An excess of P appears mainly in the form of a micronuprient deficiency , with either Fe or Zn being the first elementh to be affected. High P may also interfere with the normal metabolism os the plant. phosphorus leaf contents greacer than 100% would be considered toxic.
fertilizer sources phosphorus fertilizers vary considerably in their water solubility, which can affect crop refponse. Method of attlication A(broadcast wersus row ) Will also influence availability as appiled P can be readily fixed by the soil into unavailable forms. a list of P- containing fertilizers are given in table 2.7