Effects of the chemical environment on yellow-birch root development and top growth

Abstract

Yellow birch (Betula alleghaniensis Britton) develops a shallow root system in podzol soils in New England. Split-medium cultures were used to test the hypothesis that this condition results from subsoil nutrient disorders. The results showed that a lower substrate deficient in Ca would not permit primary root growth of yellow birch. Nitrogen deficiency inhibited root growth also. Both of these lower substrate deficiencies retarded top growth. Aluminum was toxic to birch root development, but the degree of toxicity varied for different macronutrient deficiencies. Greatest reductions in root growth by Al occurred with either -Mg or -S lower substrates. In most cases nutrientadequate forest humus in the upper substrate was not able to compensate for nutrient inadequacies in the lower substrate, especially when Al was added.