Phosphorus reference guide

This one page soil phosphorus fact sheet has information about P deficiencies, different soil test extractants for P, and the phosphorus saturation index (PSI, sometimes also PSR for P saturation ratio).

P is an important element to get right. Too much P, and there are risks of water pollution. Supply the grass with too little P, however, and growth can come to a screeching halt (in the most severe cases). Forunately, soil testing can help, to find sites where P…