Phosphate Fertilizers: Addressing the Challenges for Production, Use and Management in Developed and Developing Country Agriculture.
Lawrence Hammond, Norman Chien, and Upendra Singh. IFDC, PO Box 2040, Muscle Shoals, AL 35662
Phosphorus remains an essential input for crop production in both developed and developing country agriculture. It may be supplied both in organic and inorganic forms of fertilizer but mineral phosphate fertilizers derived from phosphate rock (PR) is the predominant source of supplying phosphorus to crops and will remain so in the foreseeable future. Overall production is down 16.5 Mt from 1988 to 1999 (about 10%). The top four producing countries (U.S., China, FSU and Morocco) still produce over 70% of the world's PR and the top 12 producing countries still produce over 90% of the world's PR. Grade is typically the primary criterion used to differentiate rocks and is often expressed in terms of tricalcium phosphate [Ca3 (PO4)2] or "bone phosphate of lime" or (BPL). Commercial PR varies in grade from about 80 to about 60 BPL. The challenge for the future is to insure a globally economic supply of phosphate fertilizer as higher grade PRs are depleted and concerns over heavy metals increase. A limited amount of PR is produced for direct application to cropland. There is wide variation among PRs, however, with respect to agronomic effectiveness due to chemical and mineralogical composition associated with the source of the PR. World consumption of direct applied PR appears to be stabilized at between 1.0 and 1.5% of world phosphate consumption (nutrient basis), or about 1.5 Mt of product (30% P2O5). In many areas of the world, particularly in developed countries with intensive agriculture, yields are well maintained through good farming practices and judicious management of both organic and mineral fertilizers. In other areas, usually in developing countries in tropical climates, where the natural soil nutrients have often been mined from soils, the maintenance and increase of agricultural production without corresponding fertilizer inputs has often resulted in nutrient imbalances and nutrient depletion of the soil. The resulting depletion of nutrients combined with weather conditions has caused crop production and productivity to stagnate or decline in many of these countries. In some cases, notably in Africa, the rates of depletion are becoming so high that even drastic measures, such as doubling the actual application of fertilizer or manure or halving erosion loses, would not be enough to offset nutrient deficits. Improving the economics of fertilizer supply, marketing and management in these areas is critical.The agricultural research and development community in the less developed countries is characterized by two primary concerns. Firstly, the need for increasing agricultural productivity in a sustainable basis and secondly the concern over limited information flows which typically exist between researchers, extension workers, policy makers, farmers, and agribusiness personnel. Information is typically available and most developing countries have adequate research systems generating relevant information and stakeholders have increasingly easy access to information systems through the Internet. The difficulties are often caused by the massive amount of available information and the lack of tools for its analysis and prioritization. More effort in required to address this challenge through the use of Information and Decision Support Systems (IDSSs). The main idea behind these IDSSs is to take advantage of modern information tools, process large and complex databases, and produce information which can be easily understandable by stakeholders acting in the agricultural sector.