Lateritic soils of Kerala, India: their mineralogy, genesis, and taxonomy

Soil Research ◽  
2005 ◽  
Vol 43 (7) ◽  
pp. 839 ◽  
Author(s):  
P. Chandran ◽  
S. K. Ray ◽  
T. Bhattacharyya ◽  
P. Srivastava ◽  
P. Krishnan ◽  
...  

In this study, we report the chemical and mineralogical characteristics of 4 benchmark Ultisols of Kerala to elucidate their genesis and taxonomy. The taxonomic rationale of the mineralogy class of Ultisols and other highly weathered soils on the basis of the contemporary pedogenesis is also explained. The Ultisols of Kerala have low pH, low cation exchange capacity, low effective cation exchange capacity and base saturation, with dominant presence of 1 : 1 clays and gibbsite. Presence of gibbsite along with 2 : 1 minerals discounts the hypothesis of anti-gibbsite effect. Since the kaolins are interstratified with hydroxy-interlayered vermiculites (HIV), the formation of gibbsite from kaolinite is not tenable. Thus, gibbsite is formed from primary minerals in an earlier alkaline pedo-environment. Therefore, the presence of gibbsite does not necessarily indicate an advanced stage of weathering. On the basis of a dominant amount of gibbsite, a mineralogy class such as allitic or gibbsitic does not establish a legacy between the contemporary pedogenesis and the mineralogy. The dominance of kaolin–HIV in the fine clays of Ultisols and their persistence, possibly since early Tertiary, suggests that ‘steady state’ may exist in soils developed on long-term weathered saprolite. Since the present acid environment of Ultisols does not allow desilication, the chemical transformation of Ultisols to Oxisols with time is difficult to reconcile as envisaged in the traditional model of tropical soil genesis.

SOIL ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 23-33 ◽  
Author(s):  
S. Czarnecki ◽  
R.-A. Düring

Abstract. Essential and non-essential metals occur in soils as a result of weathering, industrial processes, fertilization, and atmospheric deposition. Badly adapted cultivation of agricultural soils (declining pH value, application of unsuitable fertilizers) can enhance the mobility of metals and thereby increase their concentrations in agricultural products. As the enrichment of metals in soils occurs over long time periods, monitoring of the long-term impact of fertilization is necessary to assess metal accumulation in agricultural soils. The main objective of this study was to test the effects of different mineral fertilizer variations on soil properties (pH, Corg, and cation exchange capacity (CEC)) and pseudo-total and mobile metal contents of soils after 14 years of fertilizer application and to determine residual effects of the fertilization 8 years after cessation of fertilizer treatment. Soil samples were taken from a field experiment which was carried out at four different locations (210, 260, 360, and 620 m above sea level) in Hesse, Germany. During the study, a significant decrease in soil pH and an evident increase in soil carbon content and cation exchange capacity with fertilization were determined. The CEC of the soils was closely related to their organic C contents. Moreover, pseudo- and mobile metal (Cd, Cu, Mn, Pb, Zn) contents in the soils increased due to application of 14 years of mineral fertilizer treatments (N, P, NP, and NPK) when compared to control plots. Eight years after termination of the fertilization in the soil samples taken from soil profiles of the fertilized plots (NPK) for monitoring the residual effects of the fertilizer application, a decrease of 82.6, 54.2, 48.5, 74.4, and 56.9% in pseudo-total Cd, Cu, Mn, Pb, and Zn contents, respectively, was determined.


2021 ◽  
Vol 70 (1) ◽  
pp. 13-26
Author(s):  
Miodrag Tolimir ◽  
Branka Kresović ◽  
Borivoj Pejić ◽  
Katarina Gajić ◽  
Angelina Tapanarova ◽  
...  

