Discussion: Enhancing Natural Resource Use to Increase World Food Production

The natural resources available to grow food-land, water, and energy-are finite in extent, and their use for agriculture is often in competition with other uses. Recent inventories suggest that 3.4 billion hectares, or 25% of the world's land surface, in principle could be cultivated; at present the cultivated area is less than 11%. The potential for expansion of cultivated area is substantial, but much of this land is not where the people are; furthermore, its development could readily lead to drastic and irreversible resource deterioration both on site and off. A similar situation prevails for water. The currently 170 million hectares of irrigated land could be doubled but not without tremendous investment and substantial risk. The obvious alternative for increasing food production is to increase production per unit of land. Both avenues must be pursued. Two divergent, yet related, concepts are often advocated: to transfer the technology of U.S. commercial agriculture to other regions and to greatly expand basic biochemical research-photosynthesis, nitrogen fixation, genetic engineering-in "pure" academic institutions. Both have their proper place in increasing food production, but they must be placed in perspective. I propose that higher priority be given to learning to use natural resources effectively and conservatively by adapting known principles imaginatively to existing ecological and socioinstitutional circumstances and by further developing these principles to aid in constructive development. This approach is less direct and more difficult than transferring large-scale mechanization and less glamorous than biochemistry. It calls for inputs from more than the physical and biological sciences-from economics, if you wish, but not for myopic benefit-cost analysis. Some examples may clarify the issue. In Nigeria, it is not uncommon to encounter 50 plant species that make up a farming system for a small community. Introducing monoculture techniques would be socially and agronomically disastrous, as well as exposing the land to severe erosion. But the recent development of a hand-operated drill for precision planting in mulch or sod can greatly increase labor productivity. Combined with a back-carried herbicide sprayer that applies 10 liters per hectare (as compared with the more usual 500 liters per hectare), the energy required for planting is reduced more than tenfold, while production is increased by improving the existing multiple cropping system. Pereira related an experience in Kenya, where some twenty years ago forest vegetation was transformed into a tea plantation, using the best conservation practices known. Peak runoff flows quadrupled during clearing and planting and still were double those from forested watershed after a full canopy was established, even though consumptive use was equal. Brazil is committed to developing 3 million hectares of Oxisol savannahs of their Cerrado by 1979 and 50 million by 2000; Peru plans to develop 2 million hectares of its Amazon jungle by 1990. Do we know how to avoid adverse consequences? If we do, can we implement the proper measures? In Puerto Rico, intercropping a new planting of coffee with plantains the first two years, and taniers the third, increased net income more than $8,000 per hectare over the three-year period. Furthermore, imaginative management practices resulted in subsequent annual coffee yields ten times the regional average. Thus, the potential has been demonstrated of significant impact on production by adapting imaginative concepts to existing farming systems. So have the dangers of large-scale changes without full realization of the consequences. Within this framework, exciting possibilities exist for research to realize the full potential of Jan van Schilfgaarde is the director of the U.S. Salinity Laboratory, U.S. Department of Agriculture, Riverside, California. Reprints purchased by Agricultural Research Service, U.S. Department of Agriculture, for official use.