The experiments with grass and clover at Boghall and ryegrass at Bush showed that: - 1. the mineral content of different species of grass and clover varied considerably, the clovers tending to be higher in mineral content than the grasses. 2. the mineral content of white clover was affected by the grass with which it was grown and the competition with the grass for the available nutrients, particularly in the case of phosphorus. 3. the mineral content of both grasses and clover varied considerably from month to month, the nature of the variation depending on the frequency of cutting. In grasses cut monthly, the minerai content tended to increase towards the end of the season, while in uncut ryegrass, the mineral content decreased as the grass matured. 4. treatment with "nitrochalk" increased the calcium and magnesium contents of grasses throughout the season, and increased the phosphorus content initially. The effect of treatment on the clover seemed to depend on the yield and leafiness of the grass with which it was grown and the consequent competition between the grass and clover. 5. treatment with heavy dressings of MgSO4.7H2O increased he magnesium content of ryegrass throughout the season. . the uptake of minerals varied from species to species and from month to month throughout the season, the monthly variation generally following that of the yield. The uptake of minerals by clover was lower than that of the grasses /because of the lower yield of the clover. The total seasonal uptakes of calcium and of phosphorus were greater than the uptake of magnesium. 7. treatment with "nitrochalk" increased the uptake of all three elements by both grass and clover. The mineral content of a sward will therefore depend on the botanical composition of the sward, the frequency of cutting, the time of year and tiffe fertiliser treatment. The experiments with mixed herbage grown for hay and for dried grass bore out these results and showed that: - 1. the magnesium content of the herbage depended on the available magnesium in the soil. 2. the mineral content of herbage decreased with advancing maturity. 3. the effect of the fertilisers studied depended not only on the nature of the fertiliser but also on the mineral status of the soil to which it was applied and the existing cation: anion ratios. (a) magnesium sulphate raised the magnesium content of the herbage, particularly where the soil was low in available magnesium. (b) potassium sulphate depressed the magnesium and phsophorus contents of herbage and in some cases the calcium content also. (c) potassium -magnesium sulphate had little effect on the magnesium ani phosphorus contents of herbage, and was therefore more suitable for use where the soil was low in available magnesium. The experiments with turnips and kale showed that: - 1. the yield of dry matter and the uptake of minerals in the leaf was less than that of the roots in turnips and of the stem in kale. 2. the mineral content of the leaf was higher than that of the roots in turnips and of the stem in kale. 3. the magnesium content of turnip leaves depended on the available magnesium in the soil. 4. treatment with potassium -magnesium sulphate increased ¡the dry matter yield of turnip roots where the available soil magnesium was low, and increased the yield of magnesium content of kale leaves, and the uptake of magnesium by the leaves.