The impact of long-term (> 100 yr) irrigation on soil chemical properties was studied on eight plots in the Beli Drim river valley in Kosovo and Metohija near Klina, Serbia. For these studies, soil samples from shallow profiles were collected from only one or two depth zones of the Ah horizon; and from moderately deep and deep profiles, from two to three depth zones for the purpose of comparing irrigated field and non-irrigated meadow lands. Water from the Beli Drim River and surface gravity systems (irrigation furrows or border strip irrigation) were used for irrigation. Chemical variables included determination of pH-H2O, content of CaCO3, content of humus, hydrolytic acidity, sum of basic cations, cation exchange capacity, and base saturation. On irrigated soils, the results of chemical analysis showed on average a small increase in pH-H2O (0.07 pH units), as well as a significant decrease in humus content (2.00-4.75%), sum of basic cations (4.98-12.98%) and cation exchange capacity (12.8%) compared to the non-irrigated land of the study area. Long-term irrigation had no effect on hydrolytic acidity and base saturation in the Ah horizon of the investigated lands. Namely, the mentioned variations in the chemical properties of the investigated soils show that slight processes of reduction in the humus content and reduction of the content of base cations occured. Data on the chemical properties of the investigated soils indicate that the destructive processes of reduction in the humus content and leaching of base cations must be controlled in order to achieve a stable sustainable system of high productivity and prevent their further deterioration.


1963 ◽  
Vol 43 (2) ◽  
pp. 229-234 ◽  
Author(s):  
A. A. MacLean ◽  
J. J. Doyle

Residual effects of long-term annual applications of fertilizer potassium on the potassium status of an acid sandy loam Podzol were investigated, in a greenhouse experiment. Potassium accumulated in the surface soil in a form readily available to plants.On plots with higher cation exchange capacities, resulting from manurial treatments, there was no evidence to indicate leaching below 15 inches. On plots where cation exchange capacity was not increased by treatment, a higher percentage potassium saturation at greater depths indicates that leaching of potassium had occurred to a depth of 21 inches. An increased concentration of nitric acid-soluble potassium at greater depths suggests that some of the leached potassium has been converted to the non-exchangeable form.Accumulation in the surface soil was sufficient to supply most of the potassium requirement of ladino clover under conditions of intensive cropping. The results suggest that exchangeable and nitric acid-soluble potassium are reliable criteria of available potassium.


1961 ◽  
Vol 12 (2) ◽  
pp. 273 ◽  
Author(s):  
JS Russell

Changes in the cation exchange complex are one of the secondary effects arising out of the increasing organic matter content of soils, due to the influence of phosphorus fertilizers on leguminous pastures. Analysis of solonetzic soils from the long-term Kybybolite P plots indicates that there is a close relation between organic matter increase and increases in cation exchange capacity. For each increase of 0.1 % soil nitrogen, there has been a corresponding increase of 3.48 m-equiv.jl00 g in cation exchange capacity. Associated with these changes there have been increases in the level of exchangeable calcium and exchangeable hydrogen. Changes in exchangeable calcium appear related to the amount and form of fertilizer or amendment applied. Where little calcium has been added, the increase in cation exchange capacity has been satisfied almost entirely by hydrogen, and base saturation has decreased. There appears to have been little upward movement of metal cations from the lower horizons to the surface by plants, possibly owing to the species involved, or to the intractable nature of the B horizon. The possible effects of changes in the cation exchange complex on plant growth are discussed. Also, the possibility of maintaining base saturation on infertile soils where cation exchange capacity is being increased, is examined.


Soil Research ◽  
1979 ◽  
Vol 17 (1) ◽  
pp. 129 ◽  
Author(s):  
GP Gillman

The 'compulsive exchange' method of Bascomb has been modified to allow the determination of cation exchange capacity and anion exchange capacity of soils containing significant quantities of constant potential surfaces. The soil is equilibrated with unbuffered barium chloride solution at an ionic strength approximating that of the soil solution, so that the conditions under which determinations are made are similar to those found in the field. Barium on the exchange complex is then replaced by magnesium when the latter is added as magnesium sulfate, and this is accomplished without altering the solution ionic strength. If desired, exchangeable basic cations can be determined as an additional step in the procedure. Results obtained by the proposed method are compared with other commonly used procedures for determining cation exchange capacity and exchangeable basic cations.


