On the productive farm of Dr. W. I. Chamberlain, in Northern Ohio.
A Few Combinations are Safest.—It is the best judgment of scientists to-day that greater results would be obtained from the use of commercial fertilizers if the number of formulas could be reduced to ten, or even a less number. The satisfactory fertilizers fall into three classes:
1. The phosphatic fertilizer, carrying phosphoric acid to land that gets its nitrogen from clover or stable manure, and that continues to supply its own potash. Such a fertilizer should have a high content of phosphoric acid in order that the freight charge, per pound of plant-food, may be as low as possible. Acid phosphate, basic slag, and bone are chief in this group.
2. The combination of phosphoric acid and potash that is needed by soils obtaining all required nitrogen from clover or manure. In most instances the phosphoric acid should run higher than the potash, but the percentage of potash should never run lower than 4. A lower percentage of potash is not as profitable as a higher one, provided any potash is needed. The potash content should be greater than that of the phosphoric acid in case of some sandy soils and of some crops of heavy leaf growth, including various garden crops.
3. The so-called "complete" fertilizer that supplies some nitrogen with the two other plant-constituents. Such fertilizer should furnish, with few exceptions, 3 per cent of nitrogen, if no more.
Amount of Application.—In common practice fertilizers are not applied freely enough when they are used at all. The exception to this rule may be found in the case of small applications to cold and inert soils to force growth in the first few weeks of a plant's life. It is difficult to see how 80 or 100 pounds of fertilizer can affect an acre of land one way or the other, but experience teaches that such an amount can do so in respect to young plants. Phosphoric acid has peculiar power in forcing some development of roots in a small plant, and a small application in the drill or row may help the plants to gain ability to forage for themselves.
In early spring a small application of nitrate of soda has marked effect, tiding the plants over a period of need until the soil is ready to give up a part of its store.
If a soil is not fertile, and fertilizers are needed as an important source of plant-food throughout the season, the application should be liberal. If it is necessary to plant a field that is deficient in fertility, expending labor and money for tillage and seed, the only rational course is to furnish all needed plant-food for a good yield. There may be little net profit from the one crop, but there will be more than could be obtained without the liberal fertilization, and the soil will be better equipped for another crop. This applies, in a notable degree, to fertilization of a wheat crop with which timothy and clover will be seeded. The difference in cost of 350 pounds of a high-grade fertilizer and 150 pounds of a low-grade one, when applied to a poor soil under these circumstances, may be recovered in the grain crop, and at the same time a good sod will be made possible for the permanent improvement of the land. It is a safe business rule that land should be left uncultivated unless enough plant-food can be provided in some way for a good yield. The man who cannot incur a heavy fertilizer bill, when necessary, should restrict acreage for his own sake.
Similarity of Requirements.—Many of our staple crops are very similar in their fertilizer requirements, and this simplifies fertilization. Setting aside the impression gained from the dissimilarity in the so-called corn, potato, wheat, and grass fertilizers on the market, the farmer knows that the soil which is in a good state of fertility is best for any of them, and if the soil is hard-run, it should have its plant-food supply supplemented. The hard-run soil usually is lacking in available supplies of all three plant-food constituents. If a fertilizer containing 3 per cent of nitrogen, 10 per cent of phosphoric acid, and 6 per cent of potash serves the wheat well, it will serve the timothy that starts in the wheat. Likewise it will serve the corn, although a heavier application will be needed because corn is a heavy feeder. Experience has taught that it will serve the potato similarly, and that the potato will repay the cost of free use of fertilizer. If the soil is sandy and deficient in potash, the percentage of phosphoric acid may be cut to 8, and the percentage of potash raised to 10, and all these crops will profit thereby. If the nitrogen content in the soil is high, none of these crops may need nitrogen in the fertilizer. This is a general principle, and safe for guidance, though the best profit will demand some modification that readily occurs to the farmer as he studies his crops and their rotation. To illustrate: The corn is given the clover sod or the manure partly because it requires more plant-food than the wheat. It gets the best of the nitrogen, and may need only a rock-and-potash fertilizer, while the wheat that follows may need some available nitrogen to force growth in the fall. There is no fixed formula for any field or crop, and the point to be made here only is that the requirements of many standard crops do not have the dissimilarity usually supposed, except in respect to quantity. A marked exception is found in the oat crop, which does not bear the application of much nitrogen, and often fares well on the remains of the manure that fed the corn, if some phosphoric acid is added.
Maintaining Fertility.—A heavy clover sod gives assurance that a good crop of corn or potatoes can be grown. If the amount of plant-food in the sod is not excessive, a heavy crop of wheat can be produced. The condition of the soil favors many crops. The clover has placed it upon a productive basis for the time being.