The leaching of some elements from herbage plants by simulated rain.
Perennial ryegrass, wheat, red clover and lucerne were grown on soil in pots with and without added K; foliage was leached with simulated rain and the leach-ates collected on a polyethylene film which covered the surface of the soil and drained through a central tube. The concentrations of K and Na in leachates from rye-grass were greater than in those from red clover and lucerne. The addition of K resulted in greater concentrations of K in the foliage and in the leachates; K and Cl ions were present in the leachates in equivalent amounts. When foliage was leached for 7 or 12 h the concentrations of K and Na in the leachates rose to a maximum in the first 1 or 2 h, and subsequently declined. The data are discussed in relation to leaching in the field, and it is calculated that a single period of heavy rain (15 mm in 1 h) or 8 h of light rain (1.25 mm/h) could transfer the equivalent of at least 1.5 kg K/ha from ryegrass to the soil. This transfer is examined as part of the cycle of nutrients in soil/plant systems.