Journal of Agricultural Research 
voi. xxvn, n< 
becomes necessary to displace it by applying fresh water to the surface 
of the soil. This process, which is known as leaching, is commonly 
resorted to in the reclamation of saline soils. 
The reclamation of saline soils by leaching is possible where the fresh 
water applied on the surface can percolate readily into the soil and where it 
is possible for the salty water already present in the soil to move downward 
into the subsoil or laterally to drainage channels. It is, consequently, 
a matter of importance to understand the conditions that influence 
___ . ^— —— —- the percolation of water 
HKH , through the soil in deal- 
ing with the problem of 
^-• reclaiming saline soils. 
# _ Ontheotherhand.one 
j . .m . of the ways that irriga- 
H - -f ted soils become saline is 
flp ‘ ■ A T ' I through the percolation 
■ pj into them of salt-bear¬ 
ing water. Theevapora- 
tion of such water from 
the soil leaves the salt 
behind to be redissolved 
in succeeding waters. In 
' -\'-f • order to understand the 
conditions that influ- 
|| ence the rate of move- 
.i4is - ment of percolating 
waters through the soil, 
hHB"; it is necessary to be able 
* ; <4* to measure the rate of 
movement. This meas¬ 
urement of the move¬ 
ment of percolating wa¬ 
ter under field condi¬ 
tions is not less difficult 
than measuring the rate 
of the penetration of wa¬ 
ter into the dry soil. 
A simple case of the 
movement of water 
through a moist or satu¬ 
rated soil may be de¬ 
scribed as an example of 
percolation. Let it be 
assumed that an irri¬ 
gated field has an under¬ 
ground water table not 
_i with a drainage system 
When such a field is irrigated 
-Glass used for soil leaching and permeability experiments. 
