Potassium dynamics in the rhizosphere and K efficiency of crops

Nutrient efficiency is defined as the ability of plants to obtain higher re lative yields at low nutrient supply compared to other species. The size of the root system, the physiology of uptake and the ability of plants to inc rease K solubility in the rhizosphere are considered as mechanisms of uptak e efficiency. In a solution experiment wheat and sugar beet were more K eff icient than potato because wheat had a large root system and both species h ad an efficient uptake physiology. Also in soil wheat was uptake efficient because of a large root system, whereas the efficiency of sugar beet was ca used by the ability to increase K solubility. This could be shown by the us e of a model to describe K dynamics in the rhizosphere.