Studies on soil potassium. II. The Q/I relation and other parameters compared with plant uptake of potassium

Soil Research ◽  
1972 ◽  
Vol 10 (1) ◽  
pp. 95 ◽  
Author(s):  
IF Fergus ◽  
AE Martin ◽  
IP Little ◽  
KP Haydock
Keyword(s):  
Exchange Resin ◽  
Clay Fraction ◽  
Cation Exchange Resin ◽  
Mean Value ◽  
Potassium Uptake ◽  
Exchangeable Potassium ◽  
Soil Potassium ◽  
Setaria Sphacelata ◽  
Total Potassium ◽  
Equilibrium Activity

Setaria (Setaria sphacelata cv. Nandi) was grown in 10 surface soils, of contrasting properties, in pots until (after repeated harvesting of tops) plant growth virtually ceased. Uptake of potassium by tops and roots was correlated with change in exchangeable potassium during cropping, initial exchangeable potassium, and with quantities of potassium predicted from the immediate Q/I relations of the soils. Some initially non-exchangeable potassium was absorbed from seven of the soils by the plants, such that these soil quantity parameters (which were statistically equivalent) predicted two-thirds of the total potassium uptake averaged over all soils. Potassium uptake was also correlated with soil potassium soluble in constant-boiling hydrochloric acid, and with potassium extracted by a cation exchange resin (both of which predicted about twice the plant absorption). For six of the soils, uptake of initially non-exchangeable potassium was correlated with the quantity of total potassium present in each pot in the 1 0 . 1 pm clay fraction. The intensity of soil potassium (measured in dilute calcium chloride solution from the immediate Q/I relation) was reduced on all soils by exhaustive cropping to a mean value for the equilibrium activity ratio (AR0) of 4.7 10-4 mole1/2 L.-1/2 (�G = -4500 cal equiv.-1); it was suggested that the observed variations in this value were unlikely to prohibit its use for practical soil testing, except for the prediction of the quantity parameter for those soils for which the form of the isotherm is altered by cropping. A tentative value for the potential of soil potassium at which setaria has an adequate average potassium concentration in its tops was - 3600 cal equiv.-1 (AR0 2.1 x 10-4 mole1/2 L.-1/2).

RELEASE OF NON-EXCHANGEABLE SOIL POTASSIUM BY RESIN-EQUILIBRATION AND ITS SIGNIFICANCE FOR CROP GROWTH

1962 ◽  
Vol 42 (2) ◽  
pp. 266-272 ◽  
Author(s):  
T. E. Barber ◽  
B. C. Matthews
Keyword(s):  
Linear Regression ◽  
Ammonium Acetate ◽  
Cation Exchange Resin ◽  
Yield Response ◽  
Exchangeable Potassium ◽  
Quadratic Regression ◽  
Potassium Fertilizer ◽  
Crop Response ◽  
Soil Potassium ◽  
The Difference

The non-exchangeable potassium released by soil after equilibration with cation-exchange resin was determined by extraction of the mixture with neutral ammonium acetate at room temperature and compared with a similar extraction in the absence of resin. The difference obtained following a 2-day equilibration period was called moderately-available potassium.Simple linear regression of yield on exchangeable potassium or exchangeable plus moderately-available potassium accounted for only 16 and 27 per cent respectively of the variability in yield response of corn, wheat, oats and potatoes to potassium fertilizer in the field. Multiple linear regression of yield on exchangeable and moderately-available potassium accounted for an average of 37 per cent of the variation in crop response; but a multiple quadratic regression of Log (100-per cent yield) on exchangeable and moderately-available potassium accounted for an average of 56 per cent of the variability in Log (100-per cent yield). Multiple quadratic regression of absolute yield or per cent yield on exchangeable and moderately-available potassium accounted for 46 and 50 per cent, respectively, of the variability in crop response to potassium fertilizer.

