Mean Rate of Nutrient Uptake per Unit of Root and the Finess, Length and Density of Barley Roots in Soil at Various Phosphorus Levels

Abstract

With increasing P application, maximum weight, length and density of roots were reached in the soil at a P level at which the top had reached only half of its maximum dry weight. The P applications between 0-100 ppm increased the mean net influx from 0.004 to 0.11 pmol P s-1 per cm root. The P application also increased the mean net influx of N, K, Ca, Mg and Na by a factor of about 4, whereas root fineness was unaffected. Some aspects of the source-sink interrelationships between root and top are illustrated.