90 
INVESTIGATIONS ON ROTHAMSTED SOILS. 
Table 47. — Broadbalk wheat field, plats 3 and 5 — Nitrogen per acre per annum in 
crops and drainage. 
Nitrogen contained in crops 30 years (1851-52 to 1880-81) 
Estimated loss in drainage (assumed 27 inches) 
Total - 
Nitrogen derived from rain, dew, etc. (estimated) 
Difference 
Plat 3. 
Plat 5. 
Pounds. 
Pounds. 
18.6 
20.3 
10.3 
12.0 
28.9 
32. 3 
5.0 
5.0 
23.9 
27.3 
On plat 3, without manure, the average yield of nitrogen per acre 
in the crops was 18.6 pounds per annum, and the estimated quantity 
in the drainage water, to a depth of 27 inches, was 10.3 pounds, giv- 
ing a total of 28.9 pounds in crops and drainage. 
On plat 5 the quantity of nitrogen contained in the crops was, on 
the average, 20.3 pounds, and the estimated quantity in the drainage 
12 pounds, giving a total of 32.3 pounds per acre per annum in crops 
and drainage. 
The quantity of nitrogen estimated to be contained in the average 
annual rainfall, and in minor aqueous deposits, such as dew, at 
Rothamsted, is 5 pounds per acre. If this be deducted in each case, 
we have an average net yield of soil nitrogen of 23.9 pounds and 27.3 
pounds, respectively, for the two plats. 
The next results, shown in the following table, also relate to the 
Broadbalk wheat field, and indicate the quantity of nitrogen in the 
form of nitrates (or "nitric" nitrogen) found in the soils of plats 3 
and 5 to a depth of 27 inches, and, on plat 5, also the quantity found 
in a depth of 90 inches. 
Table 48. — Broadbalk wheat soils (1893) — Nitrogen as nitrates ("nitric" nitro- 
gen) in plats 3 and 5. 
Soil 27 inches deep. 
Soil 90 
inches 
deep. 
Plat 5. 
Plat 3. 
Plat 5. 
Pounds. 
21. 00 
5.00 
Pounds. 
19. 12 
5.00 
Pounds. 
25.17 
5.00 
16.60 
18.60 
14. 12 
20.30 
20.17 
20.30 
&5. 20 
34.42 
40. 47 
Nitrogen found in soil as nitrates 
Deduct nitrogen derived from rain, dew, etc. (estimated) 
Difference ... 
Add nitrogen contained in crops, 30 years (1851 52 to 1880-81) 
Total '. 
II will be seen that when the 5 pounds per acre per annum for the 
nitrogen of the rainfall, etc., are deducted, and the quantity added 
which is estimated to be contained in the crops (for which in this case 
the thirty years' estimate to 1881 is adopted), we obtain results differ- 
ing from the previous ones in so far as we have substituted for the 
