Critical Cation Activity Ratios

Beckett, P. H. T.

doi:10.1016/s0065-2113(08)60639-2

Cited by 40 publications

(15 citation statements)

References 100 publications

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“…The Q=I approach was known to be useful in understanding, characterizing, and evaluating the K þ fertility status of soils (Wang and Scott, 2001). In correlation studies, the parameters of Q=I alone or in combination have sometimes been shown to be a better prediction of K þ uptake by plants than exchangeable K þ measured by 1 M NH 4 OAc and help in understanding the mechanism of the K þ supply to plants (Beckett, 1972;Evangelou et al, 1994). Many workers used Q=I parameters for predicting K þ requirement of soils (Fergus et al, 1972;Singh and Jones, 1976;Sinclair, 1979;Sparks and Liebhardt, 1981;Evangelou and Blevins, 1988).…”

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confidence: 99%

A Study of the Quantity/Intensity Relationships of Potassium in Some Calcareous Soils of Iran

Jalali

2007

Arid Land Research and Management

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A Study of the Quantity/Intensity Relationships of Potassium in Some Calcareous Soils of Iran

Jalali

2007

Arid Land Research and Management

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“…Extending this hypothesis, a curve relating crop yield to the chemical potential of a nutrient in soil should be a characteristic of the plant, depending on its ability to remove the nutrient from the soil, under the prevailing environmental conditions. The nutrient potential is averaged over a specific period of growth (Talibudeen and Dey, 1968a;Addiscott and Talibudeen, 1969;Beckett, 1972). Talibudeen (1974) gave a schematic curve relating plant response to nutrient potential from which critical values can be identified that are characteristic of a plant during a particular growth phase.…”

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Critical potassium potentials for crops. I. The effect of soil type on the growth of ryegrass and creeping red fescue

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Talibudeen

1982

Journal of Soil Science

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The quantity : potential relationships for Ca+K exchange in six soils were evaluated, where potential is defined by ~G K , c~+ M~. Using the percentage K saturation of the CEC as the index of quantity, the Worcester Series soil, rich in hydrous micas, was shown to have the highest concentration of K selective sites, and Newport Series soil, with mainly kaolinitic clay, the lowest. The other soils, containing mainly smectites, had intermediate K selectivities.An algebraic transformation of this relationship to separate the effects of exchangeable K and CEC showed that 0.01 M C~C I , released more K than M ammonium acetate. From the exchangeable K : AG relationship, two regions of K buffering were observed for all but the Newport soil, the transition occurring at a mean A G K , c~+ M~ value of -20.7 kJ mol-1, signifying the K concentration below which K from 'perlpheral' regions of micaceous minerals is released. This may explain why the percentage K saturation of the CEC of a soil cropped exhaustively (without K manuring) in the field does not drop below a minimum value.Based on pot experiments, exhaustion and optimum K potentials (dG,,h and AGop,) were derived from second-degree polynomials fitted to the response curves of plant dry matter yield against ~G K , c~+ M~ for five soils, the Worcester soil showing little response. dG,,h was inversely related to the 2 : 1 layer silicate content of the soil (r*=0.98 and 0.94 for ryegrass and fescue respectively), and similarly, AGO,,, to their CEC values (r2=0.74 and 0.77). Potassium uptake was more closely correlated with exchangeable K than with AGO,,. Introduclion Soil K potentialThe thermodynamic potential of K in soil is taken as its partial molar free energy referred to that of calcium+magnesium, and is expressed as the free energy of K -(Ca + Mg) exchange (Woodruff, 1955a, b; Arnold, 1962):It is measured as the difference between the chemical potentials of K+ and (Ca2+ + Mg2+) in a dilute solution in equilibrium with the soil, i.e.

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“…The stocks where, K d , pat1ition parameter (dm' kg-I). Potassium activity ratio (ARK) as suggested by Beckett and Nafady (1967) and Beckett (1972) and Hamdan et al (1999) was used for the transfonnation of K solution concentrations into activities and is rep0l1ed below: of metals as well as calcium were not acidified. Solution samples for batch studies were prepared by proper diluting stocks of metals and calcium with deionized water to give metal concentrations (as above), designated further as initial metal concentrations (CJ The pH of these solutions was measured but decreased progressively from 5.09 to 3.18 with increasing total metal concentrations from 0.4 to 32 mmol c dm-\ accordingly.…”

Section: Methodsmentioning

confidence: 99%

“…On the other hand, since magnesium and calcium are divalent cations, it is assumed that their behaviour in the soil solution will be similar, and therefore potassium activity should be directly referred both to Ca and Mg. This concept is widely promulgated by several workers (Woodruff 1955;Beckett and Nafady 1967;Beckett 1972;Sparks and Liebhardt 1981;Hamdan et a1. 1999) and restricted to K~Ca or K~(Ca + Mg) influence only.…”

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Competitivity, selectivity, and heavy metals-induced alkaline cation displacement in soils

Diatta

Grzebisz

Wiatrowska

2004

Soil Science and Plant Nutrition

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The simultaneous incorporation of heavy metals into the soil is still a matter of great concern. Interaction (competitive sorption) between these metals and the soil solid phase may result in a deterioration of soil quality which relies basically on amounts of alkaline cations saturating soils sorptive complex. Results of this study indicate that Pb, Cu, Cd, and Zn have induced solution pH decreases which were more intensive at highest metal loading rates. Partition parameters (Kd)-based sequences showed that Pb and Cu were more competitive than Cd and Zn and the overall selectivity sequence followed: Pb > Cu > Cd > Zn.Metal loadings and their competitive sorption have led to a strengthened displacement of alkaline cations (Le. Ca 2 +, Mg2+, K+, Na+), especially of Ca 2 + as a factor "stabilizing" soil sorptive complex. Such metals impact jointly with soils acidification are of great environmental concern since tremendous amounts of alkaline cations (especially Ca 2 +) may be potentially leached out, irrespective of the degree of soil contamination, as evidenced in the current study. High and positive ..:1G values implied that the studied soils were characterized by generally low concentrations of exchangeable potassium which required high energy to get displaced (desorbed). Further studies on heavy metal uncontaminated or contaminated areas should be undertaken to provide with data which should be used for predictions on changes related to soil buffering capacity as impacted by heavy metal inputs.

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Critical Cation Activity Ratios

Cited by 40 publications

References 100 publications

A Study of the Quantity/Intensity Relationships of Potassium in Some Calcareous Soils of Iran

A Study of the Quantity/Intensity Relationships of Potassium in Some Calcareous Soils of Iran

Critical potassium potentials for crops. I. The effect of soil type on the growth of ryegrass and creeping red fescue

Competitivity, selectivity, and heavy metals-induced alkaline cation displacement in soils

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