SECTION IV.—QUANTITY OF INORGANIC MATTER
CONTAINED IN AN ORDINARY CROP
OR SERIES OF CROPS.

The importance of the inorganic matter contained in living vegetables, or in vegetable substances when reaped and dry, will appear more distinctly if we consider the actual quantity carried off from the soil in a series of crops.

In a four-years’ course of cropping, in which the crops gathered amount per acre to—

1st year, Turnips, 25 tons of bulbs, and 7 tons of tops.

2d year, Barley, 38 bushels of 63 lbs. each, and 1 ton of straw.

3d year, Clover and Rye Grass, 1 ton of each in hay.

4th year, Wheat, 25 bushels of 60 lbs., and 1¾ tons of straw.

The quantity of inorganic matter carried off in the four crops, supposing none of them to be eaten on the land, amounts to—

Potash,281lbs.
Soda,130”
Lime,242”
Magnesia,42”
Alumina,11”
Silica,318”
Sulphuric acid,111”
Phosphoric acid,  61”
Chlorine,39”
Total,1240

or, in all, about 11 cwt.—of which gross weight the different substances form very unlike proportions.