54 ANALYSES OF THE POTATO. 



rROPORTIONS. 



Water 77-66 



Dry matter - • • - - - - 22 45 

 Ash 0-79 



This potato was intioduced into this country by Mr. Hakpeh, from England, and is 

 found to be an excellent variety, and very little subject to decay. 



From the foregoing analyses, it will not be dilTicuU to determine the exhausting powers 

 of the potato crop. In doing this, it will be useful to consider the tuber only, as this is 

 the part whicit is removed from the field. The stalks, I believe, almost invariably are 

 left to decay upon the ground, and hence restore to the soil the substances they had taken 

 from it during their growth. Sometimes, however, it may be an object with tlie farmer 

 to put them into a compost lieap, for the purpose of securing a more perfect decomposition 

 than will usually take place upon the surface. In tiiis case, it will be observed that the 

 leaves and stem arc rich in inorganic matter : potash, from 25 to 35 per centum. Chloride 

 of potassium and sodium, as well as the phospiiales of lime, magnesia and iron, fonn also 

 important items in the ash, or inorganic matter. The tuber, however, being removed, 

 and consumed often in a distant market, its elements are lost to the soil, and so far they 

 exhaust it of important matters. But as the potato contains a large percentage of water, 

 and a small amount only of ash, it would seem not to exhaust the soil rapidly ; still when 

 it is considered that a large amount is yielded, it will not escape our observation, that the 

 loss to the soil is quite large. So also it will be observed that the ash is rich in those ele- 

 ments which it is expensive to restore, namely, the alkalies and phosphates, or bone earth 

 as it is sometimes called. Nearly one half of the ash is potash. Hence it is evident that 

 attention to the elements removed in the crop is of the highest importance. 



The amount of elements removed in an ordinary crop of potatoes, may be stated aa 

 follows : 



In one ton of tubers. Removed from an acre. 



Potash 8-40 42-00 lbs. 



Soda - - 300 15-00 



Lime 100 500 



Magnesia 1-61 8'05 



Phosphates of lime and magnesia - • 3-67 17-85 



• Sulphuric acid 1-70 8-50 



Chlorine 0-21 1-05 



Silica 0-61 2-55 



20-00 100-00 



Thus one hundred pounds of inorganic matter is removed from an acre in the course of 

 an ordinary crop of five tons; and this is a low estimate, as fourteen tons of potatoes are 

 frequently obtained from the acre. More than one half is potash and soda, and a large 

 ilem ron«i«t« of the phosphates of lime and magnesia. * 



