MIXING OF FERTILIZERS 171 



(a) Proceed as in (3). In this case there is a difference 

 from the type given under (3) in that there are two sources 

 of nitrogen given, but the amount to calculate to each source 

 is also fixed, hence we find 571 pounds cottonseed meal, 

 7-2-1.5, will carry nitrogen equivalent to 7 per cent of 

 ammonia and that 83 pounds of sulphate of ammonia 

 will carry one unit of ammonia. The available phosphoric 

 anhydride not furnished by the content of the 571 pounds 

 of cottonseed meal will be furnished by 932 pounds of 

 16 per cent acid phosphate; and the water-soluble potash 

 not furnished by the water-soluble potash content of 1.5 

 per cent contained in the cottonseed meal will be furnished 

 by 107 pounds of 48 per cent muriate of potash. 



(6) Proceed as in (1). Adding we find that 1693 pounds 

 of a mixture of cottonseed meal, sulphate of ammonia, acid 

 phosphate, and muriate of potash in the proportions shown 

 under (a) contains nitrogen equivalent to 60 pounds of 

 ammonia, 160 pounds of phosphoric anhydride, and 60 

 pounds of water-soluble potash; hence, if we divide these 

 figures by 16.93, we will obtain the number of pounds of 

 actual plant food in each hundred pounds of the mixture 

 or the per cent., 9.6 per cent available phosphoric acid, 

 nitrogen equivalent to 3.6 per cent ammonia, and 3.6 per 

 cent of water-soluble potash. 



(c) The number of pounds of this mixture equivalent 

 to 500 pounds of a 3-8-3 fertilizer is solved as under (3) : 



2000 : 1693 = 500 : z=423 pounds. 



This proportion is based on the fact that 2000 pounds, 

 the weight of a ton, is to 1693 pounds, the weight of the 

 mixture containing the amount of plant food in the ton, as 

 500 pounds, the portion of the ton used, is to x, x repre- 

 senting the proportion of the mixture equivalent to 500 

 pounds of 3-8-3 fertilizer. To use this mixture on the 3-8-3 

 basis 423 pounds should be applied where 500 is called for. 



(5) To determine the amount and composition of a fer- 



