The importance of the potassium buffer power on the critical potassium level in soils
1982
MENGEL, K. | BUSCH, R.
We studied the relationship between the K buffer power and the critical K concentration of the soil solution in pot experiments with Italian ryegrass. Critical K concentration is defined as that K concentration of the bulk soil solution below which plants respond by a yield increase when K fertilizer is applied. The K concentration of the soil solution was measured indirectly by means of the electro-ultrafiltration technique. The K buffer power was obtained by plotting the exchangeable K against the K concentration of the bulk soil solution. The steepness of the resultingcurve reflects the K buffer power.Nine soils differing widely in clay content, CEC, and K buffer power were used for the investigation. A very close correlation (r = 0.908) was found between the K buffer power and the critical K concentration of the soil solution. This relationship was reflected by a hyperbola (y = c/x), indicating that the critical K concentration was lower the higher the K buffer power was.
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