Clover as a Preparatory Crop for Wheat. 
401 
of the most exlKuistin"; crops usually cultivated in this country. 
This appears strikingly to be the case when we compare the pre- 
ceding figures with the (piantity of mineral matters which an 
average crop of wheat removes from an acre of land. 
The grain and straw of wheat contain in round numbers in 
100 parts : — 
Grain of Wheat. 
Water 15-0 .. 
*Nitrogcncms substances (flesh-lbnTiinp;^ ^^^.^ 
matters) 
Non-nitrogenous substauccs 
Mineral matter (asli) .. 
Straw. 
lG-0 
4-0 
74-0 
fyl 
100-0 
* Containing nitrogen .. .. l*7f 
The ash of wheat contains in 100 parts : — 
Grain. 
Phosphoric acid 50'0 
Sulphuric acid 0'5 
Carbonic acid 
Silica 2-5 
Lime 3'5 
Magnesia .. .. 11'5 
Potash 30-0 
Soda, chloride of sodium, oxide of iron,) 
sand, &c j 
100-0 
•G4 
Straw. 
5-0 
2-7 
0 
100-0 
G7-0 
5-5 
20 
13-0 
4-8 
100-0 
The mean produce of wheat per acre may be estimated at 
25 bushels, which, at 60 lbs. per bushel, gives 1500 lbs. ; and as 
the weight of the straw is generally twice that of the grain, its 
produce will be 3000 lbs. According, therefore, to the pre- 
ceding data, there will be carried away from the soil : — 
In 1500 lbs. of the grain .. 25 lbs. of mineral food (in round numbers) 
In 3000 lbs. of the straw.. 150 „ „ „ 
Total 175 lbs. 
On the average of the analyses, it will be found that the com- 
position of these 175 lbs. is as follows : — 
In the straw. 
Phosphoric acid 
Sulphuric acid 
Carbonic acid 
Silica .. 
Lime . . 
Magnesia 
Potash .. .. 
In the grain. 
12-5 lbs. 
0-1 „ 
0-6 „ 
0-9 „ 
2-9 „ 
7-5 ,, 
7-5 lbs. 
4-0 „ 
100-5 
8-2 
3-0 
19-5 
Soda, chloride of sodium,) 
oxide of iron, sand, etc. j 
0-5 
Total. 
20-0 lbs. 
ioi-1 „ 
9-1 „ 
5-9 „ 
27-0 „ 
7-8 „ 
25 lbs. 
150 lbs. 
175 lbs. 
