Only a small fraction of the world’s land area—about one-tenth—may be considered arable, if arable land is defined as land planted to crops. Less than one-fourth of the world’s land area is in permanent meadows and pastures. The remainder is either in forests or is not being used for agricultural purposes.

There are great differences in the amount of arable land per person in the various regions of the world. The greatest amount of arable land per capita is in Oceania; the least is in China. No direct relationship exists between the amount of arable land per capita and the level of income.

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Harvesting wheat on a farm in the grain belt near Saskatoon, Saskatchewan, Canada. A potash mine appears in the distant background.

George Hunter

The relationship between land, population, and farm production is a complex one. In traditional agriculture, where methods of production have changed little over a long period of time, production is largely determined by the quality and quantity of land available and the number of people working on the land. Until the early years of the 20th century, most of the world’s increase in crop production came either from an increase in land under cultivation or from an increase in the amount of labour used per unit of land. That generally involved a shift to crops that would yield more per unit of land and required more labour for their cultivation. Wheat, rye, and millet require less labour per unit of land and per unit of food output than do rice, potatoes, or corn (maize), but generally the latter yield more food per unit of land. Thus, as population density increased, the latter groups of crops tended to be substituted for the former. That did not hold true in Europe, where wheat, rye, and millet expanded at the expense of pasture land, but those crops yielded more food per acre than did the livestock that they displaced.

As agriculture becomes modernized, its dependence upon land as well as upon human labour decreases. Animal power and machinery are substituted for human labour; mechanical power then replaces animal power. The substitution of mechanical power for animal power reduces the need for land. The increased use of fertilizer as modernization occurs also acts as a substitute for both land and labour; the same is true of herbicides and insecticides. By making it possible to produce more per unit of land and per hour of work, less land and labour are required for a given amount of output.

In the second half of the 20th century, governments undertook to control both prices and output in the agricultural sector, largely in response to the pressures of the farmers themselves. In the absence of such control, farm prices tend to fluctuate more than do most other prices, and the incomes of farmers fluctuate to an even greater degree. Not only are incomes in agriculture unstable, but they also tend to be lower than incomes in other economic sectors.

The instability of farm prices results from several factors. One is the relative slowness with which farmers are able to respond to changes in the demand for their product. Farmers generally must produce on the basis of expectations, and if their expectations turn out to be wrong, the resulting surplus or shortage cannot be corrected until the beginning of the next production cycle. Once a crop is planted, very little can be done to increase or decrease production in response to market prices. As long as prices cover current operating costs, such as the cost of harvesting, it pays farmers to carry through their production plans even if prices fall to a very low level. It is not unusual for the prices of particular farm products to vary by a third or a half from year to year. That extreme variability results from the relatively low responsiveness of demand to changes in price—i.e., from the fact that in order to increase sales by 5 percent it may be necessary to reduce the price by 15 percent.

The instability of farm prices is accompanied by instability of farm income. While gross income from agriculture generally does not vary as much as do individual farm prices, net income may vary more than prices. In modern agriculture, costs tend to be relatively stable; the farmer is unable to compensate for a drop in prices by reducing his payments for machinery, fertilizer, or labour.

The incomes of farm workers are generally below those of other workers. There are two major reasons for that inequity. One is that in most economies the need for farm labour is declining, and each year large numbers of farm people, especially young ones, must leave their homes to seek jobs elsewhere. The difference in returns to labour is required to bring about that transfer of workers out of farming; if the transfer did not occur, farm incomes would be even more depressed. The second major reason for the income differences is that farm people generally have less education than do nonfarm people and are able to earn less at nonfarm jobs. The difference in education is of long standing and is found in all countries, developed and undeveloped; it also exists whether the national education system is highly decentralized, as in the United States, or highly centralized, as in France.