A risk assessment of sulphur deficiency in cereals using soil and atmospheric deposition data

A qualitative model was used to assess the risk of S deficiency in cereals in Britain. A risk index was generated for each of 6301 soil data points by considering the inputs of S from atmospheric deposition, the content of soil organic matter, and factors influencing the potential leaching of sulphate, i.e. soil type, texture, pH and annual rainfall. The results show that currently 11% of the British land area is at high risk of S deficiency, and a further 22% at medium risk. The high risk areas are in south-east Scotland, the Scottish Borders, East Anglia, the Welsh Borders and south-west England. These agree well with the distribution of reported incidences of S deficiency in cereals. If the UK target for reduction in SO2 emissions by the year 2003 is met, the model predicts that the high and medium risk areas will increase to 23 and 27%, respectively. Thus, agricultural use of S-containing fertilizers is likely to increase in importance in the near future.