Miscellaneous Fertilizing Materials 113 



fertilizing value, whereas analyses show them to contain 

 only traces of soluble potash and of phosphoric acid. The 

 good results from their use is undoubtedly due to their 

 beneficial indirect effect in improving the physical charac- 

 ter of heavy soils. 



Cotton-hull-ashes. 



Cotton-hull-ashes were formerly made in considerable 

 quantities in the southern states, where the hulls were 

 used as fuel in the furnaces connected with gins and 

 presses. A larger number of analyses of this product 

 show it to be exceedingly variable in composition, rang- 

 ing from 12 to 45 per cent of potash, 2 to 12 per cent 

 of available phosphoric acid and about 10 per cent 

 each of lime and magnesia. They can be safely pur- 

 chased only on the basis of their actual composition. 

 They are an excellent source of potash and phosphoric 

 acid, because free from chlorids and other deleterious 

 substances, but are not so rich in lime. They are es- 

 pecially useful for such crops as are injured by the 

 presence of chlorids. 



Corn-cob-ashes. 



Corn-cobs are a bulky by-product and accumulate 

 rapidly at elevators and milling plants. At many of these 

 plants, the cobs are burned and the ash sold for fertilizer 

 purposes. Pure corn-cob-ash thoroughly burned often 

 contains as high as 40 per cent soluble potash. The 

 average product varies in content of potash from 6 to 

 20 per cent. There is also a trace of soluble phosphoric 

 acids. Because it is so variable it should be purchased 

 only upon guarantee or analysis. 



