The Woburn Field Experiments , 1908. 353 
The farmyard manure was spread in the drills May 6-9, 
1908, and the artificials were applied on May 30, the potatoes 
being subsequently planted. The crop came up well, and there 
was very little disease. 
The results are given in Table XIII. and are of a very 
interesting character. 
Table XIII . — Experiment on Potatoes , 1908 ( Road Piece Field). 
Produce of Tubers per acre. 
Plot 
Manuring per acre 
Ware 
Seed 
Small 
Diseased 
Total 
produce 
1 
standard dressing and, 
additionally— 
Sulphate of ammonia, 
1 cwt 
T. c. q. lb. 
10 0 2 24 
O. q. lb. 
8 3 20 
C. q. lb. 
6 1 0 
O. q. lb. 
3 0 24 
T. c. q. lb. 
10 19 0 12 
2 
Nitrate of sodn, 142 lbs. 
9 4 2 16 
13 2 8 
7 0 16 
3 2 8 
10 8 3 20 
3 
“Nitrolim,” 128 lbs. . 
8 12 2 0 
12 3 12 
7 0 16 
2 3 12 
9 15 1 12 
4 
Standard dressing only 
8 8 2 8 
9 1 4 
5 2 24 
3 0 24 
9 6 3 4 
5 
Magnesia, 3 cwt. . 
8 18 3 20 
13 0 24 
5 1 12 
2 2 0 
10 0 0 0 
6 
„ 6 cwt. . 
9 14 1 4 
9 2 16 
4 1 4 
3 3 20 
10 12 0 16 
1 12 tons farmyard manure, 3 cwt. superphosphate, 1 cwt. sulphate of potash 
per acre. 
The lowest produce was with the standard dressing only. 
Of the three different nitrogenous applications, decidedly the 
best was sulphate of ammonia, the extra nitrogen supplied in 
this increasing the crop by 1 ton 12 cwt. per acre ; nitrate of 
soda, giving the same nitrogen, improved the yield by 1 ton 
2 cwt., and “ nitrolim ” by 8 cwt. 2 qrs. only. The superiority 
of sulphate of ammonia to nitrate of soda for the potato crop, 
so far at least as the Woburn soil is concerned, has been shown 
before, and it would now appear hardly likely that “ nitrolim ” 
will prove as good either, presuming its nitrogen to cost the 
same as that in sulphate of ammonia. 
Very remarkable are the results obtained from the use of 
magnesia, even in the small amounts of 3 cwt. and 6 cwt. per 
acre. Three cwt. of magnesia per acre increased the crop by 
13 cwt., although no more nitrogen was used, and 6 cwt. per 
acre of magnesia gave no less an increase than 1 ton 5 cwt., 
the crop being the second largest one of the whole series. 
Thus 3 cwt. per acre of magnesia showed itself superior in 
effect to 1 cwt. of “nitrolim,” and 6 cwt. of magnesia per acre 
acted better than did 1J cwt. of nitrate of soda. 
Turning the gains into money values, as far as possible, 
sulphate of ammonia gave a gain per acre (after deducting its 
cost) of 21. 11s. 9<2. per acre over the “standard” dressing, 
that with nitrate of soda being 1£. 10s. per acre. The cost 
of “nitrolim ” is not exactly known yet, though it may be taken 
that it will be regulated by the price of sulphate of ammonia 
and nitrate of soda. If this be so, the extra crop would just 
YOL. 69. A A 
