lon mobilities and rhizosphere depletion Distance moved by diffusion(mm in 6 days) Soil volumetric water content Diffusion rate depends on 0.3 0.1 on NO3 >K*>H2PO4 NO 30 3 · Water content: 0.3 High >low H2PO4 0.3 0.03 Rhizosphere depletion of p is common in many soilsIon mobilities and rhizosphere depletion Distance moved by diffusion (mm in 6 days) Soil volumetric water content NO3 - K + H2PO4 - 0.3 30 3 0.3 0.1 3 0.3 0.03 Diffusion rate depends on • Ion: NO3 ->K+>H2PO4 - • Water content: High > low Rhizosphere depletion of P is common in many soils