Dec. io, 1917 
Movement of Soluble Salts through Soils 
533 
extent through the compacted soil, but even after one month it had not 
moved through a distance of 6 cm. Additional experiments with heavily 
compacted soils yielded data which show that compaction increases 
the movement somewhat; but even in heavily compacted soils the hori¬ 
zontal, as well as the vertical, movement is quite slow. 
These authors also failed to detect more than a slight movement of 
salts, other than that induced by the percolation of water when soils to 
which were added the salts were exposed to 15.5 mm. of rain, or to which 
was applied water equal in amount to a rather heavy precipitation. 
. These authors conclude, as a result of their extensive studies, that 
certain fertilizer salts when placed in rather dry soils take up water 
from the surrounding soil and long remain localized in the humid area. 
As a result of this condition, seeds may not germinate; but this could 
be avoided by fertilizing and seeding at different intervals. When the 
soils are somewhat moist, the water movement does not take place; 
but, on the other hand, even in moist soils, the salts diffuse exceedingly 
slowly, on account of the discontinuity of the soil mass. Heavy com¬ 
paction aids this movement, inasmuch as more particles are brought into 
intimate contact; yet in a very compacted soil the movement is slower 
than it is in free liquid. When salts are applied to soils under field con¬ 
ditions, they remain localized for long periods, although the rainfall 
may be appreciable. 
Malpeaux and Lefort 1 report results of investigations of the move- 
ment of nitrates in a sandy and loam soil, respectively, under laboratory 
conditions. The soils were placed in tightly compacted wooden boxes- 
about 50 cm. deep. In some cases the nitrates were placed in furrows 
in the soil, while in others the salt was deposited in holes made 3 cm. 
deep in the center of the boxes. It was found necessary to spray the 
soil with water several times during the experiment in order to replace 
that lost by evaporation. Samples of soil were taken at 5, 10, and 15 
cm., distances both horizontally and vertically downward from the place: 
of application of the nitrates. The authors bring out that the move¬ 
ment of salt by diffusion, either horizontally or vertically downward, is 
indeed slow. It seems that the translocation of the salts must have: 
been affected by the movement of the water originally present in the 
soil, and by that added to it, from time to time, as evidenced by results 
of the next series. 
Another series of experiments was carried on under field conditions. 
On July 13 nitrates were deposited 25, 50, 75, and 100 cm. from the 
surface of a loam soil. Samples were taken 8 cm. from the surface on 
July 24, August 13, and August 25, respectively, and the nitrates deter¬ 
mined. The results obtained reveal that nitrates move upward quite 
rapidly, having traveled 40 cm. from the place of deposit after 31 
1 Mai,peaux, I,., and Deeort, G. la circulation des nitrates dans l,e sol. In Ann. Sri. Agron. 
s. 4, ann. i, t. 2, no. 4, p. 241-258, 8 fig. 1^12. 
