Chapter 39

CROP-ROTATIONS

The Farm Scheme.--Notwithstanding some of the theorizing that does not commend itself to the practical man, farm management is taking on the form of a science. It involves the organization of a farm for best results, and in the scheme that should be worked out for any particular farm the most important feature is the crop-rotation. The selection of crops is controlled by so many local considerations, including the personal likes and dislikes of the farmer, that very rightly the kinds of rotation are innumerable. The order in which crops may be grown with most profit is less variable, and yet even here local conditions may quickly derange the scheme of a theorist. There is, however, such right relation of facts to each other that we are getting a working philosophy, and the individual farmer can bend practice to his own liking in considerable degree, and yet not compel plants to do their part at a disadvantage. He has much liberty in the order of their growing, without endangering profits materially. Theoretically, this is not true, and the factors of production on any farm are such that the largest return is obtainable in only one scheme of farming. Practically there is rather wide liberty.

Value of Rotation.--Experience has shown the benefit of variety in crops grown on land. Among the advantages of crop-rotation are the following:

1. It enables the farmer to maintain the supply of organic matter in his soil. The roots and stubble of a grain crop are insufficient for this purpose, and the introduction of a sod or cover crop is helpful.

2. It permits the use of legumes to secure cheap supplies of nitrogen.

3. Some plants feed near the surface of the ground, and the use of other plants which send roots deeper adds to the production.

4. Some crops leave the soil in bad physical condition, and the use of other crops in the rotation serves as a corrective.

5. The keeping of livestock is made more feasible and profitable, and this leads to increase in farm manures.

6. In a proper succession of crops the soil is covered with living plants nearly all the time, and thus is prevented from washing or leaching.

7. In addition to these influences upon soil fertility, crop-rotation assists in control of insect and fungous foes and of weeds; it permits such distribution of labor on the farm that the largest total production may be secured by its employment; and it saves the farmer from sole dependence upon a single crop.

Selection of Crops.--The natural inclination of the farmer is a consideration that cannot be ignored. If a man does not like certain kinds of animals or crops, his farm or market must possess an unusual advantage to counter-balance. Illustration of this truth may be seen in every farming community.

As a rule, the crops should be those that are well adapted to the particular soils upon which they are grown. It is up-hill work to compete with producers whose soils have far better adaptation, unless the local markets equalize conditions.

The crops should follow each other in such succession that each crop naturally paves the way for the next one in the succession, or at least does not place its successor at a disadvantage.

When it is feasible, a rather large proportion of the entire produce of the rotation should be feeding-stuff for livestock, as soil fertility is most easily guarded by livestock farming. This is desirable when consistent with profit, but, as we have seen, it is not an absolute essential.

An Old Succession of Crops.--In the corn belt of the northern states some time-honored crop-rotations have been formed by corn, oats, wheat, clover, and timothy. The number of years devoted to the grain and to the sod has varied with the soil and the desire of its owner. A common succession is corn one year, oats one year, wheat one year, clover and timothy one year, timothy one year--a five years' rotation that has much substantial success behind it. Such a rotation is wholly reasonable and in accord with the nature of things. Every year furnishes some organic matter for the soil in roots and stubble, and all the produce of four years out of the five may be fed on the farm. There is one cash crop, or two if the price of the clear timothy hay justifies sale.

The manure may be hauled upon the sod when other work does not press, and it goes where the crop is one that prefers fresh manure, be that the grass or the corn. There is plenty of time after the corn to prepare for oats, and after the oats to prepare for wheat. The preparation for the wheat is sufficient for the clover and timothy. The seedings come only in the spring and the fall, when rainfall is more abundant and effective than in mid-summer. The danger of failure in case of this rotation is relatively small.

Corn Two Years.--Hunt says that the prosperity of the east, as a whole, would be greatly increased if the rotations of crops were so modified as to increase the corn acreage. He suggests the four rotations given in the table below, which is taken from Bulletin 116 of the Pennsylvania experiment station. The fertilizers recommended should maintain fertility.

CORN IN CROP-ROTATIONS

+-------+-------+-------+-------+-------------------------------------+ | 3 Yr. | 4 Yr. | 5 Yr. | 7 Yr. | | | ------+-------+-------+-------+-------------------------------------+ | | | | 1 | Corn: 6 to 10 loads of manure and 25| | | | | | pounds of phosphoric acid. | | 1 | 1 | 1 | 2 | Corn: 6 to 10 loads of manure and 25| | | | | | pounds of phosphoric acid. | | | 2 | 2 | 3 | Oats: no fertilizer. | | 2 | 3 | 3 | 4 | Wheat: 50 pounds each of phosphoric | | | | | | acid and potash. | | 3 | 4 | 4 | 5 | Clover and timothy: no fertilizer. | | | | 5 | 6 | Timothy: 25 pounds each of nitrogen,| | | | | | phosphoric acid, and potash. | | | | | 7 | Timothy: 25 pounds each of nitrogen,| | | | | | phosphoric acid, and potash. | +-------+-------+-------+-------+-------------------------------------+

The Oat Crop.--In the northern part of the corn belt the oat crop is profitable. In the southern half of Ohio and regions of like temperature the oat crop rarely pays. The heat, when the oat is in the milk stage, usually is too great. The tendency there is to eliminate this crop. Where silage is wanted, the stubble-land can be seeded directly to wheat with good results. A common practice is to seed to wheat between the shocked corn, and the wheat does poorly unless the soil is quite fertile.

