Assessment of Soil Potassium Reserves Available to Plant Roots

Abstract

Successive extraction with Ca-saturated sulphonated resin is used to remove potassium from soils. The kinetics of K-release are analysed mathematically to define three simultaneous rate processes by the amounts and rate-functions associated with them.

Long-term effects of potassium fertilization on yields and fertility status of calcareous soils of south-west France

“…Potassium release kinetics evaluated through sequential Ca-resin extraction show that only "surface" and "periphery" K as defined by Talibudeen et al (1978) are differentiated by fertilization regimes. Long-term K supply capacities are not modified by the treat-ments; KO and K4 soils had similar release rate coefficients for slow K release from the clay matrix.…”

“…The methodology developed by Talibudeen et al (1978) was applied to the soil of the KO and K4 plots from block III. Experimentally, 2 g of calciumsaturated Amberlite IR-120 resin (Serva, 20-50 mesh, 2.3 meq g-l) was placed in a centrifuge tube with 10 ml of deionized water and 1 g of soil was added.…”

“…The experimental procedure simulates release processes, as they are in close proximity to active roots (Talibudeen et al, 1978;Goulding, 1984;Havlin et al, 1985). When extraction is carried on for several weeks, it becomes possible to assess the soil's potential for long-term K supply (Goulding and Loveland, 1986).…”

Potassium in the soils of New Zealand—A review

“…Surapaneni et al (1991), however, showed that the nitric acid method was superior to the NaTPB method for yellow-grey earth soils. Alternative methods of measuring the exchangeable and non-exchangeable K-releasing power separately are mainly based on exchange processes in soils e.g., exchange isotherms (Goulding 1983(Goulding , 1986Elkhatib & Hern 1988), quantity and intensity (Q/I) relationships (Beckett 1964;Lee 1973;During & Duganzich 1979;Sparks & Huang 1985;Haby et al 1990;Cervantes & Hanson 1991;Herlihy 1992), electro-ultrafiltration (Nemeth 1982;Sparks 1987;Haby et al 1990;Liu et al 1992;Herlihy 1992), and cation exchange resins (Lee & Gibson 1974;Talibudeen et al 1978;Martin & Sparks 1985). These methods are not used in New Zealand and, according to Sparks (1987), are of little practical value for predicting K-releasing power.…”

Potassium Dynamics in Soils

“…This differs from the sequence that occurs through the cation reaction using sodium tetraphenylboron (NaTPB) . Few studies have been conducted on the kinetics of nonexchangeable K release from whole soils (Talibudeen and Weir, 1972;Talibudeen et al, 1978;Martin and Sparks, 1983;Sadusky and Sparks, 1985). Martin and Sparks (1983) investigated the kinetics of nonexchangeable K release from two coastal plain soils from Delaware using an H-resin ( Figure 11).…”