The Journal of Research ANGRAU

SREENIVAS et al.
to the amount of water applied (Fig. 3) as studied by Dieleman (1963), which takes into
consideration the amount of water applied and not the depth of soil. Plots were also developed
(Fig. 4) for the relationship between the fraction of salts retained and the depth of water per
unit depth of soil (Dw/Ds) as given by Reeve (1957). This method considers both the amount
of water applied and depth of soil to be leached.
RESULTS AND DISCUSSION
Soil saturated extract salinity levels for each incremental addition of 5 cm depth of
water in the top 15 cm soil depth are presented in table 2. Increase in the depth of water
decreased the salinity progressively.
The electrical conductivity of the soil reduced by 36% of the initial 14.1 dS m -1 by
the addition of 30 cm depth of water at location I. It reduced by 51% of the initial ECe of 32.6
at location II. This low fraction of salts leached can be attributed to higher water table (Fig.
1). During the summer fallow period, capillary rise of saline ground water or sea water intrusion
through salt stream (Upputeru) is a common phenomenon. Hence, proper leaching with copious
water for flushing of salts from the soil is recommended in the leaching programme.
Both leaching curves developed by two methods as outlined by Dieleman (1963)
and Reeve (1957) indicate similar leaching pattern of the soil. Dieleman’s leaching curve
2 m
30 cm 25 cm
20 cm 15 cm
5 m
5 cm 10 cm
(Fig. 3) relatively gives a better picture of leaching pattern under field condition and depends
mainly on evaporation, drainage conditions and salinity of irrigation water. This graph does
not give information about the depth of soil under study, which is an important parameter for
development of leaching schedule. Reeve’s leaching curve (Fig. 4) is based on the empirical
hyperbolic relationship as follows :
Dlw/DS = (ECi/5ECf)+ 0.15
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