The yield of the wheat grows less and less as one goes westward. The harvest may be injured either by late frost or drought, or, especially, by hot winds which scorch the plants and blight the half-realized hopes of the farmers in the weeks just before the harvest. But the relative poorness of the return is compensated by the extent of the farms and the cheapness of labour. The harvest is often done with machines that peel and pack the wheat, and the workers are not compelled, as they are at Santa Fé, to wait for the threshing machine. The aridity does not permit flax-growing, but oats can be grown, especially between the Sierra de la Ventana and the Sierra de Tandil; and it is good to sow oats when the land has been impoverished by consecutive crops of wheat. Exports of oats through Bahía Blanca began in 1906.

The displacement of breeding by farming is less thorough than in the maize belt. Oats, sown about the beginning of autumn, serve for fodder. The animals are kept in the fields during the winter, and the oats are cut and put into the mill, without being threshed, as a reserve fodder. Moreover, the wheat farmers have themselves taken to rearing sheep, and the sheep feed in the stubble and fallow.

From this short account of the history of colonization we draw certain important conclusions. At the time when agricultural colonization began, it was admitted that farming was the best way to exploit the soil, and that the Pampa would sooner or later pass from the pastoral to the agricultural cycle; or, to use the local phraseology, that the "colony" would replace the ranch everywhere. This idea was wrong. The only area in which the facts seem to give it any support is the corn belt. The general rule is, on the contrary, that in its progress colonization develops a mixed type of exploitation, combining farming and breeding; either one alternates with the other in a sort of periodic rotation, as in the lucerne area, or both proceed together, the farmers including breeding amongst their occupations, as in the district of the Santa Fé colonies or in the wheat area in the south of the Buenos Aires province.

It seems, moreover, that the development of colonization depends not only upon physical conditions, but upon factors of a purely economic or social character, which the geographer must not overlook. It will be enough here to indicate the chief of these.

We have seen the part that has been played in the exploitation of the soil by groups of colonists who swarm from one area to another. Whether we think of the ranchers of the eastern part of Buenos Aires transplanting themselves to Córdoba or north of Santa Fé, the sheep-breeders moving westward, or the Santa Fé colonists settling in the lucerne area, they all take with them their own habits and methods of work, and they take time to adjust them to a new environment.

MAP V.—DENSITY OF THE WHEAT CROP.

The wheat belt stretches in a broad section of a circle from Bahía Blanca to Santa Fé, which is now reached by maritime vessels. The cultivation of wheat crosses the line of 600 millimetres of rainfall and even the 400-millimetre line, in proportion as one passes from the area of summer rain to that of spring and autumn rain.

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