Elevated pH and Associated Reduced Trace-Nutrient Availability as Factors Contributing to Take-All of Wheat upon Soil Liming

Publisher Website
Google Scholar
Abstract
Studies of take-all of wheat caused by Gaeumannomyces graminis var. tritici tested whether increased severity of the disease in areas where soil had been amended with limestone was the result of increased pH of the rooting medium or of Ca or Mg supplied by the amendments. Hoagland''s solution was used as a source of plant nutrients and was applied to a silica sand rooting medium with Ca or Mg at normal (1H), twice (2H), or 3 times (3H) the amount in Hoagland''s solution, each at pH 4.5, 5.5, 6.5, 7.5 and 8.5. Take-all severity increased with increasing pH but not with increasing amount of Ca or Mg. Increasing Ca from 1H to 3H had no effect on take-all, but increasing Mg from 2H to 3H resulted in less severe take-all. Uptake of Cu, Mg and Fe (as determined by leaf-tissue analysis of plants supplied with normal [1H] Hoagland''s solution) was significantly less at pH 7.5 and 8.5 than at the 3 lower pH levels; for Zn, uptake was significantly less at pH 5.5 and above than at pH 4.5. The pH values associated with reduced uptake of trace nutrients corresponded generally to the pH values at which the incidence and severity of take-all was increased. At least part of the favorable effect of liming on take-all may result from host-plant predisposition resulting from inadequate supplies of certain essential plant nutrients at the elevated pH.

This publication has 0 references indexed in Scilit: