Chapter 27
COMMERCIAL FERTILIZERS--CONCLUDED
THE HOME MIXING OF FERTILIZERS
When a considerable amount of fertilizer is used a better plan than buying mixed fertilizer is to buy the raw materials and mix them yourself. For example, a farmer is about to plant five acres of cabbages for the market. He finds that a certain successful cabbage grower recommends the use of fifty pounds nitrogen, fifty pounds phosphoric acid and seventy pounds potash per acre. For the five acres this will mean 250 pounds nitrogen, 250 pounds phosphoric acid and 350 pounds potash. To furnish the nitrogen he can buy 1,613 pounds of nitrate of soda or 2,500 pounds dried blood or 1,250 pounds sulphate of ammonia, or a part of each. To furnish the phosphoric acid he can buy 1,786 pounds acid phosphate. Seven hundred pounds of either sulphate or muriate of potash will furnish the potash. These materials can be easily mixed by spreading in alternate layers on a smooth floor and then shovelling over the entire mass several times. The mixture can be further improved by passing it through a sand or coal screen or sieve.
By following this method of buying the raw materials and mixing them on the farm, the farmer can reduce his fertilizer bill by quite a considerable amount and at the same time can obtain just the kinds and proper amounts of plant foods needed by his crops.
KIND AND AMOUNT TO BUY
The farmer should make the best use of farm manures and through tillage to render plant food available for his crops before turning to commercial fertilizer for additional plant food.
If he grows leguminous crops for green manuring, for feeding stock or for cover crops, he can in many cases secure, chiefly through them, sufficient high priced nitrogen for the needs of his crops, and it is necessary only occasionally to purchase moderate amounts of phosphoric acid, potash and lime.
For special farming and special crops it may be necessary to use the commercial fertilizer more freely.
It is impossible to say here just what amounts or what kinds of fertilizer should be purchased, because no two farms are exactly alike as to soil, methods of cropping or methods of tillage.
There are certain factors, however, which will serve as a general guide and which should be considered in determining the kind and amount of fertilizer to buy.
These factors are:
The crop. The soil. The system of farming.
THE CROP
Crop roots differ in their powers of feeding, or their powers of securing plant foods. Some roots can use very tough plant foods, while others require it in the most available form. Some roots secure nitrogen from the air. The cowpea roots, for example, can take nitrogen from the air and they can use such tough phosphoric acid and potash that it seldom pays to feed them directly with fertilizers.
A bale per acre crop of cotton requires for the building of roots, stems, leaves, bolls, lint and seed:
103 pounds of Nitrogen. 41 " " Phosphoric Acid. 65 " " Potash.
and yet experiment and experience have proved that the best fertilizer for such a crop contains the following amounts of plant food:
Nitrogen 20 pounds Phosphoric Acid 70 " Potash 20 "
This means that cotton roots are fairly strong feeders of nitrogen and potash, but are weak on the phosphoric acid side.
The small grains, wheat, oats, barley and rye, can use tough phosphoric acid and potash, but are weak on nitrogen, and as they make the greater part of their growth in the cool spring before nitrification is rapid, they are benefitted by the application of nitrogen, particularly in the form of nitrate, which is quickly available.
Clover, peas, beans, etc., have the power of drawing nitrogen from the air, but draw from the soil lime, phosphoric acid and potash. Hence the phosphates, potash manures and lime are desirable for these crops.
Root and tuber crops are unable to use the insoluble mineral elements in the soil, hence they require application of all the important plant foods in readily available form. Nitrogen is especially beneficial to beets. Turnips are benefitted by liberal applications of soluble phosphoric acid. White and sweet potatoes require an abundance of potash.
If we are growing tender, succulent market garden crops, we need nitrogenous manures, which increase the growth of stem and foliage.
Fruit trees are slow growing plants and do not need quick acting fertilizers.
The small fruits, being more rapid in growth, require more of the soluble materials.
A dark, healthy green foliage indicates a good supply of nitrogen, while a pale yellowish green may indicate a need of nitrogen.
A well developed head of grain, seed pod or fruit indicates liberal supplies of phosphoric acid and potash.
THE SOIL
Soils that are poor in humus are generally in need of nitrogen.
Heavy soils are generally supplied with potash but lack phosphoric acid.
Sandy soils are apt to be poor in potash and nitrogen.
SYSTEM OF FARMING
A system of general or diversified farming embracing crop products and stock raising, requires much less artificial manuring than does a system which raises special crops or quick growing crops in rapid succession, as in the case of truck farming or market gardening.
TESTING THE SOIL
Every farmer should be more or less of an investigator and experimenter.
The factors mentioned previously as indicating the presence or absence of sufficient quantities of certain plant foods serve as a general guide, but are not absolute. The best method of determining what plant foods are lacking in the soil is to carry on some simple experiments.
The following plan for soil testing with plant foods is suggestive: To test the soil for a possible need of the single plant foods, a series of five plots may be laid off. These plots should be long and narrow and may be one-twentieth, one-sixteenth, one-tenth, one eighth acre or larger. A plot one rod wide and eight rods long will contain one-twentieth acre. The width of the plot may be adjusted to accommodate a certain number of rows of crop and the length made proper to include an even fraction of an acre. A strip three or four feet in width should be left between each two plots. These strips are to be left unfertilized and are for the purpose of preventing one plot being affected by the plant food of another.
The plots are all plowed, planted and cared for alike, the only difference in treatment being in the application of plant food. If the plots are one-twentieth acre in size, plant foods may be applied as follows.
+----------------------------+ PLOT 1. | Nitrate of Soda 8 lbs. | +----------------------------+
+----------------------------+ PLOT 2. | Acid Phosphate 16 lbs. | +----------------------------+
+----------------------------+ PLOT 3. | Nothing. | +----------------------------+
+----------------------------+ PLOT 4. | Muriate of Potash 8 lbs. | +----------------------------+
+----------------------------+ PLOT 5. | Lime 1 bushel. | +----------------------------+
Plot 3 is a check plot for comparison.
The measuring of the plots, weighing and application of the fertilizers, planting and care of the crops, weighing and measuring at harvest, should be carefully and accurately done.
A number of additional plots may be added if desired to test the effect of plant foods in combination. For instance:
+----------------------------+ PLOT 6. | Nitrate of Soda 8 lbs. | | Acid Phosphate 16 " | +----------------------------+
+----------------------------+ PLOT 7. | Nitrate of Soda 8 lbs. | | Muriate of Potash 8 " | +----------------------------+
+----------------------------+ PLOT 8. | Nothing. | | | +----------------------------+
+----------------------------+ PLOT 9. | Muriate of Potash 8 lbs. | | Acid Phosphate 16 " | +----------------------------+
+----------------------------+ PLOT 10. | Nitrate of Soda 8 lbs. | | Acid Phosphate 16 " | | Muriate of Potash 8 " | +----------------------------+
If the amount of fertilizer is too small to distribute evenly over the plot, mix it thoroughly with a few quarts of dry earth or sand to give it more bulk and then apply it.
In the use of fertilizers it should always be remembered that small crops are not always due to lack of plant food, but may be caused by an absence of the other conditions necessary for root growth and development. The soil may not be sufficiently moist to properly supply the plants with water. Too much water may check ventilation. Poor tillage may check root development. Unless the physical conditions are right the possible effects of additional plant food in the form of fertilizers are greatly diminished. The farmer who gets the largest return from fertilizers is the one who gives greatest attention to the physical properties of the soil. He makes use of organic matter and is very thorough in his methods of tillage. Every farmer should apply to his State Experiment Station for bulletins on the subject of fertilizers.