POTATO-GROWING EXPERIMENTS. 
295 
The Effects of Nitrate of Soda upon the Yield, when applied 
AT THE time OF PLANTING, AND ALSO AS A ToP-DRESSING TWO 
MONTHS LATER. 
Variety, ' Hough Giant.' 
Yield per acre. 
Manures applied 
Saleable 
Small 
Diseased 
Total 
Iiicrease 
Net gain 
15 tons farmyard manure ."j 
3 cwt. superphosphate . [ 
1^ cwt. nitrate of soda, ap- i 
plied when planting . . ' 
T. C. 
13 1^ 
CWT. 
16J 
CWT. 
10 
T. c. 
15 
T. C. 
£ s. d. 
0 8 6 
15 tons farmyard manure .\ 
3 cwt. superphosphate 
ly\ cwt. nitrate of soda, ^ 
applied as a top-dressing, 
June 21 . ' 
13 15| 
19^ 
11 
15 6]- 
No. 4. — To see which nitrogenous manure produces the best results, 
sulphate of ammonia or nitrate of soda. 
Sulphate of ammonia gave 28| cwt. more saleable potatos than 
nitrate of soda, leaving a net gain of £4. 5s. 6d. per acre. On these 
plots exactly the same quantity of nitrogen was applied in each case, 
and the artificials were applied at the same time, on top of the farmyard 
manure when planting the sets. There was no difference in the quantity 
of small potatos. 
Sulphate of ammonia produced more liaulm than nitrate of soda ; it 
also increased the percentage of saleable by 1 per cent., and reduced the 
percentage of small, besides increasing the size of the saleable tubers. 
Last year's results confirm these, viz. :— 
That sulphate of ammonia produces better results than nitrate of 
soda. 
The yield for sulphate of ammonia was 18 tons 11 cwt. 1 qr., with 
a net profit of £G. 8s. dd., whereas nitrate of soda gave a yield of 
17 tons 5 cwt. 8 qrs., leaving a net profit of £2. 13s. 4(7. If we sub- 
tract these it shows a gain in favour of sulphate of ammonia of £3. 10s. 5d. 
per acre. 
These results have also been confirmed by the experiments carried 
out on nineteen farms in the centre and south-west of Scotland, by 
Professor Wright of the Agricultural College, Glasgow, and by those in 
Yorkshire conducted by Professor Campbell. 
To see the effects of nitrate of soda applied at the time of planting 
and as a top-dressing two months later : — 
This year nitrate of soda, when applied at the time of planting, on 
April 25, gave better results : it increased the yield of saleable potatos 
by 3| cwt., and diminishod the small potatos by 2| cwt., leaving a net 
gain of 8s. M. per acre. On June 21 the nitrate of soda was applied as 
a top-dressing on the other plot, being sown up the drill, and then covered 
in with a turn of the drill plough. 
