Roles and requirements of sulfur in plant nutrition

Increasing awareness of sulfur (S) deficiencies in many parts of the world has led to an increased interest in the plant nutrition role of S. This interest is also due largely to a recognition that the roles of S in plants greatly affect plant S requirements. This chapter discusses how S deficiencies may result in changes in the physiology of plants and how the changes can limit plant productivity and quality. It also discusses link between S and nitrogen deficiency. Data on crop contents of S are useful in estimating fertilizer requirement, for mass balance computations, and in appraising rates of cycling. Knowledge of the functions of S-containing compounds in plant physiology and biochemistry is necessary to understand the role of S in plant nutrition. Many S-containing peptides and proteins appear to be ubiquitous and to function identically or similarly in all living things.