On his 500-acre farm near Gilman, in the heart of the Illinois Corn Belt, Mr. Frank I. Mann has produced a 70-bushel average yield of corn for a five-year period, and with 200 acres of land in corn annually. It cost him only $1 an acre a year in fine-ground natural rock phosphate to produce increased yields of 16 bushels more corn, 23 bushels more oats and 1 ton more clover than the average yields secured without adding phosphorus.
But this progressive, practical farmer is only putting into profitable practice the results of the long-continued careful investigations with raw phosphate conducted by such public-service institutions as the agricultural experiment stations of Pennsylvania, Maryland, Rhode Island, Massachusetts, Ohio and Illinois. He knows also that on four different fields of typical Corn-Belt land in McLean county, Illinois, the total crop values per acre for a period of ten years were $148.75 $151-30, $149.43 and $149.96, respectively, and that on four other adjoining or intervening fields, which differed only by two liberal additions of phosphorus during the ten years, the respective crop values for the same time were $229,37, $221.30, $229.20 and $225.57.
Of course, Mr. Mann does not buy nitrogen, but he takes it from the inexhaustible supply in the air by means of clover and alfalfa or other legumes. He does not buy potassium because he knows how to liberate it from the inexhaustible supply contained in the soil, and because he knows that in the Illinois investigation just cited the crop values from four different fields not receiving potassium were $148.75, $151.30, $229.37 and $221.30; while four other adjoining fields, which differed only by liberal applications of potassium, produced during the same ten years $149.43, $149.96, $229.20 and $225.57, respectively.
Thus, as a general average, phosphorus increased the crop values by $76.50 an acre, which amounts to more than 300 per cent on the investment, and at the end of the ten years the soil on the best treated and highest yielding land was 10 per cent richer in phosphorus than at the beginning; while the crops from the unfertilized land removed an amount of phosphorus equal to nearly one-tenth of the total supply in the plowed soil. But a similar general average shows that potassium produced increased crop values worth only 86 cents, or 3 per cent of its cost.
What other results should be expected from land containing in the plowed soil of an acre less than 1200 pounds of phosphorus and more than 36,000 pounds of potassium?
"Working" the Land
If there is one agricultural fact that needs to be impressed upon the American people it is that the farmers of this country have been living, not upon the interest from their investments, but upon their principal; and whatever measure of apparent prosperity they have had has been taken from their capital stock. The boastful statement sometimes made, that the American landowner has become a scientific farmer, is as erroneous as it is optimistic. Such statements are based upon a few selected examples or rare illustrations, and not upon any adequate knowledge of general farm practice. Even to this date almost every effort put forth by the mass of American farmers has resulted in decreasing the fertility of the soil.
The productive power of normal land in humid climates depends almost wholly upon the power of the soil to feed the crop; but the American farmer does everything except to restore to the soil the plant food required to maintain permanently its crop-producing power. These ought be to have done, but not to leave the other undone. Thus, tile drainage adds nothing to the soil out of which crops are made, but only permits the removal of more fertility in the larger crops produced on the well-drained land. More thorough tillage with our improved implements of cultivation is merely "working the land for all that's in it." The use of better seed produces larger crops, but only at the expense of the soil. Even the farm manure is so limited and is spread so thinly with manure-spreaders made for the purpose that it adds but little to the soil in comparison with the crops removed and sold in grain and hay as well as in meat and milk. Clover, as commonly produced and harvested, adds little or no nitrogen to the soil.
The ordinary high-priced, manufactured, acidulated, so-called "complete" commercial fertilizers, in the small amounts that farmers can afford to use, and do use quite generally in the older states, serve in part as soil-stimulants and commonly leave the land poorer year by year; and if the farmers of the great Corn and Wheat Belts are ever to adopt systems of permanent agriculture, it must be done in the near future, or they too will awake to find their lands impoverished beyond self-redemption.
Even in the state of Massachusetts, where a most active campaign has been waged for forty years by the mixed commercial fertilizer interests, urging and persuading many farmers to use their high-priced artificial soil stimulants, very large areas of land are being agriculturally abandoned. Thus the following statement appears in the report of the United States Bureau of Census in regard to the farm land of Massachusetts: