Chapter 53 Fertilizers and other farm chemicals

Demand for fertilizer in developing countries has expanded at a rapid rate over the past forty years. The relative scarcity of agricultural land has been a major underlying cause of this expansion in demand. More proximate causes include the development of complementary Green Revolution technologies – high yielding, fertilizer responsive seed varieties and expansion of irrigation or better water control within irrigated systems. At the same time, real fertilizer prices have declined over time, driven by technical change in fertilizer production. Expansion of fertilizer consumption has been particularly high in many Asian countries, and particularly low in much of Sub-Saharan Africa, where infrastructural and institutional constraints have restricted use. Pesticide use has also expanded in developing countries, albeit in more localized circumstances. Relative scarcity of agricultural labor has been one cause of increased herbicide demand. Disease pressure and the availability of disease-resistant cultivars have influenced insecticide and fungicide demand. Integrated pest management (IPM), over the past 20 years, and genetically modified crops, over the past five to ten years, are new technologies that have the potential to curb the growth in pesticide use. Price policies, environmental policies, and related investments in agricultural research and development, infrastructural expansion, or education all influence the markets for fertilizer and other farm chemicals in developing countries. One major policy issue is how to reduce or eliminate fertilizer subsidies at the same time that measures are taken to increase demand in areas such as Sub-Saharan Africa where fertilizer use is below the social optimum. At the same time, in intensive agricultural systems where agricultural chemical use is high, resource degradation and human health risks from pesticide use compromise productivity growth. In areas of both high and low use of chemical inputs, meeting the production and environmental challenges of the future will require increasing reliance on knowledge-intensive technology.