Why Crop Rotation?
Crop rotation is essential for successful farming. Corn prices are prevailing. As a result, farmers on the best lands in the corn-growing belt have found it profitable to grow corn.
For years after years. Similarly, on the best wheat lands in Minnesota, the Dakota and Canada, wheat grown continuously has proven a profitable enterprise.
In that region, farmers find no financial interest in fencing their farms, constructing farm buildings, feeding cattle and milking cows. When they can make much more money.
By a system of farming that occupies their time for a little more than one-half the year. Thus allowing them leisure during the remainder of the year. A single crop system, while successful for a time, however, will not prove successful in the long run.
Successful farming calls not only for the best possible utilization of the soil. And also for the maintenance of its fertility. But also demands the fullest possible utilization of the labour.
The efficiency of the labour of men and teams on farms is measured largely by the proportion of time for which they are profitably employed.
In nearly all other enterprises labour is fully and continuously employed. In order that farming may compete with other enterprises for labour, it must be likewise employed on the farm.
What is Crop Rotation?
Crop Rotation Definition
Crop rotation is growing different crops on the same piece of land periodically. Good crop rotation is a systematic succession of the three general classes of farm crops, namely, cultivated crops, grain crops and grass crops.
This is practiced in such a way to give large yields and provide pasture and forage on the farm at the least expense of labour and soil fertility.
The rotation is definite when the crops recur in a fixed order, and it is in the fixed rotation. When they not only recur in a fixed order but also at regular intervals. A rotation consisting of corn, oats, wheat and clover and timothy is a definite one, regardless of whether the clover and timothy remain for one, two or three years.
But it becomes a fixed rotation when not only the order of the crops is named, but the length of time of each crop is also specified.
In fixed rotation when they not only recur in a fixed order but also at regular intervals. A rotation consisting of corn, oats, wheat and clover and timothy is a definite one, regardless of whether the clover and timothy remain for one, two or three years, but it becomes a fixed rotation when not only the order of the crops is named, but the length of time of each crop is also specified.
Purpose of Rotations
(1) A rotation of crops provides for maintaining the soil in good tilth.
(2) Supplies organic matter and nitrogen.
(3) Prevents destructive outbreaks of insect pests.
(4) Reduces plant diseases.
(5) Provides for the economic destruction of weeds.
(6) Maintains crop yields.
(7) Distributes the labour of men and horses.
(8) Saves labour in the cultivation of land.
(9) Keeps the soil occupied.
(10) Provides for a balanced removal of plant food.
(11) Systematizes farming.
(12) May control spread of toxic substances.
Maintain Good Physical Condition of Soil
Deep-rooted plants, such as alfalfa and clovers, improves the physical condition of the subsoil as a result of root penetration. The cultivation was given to inter-tilted crops, such as corn, potatoes, bets and the rock crops.
This improves the physical condition of the surface soil. Such frequent cultivation may tend to reduce the organic matter of the soil. But this will be largely overcome by the stubble and roots of the grasses. And clovers that follow the grain crops.
Conserve Organic Matter and Nitrogen
Extensive rotation experiments at the Minnesota Experiment Station show that standard rotations, which include an inter-tilled crop, small grains and grasses with clover, all give net profits.
A four-years’ rotation of millet, barley, corn and oats was no better than four years of continuous growing of wheat. All of these are classified as exhaustive crops. They cause a reduction in both the organic matter and nitrogen supply of the soil.
Land cropped continuously to wheat, corn, potatoes or mangels for a period of ten years, showed a loss of 1100 pounds of nitrogen and 20,000 pounds of carbon per acre.
In twelve standard rotations covering the same period of time, there was a gain of 300 pounds of nitrogen per acre, while the carbon and humus in the soil were maintained and in some cases increased. In the standard rotations, eight tons of manure per acre were applied during the rotation.
Provide for Extermination of Weeds
Noxious weeds often cause a serious loss in farming. Weeds rob the crops of plant food moisture. Thus reducing the yield and sometimes causing absolute failure. But they entail additional labour in the process of cultivation.
Many weeds grow best in certain kinds of crops. For example, mustard is a common weed in the small grain crops in the prairie states. The seeds ripen a little earlier than the grain. As a result in the process of harvesting are freely shattered and seed the land for the succeeding year.
Where small grain is grown continuously this weed becomes a serious pest. Its extermination calls for an inter-tilled crop following the small grain.
