Relationships of the Cation Suite and Yield of Turnip Greens for Selected Extremes of Soils, Fertilizers, and Environment1

Abstract

Two contrasting soils representing the kaolinitic and montmorillonite types of clay were used to study the interactions of soil type, fertility, soil temperature, and season on the growth and cation content of turnip plants. Growth was closely associated with soil calcium status and soil temperature. Growth response to soil temperature differentials was affected by season. Cation content of the tops was markedly influenced by the exchangeable cation levels and by the predominating clay minerals of the respective soils. Sodium, the content of which tended to decrease in the tops with an increase in soil temperature, was the only macrocation materially affected by soil temperature. The K:Na ratio of plants was also dependent upon the soil temperature. Aerial environmental conditions, although not individually characterized, were shown to be of equal importance to soil factors in determining cation content of plants. The magnitude of seasonal effects on cation concentration in leaves, however, was influenced by type of clay mineral and the percent Ca and Mg saturation in the soil. The interrelationships of growth and macrocation content are discussed.