negligible effect on the natural solid characteristics, was applied to the pH range between 6 and 8, and the sorption coefficients (Kd) of both species were estimated. The Kd of ionized species (phenolate anion) was smaller than that of non-ionized species. The Kd of both species had poor correlation to the organic carbon content of natural solids. The Kd, however, correlated well with the swelling clay content and cation exchange capacity of natural solids. These results indicated that the sorption of PCP was not controlled by the organic carbon referenced hydrophobic sorption. For broader pH range (i.e., below 6 or above 8), the dependence of the natural solid characteristics on pH must be additionally included in the model.


2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Nenad Tomašić ◽  
Štefica Kampić ◽  
Iva Cindrić ◽  
Kristina Pikelj ◽  
Mavro Lučić ◽  
...  

AbstractThe adsorption properties in terms of cation exchange capacity and their relation to the soil and sediment constituents (clay minerals, Fe-, Mn-, and Al-oxyhydroxides, organic matter) were investigated in loess, soil-loess transition zone, and soil at four loess-soil sections in North-Western Croatia. Cation exchange capacity of the bulk samples, the samples after oxalate extraction of Fe, Mn and Al, and after removal of organic matter, as well as of the separated clay fraction, was determined using copper ethylenediamine. Cation exchange capacity (pH∼7) of the bulk samples ranges from 5 to 12 cmolc/kg in soil, from 7 to 15 cmolc/kg in the soil-loess transition zone, and from 12 to 20 cmolc/kg in loess. Generally, CEC values increase with depth. Oxalate extraction of Fe, Mn, and Al, and removal of organic matter cause a CEC decrease of 3–38% and 8–55%, respectively, proving a considerable influence of these constituents to the bulk CEC values. In the separated clay fraction (<2 μm) CEC values are up to several times higher relative to those in the bulk samples. The measured CEC values of the bulk samples generally correspond to the clay mineral content identified. Also, a slight increase in muscovite/illite content with depth and the vermiculite occurrence in the loess horizon are concomitant with the CEC increase in deeper horizons, irrespective of the sample pretreatment.


Clay Minerals ◽  
2012 ◽  
Vol 47 (4) ◽  
pp. 499-511 ◽  
Author(s):  
A. Mbaye ◽  
C. A. K. Diop ◽  
B. Rhouta ◽  
J. M. Brendle ◽  
F. Senocq ◽  
...  

AbstractThere is interest in exploiting and developing natural resources, particularly deposits of natural clays. Senegal has several clay mineral deposits for which chemical and mineralogical compositions have been little studied. Some of these natural materials are nowadays used in pottery and ceramics. To extend applications, a better basic knowledge is required and, for this objective, the raw clay and separated <2 μm clay fraction from Keur Saër (Senegal) were subjected to chemical and mineralogical studies. Several techniques including X-ray diffraction (XRD), thermal analysis (TG-DTA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), N2 adsorption-desorption isotherms, cation exchange capacity (CEC) measurements and solid state nuclear magnetic resonance (NMR) have been used to characterize the material. It was found that the raw clay and the separated clay fraction consist of a mineral mixture in which kaolinite is the main component. 29Si and 27Al MAS-NMR spectra show the presence of silicon atoms linked to three other silicon atoms via an oxygen atom and six coordinated Al atoms. Significant increases in the specific surface area and cation exchange capacity were observed on purification, reaching a maximum of about 73.2 m2g–1 and 9.5 meq/100 g for the separated fine clay fraction while the values for the raw material were around 28.9 m2g–1 and 7.3 meq/100 g.


