EXPERIMENTS ON THE MIXED HERBAGE OE PERMANENT MEADOW. 343 
ancl in some including silica. We have yet to consider the comparative effects of a 
given amount of nitrogenous manure, 400 lbs. ammonia-salts—when used alone (plot 5); 
when in conjunction with superphosphate of lime alone (plot 4-2) ; with superphos¬ 
phate of lime, and salts of soda and magnesia, without potass (plot 10); and when 
with superphosphate of lime, salts of soda and magnesia, and potass also (plot 9). 
The first comparison will be between ammonia-salts alone, and in conjunction with 
superphosphate of lime, plots 5 and 4-2 ; and as the experiment with the superphos¬ 
phate did not commence until the fourth year, the periods selected are 7, 10, and 
17 years. 
Table XV.—Average, per acre per annum, by 400 lbs. Ammonia-Salts, and 
Superphosphate of Lime ; Plot 4-2. 
Average per acre per annum. 
Plot 5. 
Ammonia-salts, 
Plot 4-2. 
Ammonia-salts, 
and 
superphosphate. 
Plot 4-2 
+ or — 
alone. 
plot 5. 
Hay. 
lbs. 
lbs. 
lbs. 
First period, 7 years, 1859-1865 . 
3202 
4440 
+ 1238 
Second period, 10 years, 1866-1875 . 
2471 
3414 
+ 943 
Total period, 17 years, 1859-1875 . 
2772 
3837 
+ 1065 
Second period, per cent. + or — first period . 
-22-8 
— 23 1 
Nitrogen. 
First period, 7 years, 1859-1865 . 
56-0 
67-6 
+ 11-6 
Second period, 10 years, 1866-1875 . 
47-3 
57-8 
+ 10-5 
Total period, 17 years, 1859-1875 .. 
509 
61-8 
+ 10-9 
Second period, per cent. + or — first period . , 
-15-5 
-14-5 
Mineral Matter (Ash). 
First period, 7 years, 1859-1865 . 
163-0 
250-0 
+ 87-0 
Second period, 10 years, 1866-1875 . 
108-9 
162-3 
+ 53-4 
Total period, 17 years, 1859-1875 . 
131-2 
198-3 
+ 67-1 
Second period, per cent. + or — first period . . . 
-33-2 
-35-1 
Over the 20 years, ammonia-salts alone gave about one-fourth more produce than 
was obtained without manure; and the results quoted above show that, over the 17 
years of the comparative trial, the mixture of ammonia-salts and superphosphate of 
lime gave more than one-third more produce than the ammonia-salts alone. Super¬ 
phosphate of lime alone, however, gave scarcely any more produce than that without 
