The Experts below are selected from a list of 132 Experts worldwide ranked by ideXlab platform
V. V. Prokoshev - One of the best experts on this subject based on the ideXlab platform.
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Effect of Potassium fertilizer composition on the Potassium status of soddy-podzolic soils under model experimental conditions
Moscow University Soil Science Bulletin, 2007Co-Authors: S. G. Borzenko, T. A. Sokolova, V. V. ProkoshevAbstract:A model experiment was conducted with samples from arable horizons of loamy sandy and loamy soddy-podzolic soils under laboratory conditions. The samples were stored with KCl, K2SO4, and Potassium-E was added at rates of 240 and 960 kg/ha under alternating moistening and drying for 90 days. The contents of nonExchangeable, Exchangeable, and easily Exchangeable Potassium and the K+ activity in 1: 2.5 water suspensions were measured in the original samples and after the end of the experiment. The contents of nonExchangeable, Exchangeable, and easily Exchangeable Potassium were found to not be reliably affected by the composition of Potassium fertilizers; the K+ activity was lower when Potassium was added as K2SO4 than in the cases of KCl and Potassium-E.
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Kinetics of readily Exchangeable Potassium displacement by calcium from soddy-podzolic soils of different textures
Eurasian Soil Science, 1999Co-Authors: T. A. Sokolova, V. V. Nosov, V. V. ProkoshevAbstract:The release of readily Exchangeable Potassium from sandy soddy-podzolic soils during a time period from 12 to 315 min is adequately described by the equations of the first-order reaction and external diffusion; its release from loamy soddy-podzolic soils during the interval from 22 to 428 min is described by the equations of first- and second-order reactions and, possibly, internal diffusion.
Arvind Kumar Shukla - One of the best experts on this subject based on the ideXlab platform.
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spatial distribution of surface soil acidity electrical conductivity soil organic carbon content and Exchangeable Potassium calcium and magnesium in some cropped acid soils of india
Land Degradation & Development, 2015Co-Authors: Sanjib Kumar Behera, Arvind Kumar ShuklaAbstract:Land degradation is a global problem. Best management of degraded land can be done by evaluating the spatial variability of soil properties including chemical properties of degraded land and mapping such variations. Since, a significant portion of arable land in India is chemically degraded due to soil acidity; the present study was conducted to study the spatial variability of soil acidity (pH), electrical conductivity (EC), soil organic carbon (OC) content, Exchangeable Potassium (K+), calcium (Ca2+) and magnesium (Mg2+) contents in some cropped acid soils of India. A total of four hundred (one hundred from each series) representative surface (0–0.15 m depth) soil samples were collected from arable soils representing four soil series namely Hariharapur, Debatoli, Rajpora and Neeleswaram situated in Orissa, Jharkhand, Himachal Pradesh and Kerala states of India, respectively, and were analyzed. Soil acidity (pH between 3.90 and 6.45) showed a low variability, in contrast to other soil properties, which showed moderate variability. The coefficients of variation varied from 32.4 to 74.3, 31.2 to 50.9, 45.6 to 100, 71.9 to 93.0 and 59.0 to 79.8% for EC (mean between 0.05 and 0.09 dS m−1), OC (mean between 0.29 to 1.86%), Exchangeable K+ (mean between 39.1 and 77.7 mg kg−1), Ca2+ (mean between 148 and 293 mg kg−1) and Mg2+ (mean between 111 and 191 mg kg−1), respectively. Soil pH and OC content were positively and significantly correlated with Exchangeable K+, Ca2+ and Mg2+ content. Geostatistical analysis revealed that the best fit models were gaussian, exponential and spherical for different soil properties with moderate to strong spatial dependency. Copyright © 2014 John Wiley & Sons, Ltd.
A. Schneider - One of the best experts on this subject based on the ideXlab platform.
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Release and fixation of Potassium by a loamy soil as affected by initial water content and Potassium status of soil samples
European Journal of Soil Science, 1997Co-Authors: A. SchneiderAbstract:Summary To understand the contribution of non Exchangeable Potassium to plant nutrition the release and fixation of K was studied on a range of soil samples of varying K status, obtained from a long-term fertilizer trial. The soil samples were either air-dried or not prior to use so as to determine the influence of pretreatment on release and fixation of K. Sorption and desorption of K were measured by following the changes in solution K and Exchangeable K, and calculating the relative contributions of Exchangeable and non Exchangeable K to K dynamics in the soil-solution systems. The change in the amount of non Exchangeable K is proportional to the difference between the initially imposed concentration and the concentration for which neither sorption nor desorption occurred. Whether release or fixation occurs depends on the sign of this difference. Soils containing much K release more K than those containing little K at the same initial or final concentration in solution. The threshold Exchangeable Potassium and the threshold K concentration for which release becomes large increase when K content increases in the soil. For air-dried soils K-enriched soils fixed less K than those containing little K. But when kept moist the soils fixed no K. The threshold Exchangeable Potassium of release and the minimal Exchangeable Potassium, i.e. that part of Exchangeable Potassium extracted by ammonium acetate but which is not in exchange equilibrium with Ca, are useful criteria to assess the meaning of the Exchangeable Potassium when used as a fertility indicator.