Soil Research ◽  
1994 ◽  
Vol 32 (5) ◽  
pp. 1015
Author(s):  
PW Moody

Krasnozems (Ferrosols) characteristically have high contents of citrate-dithionite extractable Fe and moderate to high contents of clay throughout the profile. They typically have low cation exchange capacity (2-20 cmolc kg-1), high P sorbing ability, and a significant anion exchange capacity at depth. The chemistry of krasnozems is dominated by the variable charge characteristics of the organic matter and the oxy-hydroxides of Fe and Al which occur in the predominantly kaolinitic clay fraction. The effects of surface charge characteristics, organic matter, and extractable iron and aluminium on the cation and anion exchange capacities, P sorbing abilities and pH buffer capacities of Australian krasnozems are reviewed. A selection of reports of nutrient deficiencies and toxicities in these soils is presented and briefly discussed. Published data on the chemical composition of the soil solutions of krasnozems are reviewed. Data from a suite of paired (undeveloped and developed) krasnozem profiles from eastern Australia indicate that exchangeable Ca and Mg, effective cation exchange capacity (ECEC), pH buffer capacity (pHBC) and total N decrease significantly (P < 0.05) in the A horizon following development, while exchangeable K, ECEC and pHBC decrease (P < 0-05) in the B horizon. The decreases in the A horizon are shown to be a direct consequence of the decline in organic matter which occurs following development. Because of the crucial role that organic matter plays in the chemical fertility of krasnozems, they are less likely to maintain their fertility under exploitative conditions than other productive clay soils such as Vertosols. It is concluded that the sustainable use of krasnozems will depend on maintenance or enhancement of organic matter levels, maintenance of surface and subsoil pH by regular application of amendments, minimization of erosion, and replacement of nutrients removed in harvested products.


2017 ◽  
Vol 29 (2) ◽  
pp. 123-131
Author(s):  
Reshma Akter ◽  
Md Jamal Uddin ◽  
Md Faruque Hossain ◽  
Zakia Parveen

A study was carried out to evaluate the effects of brick manufacturing on phosphorus (P) and sulfur (S) concentrations in soil and plant collected from different distances of brick kilns in four AEZs of Bangladesh. Forty eight composite soil samples (0 - 15 cm depth) were collected from 48 points in 12 different sites at 0 m, 300 m, 800 m and 1500 m from brick kilns, where most (site 2, site 3, site 5, site 6, site 7, site 9 and site 10) of the brick kilns used coal for brick burning purposes. Plant samples (rice straw and different vegetables) were also collected from the respective fields except 0 m distances. Significantly (p ? 0.05) lower organic matter, cation exchange capacity, clay content and soil pH were found at 0 m distances compared to other distances. Highest concentration of total P in soil were recorded at 0 m distances and these concentrations decreased with increasing distances from the brick kilns in most of the sites; whereas available P is significantly lower at 0 m distances than that of other distances. Total and available concentration of S in soil followed the trend 0 m>300 m>800 m>1500 m. Maximum accumulation of P (69.15 mg kg-1) and S (0.14%) in plant was found at 800 m away from the brick kiln.Bangladesh J. Sci. Res. 29(2): 123-131, December-2016


1971 ◽  
Vol 51 (3) ◽  
pp. 405-410
Author(s):  
A. K. Ballantyne

Leaching a silt loam soil (cation exchange capacity 23 meq/100 g) with water containing increasing rates of potassium dust (KCl) indicated that high levels adversely affected germination and yields of wheat as well as response to fertilizer. Germination was greatly reduced by the treatment with 22.4 metric tons per hectare and nearly eliminated by 44.8 tons. The 44.8-ton/ha treatment also greatly reduced the yield of grain, but straw weights were affected very little by increasing rates of potassium dust. Response to fertilizer was also reduced by 22.4 and 44.8 tons. The exchangeable Ca and Mg decreased and K increased as increasing amounts of K dust were leached through the soil. The 44.8-ton treatment decreased the exchangeable Ca from 56.0 to 24.9% and the Mg from 21.2 to 4.9%, and increased the K from 7.2 to 51.9%. It would appear that K salts can be added to the soil, without any adverse effects, until the exchangeable K is increased to about 30%. With the soil under study this took more than 11.2 tons per ha (5 short tons/acre). The application of dolomite ameliorated the effect of excess K.


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