FOR BETTER CROPS IN THE SOUTH 19 



swamp lands and some very sandy lands, the potassium contained 

 in most soils is practically inexhaustible. 



Of course the stalks, which are rich in potassium, should be 

 returned to the soil, either directly or in manure. Even if they 

 are burned (which should be the exception and not the rule) the 

 potassium remains in the ash. 



Peaty swamp soils are frequently exceedingly deficient in both 

 available and total potassium as compared with normal soils, 

 and, where the supply of farm manure is limited, commercial 

 potassium salts may be applied to such land with very great 

 profit. Potassium sulphate and potassium chloride (frequently, 

 though incorrectly, called muriate of potash) are the most 

 economical and satisfactory commercial potassium fertilizers. 



Kainit is sometimes used, but it contains only 10 per cent of 

 potassium while potassium sulphate usually contains 40 per cent, 

 and potassium chloride contains about 42 per cent of the element 

 potassium. 



About 200 pounds of potassium sulphate or potassium chloride 

 will supply sufficient potassium for a hundred-bushel crop of 

 corn, and on very peaty land, where corn will not grow, such an 

 application is recommended. The subsequent applications may 

 be reduced in accordance with the amounts of potassium 

 returned in the stalks and in the farm manure made from feed- 

 ing the crop. But in dealing with soils of low productive capac- 

 ity, of whatsoever class, it must be remembered that we must 

 first grow large crops before we can make large amounts of 

 manure, and if necessary we must always be ready to supple- 

 ment our farm manure with any needed plant food if it can be 

 obtained and used with profit. 



Because soils deficient in potassium are usually abnormal and 

 exist only in restricted areas, this class of soils will not be further 

 considered except to mention in this connection that where such 

 soils are found, as in some swamp regions, then the addition of 

 potassium frequently produces most astonishing increases in 

 crop yields. This is well illustrated by the results obtained on 

 the University of Illinois soil experiment field near Momence, 

 Illinois, in the Kankakee swamp area. 



Crop Yields in Soil Experiments 

 Peaty Swamp Land near Momence, Illinois 



Plant Food Applied 



None 



Nitrogen . . . 

 Phosphorus 

 Potassium _ 



Nitrogen, phosphorus 



Nitrogen, potassium 



Phosphorus, potassium 



Nitrogen, phosphorus, potassium 



