364 
MESSRS. J. B. LAWES AND J. H. GILBERT ON THE RESULTS OF 
Table XIX.—Average, per acre per annum, by a Mixture supplying the Ash- 
constituents, and the Nitrogen, of 1 ton of Hay ; Plot 18. 
Average per acre per annum. 
Plot 18. 
Nitrogen and 
ash-constituents 
of 1 ton of hay. 
Plot 3. 
Without 
manure. 
Plot 18. 
+ or — 
unmanured. 
Hat. 
lbs. 
lbs. 
lbs. 
First period, years. 
3908 
2514 
+ 1394 
Second period, 5-j years. 
3301 
1787 
+ 1514 
Total period, 11 years, 1865-75. 
3604 
2151 
+ 1453 
Second period, per cent. + or — first period . . . 
-15-5 
-28-9 
NITROGEN. 
First period, 5^ years. 
50T 
35-1 
+ 15-0 
Second period, 5| years. 
39-9 
24-3 
+ 15'6 
Total period, 11 years, 1865-1875 . 
45-0 
29-7 
+ 15-3 
Second period, per cent. + or — first period . 
-20-4 
-30-8 
Mineral Matter (Ash). 
First period, 54 years. 
222-7 
146-7 
+ 76-0 
Second pei’iod, 5|- years. 
175-7 
96-9 
+ 78-8 
Total period, 11 years, 1865-1875 . 
199-2 
121-8 
+ 77"4 
Second period, per cent, -j- or — first period . 
-21-1 
-33-9 
The average yield obtained on the application of the mineral constituents and the 
nitrogen contained in 1 ton of hay was, over the first half of the period, about 35 cwts., 
over the second half rather less than 30 cwts., and over the whole period rather more 
than 32 cwts. of hay. There was, therefore, a reduction in the total produce in the 
later years. 
But, obviously, before we can estimate the effects of the manure, we must deduct 
something for the annual yield of the soil and seasons ; and, as plot 18 had, like plot 3, 
been unmanured from the commencement of the experiments in 1856, and for some 
years previously, we shall arrive at an approximate estimate of the amount of produce 
due to the manure, if we deduct from the total amount that obtained on the unmanured 
plot over the same seasons. Beckoned in this way, we have an average annual 
increase of produce, due to the manure, of not quite 12| cwts. during the first period, 
about 13lr cwts. during the second, and not quite 13 cwts. over the whole period. The 
increased amount of nitrogen in the produce is only about 45 per cent, of that supplied ; 
