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 diminishing 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.