bone, tankage, or blood and bone, fish, and finely 

 ground and screened guano, the nitrogen is in good 

 form and soon becomes available. 



As these forms require different lengths of time to 

 become available, judgment must be used in their 

 application. Nitrate of soda and sulphate of ammo- 

 nia dissolve almost immediately in water, so the full 

 amount of a year's supply should not be applied at 

 once, as some will be sure to be lost in waste water. 

 Blood and bone, as a source of nitrogen and phos- 

 phoric acid, would be a better combination than 

 nitrate and bone. Blood and fish require more time 

 to become available than nitrates, and bone a longer 

 time than blood. 



"The most valuable sources of organic nitrogen, 

 from the standpoints of uniformity in composition, 

 richness in the constituent, and availabilty, are dried 

 blood, dried meat, and concentrated tankage, which 

 are produced in large quantities in slaughter houses 

 and rendering establishments. " (Farmers' Bulletin, 

 No. 44, U. S. Dept. Agriculture.) 



The most concentrated form of nitrogen is 

 ammonium sulphate, containing about 19% or 24% 

 of ammonia. Nitrate of soda contains as high as 

 16% nitrogen, blood 14%, hoof and horn meal 14%, 

 slaughter house tankage from 5% to 10%, raw bone 

 3%%, bat guano 9%, sea fowl guano 12%. There 

 are numerous other sources of nitrogen, but the 



