THE CALCIFUGE BEHAVIOR OF VISCARIA-VULGARIS

Soil factors responsible for the inability of Viscaria vulgaris to colonize or survive on calcareous soils in Scandinavia were studied using experiments with plant establishment from seeds and re-establishment of mature plants, in soils of naturally differing or artificially varied chemical properties. Limestone soil proved less suitable for re-establishment of mature plants, and establishment from seeds was not possible in this soil. The plants grown on limestone had a very low phosphorus content and displayed deficiency symptoms. Acid leptite soil and soil from the A-horizon of a dystric cambisol were suitable for plant establishment from seeds and re-establishment of adult individuals, respectively. However, growth increased significantly when pH-KC1 was raised to 7.6 by adding CaCO3. Establishment from seeds was successful in the Archaean and Ordovician limestone soils only when CaHPO4 was added. The calcifuge behaviour of Viscaria vulgaris is not due to negative effects of a high pH or a high Ca concentration in the soil. Inability to utilize the native phosphorus of such soils is the most evident explanation.