The leaching of some elements from herbage plants by simulated rain.
In pot experiments using fine sandy loam (pH 6.3) ryegrass (Lolium perenne L.), winter wheat (Triticum aestivum L.), red clover (Trifolium pratense L.), and lucerne (Medicago sativa L.) were grown with or without added K, and the foliage was leached with simulated rain. The concentrations of K and Na in leachates (collected on polyethylene film which covered the soil surface) were greater from ryegrass than from red clover or lucerne. After 7 or 12 h leaching the K and Na concentrations rose to a maximum during the first 1 or 2 h and then declined. It is calculated that in the field a single period of heavy rain or 8 h light rain could transfer at least 1.5 kg K/ha from ryegrass to the soil.