Fig. 2. Mean mass of total dissolved phosphorus (TDP) in runoff summed over four rain events and plotted in relation to soil-test P (acidified ammonium acetate EDTA extract) measured at end of spring monitoring period. The mean losses for sprigged plots top-dressed with 50 or 100 kg P ha^–1 as composted manure or 50 kg P ha^–1 as fertilizer were not included in the regression relationship represented by the trend line plotted for control (soil-test P = 53 mg kg^–1) and imported sod treatments.