The influence of method of watering on phosphate uptake by ryegrass grown in pots: Effect on the L-value

Summary The influence of method of watering (overhead or sub-irrigation) on quantity, location and specific activity of phosphate taken up by ryegrass was examined in a pot experiment on two contrasting soils.It is concluded that watering method has no influence on L value provided that P-32 is uniformly distributed. Where, however watering regime leads to uneven root activity the L-value may be modified by uneven distribution of P-32.Sub-irrigation with occasional overhead watering is likely to provide the most satisfactory moisture regime.