72 
INVESTIGATIONS ON EOTHAMSTED SOILS. 
are capable of such rapid conversion into nitrate that they give in 
practical farming, under favorable conditions of soil and weather, 
results closely approaching those obtained by the application of 
sodium nitrate itself. 
COMPARISON OF PLATS RECEIVING AMMONIUM SALTS AND SODIUM 
NITRATE, RESPECTIVELY. # 
It is of interest to compare the plats receiving their nitrogen as 
ammonium salts with those receiving a corresponding quantity of 
sodium nitrate. These are plats 6 and 9a, receiving 43 pounds of 
nitrogen annually per acre; and plats 7 and 16, receiving 86 pounds 
of nitrogen per acre per annum, full minerals being also supplied in 
all cases. We have also plat 9b receiving 43 pounds of nitrogen per 
acre per annum as sodium nitrate, but without any mineral manures. 
Table 37. — Broadbalk wheat soils, plats 6, 9a, 9b, 7, and 16 — Nitrogen as: 
nitrates (" nitric'''' nitrogen) in samples collected in October, 1893. 
Depth. 
Plat 6, full 
minerals, 
with 43 
pounds ni- 
trogen per 
acre as am- 
monium 
salts. 
Plat 9a, full 
minerals, 
with 43 
pounds ni- 
trogen per 
acre as so- 
dium ni- 
trate. 
Plat 9b, no 
minerals, 
43 pounds 
nitrogen 
per acre as 
sodium 
nitrate. 
Plat 7, full 
minerals, 
with 86 
pounds ni- 
trogen per 
acre as 
ammonium 
salts. 
Plat 16, full 
minerals, 
with 86 
pounds ni- 
trogen per 
acre as 
sodium 
nitrate. 
Nitric nitrogen, per acre, in 
1893 samples: 
First 9 inches 
Pounds. 
14.13 
12. 74 
5. 81 
2.98 
3.47 
3. 72 
3. 25 
1.89 
32. 68 
47.94 
Pounds. 
16.62 
19.23 
6.70 
Pounds. 
11.10 
34.86 
18.58 
Pounds. 
14.96 
19. 21 
8. 54 
5.32 
4.64 
4. 40 
4. 51 
4.02 
42.71 
65.60 
Pounds. 
13. 59' 
42. 58 
20. 77 
13.03 
7.82 
5.96 
5. 45 
6.28 
76.94 
115. 48 
Second 9 inches 
Third 9 inches 
Fifth 9 inches 
Sixth 9 inches 
Seventh 9 inches 
Eighth 9 inches 
• 1 to 27 inches 
42. 55 
61.54 
1 to 72 inches 
Animal produce per acre, six 
years, 1889-1894: 
Grain 
1,598 
2,436 
1,807 
3,362 
1,126 
1, 932 
2,113 
3,766 
2,070 
4,270 
Straw 
Total 
4,034 
5,169 
3,058 
5,879 
6,340 
Comparing plats 6 and 9a, We find that in the first 27 inches of the 
nitrated plat 9a there are about 10 pounds more of nitric nitrogen per 
acre than in the ammonium-salts plat, both plats having received the 
same dressing of nitrogen, but indifferent forms. As this excess is 
I'oiiimI mainly in the t wo upper depths, it seems scarcely likely that it 
wholly or even mainly due to the rest ing on the surface soil of the 
actual nit rate sown in ihe spring. The nitrated plat 9a is a great deal 
more fertile than t lie ammonium-salts plat-, and it, seems just. possible 
thai the greater richness of plat 9a in nitric nitrogen in October may 
be related to the greater fertility persistently maintained on plat 9a 
by lie- use of nit rate and t he consequently greater richness of the soil 
in mop residue, and therefore in organic nitrogen, and to thenitriffi 
cation or oxidation of this residue. On the other hand, it may well be 
