Effect of phosphorus on the colonization of barley rhizosphere by microorganisms

The mineral phosphorus supply produced two outbreaks in the bacterial population of the barley rhizosphere and rhizoplane but inhibited the growth of fungal mycelium. The inhibition of mycelial growth might be due to the exudation of specific inhibitors by barley roots, since the most pronounced inhibition was observed at high doses of supplementary phosphorus.