In many cases there is a distinct connection between the size or type of farm and the kinds of farm crop it supports. In view of the de velopment of agricultural machinery, which, however, remains comparatively expensive, the cereals (except corn) are grown as money crops mainly on large farms where enough can be planted to warrant an investment in seeders, harvesters, binders, etc. On the other hand, any farm that supports livestock, especially if it includes dairy cows, is very likely to include some corn, even though it may not be enough to justify the purchase of horse or power ma chinery and, therefore, entails more hand labor in planting and harvesting.
Similarly, a majority of farms in the United States report potatoes, although many of them probably grow the crop only for home con sumption and not on the same scale or in ac cordance with the improved, economical meth ods found in such sections as Aroostook County, Me., the Greeley District of Colorado, etc.
A distinct tendency on the part of livestock farmers — and one that is approved and urged by investigators, educators and other authori ties — is that of raising all the feed they can at home. Both because it is more difficult and bulky to because it is becoming a relatively more important factor in feeding operations, roughage (including silage corn, leguminous hays and green forage crops) is given the most acreage in such cases, the farmer preferring and finding it most profitable to buy the grains or mixed feed needed to supplement his home-grown forage. However, grain farm ers are learning that an exclusive program is a hard one on any soil, and are, in consequence, tending to include some livestock in their operations. Such a transition natu rally involves the growing of pasture hay and perhaps green forage or °soiling° crops, which ultimately gives rise to a much more beneficial rotation system.
Factors in the Selection of Farm Crops. — The choice of one or more farm crops as features of a farming enterprise depends in part upon the personal preference of the farmer, but to an even greater extent upon con ditions peculiar to his locality. The more im portant of these are climate, soil type and con dition, labor supply, market demands and trans portation facilities, and the system according to which the farm in question is operated.
of the most important farm crops of North America show a maximum cos mopolitanism, being grown in all 48 States. These are corn, potatoes, oats, tame grasses and alfalfa. In other words, either these are nat urally adaptable to a wide range of climatic conditions or, as in the case of corn, plant breeders have developed special varieties and strains to meet the needs of or withstand the conditions in different sections. Of the other cereals, winter wheat has a cultural range of 39 States, rye of 38, barley of 34, buckwheat of 23, and winter wheat of 18, the last two being limited in farm practice to the cooler latitudes — the former to the northeast quarter of the United States and the latter to the North Central and Northwestern States.
Among the forage crops two important grasses — Johnson and Bermuda — also sor ghum and teosinte (a corn-like species of recent introduction) are restricted to the South, as are also velvet beans, lespedeza and kudzu, of the legumes. Peanuts, cowpeas and soy beans are also primarily Southern plants though often grown in the Central and Northern States for hay, soiling, silage and other uses in con nection with which a matured seed crop is not required. The vetches are correspondingly hardy representatives of the legume forage crops, being grown mainly in the North.
Cotton is definitely limited to the 15 States of the Southl'• rice to 11 Southern States of which three— Louisiana, Texas and Arkan sas — include nearly 800,000 of the 900,000 acres that represent an average year's planting; and sugar-cane to an even smaller number, Louisi ana being the chief producing centre.
Tobacco has a range of some 24 States east of the Mississippi River, but is grown on but limited areas of most of them. Hops are re stricted to a half dozen States in the extreme northeast and northwest sections, not so much because of their climatic requirements as be cause they are a special and not widely utilized crop. Flax and the root crops — both sugar beets and the sorts grown for stock feeding— are cool weather sorts and are restricted to the northern half of the country, flax to the States of Minnesota, North Dakota and South Dakota. Sweet potatoes are important in the humid sec tions of the South, especially in the southeast ern group of States.