POTASSIUM-SUPPLYING POWER OF SOME CANADIAN SOILS

1961 ◽  
Vol 41 (2) ◽  
pp. 196-206 ◽  
Author(s):  
A. J. MacLean
Keyword(s):  
Exchange Resin ◽  
Initial Level ◽  
Water Soluble ◽  
Exchangeable Potassium ◽  
K Uptake ◽  
Soil Potassium ◽  
Surface Samples ◽  
Canadian Soils ◽  
Different Levels ◽  
Exchangeable Form

The amounts of exchangeable potassium in surface samples of 11 Canadian soils were significantly correlated with uptake of potassium by plants in the greenhouse. Per cent K-saturation and water-soluble potassium were indicative of the percentage of K-uptake that was derived from soil potassium in exchangeable form at the time of seeding.Amounts of non-exchangeable potassium extracted from the soils by repeated boiling in 1 N HNO3, by H-saturated exchange resin, and by continuous leaching with 0.01 N HCl were significantly correlated with each other and with the amounts of this form of potassium removed by plants.Following cropping, release of non-exchangeable potassium to exchangeable form during moist incubation of the samples for 112 days was slight. When samples containing different levels of exchangeable potassium were incubated moist for 13 months and then wetted and dried five times, potassium tended to be released to exchangeable form or converted to non-exchangeable form depending on initial level established. The degree of K-saturation at which potassium in six Ontario soils would be expected to be at equilibrium was estimated by regression to be 1.21 per cent. There was evidence that the degree of K-saturation for equilibrium in a Brown soil from Saskatchewan was at least 4.5 per cent.

THE EFFECTS OF AMMONIUM NITRATE AND UREA ON THE RELEASE OF NON-EXCHANGEABLE POTASSIUM BY EIGHT EASTERN PRAIRIE SOILS DURING CONTINUOUS CROPPING IN THE GREENHOUSE

1974 ◽  
Vol 54 (3) ◽  
pp. 255-263 ◽  
Author(s):  
L. D. BAILEY
Keyword(s):  
Ammonium Nitrate ◽  
Nitrogen Content ◽  
Plant Material ◽  
Total Yield ◽  
Continuous Cropping ◽  
Exchangeable Potassium ◽  
Total N ◽  
Prairie Soils ◽  
Soil Potassium ◽  
Total Potassium

Continuous cropping of eight Manitoba soils to alfalfa in the greenhouse decreased the exchangeable potassium of the soils to low equilibrium levels. Non-exchangeable potassium was removed from the soils by the alfalfa. The rate of decrease of exchangeable potassium and the quantity of non-exchangeable potassium mobilized was significantly influenced by the addition of ammonium nitrate or urea to the soils. However, there were no significant differences between the soils treated with ammonium nitrate and those treated with urea. There was considerable variation among soils in the rate of decrease of exchangeable potassium and the quantity of non-exchangeable potassium mobilized. The total yield of soil potassium was related to the initial exchangeable potassium levels of the soils. Addition of NH4NO3 increased the percentage of total N in the plant material harvested prior to the eighth harvest. After this eighth harvest the added nitrogen had no effect on the nitrogen content of the harvested material. In general, fine-textured soils yielded more plant material and total potassium, and maintained a higher level of exchangeable potassium than coarse-textured soils.

Effects of Grass Mulch on Groundnuts in the Gambia

1965 ◽  
Vol 1 (2) ◽  
pp. 145-152 ◽  
Author(s):  
M. I. Ashrif ◽  
I. Thornton
Keyword(s):  
Potassium Uptake ◽  
The Gambia ◽  
Physical Factors ◽  
Potassium Fertilizer ◽  
Luxury Consumption ◽  
Calcium Antagonism ◽  
Soil Potassium ◽  
One Year ◽  
Total Potassium

SUMMARYThe effect of grass mulch on groundnut yield and shelling percentage has been studied at three locations in the Gambia. Yield increases have been mainly attributed to physical factors but residual increases were found for only one year after application. Mulching gave rise to significant increases in exchangeable soil potassium, in percentage potassium in the plant at harvest and in total potassium uptake by the plant. In the absence of response to potassium fertilizer, increased uptake was ascribed to luxury consumption. It was suggested that reduced shelling percentage from mulched plots was due to potassium-calcium antagonism.

The use of chemical extractions and continuous cropping to measure the potassium status of soils

1978 ◽  
Vol 29 (6) ◽  
pp. 1247 ◽  
Author(s):  
AM Graley
Keyword(s):  
Nitric Acid ◽  
Critical Level ◽  
Potassium Uptake ◽  
Continuous Cropping ◽  
Exchangeable Potassium ◽  
Soil Potassium ◽  
Chemical Extractions ◽  
Plant Yields ◽  
Yield Responses ◽  
Soil Groups

