10 FOR BETTER CROPS 



phosphorus required for ordinary grain crops is stored in the 

 seed or grain, while only one-fourth remains in the straw or 

 stalks. Consequently, when corn or wheat is sold from the farm, 

 three-fourths of the phosphorus required to produce the crop 

 leaves the farm in the grain. 



When the crops are fed to growing animals or milch cows, about 

 one-fourth of the phosphorus contained in the feed is retained 

 in the bones, flesh, and milk, while about three-fourths is 

 returned in the manure. 



The total phosphorus content of the soil on any given farm 

 may be increased by the purchase of stable manure, or by using 

 manure made from purchased feeds, especially from grains or 

 other concentrates, as bran, oil meal, or gluten feed; or we may 

 purchase steamed bone meal from the stock yards companies who 

 buy our cattle, slag phosphate from the steel works— if the slag 

 contains sufficient phosphorus to make it valuable — or natural 



When manure is left in piles, a large per cent of the plant food is 

 lost through evaporation and surface drainage 



rock phosphate direct from the extensive natural phosphate 

 deposits in Tennessee, South Carolina, or Florida, where this 

 mineral is being mined and ground in large amounts. It may 

 be noted that the original stock of phosphorus naturally in the 

 soil is powdered rock phosphate. 



Potassium — Potassium, like phosphorus, is a mineral ele- 

 ment contained in the soil, and if the supply in the soil is de- 

 ficient it can be increased only by a direct application to the soil 

 of some material. As a matter of fact, aside from peaty swamp 

 lands and some very sandy lands, the potassium contained in 

 most soils is practically inexhaustible. The average corn belt 

 soil of central and northern Illinois contains as much total 

 potassium per acre in the first seven inches as would be re- 

 quired for 100 bushels of corn (grain only) each year for nineteen 

 centuries. 



