The Co^rposixioN and Use of Fertilizers. 225 



(2) Commercial Fertilizing Materials Containing Vegetable Ni- 



trogen Compounds. 



While nitrogen may be supplied by many forms of vegetable 

 matter, only a few substances of this kind are used in commercial 

 fertilizers, chief of which are cotton seed meal, castor bean pomace, 

 linseed meal, and tobacco stems. 



Cotton seed Meal is the product formed by removing the oil 

 from the seed by pressure, after which the material is dried and 

 ground. It has been used at the South mainly for fertilizing 

 purposes. One ton of cotton seed meal contains about 140 

 pounds of nitrogen, 60 pounds of phosphoric acid and 40 pounds 

 of potash. It is valued highly as a food for cattle, and, when 

 thus fed, practically all of the fertilizing value is recovered in the 

 manure. When it can be purchased at a moderate price, it makes 

 a valuable fertilizer to be applied directly to the soil. The hulls 

 of the cotton seed also possess considerable fertilizing value. 



Castor Bean Pomace is a by-product of castor-oil factories ; 

 it is made by about the same process as that used in producing 

 cotton seed meal. As a rule, it has less fertilizing value than 

 cotton seed meal, one ton containing about 110 pounds of nitro- 

 gen, 40 pounds of phosphoric acid and 20 pounds of potash. 



Linseed Meal is the product left after removing oil from flax 

 seed. One ton of linseed meal contains about' 110 pounds of 

 nitrogen, 37 pounds of phosphoric acid, and 28 pounds of potash. 

 Its extensive use as a cattle food makes it too high priced for 

 common use as a source of nitrogen for fertilizers. 



(3) Commercial Fertilizing Materials Containing Animal Nitro- 



gen Compounds. 



Probably the larger proportion of the nitrogen occurring in 

 commercial fertilizers is at present furnished by animal matter in 

 one form or another. This material comes mainly from slaughter- 

 houses, rendering works and fish-oil factories. The following 

 list contains most of the substances of animal origin commonly 

 used: Azotin or ammonite, dried blood, dried fish, fish scraps, 

 garbage tankage, ground fish, hair, hoof meal, horn dust, leather 

 meal, nitrogenous guanos, tankage, wool-waste, etc. 



Azotin or Ammonite consists of dried and ground meat, ten- 

 dons, membranes, etc., from which fat has been extracted. It 

 usually contains over 10 per cent, of nitrogen along with 3 or 4 

 per cent, of phosphoric acid. 



15 