Pigweed, bindweed, foxtail and crab-grass are common in corn and potato fields. But they seldom become serious in small grain fields or grassland. Consequently, cultivated crops followed by grasses and small grains make for the extermination of these weeds.
Daisies, wild carrot and buckhorn are common weeds in hayfields. They generally grow worse the longer the land remains in the hay. Such weeds, however, give no trouble in cultivated fields devoted to corn, potatoes, etc.. Their cultivation helps to exterminate them.
Lessen Insect Depredations.
Most insect pests live on some particular crop or a few closely related crops. A crop of related crops, grown continuously on the same land, affords an opportunity for the associated insects to multiply and become very numerous.
The remedy is to plant the infested fields with a crop which will not be injured by the pest in question. Unless these insects have the power of migration they will perish for the want of suitable food or for lack of conditions suitable for multiplication.
Crop Rotation in Insect Extermination
However efficient the rotation of crops may be in the extermination of insects, some rotations may prove not only ineffective but actually disastrous.
For example, land that has been long in grass sometimes becomes so infested with wire-worms as to cause a practical failure when devoted to corn. Grass affords conditions favourable to the multiplication of wire-worms, and they may live in the soil sufficiently long after the grass is ploughed up to destroy a crop of corn which follows.
Under such conditions fall ploughing or bare fallow should precede the planting of the corn.
The billbug breeds freely in the bulbous roots of timothy, and when timothy sod is ploughed late in the spring and planted to corn, this insect transfers its attention to the corn with disastrous results.
Such trouble may be avoided by destroying the existing vegetation some time in advance of planting the corn. The insect under such conditions will either be starved or forced to leave the field before it is planted to corn.
Cutworms are a great menace to newly planted tobacco and many other crops, but their presence depends largely on the preceding crop. They multiply extensively only in grassland where the eggs are laid.
Many similar examples could be cited, and success in preventing insect depredation by crop rotation calls for a knowledge of life history. And habits of the insect pest concerned.
Reduce Plant Diseases
Plant diseases, like insect pest, are generally restricted to a particular crop or all group of closely related crops. The potato scab, so far as is known, is confined solely to potatoes. Its presence in the soil prevents the continuous growing of potatoes.
Calling for crop rotation in which the interval between successive potato crops is sufficiently long to provide for the disappearance of the disease. In a similar manner flax wilt or cotton, wilt demands a rotation of crops to prevent the disease from becoming disastrous.
Bacterial diseases of tomatoes, potatoes, eggplants, cabbage and numerous other vegetables, the rusts and smuts of small grains, and many other diseases accumulate in the soil under the one-crop system. These troubles can be largely avoided and the crop-producing power of the soil maintained by intelligent systems of rotation.
The Environment of Crop.
Aside from insect pest, plant diseases and weeds which flourish under the one-crop system to the disadvantage of the crop, there is another factor inimical to best plant growth. This consists of excreta given off by the roots of plants that accumulate in the soil to their detriment.
As a rule, such excreta are not equally injurious to a different class of crops, and a rotation, therefore, lessens the injury. The excreted substances are organic in nature and are either changed in character or entirely disappear with time, so that the crop giving rise to them may be returned to the land after a year or more without injury.
Rotations Ensure Returns
The old adage, “Don’t place all your eggs in one basket,” applies with equal force in the production of crops. Unfavorable conditions in any locality are seldom such as to cause a failure of all kinds of crops, although a complete failure of a particular crop in a certain locality is not uncommon.
A rotation of crops which includes a variety of crops, therefore, avoids complete failure.
Prevent Reduced Crop Yields.-
The tillage given to cultivated crop, such as corn or potatoes, increases the yield of the crop that follows by providing a better physical condition of the soil.
In like manner, legumes leave organic matter and nitrogen in the soil which is utilized to the advantage of corn or potatoes which may follow. The cultivation has given crops destroy weeds to the advantage of crops which follow, and which do not receive cultivation.
Rotations Systematize Farming.
A well-planned rotation of crops enables the farmer to know definitely what is to be done each year and makes a possible estimation of the general expenses and returns that may be expected.
It also enables him to plan his work and secure his materials, such as seed, fertilizers, etc., in advance of the time they are needed.
Rotations Distribute Labor
A good rotation of crops will enable the farmer to do a larger proportion of his own work than would be possible if the land was devoted to one crop. This enables him to utilize his Own labor to the fullest possible advantage, and to reduce the expense necessary for hired labour.
