Growth and composition of corn,alfalfa, and orchardgrass grown on soils contaminated with airborne dust containing Ca and Mg |
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| Abstract: | Abstract A greenhouse experiment was conducted with soils allegedly contaminated with airbourne dust containing Mg and Ca oxides and carbonates to study the growth and composition of corn, orchardgrass, and alfalfa plants. Soils were obtained from sites varying in distance from the alleged source of airbourne dust. Soil pH values ranged from 6.2 to 8.7. Plant yields decreased only when the soil pH increased above 7.7. There was no apparent relationship between the observed yield decrease and the N, P, K, and B concentrations in the plants. Although the Mn and Zn concentrations generally decreased with increasing soil pH, the decrease was not great enough to account for the yield depressions. The obviously minor symptoms occurring on the plants growing on the most affected soils could not be associated with a deficiency or excess of any other element. The Ca/Mg ratio in the alfalfa plants decreased as soil pH increased over the range from 6.2 to 8.7. However, the Ca/Mg ratios in the corn and orchardgrass plants decreased only when the soil pH values increased above 7.7. The apparent imbalance of Ca and Mg in the tissues may account for the yield depressions. |
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| Keywords: | contaminated soils Ca/Mg ratio |
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