282 Bureau of Farmers' Institutes. 



amount is given. To illustrate: Instead of prescribing 100 pounds 

 of nitrate of soda for a certain crop, we give the amount as " 100 

 to 200 pounds." This means that, if the land is in good con- 

 dition, 100 pounds may answer, but if in poor condition, more 

 should be used up to 200 pounds. Thus, it will be seen that 

 even with the most specific directions that can be given, muck 

 must be left to the individual for experiment. 



The materials which are given for use iu the following pages 

 are assumed to have a fairly definite composition and our cal- 

 culations are based on the following conditions of composition : 



(1) Nitrate of soda, 95 to 96 per cent, pure, containing 16 per 

 cent, of nitrogen. 



(2) Dried blood, containing 10 per cent, of nitrogen. 



(3) Sulphate of ammonia, containing 20 per cent, of nitrogen. 



(4) Stable manure, containing .5 per cent, of nitrogen, one- 

 half available at once. 



(5) Cotton seed meal, containing 1 per cent, of nitrogen. 



(6) Bone-meal, containing 20 per cent, of total phosphoric 

 acid, one-half being calculated as available during first season of 

 application; also containing 4 per cent, of nitrogen. 



(7) Dissolved bone, containing 15 per cent, of available phos- 

 phoric acid and 3 per cent, of nitrogen. 



(8) Dissolved bone-black, containing 15 per cent, of available 

 phosphoric acid. 



(9) Dissolved rock, containing 15 per cent, of available phos- 

 phoric acid. 



(10) Muriate of potash, 80 per cent, pure, containing 50 per 

 cent, of potash. 



(11) Sulphate of potash, 90 to 95 per cent, pure, containing 50 

 per cent, of potash. 



(12) Ivainit, containing 12 to 13 per cent, of potash. 



(13) Wood ashes, containing 5 per cent, of potash. 



To make the foregoing statements in different form, we can 

 eayj approximately : 



One pound of Niirogen is furnished hy 

 Five pounds of sulphate of ammonia, or 

 Six and one-fourth pounds of nitrate of soda, or 

 Ten pounds of dried blood, or 

 Fourteen pounds of cotton seed meal, or 

 Twenty-five pounds of high-grade bone-meal, or 

 Two hundred pounds of good stable manure. 