It is important, therefore, in selecting crop for rotation, to select that will compete with each other for the labour of men and teams a little as possible. The common rotation of corn, oats, wheat, and hay fulfill these requirements fairly well.
To illustrate, the preparation of land and seeding of oats take place in the early spring. Between the seeding time of oats and the time for planting corn, there is sufficient time to prepare the land for the latter crop.
The cultivation of corn will precede the harvest of hay and oats. The preparation of land for winter wheat will take place after the harvest period and prior to the harvest of corn.
This fully occupies the time of the farmer during the growing season. There will sometimes be a conflict between the harvest of wheat and hay, and the cultivation of corn, requiring a little extra labor at that time.
Principles of Crop Rotation
Good crop rotation should contain
(1) An inter-tilled crop.
(2) A cash crop.
(3) Crops to feed.
(4) A crop to supply humus and nitrogen.
All crops may be roughly classified under three heads, namely: exhaustive, intermediate and restorative. All crops, when harvested, remove from the land more or less plant food, and in this sense they are exhaustive.
No crop restores to the soil any considerable amount of plant food unless it is plowed under or allowed to decay on the surface of the soil. Notwithstanding these facts, certain crops leave the land in poorer condition for subsequent crops than it was before.
These are designated as exhaustive crops and include wheat, oats, rye, barley, and millet. Their ill effect upon subsequent crops may be due to anyone or a combination of a number of factors, among which are physical condition of the soil, injurious insects, plant diseases, reduction of soil moisture and a failure to supply either organic matter or nitrogen in any appreciable quantity.
It is wise, therefore, to select as many restorative crops as possible and so arrange the crops that these will be followed by the exhaustive crops. These two classes of crops should alternate as far as possible.
In conjunction with this, one should select crops that will yield well and for which there is a demand, either for feeding on the farm or as a cash crop. The best varieties of the crops entering into the rotation should always be used. These will be determined largely by local conditions.
The Sequence of Crops for Crop Rotation
It is a good plan to follow a crop with a long growing season by one having a short growing season. This is typified when corn is followed by oats. In turn, oats or barley is removed from the land in ample time for seeding winter wheat.
Which occupies the land for a rather long period. In this connection, it is wise to provide in the crop rotation a place where manure may be hauled directly from stables and barnyards and applied to the fields.
Where there is an abundance of manure and corn is extensively and advantageously used as feed for livestock corn may be grown two years in succession, especially when the soil is fertile and manure is available for both the first and second crops.
It is desirable that crops be arranged in such a way that the improving acts of each crop shall be regularly received and the ill effects of the exhaustive crops are systematically neutralized by the crop that follows.
Length of Crop Rotation
The length of crop rotations will be determined by local conditions and the character of crops grown, together with the value of land and cost of labor.
Crops that are costly to establish, such as alfalfa, should occupy the land for two or more years in order to minimize the annual cost of production. The length of time that a crop remains productive is also a factor.
The annual cost of seed and the preparation of the land for the crop is one-half or one-third as much if the crop is continued for two or three years respectively, as it is if allowed to remain only one year. So long as the yield is satisfactory, it generally pays to continue the crop. This tends toward a longer crop rotation.
What Crops to Grow
The crops to be grown in a rotation will be determined by a number of factors, as soil adaptation, length of the growing season, market demands, transportation facilities, and the system of farming that prevails.
Aside from these facts, there is another consideration that must not be overlooked. Usually, it is unwise to follow a crop like tobacco, which is considered a gross feeder, with another crop such as corn having similar feeding habits.
Such a practice is permissible only on very fertile soil or where the quality of the following crops is to be influenced through a reduction in organic matter or available plant food. For example, coarseness in tobacco might be reduced by having it preceded by corn.
When to Apply Manure and Fertilizers
It is generally advisable to apply barnyard manure to those crops in the rotation that have a long growing season or a high monetary value, or to those that are considered gross feeders, such as corn. In the absence of manure, the same rule applies in the applications of commercial fertilizers.
When manure is supplemented with fertilizers, the fertilizers are best adapted to crops of the short growing season or to those influenced in quality by the character or form of a particular fertilizer ingredient.
In this connection, it should be borne in mind that the legumes require only mineral fertilizers and that crops that demand much nitrogen should follow the legumes.