Farhad Khormali - One of the best experts on this subject based on the ideXlab platform.
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Kinetics of non-Exchangeable Potassium release as a function of clay mineralogy and soil taxonomy in calcareous soils of southern Iran
Archives of Agronomy and Soil Science, 2011Co-Authors: Najafi Ghiri, Ali Abtahi, Najafali Karimian, H. R. Owliaie, Farhad KhormaliAbstract:The release of non-Exchangeable Potassium from 16 calcareous soils collected from southern Iran was examined. For this study, a method was used involving a total of 14 successive 15-min extractions with 0.01 M CaCl2 as an extractant. Cumulative Potassium released from soils was in the range of 144–509 mg kg−1 for surface and 115–445 mg kg−1 for subsurface soils. The studied soils were categorized into two groups based on the cumulative K released, clay mineralogy and soil taxonomy. (I): Smectitic soils including Vertisols, Vertic subgroups and some Alfisols and Inceptisols; (II) other soils including Mollisols, Entisols, and other subgroups of Inceptisols and Alfisols. Cumulative K release was significantly (p
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kinetics of non Exchangeable Potassium release as a function of clay mineralogy and soil taxonomy in calcareous soils of southern iran
Archives of Agronomy and Soil Science, 2011Co-Authors: Mahdi Najafi Ghiri, Ali Abtahi, Najafali Karimian, H. R. Owliaie, Farhad KhormaliAbstract:The release of non-Exchangeable Potassium from 16 calcareous soils collected from southern Iran was examined. For this study, a method was used involving a total of 14 successive 15-min extractions with 0.01 M CaCl2 as an extractant. Cumulative Potassium released from soils was in the range of 144–509 mg kg−1 for surface and 115–445 mg kg−1 for subsurface soils. The studied soils were categorized into two groups based on the cumulative K released, clay mineralogy and soil taxonomy. (I): Smectitic soils including Vertisols, Vertic subgroups and some Alfisols and Inceptisols; (II) other soils including Mollisols, Entisols, and other subgroups of Inceptisols and Alfisols. Cumulative K release was significantly (p < 0.01) higher in Group I than in group II. The release kinetics of non-Exchangeable K showed the best fit to Elovich, parabolic and power function kinetic models. The Elovich and parabolic release rate constants were significantly (p < 0.05) higher in Group I than in Group II. Greater K release rat...
Saroj Kumar Sanyal - One of the best experts on this subject based on the ideXlab platform.
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release pattern of non Exchangeable Potassium reserves in alfisols inceptisols and entisols of west bengal india
Geoderma, 2013Co-Authors: Gautam Kumar Sarkar, Asoke P Chattopadhyay, Saroj Kumar SanyalAbstract:Abstract Eight surface soil samples representing three soil orders viz., Inceptisols, Alfisols and Entisols were analyzed to characterize the non-Exchangeable Potassium (K) reserves. The mineralogical composition of the experimental soils varied widely. The reserves of Step-K and Constant rate K were computed by repeated extraction of soils with boiling1 M HNO 3 . The cumulative release of non-Exchangeable K by such repeated extraction followed a semi-logarithmic behavior with number of extractions, suggesting that the release of non-Exchangeable K decreased with successive extractions. The threshold levels of K in soil solution below which the release of K from the initially non-Exchangeable K reserves starts were also evaluated for the selected soils in terms of K activity ratio, K concentration and Exchangeable K in 0.01 M and 0.002 M CaCl 2 solution. Higher threshold value of Entisols and Inceptisols compared to Alfisols indicates less tenacity with which K is held in wedge zones of micaceous minerals. These threshold values changed considerably for all the soils as the electrolyte concentration decreased from 0.01 M to 0.002 M. Specifically held K, determined as Exchangeable K below which the Gapon constant (K G ) showed a sharp rise, varied from soil to soil in almost the same manner as noted for threshold K levels in these soils.
