Competition between grass and clover for phosphate

Factors studied were the relative foot activities for P uptake by white clover and browntop at different depths in the soil,the root tip numbers per unit volume of soil,the loss of soil moisture caused by the presence of browntop, and the response curves of white clover and browntop to applied P. It was concluded that grass and clover roots can directly compete for P in the top 2.5 em of topdresscd soil,the grass can decrease the availability of P by increasing soil moisture tension, and both these results will affect white clover more adversely than browntop,because of the markedly less efficient response to applied P of clover than of browntop.This result will be most strongly expressed in soils whieh strongly fix P and easily develop high moisture tension.