Effects of fertilizers on the sulphur content of herbage
1976
McLAREN, R.G.
The sulphur concentrations in herbage samples from the plots of a long‐term fertilizer experiment have been examined in relation to levels of fertilizers applied. Sulphur applied as superphosphate increased herbage sulphiir concentrations whereas reduction in concentrations were observed with applications of nitrogen as ‘Nitro‐chalk’ and potassium as potassium chloride. Reduction in sulphur concentration occurred most likely as a result of increased dry matter production brought about by the added nitrogen and potassium, effectively diluting the sulphur content of the plant material. Potassium chloride may also have exerted an anion‐antagonistic effect on sulphate uptake by the plants. Levels of soil extractable sulphate were low in plots receiving no sulphur as fertilizer and high levels of nitrogen applied to these plots resulted in wide nitrogen: sulphur ratios in the herbage. Most of the sulphur applied to the soil in the spring was leached out of the topsoil by the end of the growing season. In some areas of Britain it seems possible that optimum utilization of applied nitrogen may only be obtained where sulphur is also added to the soil.
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