Dp. Sharma et Kvgk. Rao, STRATEGY FOR LONG-TERM USE OF SALINE DRAINAGE WATER FOR IRRIGATION INSEMIARID REGIONS, Soil & tillage research, 48(4), 1998, pp. 287-295
In arid and semi-arid regions, effluent from subsurface drainage is of
ten saline and in the absence of a natural outlet, its disposal is a s
erious environmental threat. A field experiment was conducted for 7 ye
ars using drainage water of different salinity levels (ECiw=6, 9, 12 a
nd 18.8 dS/m) for irrigation of wheat during the dry winter season. Th
e objective was to find whether crop production would still be feasibl
e and soil salinity would not be increased unacceptably by this practi
ce. The experimental crop was wheat during the winter season and pearl
-millet and sorghum in the rainy season, grown on a sandy loam soil pr
ovided with subsurface drainage system. All crops were given a pre-pla
nt irrigation with non-saline canal water and subsequently, saline dra
inage water of different salinity levels was used for the irrigation o
f wheat as per the treatment. On an average, the mean yield reduction
in wheat yield at different ECiw was 4.2% at 6, 9.7% at 9, 16.3% at 12
and 22.2% at 18.8 dS/m. Pearl-millet and sorghum yields decreased sig
nificantly only where 12 dS/m or higher salinity water was applied to
previous wheat crop. The high salinity and sodicity of the drainage wa
ter increased the soil salinity and sodicity in the soil profile durin
g the winter season, but these hazards were eliminated by the subsurfa
ce drainage during the ensuing monsoon periods. The results obtained p
rovide a promising option for the use of poor quality drainage water f
or the irrigation of winter wheat without undue yield reduction and so
il degradation. (C) 1998 Elsevier Science B.V. All rights reserved.