Estimating Sulfur Requirements, Supplies, and Gaps

The empirical evidence presented earlier indicates that S deficiency has become a problem in most tropical countries. Unless appropriate corrective actions are taken, S deficiency poses a threat to national and international efforts to accelerate food and agricultural production in these countries. However, in order to design nationally acceptable and economically viable S supply strategies, there is a need to accurately estimate S requirements, supplies, and gaps. The primary purpose of this chapter is threefold: (1) to estimate S requirements for crop production and fertilizer manufacturing, (2) to determine trends in S supply from fertilizer use, and (3) to estimate S gaps between requirements and supplies. The empirical estimation of the mathematical model deals with major crops, selected countries and world regions, and S-containing fertilizers from 1960 to 2000.