52 
On the Rain and Drainage - Waters at.Rothamsted. 
total amount in crop and drainage together, exceed the supply 
by manure alone. 
Referring to the results a little more in detail, Plots 6, 7, 
and 8, with the mixed mineral manure, and 200 lbs., 400 lbs., % 
and 600 lbs. of ammonium-salts, respectively, yielded in the 
crops 27 lbs., 40 lbs., and 49 lbs., and in the drainage 22 lbs., 
28 lbs., and 43 lbs., of nitrogen per acre per annum. There 
is, therefore, notwithstanding the increased amount in the crop, 
the greater estimated loss by drainage the greater the excess in 
the manure. Still, much more remains unaccounted for in 
either crop or drainage the greater the amount supplied. 
Compared with these results from spring sowing, we have in 
the case of Plot 15, with autumn sowing, considerably more 
nitrogen in the crop and drainage together than was supplied in 
the manure. In fact, with 88 lbs. supplied in the manure, it is 
estimated that there were 74 lbs. in the drainage alone; whilst 
only 28 lbs. were so accounted for on Plot 7 with the same amount 
of ammonium-salts not applied until the spring. Taking the 
amounts in crop and drainage together, there was with autumn 
sowing about one-fifth more, but with spring sowing about 
one-fifth less, accounted for than was supplied in the manure. 
There was then, in these two seasons, much less of the nitrogen 
of the manure accounted for in crop and drainage with spring 
sowing than with autumn sowing; and the unaccounted-for 
amount was the greater, the greater the excess in the manure. 
We shall have to refer to this point again further on. 
Such are the results of two years' direct experiment, for which 
we have the analysis of the drainage-waters of every running 
from the pipes. It has been seen that, reckoning only the 
iiitrogen supplied in the manure against the amounts in the 
■crop and drainage, a considerable quantity of that so supplied 
remains unaccounted for. We shall now endeavour to make an 
estimate of the average loss by drainage on the different plots, 
over the thirty years — 1851-2 to 1880-1 — during which (with 
a few special exceptions) the same description and amount of 
manure has been applied year after year on the same plot. 
Excepting for the crop of the second year, 1853, when the 
previous autumn and winter were extremely wet, the ammonium- 
salts were, until the last four years of the thirty, applied in the 
autumn ; but during those four years they have not been applied 
until the spring. Plot 15 is the only exception to this ; lor the 
five crops — 1873 to 1877 inclusive — it received the ammonium- 
salts in the spring; but for the last four crops — 1878-1881 — 
when all the other plots received them in the spring. Plot 15 
received them in the autumn. To Plot 9, the nitrate of sodium 
has always been applied in the spring. 
