432 
Journal of Agricultural Research 
Vol. XI, No. 9 
A large series of soils ranging from pure sand, and soils with a large 
percentage of gravel, to heavy adobe was then treated as before, suffi¬ 
cient air from the standard hydrocyanic-acid-gas solution being aspirated 
through 50 gm. of the different soils until enough hydrocyanic-acid gas 
came over to decolorize 5 c. c. of N/100 iodin. 
Table IX gives the results of the experiments with the soil samples 
used. The column headed “Titration” gives the quantity of air from 
the hydrocyanic-acid-gas solution that was aspirated through 50 gm. of 
soil and then through 5 c. c. of N/100 iodin until the latter was decolor¬ 
ized. The “Control” column gives the quantity of air from the same 
hydrocyanic-acid-gas solution that was aspirated directly through a 
second 5 c. c. of Njioo iodin until it was decolorized, the difference be¬ 
tween these two figures being an index of the amount of hydrocyanic- 
acid gas retained by the soil. The sixth column is a calculation of the 
number of pounds of sodium cyanid required to furnish as much hydro¬ 
cyanic-acid gas for 1 acre, 3 feet deep, as was found to be adsorbed or 
decomposed chemically by the experimental sample, this amount 
being based on the difference between the results given in the 
columns under “Titration” and “Control,” plus the amount re¬ 
quired to saturate the soil at a definite partial pressure of hydro¬ 
cyanic-acid gas. The seventh column gives the amount of sodium 
cyanid which it is estimated will give a killing strength of hydro¬ 
cyanic-acid gas in the pore space of the soil and should be added to the 
amount which is adsorbed or decomposed chemically by the soil. The 
pore space in most soils was figured at 35 per cent by allowing 1 ounce 
of sodium cyanid per 100 cubic feet, it would require 28.5 pounds of 
cyanid to fumigate this space. This gives the effective dose for 1 acre, 
the amount being given in the eighth column. The estimated cost for 
fumigating 1 acre to a depth of 3 feet is given in the last column. 
Table IX .—Amounts of sodium cyanid required on different soils a 
Sample. 
locality. 
Character of soil. 
Titra¬ 
tion. 
Control. 
Quantity 
of sodium 
cyanid per 
acre neu¬ 
tralized by 
soil. 
Estimated 
amount 
per acre to 
give killing 
strength. 
Effective 
dose per 3 
acre-feet. 
Cost 
per 
acre.& 
1, 
2, 
3 
4 
5 
6 
7 
8 , 
9 
10 
11, 
12. 
Orland. 
.do. 
.do. 
Marysville. 
Chico. 
.do. 
Oroville..,. 
Sacramento 
.do. 
Berkeley... 
Stockton... 
.do. 
Gravelly... 
_do. 
.do. 
Sandy loam 
Clay loam.. 
_do. 
_do. 
_do. 
,.... do. 
,.... do. 
_do. 
.do. 
C. c. 
i>742 
2,450 
x. 260 
3,868 
5,063 
4,990 
2,106 
•3,540 
2,240 
3,632 
4 ,H 5 
2,740 
C. c. 
404 
650 
438 
913 
379 
620 
446 
515 
560 
728 
515 
540 
Pounds. 
831 
673 
458 
789 
3,000 
1,720 
940 
i,43o 
730 
975 
1,700 
990 
Pounds. 
25 
25 
25 
28 
30 
30 
28 
28 
28 
30 
28 
27 
Pounds. 
856 
698 
483 
807 
3,030 
i,75o 
968 
1,458 
758 
1,005 
1, 728 
1,017 
$231.52 
188.46 
130.41 
217.89 
818.10 
472.50 
261.36 
393 - 66 
204.66 
271-35 
466.56 
274.56 
a Three feet, or even more, is the depth necessary to fumigate soil for phylloxera. For most insects 
one-half of this depth would be sufficient, 
& The cost is figured on a basis of 27 cents a pound for sodium cyanid. 
