360 
MESSRS. J. B. LAWES AND J. H. GILBERT ON THE RESULTS OF 
Table XVIII.—Average, per acre per annum, by Nitrate of Soda and Sulphate of 
Potass, and by Nitrate of Potass, containing equal Nitrogen and equal Potass, in 
each case with Superphosphate; Plots 19 and 20. 
Per acre per annum. 
Plot 16. 
275 lbs. nitrate 
soda, 300 lbs. 
Plot 19. 
275 lbs. nitrate 
Plot 20. 
sulphate potass, 
100 lbs. sulphate 
soda, 100 lbs. 
sulphate mag¬ 
nesia, 31 cwts. 
soda, 290 lbs. 
sulphate potass, 
327 lbs. nitrate 
poiass, 3J cwts. 
31 cwts. super¬ 
phosphate. 
superphosphate. 
superphosphate. 
Hat. 
lbs. 
lbs. 
lbs. 
14 years, 1858-1871. 
One crop only eacli year .... 
5451 
. . 
. . 
7 years, 1872-1878. 
First crop only each year .... 
Including second crops, 1875—77—78 
4716 
5639 
4368 
5273 
4362 
5191 
Nitrogen. 
14 years, 1858-1871. 
One crop only each year .... 
66-1 
t # 
7 years, 1872-1878. ■ 
First crop only each year .... 
Including second crops, 3875-77-78 
54-0 
69-0 
49-1 
62-5 
47-9 
61-1 
Mineral Matter (Ash). 
14 years, 1858-1871. 
One crop only each year .... 
3314 
# , 
254-4 
322-6 
7 years, 1872-1878. < 
First crop only each year .... 
Including second crops, 1875-77-78 
283-8 
369-9 
261-4 
336-4 
It will be seen that the three plots received the same amount of nitrogen as nitric 
acid. Plots 19 and 20 received the same amount of potass, and plot 16 about 5 lbs. 
per acre per annum more. All three received the same amount of superphosphate of 
lime. But plot 16 received annually 100 lbs. sulphate of soda, and 100 lbs. sulphate 
of magnesia, in addition. Thus, plot 16 received rather more potass, and more soda, 
magnesia, and sulphuric acid, than plot 19 ; and plot 20, with the same amount of 
nitrogen and potass as 19, received no soda, and less sulphuric acid, but the nitric 
acid and the potass were applied to the soil in combination. 
It is to be borne in mind that, in each of the 14 seasons (1858-1871), only one crop 
was removed each year ; the after-growth being either fed off by sheep having no other 
food, or mown, spread on the land, and left to decay; but, in 1875, 1877, and 1878, a 
second crop was removed from these and all the other plots. The table therefore 
gives the average annual produce of one crop only each year, over the 14 years on 
plot 16, but over the seven years (1872-1878), for each plot, both excluding and 
including any second cuttings, It is seen that plot 16, which annually received the 
