PLANT TEEDING. 17 



51. When 500 pounds are used per acre, how many 

 pounds of each element are added to the soil ? 



A Widely Used Tobacco Fertiliser. 

 Acid phosphate, 1,000 pounds 



Dried blood, 500 pounds 



Nitrate of soda, 100 pounds 



Sulphate of potash, 400 pounds 



Total, 2,000 pounds 



52. What percentages of phosphoric acid, nitrogen, 

 and potash are contained in above fertilizer? 



A Widely Used Wheat Fertiliser. 



Dissolved bone, 1,200 pounds 



Sulphate of ammonia, 500 pounds 



Muriate of potash, 300 pounds 



Total, 2,000 pounds 



53. W'hat percentages of phosphoric acid, nitrogen, 

 and potash are contained in this fertilizer? 



54. When 200 pounds are used per acre, how many 

 pounds of potential plant food are added to the soil? 



55. When wheat yields 25 bushels of grain and two 

 tons of straw, a total of 94.5 pounds of plant food is 

 removed. What proportion of this amount is furnished 

 when 200 pounds of the above wheat fertilizer is applied 

 to each acre? 



Important truth. Even with heavy application of 

 fertilizer only a small part of the plant food used by the 

 crop is furnished by the fertilizer. The soil must always 

 be the chief source of plant food for any growing crop. 

 It is also true that only a part of the fertilizer is taken up 

 by the crop immediately following its application. 



Working from percentages. Given the percentages 

 of phosphoric acid, nitrogen, and potash suitable to a crop 



