Release of Potassium by 18 Ontario Soils During Continuous Cropping in the Greenhouse

Abstract

Eighteen Ontario soils riu-ere ranked according to their capacity to supp11' potassium from non-exchangeablc forms to eight strccessive crops of alfalfa.i'his capacity u.as found to 5e closely rclated to the percentage of clay in the soils. Potassium cortent of the alfalfa anci total uptake of potassium rvere highly correlated u.ith both cxchangeable soil pctassium attd release of potassium from non-excl'rangeable forn-rs. Exchangeable

Potassium-Supplying Power of Some Canadian Soils

“…In other field tests in this province yield responses of tomatoes to potassiunr ferttlizer were reiated to the amounts of exchangeable potassium in sandy loam soiis but there was no such relationship within loam and clay loam groups (5). Non-exchangeable potassium has been found to be closely related to clay content of Ontario soils (14,9).…”

Potassium status of some selected soils under different land‐use systems in the subhumid zone of Nigeria

“…For soils that have their different forms of K more or less in equilibrium, the level of available K may be a reliable indication of their K-supplying power (Smith and Matthews, 1957). The negative release shown by soils with very high initial K implies that there was no need to take from the non-exchangeable form.…”

The Potassium Status of Six Loessial Soils of Canterbury, New Zealand, in Relation to Rainfall and Rate of Loess Accumulation

“…Haylock 1956), Smith and Matthews (1957), Arnold (1960Arnold ( , 1970 to soil K-supplying ower. Plant uptake from these soils appeared to be The small differences in clay content among soils resulted in the type of clay rather than the amount of clay being the major factor determining K-supplying power.…”