346 
MESSRS. J. B. LAWES AND J. H. GILBERT ON THE RESULTS OP 
Table XVI.—Average, per acre per annum, by 400 lbs. Ammonia-Salts, and Mixed 
Mineral Manure, with and without Potass; Plots 9 and 10. 
Average per acre per anunm. 
Plot 9. 
Witli potass 
20 years. 
Plot 10. 
With potass 
6 years, 
without 14 years. 
Plot 10 
+ or — 
plot 9. 
Hat. 
_ 
lbs. 
lbs. 
lbs. 
First period, 6 years, 1856-1861 . 
6349 
6223 
- 126 
Second period, 14 years, 1862-1875 . 
5438 
4725 
- 713 
Total period, 20 years, 1856-1875 . 
5711 
5174 
- 537 
Second period, per cent. + or — first period . 
-14-3 
-24-1 
Nitrogen. 
First period, 6 years, 1856-1861. 
78-7 
73-3 
- 5-4 
Second period, 14 years, 1862-1875 . 
70-9 
72-7 
+ 1-8 
Total period, 20 years, 1856-1875 . 
73-2 
72-9 
- 0-3 
Second period, per cent. + or — first period . 
- 9-9 
- 0-8 
Mineral Matter (Ash). 
First period, 6 years, 1856-1861 . 
406-8 
419-8 
+ 13-0 
Second period, 14 years, 1862-1875 . 
303-7 
243-8 
-59-9 
Total period, 20 years, 1856-1875 . 
334-6 
296-6 
-38-0 
Second period, per cent. -(- or — first period . 
-25-3 
-41-9 
Of hay, the average produce per acre per annum over the 20 years was—without 
manure, 2383 lbs. ; with ammonia-salts alone, 2946 lbs. ; with ammonia-salts and 
superphosphate of lime ( 17 years), 3837 lbs. ; with ammonia-salts and mixed mineral 
manure, with potass for six years and without potass 14 years, 5174 lbs. ; and with 
ammonia-salts and the mixed mineral manure, including potass every year, 5711 lbs. 
The table shows that, even where the application of sulphate of potass was con¬ 
tinued, there was a falling off of annual produce amounting to 14’3 per cent, over the 
last 14 compared with the first six years. But where the potass was discontinued 
there was a falling off, over the same period, of 24 per cent. 
It is remarkable that there was, over the 20 years, almost identically the same 
amount of nitrogen taken up where the potass was discontinued as where it was con¬ 
tinuously applied, and during the period of the omission there was even rather more. 
There was, moreover, scarcely any reduction in the amount taken up over the second 
period compared with the first. Indeed, the greater average yield of nitrogen over 
