442 
On the Continuous Groioth of Wheat on the 
Although the ingredients furnished to the soil in plot 7 differ 
greatly from those furnished by the dung, the produce of both 
crops resemble each other very closely, as will be seen in the 
following table : — 
Table XXIX.— Showing the Amount of Wheat Gbain, and 
Total Peoduce (Cokn and Straw) upon Plot 2, Manured with 
14 Tons of Farmyard - Manure per Acre per Annum ; and 
Plot 7, Manured with Minerals and Salts of Abimonia, in 
Periods of 8 Years. 
Farmyard- 
Manure. 
14 tons. 
Minerals and 
Salts of 
Ammonia. 
86 lbs. 
Nitrogen. 
Farmyard- 
Manure. 
14 tons. 
Mineral* and 
Salts of 
Ammonia. 
86 lbs. 
Nitrogen. 
Dressed Grain in Bushels per 
Acre. 
Total Produce in Corn and 
Straw. 
8 years, 1852-1859 .. 
8 years, 1860-1867 .. 
8 years, 1868-1875 .. 
8 years, 1876-1883 .. 
m 
35| 
35i 
285 
m 
3G1 
31 
28 
6100 
5926 
5932 
4798 
0490 
6262 
5379 
5248 
32 years, 1852-1883 . . 
33J 
3-2f 
5689 
5815 
40 years with farmyard ■> 
dung / 
32i 
5516 
Taking the whole period of thirty-two years — during which 
the two experiments received the same manure each year — it 
will be seen that the difference in the produce of the two plots is 
less than one bushel per acre, the dung yielding an average 
produce of 33^ bushels per acre, and the artificial manures one 
of 32| bushels per acre. While of the total produce, in corn 
and straw, the artificial manures on plot 7 give an increase over 
that on plot 2 of 156 lbs. per acre. 
The most striking contrast between the two manures which 
give these very nearly identical results, is, that while the farm- 
yard dung furnishes to the soil a large amount of organic matter, 
the artificial manure supplies none. 
On plot 2, each year, about 8540 lbs. of organic matter were 
placed in the soil, of which not not more than one-half was 
recovered in the crop ; and yet the artificial manures, which 
supplied no organic matter whatever, produced a crop which 
gave rather the larger amount of organic matter of the two : and 
we have further evidence to show that by merely increasing the 
amount of nitrogen, a still larger amount of organic matter can 
be obtained in the crop, as plot 8 — which receives 129 lbs. of 