Soil potassium, measured by simple chemical extractions, was compared with potassium availability assessed during continuous cropping of perennial ryegrass in pots, on 12 surface soils representing four Tasmanian soil groups. For three soil groups with mainly kaolinitic clay, potassium uptake by the plant (the main measure of potassium availability) was related to a decrease in the potassium extracted from the soil by boiling lM nitric acid during the experiment. The decrease in soil potassium extracted by repeated nitric acid digestions averaged 95% of the total potassium uptake. However, a large and rapid uptake from the illitic yellow podzolics was only partly assessable by chemical extractions. For all soils, much of the large amount of potassium taken up early was stored in the plant roots and transferred to the tops much later. Plant yields were related to exchangeable potassium only within soil groups; over most soils they were related to nitric acid-soluble potassium. Yield responses to added potassium usually occurred when exchangeable potassium became depleted to a critical level of 0.2–0.25 m-equiv./100 g or nitric acid-soluble potassium to 0.4–0.7 m-equiv./100 g. The critical level of potassium in ryegrass tops was 0.5–0.8%. On average nearly two-thirds of the potassium released from soils came from exchangeable sources. Potassium initially non-exchangeable was differentiated into quickly released 'intermediate' potassium and slowly released 'constant rate' potassium. Release of intermediate potassium predominated from the yellow podzolics and from one non-calcic brown soil with much randomly interstratified material in its clay.

scholarly journals Fixation of potassium by soil samples under various conditions

1965 ◽  
Vol 37 (3) ◽  
pp. 195-206
Author(s):  
Armi Kaila
Keyword(s):  
Room Temperature ◽  
Ammonium Acetate ◽  
Clay Fraction ◽  
Soil Samples ◽  
Soil Reaction ◽  
Soil Drying ◽  
Exchangeable Potassium ◽  
Heavy Clay ◽  
Mineral Soils ◽  
Total Potassium

The fixation of added potassium under various conditions was studied using soil samples collected from three layers of ten mineral soils. The type of soil ranged from finesand to heavy clay, the soil reaction from pH 3.3 to pH 6.4 (in 0.01 M CaCl2), and the total potassium content from 1.99 to 3.41 per cent. The fixation against an extraction with neutral ammonium acetate distinctly depended on the conditions used for the application of potassium: on the average, without drying the samples fixed during one hour somewhat more than 80 per cent of the amount fixed during 18 hours, when the samples were treated with KCI-solutions corresponding to 2.5 me K/100 g soil. Drying the suspension at 80°C resulted in a fixation 1.2 to 4.1 times as high as that under the »wet» conditions within one hour. The results of these two methods were not particularly closely correlated (r = 0.73***). The results of the »dry» method were found to be of the same order as the fixation of potassium in samples incubated for three months at room temperature. The results of the »dry» fixation were positively correlated with the pH (r = 0.75***) and negatively correlated with the contents of organic carbon (r = —0.63***) and exchangeable potassium (r = —0.40*), but they were not correlated with the contents of clay or the acid soluble potassium. Under the »wet» conditions the relative fixation generally decreased with an increase in the application of potassium, but there were samples which fixed a rather low but almost equal portion of all the applications from 0.625 to 40 me K/100 g soil. The fixation from the highest addition was correlated with the clay fraction

Assessing the availability of potassium in soils

1981 ◽  
Vol 21 (112) ◽  
pp. 543 ◽  
Author(s):  
AM Graley
Keyword(s):  
Nitric Acid ◽  
Root System ◽  
Perennial Ryegrass ◽  
Podzolic Soil ◽  
Subterranean Clover ◽  
Root Systems ◽  
Exchangeable Potassium ◽  
Soil Potassium ◽  
Whole Plant ◽  
Total Potassium

Two forms of depletion cropping were examined. Perennial ryegrass was continuously cropped on two contrasting soils in pots. Simultaneously, repeated crops of ryegrass, subterranean clover, and marrow-stem kale were grown by a modified system of depletion cropping in which the whole plant was harvested and the soil sampled before being repotted for further crops. Fractions of soil potassium determined by chemical extractions were compared with the results from depletion cropping. Although the modified system needed added attention, particularly between crops, the available potassium was well exploited because of the thorough mixing of the soil. A further benefit was that the depletion of potassium in soils and plants could be followed progressively. Different root systems of the plant species greatly influenced the total potassium uptake. Reserves of initially non-exchangeable potassium contributed much to the uptake while decrease in soil potassium measured by repeated nitric acid extractions ranged from 63 to 80% of the uptake. Ryegrass with its dense root system was able to take up more non-exchangeable potassium from a yellow podzolic soil than clover and kale.

