ISSN:
1573-5036
Keywords:
Edge-weathering
;
Exchangeable K
;
Interlayer K release
;
K depletion
;
K sorption isotherms
;
Nonexchangeable K
;
Plant-available K
;
Ryegrass
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary The concentration of K in the soil solution at zero change of non-exchangeable K (Co) was determined at 20°C and 50°C for six topsoils of widely different clay mineralogy. This was done with and without prior removal of the K that was exchangeable to dilute salt solutions in a two to three hour leach. Except for one case Co was greater for leached than for not leached samples, particularly at the higher temperature. This is attributed to rapid ‘edge-weathering’ during leaching caused by interlayer penetration at the clay edges by calcium, sodium or hydronium ions. It is assumed that K newly exposed in this manner is not immediately exchangeable but that it exerts an influence on the equilibrium concentration of K in solution. Among soils Co was not related to the K available to ryegrass nor to the non-exchangeable K fraction of the uptake by ryegrass. However, much reduced values of Co were obtained after depletion by ryegrass in the new two soils examined.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02232883
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