AT the 1963 New Zealand Grassland Association Conference, I. L. Elliott gave a short description of a new laboratory technique for determining the ability of soils to retain nutrients against leaching. At that time, only a very few soils had been examined and since no comparable evidence from field trials was available, the value of the test was largely a matter of conjecture. The technique was applied to measure the ability of soils to retain potassium, phosphorus and sulphur. This paper is particularly concerned with sulphur. Following the examination of a larger number of samples, some clear patterns of leaching losses are now emerging and a better position exists to predict where sulphur deficiency is likely to arise.