208 
MESSRS. J. B. LAWES AND J. H. GILBERT OH THE RESULTS OF 
experiments, to direct attention to the average produce obtained before and after such 
chancre. 
As a preliminary to such a consideration of the effects of the different manures, it 
will be useful to call attention to the amounts of some of the most important 
constituents removed from a given area of land in a fair average hay-crop, compared 
with the amounts of the same removed in some other crops. For the purposes of such 
a comparison, wheat and barley may be selected, and we may assume the following 
amounts of produce per acre :— 
Wheat, 30 bushels=1800 lbs., and 3000 lbs. straw= 4800 lbs. total produce. 
Barley, 40 bushels=2080 lbs., and 2500 lbs. straw=4580 lbs. total produce. 
Meadow hay, lijr ton, or 3360 lbs. 
The following table shows the average amounts of nitrogen, and of most of the 
mineral constituents, in the above quantities of wheat gram and straw, and barley 
grain and straw. As already indicated, and as will be very fully illustrated further 
on, meadow hay may vary so extremely in its botanical, and coincidently in its chemical 
composition, according to soil, climate, and manuring, that it is not possible to adopt 
an average composition for such produce with as much confidence as for either wheat 
or barley. This is well illustrated in the figures given in the four columns of the table 
relating to meadow hay. Assuming in each case the same weight, 1^ ton, of hay, 
we have the amounts of the several constituents calculated as follows :—In the first 
of the four columns according to the average composition, as determined by actual 
analysis, of the hay grown for eight years successively by farm yard manure ; in the 
second column according to the average composition of the hay grown during the 
same eight seasons without manure ; in the third column is given the mean of the 
two ; and in the fourth are given the amounts according to the average percentage 
of nitrogen adopted by E. Wolff, and the average composition of the ash adopted by 
him, founded on the results of 39 analyses by various experimenters. 
Table I.—Composition of average crops of Wheat, Barley, and Meadow Hay. 
In corn. 
In straw. 
In total produce. 
lj ton 
= 3360 lbs. meadow hay. 
Wheat.. 
(1800 lbs.) 
Barley. 
(2080 lbs.) 
Wheat,. 
(3000 lbs.) 
Bariev. 
(2500 lbs.) 
Wheat. 
(4800 lbs.) 
Barley. 
(4500 lbs.) 
8 years 
farmyard 
manure. 
8 years 
without 
manure. 
Mean. 
Average 
E. Wolff. 
lbs. 
lbs. 
lbs. 
lbs. 
lbs. 
lbs. 
lbs. 
lbs. 
lbs. 
lbs. 
Nitrogen. . . 
320 
33-0 
13-0 
12*0 
45-0 
45'0 
40-8 
47-2 
4 4'0 
520 
Lime .... 
no 
1-5 
7-5 
9-0 
8-5 
10-5 
27-1 
35-3 
3P2 
33-8 
Magnesia . . 
3-5 
4-0 
3 0 
2'5 
6*5 
6'5 
74 
9-4 
S-4 
12-8 
Potass . . . 
9-5 
110 
22-0 
23-0 
3P5 
3P0 
72-8 
405 
56‘6 
51-7 
Soda .... 
0-2 
0*5 
1-0 
3-0 
P2 
3 5 
7-9 
16-0 
119 
9-0 
Phosphoric acid 
15-0 
16-5 
6-0 
4'5 
21-0 
2P0 
16 4 
1P0 
13-7 
16-2 
Sulphuric acid . 
0'2 
0-75 
4-0 
4 0 
42 
4 75 
11-3 
13-6 
12 5 
9-2 
Chlorine. . . 
o-o 
0-2 
3-0 
4 0 
3-0 
4-2 
21-3 
12-3 
16 8 
14-6 
Silica.... 
0-5 
11-0 
9o-0 
55-0 
95'5 
66-0 
59-9 
51-8 
55-9 
54'6 
