528
EXPOSITION AT VIENNA.
hundred-weight of superphosphate per acre. I then selected a third piece of the same field, but of inferior soil, and gave it 7.8 hundred-weight of the same substance per acre. The yield from the first averaged 253 sheaves per acre, from the second 506. The use of 2.6 hundred-weight addition superphosphate per acre thus doubled the yield. After subtracting $4.97 as the cost of this additional manure, from the value of the increase in yield of 253 sheaves, w T e have a remainder which can be considered as net profit, since there were no other expenses connected with its use. Judging from the appearance of the grain, still more manure might have been employed, and the yield thus still further increased. Less than 5.2 hundred-weight of superphosphate per acre would have paid no better than an insufficient supply of stable- manure.
Basing my system upon these trials, I commenced manuring the fields every second year from 1872 on, but each year only with small quantities, so that they only gradually reached their full productive power and a condition in which more manure would have been injurious. It is not always easy to determine beforehand how much manure should be spread, as changes in the weather cause great difference in the quantity required. In fact, the manuring begun in 1872 for all summer crops caused me great uneasiness on account of the warmth and wetness of the spring, for after every heavy fall of rain, accompanied generally by violent winds, the grain was beaten down as if by a roller. It was only through the strength of the stalks arising from the use of the superphosphate that the grain arose after being six times prostrated, and at this moment is almost all in good condition.
In the year 1872 the condition of the crops had become so luxurious through the application of manure, that they surpassed in appearance anything I had ever before seen.
As mentioned, however, there is great danger attending the use of manure each year, since the effects of the weather cannot be calculated upon in advance.
The gradual increase in the quantity of manure employed each year is as follows :—