A PERCOLATION METHOD FOR MEASURING POTASSIUM-SUPPLYING POWER OF SOILS

1957 ◽  
Vol 37 (1) ◽  
pp. 21-28 ◽  
Author(s):  
B. C. Matthews ◽  
J. A. Smith
Keyword(s):  
Cation Exchange ◽  
Soil Sample ◽  
Soil Type ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Exchangeable Potassium ◽  
Percolation Method ◽  
Perfusion Apparatus ◽  
Different Soils

An apparatus for continuous circulation of water through a soil sample and a cation exchange resin has been devised by modification of the Lees perfusion apparatus. The amount of exchangeable and non-exchangeable potassium released from the soil and adsorbed by the resin was found to correlate highly with the amount of potassium taken up by alfalfa grown continuously in the greenhouse (r = 0.91). The rate and amount of release differed for different soils and the rate of release showed little correlation with the original level of exchangeable potassium. It is suggested that the rate of release, i.e., potassium-supplying power, is a soil type characteristic and not a function of management or fertilization. The percolation method proposed will permit ready evaluation of the potassium-supplying power of Ontario soils.

Rates of growth, potassium uptake, and changes in the potassium properties of four Queensland soils during intensive cropping by buffel grass, Cenchrus ciliaris

Soil Research ◽  
1975 ◽  
Vol 13 (2) ◽  
pp. 217 ◽  
Author(s):  
DC MacKay ◽  
JS Russell
Keyword(s):  
Potassium Deficiency ◽  
Potassium Uptake ◽  
Controlled Environment ◽  
Exchangeable Potassium ◽  
Cenchrus Ciliaris ◽  
Buffel Grass ◽  
Soil Potassium ◽  
Matter Production ◽  
Intensive Cropping ◽  
Rates Of Growth

Four Queensland soils were intensively cropped by buffel grass, Cenchrus ciliaris, in controlled environment growth rooms at three temperatures. Rates of growth (dry matter production) of tops and roots, of potassium uptake, and of changes in soil potassium properties were examined. With adequate potassium applied, growth rates for 31 weeks were nearly constant at 2.7, 2.6, 2.0, and 2.0 t/ha/week on a brigalow, grey clay, podzolic, and solodic soil, respectively. Without potassium, exchangeable potassium decreased quickly to a nearly common level on all soils, corresponding decreases occurred in the potassium content of tops and roots, and severe deficiencies with restricted yields soon resulted. Without applied potassium, moderate release of non-exchangeable potassium occurred on all soils during the first 4 weeks of cropping (0.10-0.18 m-equiv./100 g). Apparent fixation of potassium resulted in the succeeding 6-9 weeks, and, on the fine-textured soils (brigalow and grey clay) only, further slow release took place during the period of potassium deficiency when growth was slow. The overall release of non-exchangeable potassium by all four soils was small (0.02-0.16 m-equiv.1 100 g). Higher temperatures significantly increased yields of tops and roots, decreased the potassium concentration in the plants, increased the rate of depletion of exchangeable potassium, and had no effect on the release of non-exchangeable potassium. It is concluded that on these soils, particularly the solodic and podzolic, potassium deficiency will occur under intensive cropping.

Studies on soil potassium. III. The intensity of soil potassium following exhaustion by different plants

Soil Research ◽  
1973 ◽  
Vol 11 (2) ◽  
pp. 209 ◽  
Author(s):  
AE Martin ◽  
IF Fergus
Keyword(s):  
Calcium Chloride ◽  
Activity Ratio ◽  
Mean Value ◽  
Soil Potassium ◽  
Peculiar Behaviour ◽  
The Mean ◽  
Differential Ability ◽  
Equilibrium Activity

Exhaustive cropping of four soils by four species revealed only small differences in the limiting intensity (expressed as the equilibrium activity ratio, ARo) of soil potassium, for which the mean value was 5.0 x 10-4 mole1/2 L 1/2. Replanting of depleted soils led to slightly lower values. With a fifth soil, which contained significant amounts of potassium felspar in both clay and sand fractions, grasses reduced the intensity to a lower level (3.8 x 10-4 mole1/2 L 1/2) than did legumes (21.0 x 10-4 mole1/2 L 1/2), and these values were substantially reproducible with replantings of the same species. It was suggested that the peculiar behaviour of this soil may have been associated with the differential ability of the various plants to use potassium from orthoclase. The intensity at which potassium was first absorbed from sources not initially in equilibrium with 0.001M calcium chloride varied from 8 to 29 x 10-4 depending on the soil, and, in the case of the felspathic soil, depending on the plant.

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