Some Suggested Examples of Crop Rotation
Crops should naturally follow each other. Each crop should pave the way for the one crop that is to follow. Best results will be secured when plants are not compelled to do their part at a disadvantage.
Wherever feasible, a large proportion of the product of rotation should be food for livestock. This provides for the maintenance of soil fertility.
Crop Rotation in the Northeastern Part of the United States
In the northeastern part of the United States, a rotation of corn, oats, wheat, and hay with various modifications dominates most of the general and livestock types of farming.
By omitting oats a three-crop rotation results, which, if restricted to three years in length, makes for soil fertility, provides a cash crop and at the same time furnished an abundance of livestock food and bedding.
This may be supplemented with alfalfa, thus increasing the protein supply. On soils poorly adapted to wheat, this crop may be omitted and oats will take its place. In the northernmost latitudes and at higher elevations the acreage of corn will be reduced and that of oats and hay increased.
Where markets are favourable and the soil is adapted to potatoes, this crop may be substituted for a portion of the corn, thus increasing the cash crops at the expense of forage.
Wheat for Crop Rotation
Wheat generally proves a better crop in which to seed clover and the grasses than oats. In most parts of this section of the country, the grasses are needed in the autumn. And the clover seeded early in the spring.
Further south, both clover and the grasses may be seeded in the autumn. The four staple crops above mentioned may be arranged into several rotations with manure and fertilizers applied.
Crop Rotation in New Jersey, Delaware, Maryland and Virginia
In the trucking regions of New Jersey, Delaware, Maryland, and Virginia, two crops may frequently be secured in one season. Over much of this region tomatoes may be set as late as June 1st. This gives the opportunity to grow a quick-maturing crop before the land is needed for tomatoes.
If hay is needed, crimson clover may be seeded in the fall and cut for hay next spring, before the land is needed for tomatoes. Where canneries available, early peas may be harvested before time to set tomatoes.
This gives two crops in one season, both of which provide for the operation of the cannery and prolong its season of activity. Crimson clover may be seeded in the tomatoes at the last cultivation, and growth turned under the following spring for the benefit of a succeeding crop.
Two-Year Crop rotation
In this district, a two-year rotation in which four crops are grown is found to be quite successful. Two of these are cash crops and two are renovating crops. The cash crops are corn and either potatoes or tomatoes. The renovating crops are crimson clover or soybeans or winter rye mixed with winter vetch.
This makes the purchase of nitrogen in fertilizers unnecessary. Acid phosphate and potash are applied in moderate quantities and generally to the cash crops only. This system, without any manure and with the occasional use of lime, maintains the fertility of the soil.
Crop rotation in Ohio and Indiana
In portions of Ohio and Indiana, a three-year rotation of corn, wheat, and clover is common. One strong point in this rotation is that one plowing answers for three crops. When the clover sod is ploughed for corn in the spring the ground breaks up easily. Thus making an ideal seed-bed for corn.
The cultivation given the corn provides a good seed-bed for wheat with no other preparation than thorough disking and harrowing of the corn stubble. This, of course, necessitates the removal of the cornstalks sufficiently early to seed wheat. It is not applicable where the growing season is too short.
This rotation not only economizes in labour as above suggested but makes a good distribution of labour. Furthermore, it provides for rather a continuous occupation of the soil.
If the sod devoted to corn is not ploughed until spring and corn are followed by fall seeding of wheat in which grass and clover are seeded. The soil will be subject to erosion only during the time it is in corn.
Corn furnishes the material for the silo. Clover hay supplies the protein in which corn is deficient, thus giving & well-balanced ration. The wheat straw makes good bedding, while the wheat may either sold exchanged for concentrates.
On farms having no permanent pasture, the clover and timothy may be left for another year. Cut once and pastured afterwards.
Methods of Planning and Recording Rotations
It is a principle that there should be as many fields as there are years. And crops in the rotation unless two crops can be harvested from the land in one year.
It is also advisable that the fields be as nearly of equal size and productivity as possible. This provides for uniformity in distribution of work from year to year. Ensuring proper product utilization.
Where livestock dominates the type of farming, it will often be found advisable to adopt two rotations. One crop rotation is known as the major. And the other as the minor rotation.
The former will include the staple crops grown both for feed and market. While the latter provides soiling and annual pasture crops. In such a scheme the minor rotation should be located near the farmstead. Thus the small fields will be easily accessible.