Soil Research ◽  
2001 ◽  
Vol 39 (4) ◽  
pp. 799 ◽  
Author(s):  
G. P. Gillman ◽  
D. C. Burkett ◽  
R. J. Coventry

Surface (0–10 cm) samples from 7 highly weathered soils in tropical coastal Queensland were incubated for 3 months at room temperature and at field moisture capacity with basalt dust applied in 2 size fractions: <150 µm and 40 µm. The basalt application was mixed at 0, 1, 5, 25, and 50 t/ha to cover situations of moderate applications as well as where the amendment might be banded to achieve high local concentrations. Basalt dust application caused desirable increases in soil pH, reduced the content of exchangeable acidic cations, increased soil cation exchange capacity, and increased the content of base cations in all soils. By determining fundamental surface charge characteristics of these variable charge soils, it was possible to show that the additional base cations released from the basalt dust were present as exchangeable cations, and that the amounts released were controlled by the number of negatively charged sites available, i.e. soil cation exchange capacity. Selected treatments were then subjected to a strong leaching environment to assess the longevity of the effects obtained. Soil properties remained virtually unchanged by the leaching treatment, except that significant amounts of monovalent K and Na were removed. At the higher rates of application, the amounts of base cations released from the basalt were small in comparison with the actual amounts applied, indicating that the amendment could be effective over a considerable period of time.


Soil Research ◽  
2015 ◽  
Vol 53 (4) ◽  
pp. 377 ◽  
Author(s):  
D. Curtin ◽  
P. M. Fraser ◽  
M. H. Beare

Cultivation of grassland is known to lead to the depletion of soil organic matter (SOM), but the effect on the size and composition of the exchangeable cation suite has not been documented. We measured cation exchange capacity (CEC) and exchangeable cations (calcium, Ca; magnesium, Mg; potassium, K; sodium, Na), as well as soil carbon (C) and nitrogen (N) (0–7.5, 7.5–15, and 15–25 cm), 8 years after conversion of long-term ryegrass–white clover pasture (grazed by sheep) to annual crop production. The trial was near Lincoln, Canterbury, New Zealand. The trial included three tillage treatments: crops established using intensive cultivation (mouldboard ploughing), minimum tillage (shallow cultivation, ~10 cm), or no-tillage. The 8-year rotation was barley, wheat, pea, barley, pea, barley, barley, barley. A sheep-grazed pasture was maintained as an experimental control. The experiment also included a permanent fallow treatment (maintained plant-free using herbicides; not cultivated). After 8 years under arable cropping, soil C stocks (0–25 cm) were 10 t ha–1 less, on average, than under pasture. The vertical distribution of soil organic matter (SOM) was affected by tillage type, but the total amount of organic matter in the top 25 cm did not differ (P > 0.05) among the tillage treatments. Under permanent fallow (C loss of 13 t ha–1 relative to pasture), total exchangeable cation (Ca + Mg + K +Na) equivalents declined by 47 kmolc ha–1, a 20% decrease compared with pasture. Loss of exchange capacity resulted in the selective release of cations with lower affinity for SOM (K, Na, Mg). Smaller losses of exchangeable cations were recorded under the arable cropping rotation (average 31 kmolc ha–1), with no differences among tillage treatments. Effective CEC (at field pH) decreased under permanent fallow and cultivated treatments because of: (1) depletion of SOM (direct effect); and (2) soil acidification, which eliminated some of the remaining exchange sites (indirect effect). Acidification in the permanent fallow can be attributed to the N mineralisation process, whereas in the cropped systems, excess cation removal in harvested straw and grain accounted for about half of the measured acidification. There was evidence that the organic matter lost under arable cropping and fallow had lower CEC than SOM as a whole.


Sign in / Sign up

Export Citation Format

Share Document