Experimental Plots at Rothamsted, from 1864 to 1883. 431 
plots, made at different times, show that both have lost a large 
amount of organic nitrogen ; and that, in the first 9 inches 
from the surface, the mineral-manured soil has lost rather the 
most. 
The total loss of nitrogen in the soil is larger than the 
amount of this substance which has been removed in the crops, 
and the reason for this will be found in an examination of the 
drainage-water. Except when the crop is in full vigour of 
growth, the drainage-water contains nitric acid. In our paper on 
Rain and Drainage, published in this Journal, we have gone 
so fully into this question that it will be sufficient here to say 
that of the 28 lbs. to 32 lbs. of nitrogen (as nitric acid) per acre, 
which is at the disposal of the crop each year, we estimated that 
about % are taken up by the crop, and that ^ goes into the 
drains and is lost. 
There was rather more nitric acid formed in the soils which 
received minerals, and in consequence the crop was slightly 
increased ; but the evidence is distinct and conclusive as regards 
the very small effect which followed the large applications of 
mineral matter. 
On the unmanured soil the minerals at the disposal of the 
crop were quite sufficient to utilise the whole of the nitric acid 
liberated ; and in fact the results obtained on plot IOa nrove 
conclusively that the available minerals were competent to 
grow a much larger crop than that actually produced ; further, 
as very little more nitric acid was liberated upon the mineral 
soil — and the crop was unable to obtain nitrogen from the 
atmosphere — we have as the result a produce very slightly in 
excess of that grown on the permanently unmanured land. 
By means of these experiments we more readily arrive at an 
explanation of the fact that on some soils — more especially the 
newly cultivated soils of the United States — a large increase in 
the wheat crop frequently follows the application of mineral 
manures. Soils rich in organic matter may yield an increased 
amount of nitric acid by the application of phosphates and 
potash, but in all cases the source of the nitrogen is the soil, 
and the loss in these experiments of about 1000 lbs. of soil 
nitrogen per acre is a fact of the greatest importance. 
Ammonia without Minerals. Plots 10 x, B, and 17, 18. 
The recent legislative enactments, giving the cultivator of the 
soil a claim for the manure ingredients possessing a pecuniary 
value, which he has applied to the land, add greatly to the 
interest of all investigations which have a bearing upon this 
important subject. 
