FERTILIZERS FOR GRAIN- CROPS. 133 



safer and preferable to apply phosphoric acid in a 

 more immediately available form, as in dissolved 

 bone black or acid phosphate (dissolved rock). 

 These materials cost fifteen to twenty dollars per 

 ton, and have fifteen or more per cent of phosphoric 

 acid. The application of 200 or 250 pounds, in an 

 occasional rotation with stable manure, while cost- 

 ing but an insignificant sum, will yet serve to set 

 things right, and will answer every purpose of the 

 six ton manure application with its unnecessary ex- 

 cess of nitrogen and potash. 



This explains why grain farmers often find the 

 use of phosphatic manure desirable and profitable. 

 We may expect to find just such condition of afi'airs 

 on farms where enough animals are kept to con- 

 sume, besides a portion of the grain raised, all the 

 straw and other stover so that the coarser farm pro- 

 ductions are returned to the soil in the shape of 

 manure or absorbents. Where milk, and animals 

 (dead or alive) are sold off the place, phosphoric 

 acid is removed all the faster, and the use is all the 

 more in accord with rational crop feeding, and 

 therefore with good farming. 



I have to say a word of warning against a very 

 common, and a very great mistake. Farmers who 

 find their crops materially increased by an applica- 

 tion of plain phosphatic manures, are only too apt 

 to imagine, that phosphates are specially suited to 

 their soil or crop, and that equally good results will 

 be secured year after year by the same means. 

 Nothing can be further from the truth. If plain 

 phosphates or superphosphates, and nothing more, 

 are put into the soil for a number of years in return 

 for grain and straw, these applications must soon 

 cease to be effective, and the yields will soon fall off. 



