Abstract

The influence of base cation concentrations on pH and aluminium sensitivity of the woodland grasses Bromus benekenii and Hordelymus europaeus was studied in flowing solution culture experiments. Plants were exposed to low pH (3.9, experiment 1) and Al concentrations of 19 and 37 mu M (experiment 2) at two base cation (Ca+Mg+K) levels, all within the ranges measured in natural forest soil solutions. Elevated base cation concentrations ameliorated both H and Al toxicity, as indicated by increased root and shoot growth. In the third experiment, interactions between pH (4.3 and 4.0) and Al (0 and 19 mu M) were investigated. It was shown that the combined toxicity effects of H and Al were not greater than the separate H or Al effects. Tissue concentrations of base cations and Al increased with increasing concentrations in the solution, but were also influenced by the base cation : Al ratio. Relating the experimental evidence with the composition of forest soil solutions suggests an important role of soil pH and Al in controlling the distribution of the two species. Growth conditions also differ at various soil depths. Concentrations of free cationic Al were higher and base cation concentrations lower at 5-10 cm than at 0-5 cm soil depth. Increasing base cation concentrations may protect roots from both H and Al injury during periods of drought when concentrations of most elements increase in the soil solution, whereas molar ratios between base cations, H and Al remain unchanged.

Keywords

BASE CATION AMELIORATION; FLOWING SOLUTION CULTURE; H AND AL TOXICITY; QUICKLY REACTING ALUMINUM; SOIL CENTRIFUGATION; SOIL SOLUTION PH

Published in

Plant and Soil
1994, Volume: 161, number: 2, pages: 157-166
Publisher: KLUWER ACADEMIC PUBL

UKÄ Subject classification

Soil Science
Botany
Ecology


Publication identifier

DOI: https://doi.org/10.1007/BF00046387

Permanent link to this page (URI)

https://res.slu.se/id/publ/40386