Split-root experimentIn this experiment, the effects of K supply in combination with aerobic or anaerobic conditions in nutrient solutions on growth and K uptake of barley were investigated. Therefore, six 16 days old barley seedlings cultivated in nutrient solution (mineral concentration already described) were carefully transferred into split-root pots so that the root system was equally divided into two halves. Each compartment was filled with 10.5 l of nutri-ent solution. Plants were cultivated for 15 days in split-root containers in a growth chamber (day: 16 hrs light, 80 W/m2, 25°C; night: 8 hrs dark, 18°C). the experiment comprised five treatments, which were replicated three times (Table 2).During the growth of barley, the nutrient solution was changed twice a week and the K concentra-tion of the solutions in the split-root compartments was determined daily. After 15 days shoots were harvested and roots were separately harvested from each split-root compartment.