Long term supply factors which regulate grain production are natural resources such as land, water and irrigation, and agricultural technology. The global cultivated area for grains has been falling annually by 0.33% in the sixties, by 0.28% in the seventies, and by 0.18% in the eighties according to the FAO data. As shown in Chart 3, the global per capita grain harvested area has fallen from 0.24 hectares in 1950 to 0.12 hectares in 1994 as a result of the population explosion and the economic limit in the expansion of the cultivated area during this period. The total grain harvest area in the world increased to a peak of 760 million hectares in 1977 as shown in the same chart, but it had since fallen to 690 million hectares in 1994. According to the data from the USDA, the grain harvest area in China has been falling since reaching a post-war peak of 98 million hectares in 1976, and had reduced by 7% to 91 million hectares by 1992. Although the grain harvest area in India increased by 14 million hectares from 1961 to its peak of 106.6 million in 1983, it had fallen by 6.26 million hectares by 1992, and this trend will continue in the future.
According to the FAO data for 1989, the total cultivated area in the world is approximately 1,500 million hectares, about 800 million hectares of which are in developing countries. Also, the total area of pasture and forest in the world is 7,400 million hectares, 42% of which is in developing countries. How much of this pasture and forest area in the developing countries can be turned into arable land for grain production is the most critical issue in order to cope with the food problem there, and the convertibility of pasture and forest to arable land in the developed countries is not relevant regarding this problem. More supply of agricultural land in developing countries is needed in order to cope with the rapid economic growth and population explosion that has been concentrated there and will be so as we head towards the 21st century. An FAO report estimated the potentailly cultivable area for at least one of the 21 important crops in 92 developing countries, excluding China, based on the data for soil