Two Crops of Wheat.--A common practice has been to grow two crops of wheat, seeding first in the corn stubble-land, and plowing the ground for the second wheat crop, making a smooth surface for mowing. This method ceased to pay well when wheat became low in price. It has the advantage of giving two cash crops to the rotation.

Where winter wheat does not thrive in the north, it is dropped out, and the seeding to clover and grass is with the oat crop. There is the compensation of a large oat yield where the climate is too cold for a good crop of wheat.

The Clover and Timothy.--The timothy and clover sod is made inexpensively so far as labor is concerned. The first crop of hay is chiefly clover, and the soil is enriched by the roots and stubble, while the hay is converted into manure.

The second year the hay is nearly clear timothy. The sod should not be left until it becomes thin, but should be turned under while heavy, no matter if this must be after one season's harvest, or two. A sod stands three or four years for harvest on some farms, and without heavy fertilization there is decrease in fertility.

Two Legumes in the Rotation.--If all the crops of this five years' rotation, excepting wheat, were fed on the farm, and if all the manure were saved and rightly applied, there would be little or no difficulty in maintaining fertility, provided the soil were friendly to clover. The fact is that much such land has grown poorer, and it is known that another legume is needed in the rotation. The substitution of the soybean or cowpea for the oat crop gives excellent results. It makes a large supply of rich hay, and it fits the soil nicely for winter grain. The use of the breaking-plow is escaped. The surface of the land is in good tilth, especially if the legume was planted in rows so that cultivation could be given. A cutaway harrow, run shallow, and a roller make the seed-bed. Near the southern edge of the oat belt this substitution gives more value in the crop following corn, and at the same time conserves soil fertility.

Where land is thin, a four years' rotation of corn, soybeans or cowpeas, wheat, and clover is one of the best, because it contains two leguminous crops, and because one of them favors the wheat which follows and the clover seeded in the wheat.

Potatoes after Corn.--When potatoes are grown in the corn belt, a five years' rotation of corn, potatoes, oats, wheat, and clover, or corn, potatoes, wheat, clover, and timothy, is one of the best. When a late potato crop is grown, there is not time for seeding to wheat in cool latitudes, and the oat crop, or the soybean, fits in best. Farther south, where the oat crop is less profitable, there usually is time to go directly to wheat.

The advantage in this rotation is that the fresh manure can be used on the sod for the corn, and the potato thrives in the rotted remains of the sod and manure. Corn leaves the soil in good physical condition for the potato. Commercial fertilizer is used freely for the potato, which repays fertilization in higher degree than most other staple crops. The land can be prepared for seeding to wheat and grass with a minimum amount of labor. The rotation is excellent where there is enough fertility for the potato, which usually can be by far the most profitable crop in the entire rotation.

A Three Years' Rotation.--Farm conditions may require that certain fields in the farm go under a crop-rotation covering three years. In the winter wheat belt this may be clover, corn, and wheat, or clover, potatoes, and wheat. It is an excellent rotation when early planted potatoes or silage corn follows the sod, favoring the wheat in which the clover again is seeded. The ground is plowed only once in three years. The clover furnishes hay for the farm, and organic matter with nitrogen for the land. There are two cash crops in the rotation when potatoes are grown, and that makes a heavy draft upon fertility. Experience has demonstrated that commercial fertilizers or manure become necessary as a supplement to clover in a three years' rotation embracing potatoes. This rotation gives good control of most weeds and insect enemies.

Where wheat is unprofitable, the oat crop is used in its stead. If mixed hay is wanted, timothy is sown with the clover. This is poor practice from the standpoint of soil fertility because the draft upon humus is heavy in a close rotation embracing a tilled crop and small grain. The sod should be chiefly clover, or manure should be used in connection with commercial fertilizer.

Grain and Clover.--In the case of some soils it is possible to grow a wheat or corn crop each year, clover being grown as a catch crop. In the long run, this practice will fail because the clover will cease to make a thrifty growth when grown so nearly continuously. It succeeds best on fertile land.

Potatoes and Crimson Clover.--In some potato-producing sections in warm latitudes it is a not uncommon practice to grow potatoes year after year on the same land, seeding to crimson clover after the removal of the crop in August, and plowing the clover down early in the spring. Rye has been similarly used farther north. In each instance available plant-food must be freely supplied. The practice is a temporary expedient of value, but probably cannot be pursued indefinitely with profit. This is likewise true of similar close rotations.