How large a part of the ashes of grain consists of phosphoric acid?
Of what other substances does it form a leading ingredient?
How many pounds of sulphuric acid are contained in one hundred bushels of wheat?
We come now to the consideration of one of the most important of all subjects connected with agriculture, that is, phosphoric acid.
Phosphoric acid, forming about one half of the ashes of wheat, rye, corn, buckwheat, and oats; nearly the same proportion of those of barley, peas, beans and linseed; an important ingredient of the ashes of potatoes and turnips; one quarter of the ash of milk and a large proportion of the bones of animals, often exists in the soil in the proportion of only about one or two pounds in a thousand. The cultivation of our whole country has been such, as to take away the phosphoric acid from the soil without returning it, except in very minute quantities. Every hundred bushels of wheat sold contains (and removes permanently from the soil) about sixty pounds of phosphoric acid. Other grains, as well as the root crops and grasses, remove likewise a large quantity of it. It has been said by a contemporary writer, that for each cow kept on a pasture through the summer, there is carried off in veal, butter and cheese, not less than fifty lbs. of phosphate of lime (bone-earth) on an average. This would be one thousand lbs. for twenty cows; and it shows clearly why old dairy pastures become so exhausted of this substance, that they will no longer produce those nutritious grasses, which are favorable to butter and cheese-making.
How much phosphate of lime will twenty cows remove from a pasture during a summer?
What has this removal of phosphate of lime occasioned?
How have the Genesee and Mohawk valleys been affected by this removal of phosphoric acid?
That this removal of the most valuable constituent of the soil, has been the cause of more exhaustion of farms, and more emigration, in search of fertile districts, than any other single effect of injudicious farming, is a fact which multiplied instances most clearly prove.
It is stated that the Genesee and Mohawk valleys, which once produced an average of thirty-five or forty bushels of wheat, per acre, have since been reduced in their average production to twelve and a half bushels. Hundreds of similar cases might be stated; and in a large majority of these, could the cause of the impoverishment be ascertained, it would be found to be the removal of the phosphoric acid from the soil.