AVAILABLE NITROGEN OF THE SOIL. 285 
TABLE II. 
AMOUNT OF NITRIC ACID. 
Beet plot, poet plot. Vetch plot. Oat plot. Vacant plot. 
sifted soi. 
End of April, 56 56 56 56 56 
12th June, 281 270 102 28 106 
30th June, 328 442 15 93 318 
22d July, 116 89 58 0 43 
18th August, 53 6 71 14 81 
Qth September. 0 0 12 0 0 
- TABLE IU. 
TOTAY ASSIMILABLE NITROGEN (OF AMMONIA AND NITRIC ACID). 
. clad a Beet plot. Vetch plot. Oat plot. Vacant plot. 
End of April, 63 63 63 63 63 
12th June, 84 109 | 60 33 50 
30th June, 95 148 23 57 108 
22d Juty, 37 Aq 31 18 35 
18th Angust, 21 14 31 13 56 
9th September, 0 13 16 6 19 
TABLE IV. 
TOTAL NITROGEN OF THE SOIL, 
cited edi, Beet plot. Vetch plot. Oat plot. Vacant plot, 
End of April, 4652 4652 4652 4652 4652 
12th June, 4861 5209 5606 6140 4720 
30th June, 4667 5744 5688 5514 4482 
22d July, 5398 5485 4724 4924 
13th August. 5467 6316 6316 6266 4412 
9th September, 5164 4656 6522 5004 4294 
From the first Table we gather that the quantity of 
ammonia, which was considerable in the spring, dimin- 
ished, especially in a porous (sifted) soil until September. 
In the compact earth of the uncultivated path, its diminu- 
tion was less rapid and less complete. The amount of 
nitric acid (nitrates), on the other hand, increased, though 
not alike in any two cases. It attained its maximum in 
the hot weather of June, and thence fell off until, at the 
close of the experiments, it was completely wanting save 
in a single instance. 
The figures in the second Table do not represent the 
absolute quantities of nitric acid that existed in the soil . 
