[381] SCIENTIFIC MANUAL. 95 



of ash, of which there will be of the most important min- 

 eral elements: 



Potash 8.30 pounds. Magnesia 5.05 pounds. Sulphuric acid....0.50 pounds. 



fe'oJa 3.20 pounds. Chlorine 0.30 pounde. Phosphoric acid..7.20 pounds. 



Lime 0.83 'pounds. 



A crop of 8J bushels of wheat, with an equal quantity, 

 by weight, of straw, will carry off 11.50 pounds of nitro- 

 gen, and of the mineral elements : 



Potash 2.12 pounds. Magnesia 0.74 pounds. Phosphoric acid..2.57 pounds. 



Soda 0.31 pounds. Chlorine trace* 



Lime 0.46 pounds. Sulph'ric acid.0.26 pounds. Total ash 35.15 pounds. 



A crop of Indian corn, in the ear, equal to 9 bushels of 

 grain, will carry off from an acre of land, in pounds : nitro- 

 gen, 9.00. 



Potash 2.13 Magnesia 0.76 Chlorine trace. 



Soda 0.09 Phosphoric acid 2.27 



Lime 0.18 Sulphuric acid 0.09 Total ash 7.94 pounds. 



A crop of oats, grain and straw, allowing that the 

 weight of the straw is double that of the grain, the crop 

 being 12 bushels per acre, will carry off: 



Nitrogen 12.0 pounds. Lime 1.62 pounds. Phosphoric acid... 2.27 pounds. 



Magnesia 12.0 pounds. Soda 1.52 pounds. Sulphuric acid 0.59 pounds. 



Chlorine trace. Potash 4.72 pounds. Total ash 32.76 pounds 



A crop of peas, consisting of the seed, equal to 9 bush- 

 els per acre, will carry off: nitrogen, 16.50 pounds. Min- 

 eral substances : 



Soda 0.18 pounds. Sulphuric acid. 0.1 7 pounds. Chlorine 1.11 pounds. 



Phosph'ric acid. 1.81 pounds. Potash .2.02 pounds. 



Magnesia 0.40 pounds. Lime 0.21 pounds. Total ash 14.05 pounds. 



By reference to these tables, the farmer can not only 

 learn the amount of plant-food extracted from the soil by 

 any of the crops mentioned, but has a reliable indication 

 of the amount of those elements, which are first exhausted, 

 that he must apply to the soil to produce a given crop. 

 It is fair to presume that most soils will be benefitted by 

 the application of ammonia, phosphoric acid, and potash, 

 though some probably have a sufficient quantity of each 

 in their virgin state. 



Knowing the amount of each element of plant-food re- 

 quired for the production of a given crop, the farmer may 



