54 
ANALYSES OF THE POTATO. 
PROPORTIONS. 
Water ...... 
Dry matter .... 
Ash. 
77 55 
22-45 
0-79 
This potato was introduced into this country by Mr. Harper, from England, and is 
found to be an excellent variety, and very little subject to decay. 
From the foregoing analyses, it will not be difficult 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 which 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 the farmer 
to put them into a compost heap, for the purpose of securing a more perfect decomposition 
than will usually take place upon the surface. In this case, it will be observed that the 
leaves and stem are rich in inorganic matter : potash, from 25 to 35 per centum. Chloride 
of potassium and sodium, as well as the phosphates of lime, magnesia and iron, form 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 as 
follows : 
In one ton of tubers. 
Removed from an acre 
Potash ...... 
8-40 
42-00 lbs. 
Soda ...... 
3-00 
15-00 
Lime ...... 
1-00 
5-00 
Magnesia ..... 
1-61 
8-05 
Phosphates of lime and magnesia 
3-57 
17-85 
Sulphuric acid .... 
1-70 
8-50 
Chlorine 
0-21 
1-05 
Silica ...... 
0-51 
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 
item consists of the phosphates of lime and magnesia. 
