The First Book of Farming Part 30

----------------------+-----------+------------+--------- Cotton (whole plant) | 103 | 41 | 65 Corn (whole plant) | 84 | 26 | 61 Oats (whole plant) | 32 | 13 | 27 Cowpea | 78 | 23 | 66 ----------------------+-----------+------------+---------

Now suppose we sell the lint of the cotton, keeping all the rest of the plant, including the seed, on the farm and turning it back into the soil.

Of the corn suppose we sell one-half the grain and keep the other half and the fodder for use on the farm.

Suppose the oats be made into oat hay and be fed on the farm and the cowpeas be turned under.

a.s.suming that the cowpeas take half their nitrogen from the air.

This will mean that in the course of three years we take out of the soil of each acre in the crops:

Nitrogen. Phosphoric Acid. Potash.

258 pounds. 103 pounds. 219 pounds.

but we return to the soil in crop refuse and manure from the stock:

Nitrogen. Phosphoric Acid. Potash.

256 pounds. 87 pounds. 197 pounds.

This a.s.sumes that we have taken from the farm in products sold:

------------------+-----------+------------+------------+ | Nitrogen. | Phosphoric | Potash. | | | Acid. | | ------------------|-----------|------------|------------| Cotton Lint | 2 | 1 | 2 | Corn | 28 | 12 | 10 | Animal products | 11 | 3 | 10 | +-----------+------------+------------+ Totals | 41 | 16 | 22 | ------------------+-----------+------------+------------+

The plant food charged to animal products is twenty per cent. of that in the grain and forage fed to the stock.

At the end of the three years the plant food account will balance up with:

Nitrogen a gain of 2 pounds.

Phosphoric Acid a loss of 16 "

Potash a loss of 22 "

This result is of course approximate. There will be some loss of nitrogen through leaching and denitrification. Some of the potash and phosphoric acid will be converted into unavailable forms. This can be made good by applying to the cotton a fertilizer containing twenty pounds of nitrogen, sixty pounds of phosphoric acid and twenty pounds of potash.

Additional nitrogen and organic matter can be grown to turn under by planting crimson clover in the cotton at the last working for a winter cover crop to be turned under for the corn, and by planting cowpeas or soy beans between the rows of corn.

If this is done it may not be necessary to add any nitrogen in the fertilizer, letting that supply only phosphoric acid and potash.

If commercial fertilizer is used on the cotton, it would be a good plan to apply the manure from the stock to the corn.

To follow our crop on Field 1 through the three years we will have, first, cotton drawing large amounts of plant food from the soil and diminis.h.i.+ng the humus of the soil.

Growing a winter crop of crimson clover, turning back all the cotton refuse except the lint and oil, and applying the barn manure will furnish ample plant food for the corn and replenish the organic matter.

The corn is a rather stronger feeder of phosphoric acid than cotton and will be able to get sufficient from that left by the cotton.

The oats will be able to get a full ration after the corn, and the cowpeas will readily take care of themselves on the score of plant food and will put the soil in fine condition for cotton again.

The peas may be left on the ground to turn under in the spring at cotton planting time, or they may be plowed under in the early fall and a crimson clover or vetch cover crop planted, which will be plowed under for the cotton.

These same facts will be true of each of the three fields. The humus and, therefore, texture will be taken care of; ventilation, soil temperature and plant food will be controlled to advantage.

Each of the crops will be represented on the farm each year and the yields of each crop will be better than if grown continuously alone.

The quality and therefore the market value will be greater. Insects and disease will be easier kept in control, and stock will be more economically furnished with a variety of foods.

BENEFITS DERIVED FROM ROTATION OF CROPS

Rotation of crops economizes the natural plant food of the soil and also that which is applied in the form of manure and fertilizer. This is because:

Crops take food from the soil in different amounts and different proportions.

Crops differ in their feeding powers.

Crops differ in the extent and depth to which they send their roots into the soil in search of food and water.

Crops differ in the time of year at which they make their best growths.

Rotation helps to maintain or improve the texture of the soil because the amount of humus in the soil is maintained or increased by turning under green manure and cover crops which should occur in every well-planned rotation.

Rotation helps to maintain or increase the plant food in the surface soil. When crops like cowpeas or clover which take mineral food from the subsoil and nitrogen from the air, are plowed under, they give up the plant food in their leaves, stems and upper roots to the surface soil, and thus help to maintain or increase fertility.

Rotation tends to protect crops from injurious insects and diseases.

If one kind of crop is grown continuously on one piece of land the soil becomes infested with the insects and diseases which injure that particular crop. If the crop is changed, the insects and diseases find difficulty in adapting themselves to the change and consequently diminish in numbers.

Rotation helps to keep the soil free from weeds. "If the same kind of crop were grown year after year on the same field, the weeds which grow most readily along with that crop would soon take possession of the soil." For example, chick weed, dock, thistle, weeds peculiar to grain and grain crops tend to increase if the land is long occupied by these crops.

Rotation helps the farmer to make a more even distribution of labor throughout the year. This is because crops differ as to the time of year at which they are planted and harvested.

Rotation of crops enables the farmer to provide for his stock more economically. Live stock fares better on a variety of food, which is more cheaply secured by a system of rotation than otherwise.

THE TYPICAL ROTATION

A typical rotation for general farming should contain at least:

One money crop which is necessarily an exhaustive crop.

One manurial crop which is a soil enricher.

One feeding crop which diminishes fertility only a little.

One cleansing crop, a hoed or cultivated crop.

CONDITIONS WHICH MODIFY THE ROTATION

There are certain conditions which tend to modify the rotation or to influence the farmer in his choice of crops. They are as follows:

First of all the climate will set a limit on the number and varieties of crops from which a choice can be made for a given locality.