(1) To produce 100 pounds of grain requires about 3 pounds of nitrogen, of which 2 pounds are deposited in the grain itself and 1 pound in the straw or stalks.

(2) In live-stock farming one-fourth of the nitrogen in the food consumed is retained in the animal products—­meat, milk, wool, and so on—­and three-fourths may be returned to the land in the excrements if saved without loss.

(3) When grown on soils of normal productive capacity legumes secure about two-thirds of their total nitrogen from the air and one-third from the soil.

(4) Clover and other biennial or perennial legumes have about two-thirds of their total nitrogen in the tops and one-third in the roots, while the roots of cowpeas and other annual legumes contain only about one-tenth of their total nitrogen.

(5) Hay made from our common legumes contains about 40 pounds of nitrogen per ton.

(6) Average farm manure contains 16 pounds of nitrogen per ton.

Question:  How many tons of average farm manure must be applied to a 40-acre field in order to provide as much nitrogen as would be added to the soil by plowing under 2-1/2 tons of clover per acre?  Answer:  400 tons.

Either method will furnish about as much nitrogen as would be taken from the soil by a 50-bushel crop of wheat, a 75-bushel crop of corn or a 100-bushel crop of oats per acre.  The decision by the individual between live-stock farming and grain farming should be based upon preference and profit rather than upon the erroneous teaching that farm manaure is either essential or sufficient for the maintenance of soil fertility in this country.

Bread is the staff of life, and many must sell grain.  I do not advise all grain farmers to become live-stock farmers; but I do advise both grain farmers and live-stock farmers to enrich their soils by practical, profitable and permanent methods.  Both classes of farmers may secure new nitrogen—­that is, they can positively increase their nitrogen supply by sufficient use of legume crops.

How to Supply Nitrogen

The cotton-grower who sells cotton lint at 10 cents a pound and the market gardener who sells from $100 to $300 worth of fruits and vegetables from one acre may well make liberal use of commercial nitrogen at 15 or 20 cents a pound; but if after deducting the cost of harvesting, threshing, storing and marketing the average farmer receives only 1 cent a pound for his grain and if 40 per cent of the commercial nitrogen applied is lost by leaching, then the total crop of grain would bring only enough money to pay for the nitrogen required to produce it, at 20 cents a pound.  We may sometimes advise the American grain-grower to buy water with which to irrigate his crop, but not to buy nitrogen with which to fertilize it.