/ 
402 The Woburn Field Experiments , 1913. 
Table VIII . — Experiment with Nitrogenous Top-dressings 
on Wheat , 1913. 
Warren Field — Produce per acre. 
Plot 
Manures per acre 
Head corn 
Tail 
corn 
Straw 
Value of 
corn per 
quarter 
on basis 
of 32s. 
Weight 
Bush. 
Weight 
per 
bush. 
Weight 
Lb. 
Lh. 
Lh. 
C. q. lb. 
s. d. 
1 
Sulphate of ammonia 
1,796 
28-7 
62-5 
239 
26 3 22 
31 0 
2 
No top-dressing 
1,654 
26-6 
62*2 
205 
24 1 25 
31 0 
3 
Nitrate of ammonia 
1,934 
31-2 
62-0 
232 
29 2 20 
31 0 
4 
Nitrate of soda 
1,870 
30-3 
61-7 
230 
30 3 8 
31 0 
The nitrate of soda cost 1 21. 5s., the sulphate of ammonia 
14 1. 5s., on rail in London. For nitrate of ammonia no regular 
price could be affixed, as it has not come into regular use as a 
fertiliser. 
It will be seen that nitrate of ammonia produced the highest 
result, and about one bushel per acre in excess of nitrate of soda, 
the latter, however, producing more straw. Sulphate of 
ammonia was this year hardly so effective, the produce being 
1^ bushels less than from nitrate of soda, and the straw 4 cwt. 
less per acre. The four lots were valued and were all put at 
the same figure, namely, 31s. per quarter, upon a basis of 32s. 
per quarter. They were all much alike, and would just pass for 
milling purposes. 
Influence of Magnesia on Wheat. 
Experiments on this subject having for a considerable time 
been conducted on a small scale in the Pot-culture Station, it 
was thought well to try it on a larger scale in the field. For 
this purpose an area T ’o of an acre in extent, in Lansome Field, 
and bordering on the green-manuring experiments, was marked 
out in the autumn of 1912. This was halved ; one half was left 
without treatment, and on the lower half, of an acre, 2 cwt. 
of Magnesia (Mgo.) were spread on November 28, and worked 
into the top 6 inches of the soil, wheat being subsequently 
drilled on the two halves. 
Previous analyses of the soil had shown this to contain 
lime, ‘40 per cent. ; magnesia, ‘20 per cent. ; and the addition of 
magnesia had the effect of raising the magnesia, if reckoned on 
the first six inches depth of soil, to ‘40 per cent., or the same 
amount of magnesia as of lime. 
On the untreated portion the wheat came up quite well, but 
on the treated portion, for some inexplicable reason, great 
trouble was experienced in obtaining anything like a “ plant ” 
