ASSESSMENT OF GROUNDWATER QUALITY USED FOR IRRIGATION IN WEST GODAVARI DISTRICT OF ANDHRA PRADESH
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Date
2017
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Acharya N.G. Ranga Agricultural University
Abstract
Present study entitled, “Assessment of groundwater quality used for irrigation in
West Godavari district of Andhra Pradesh” was under taken in West Godavari district.
A total number of 860 groundwater samples from 46 mandals of West Godavari district
were collected during pre and post monsoon periods.
Water reaction (pH), EC, SAR and RSC in irrigation waters of study area varied
from 6.5-8.6 and 6.5-8.8, EC ranged from 0.2-26.0 dS m-1
and 0.2-26.0 dS m-1
, SAR
ranged from 0.1-63.1 and 0.1-29.2, RSC ranged from -74.6 to 20.5 me L-1
and -68.1
to 20.8 me L-1
during pre and post-monsoon seasons respectively. Dominant cation
was sodium followed by calcium, magnesium and potassium, the trend was Na+
>Ca2+
>Mg2+
>K+
. Likewise, in case of anions, chloride was the dominant anion followed by
bicarbonate, sulphate and boron. The trend was Cl-
>HCO3
-
>SO4
2-
>B during premonsoon.
Similarly, during the post-monsoon water was Na+
>Ca2+
>Mg2+
>K+
type
waters and Cl-
> HCO3
-
> SO4
2-
> CO3
2-
type water in respect of anions.
In both pre and post monsoon seasons in all mandals of West Godavari district
majority of the underground water samples had pH between 6.5 to 7.5 and majority of
the samples recorded under neutral class. Based on EC, maximum number of
underground water samples had EC between 0.75 to 2.25 dS m-1
(C3) i.e. high salinity.
Based on SAR classification, during the pre-monsoon season 89.8, 8.8, 1.2 and 0.2 per
cent samples recorded under S1, S2, S3, and S4 class, whereas, in post-monsoon season
90, 8.8, 0.9 and 0.2 per cent samples recorded under S1, S2, S3, and S4 class respectively.
In both pre and post monsoon seasons majority of the samples were found under S1
class i.e. low sodium hazard. Based on RSC classification, during the pre-monsoon
season 65.1, 10.7 and 24.2 per cent samples recorded under A1, A2 and A3 classes,
whereas in post-monsoon season 66.7, 13.0 and 20.2 per cent samples recorded under
A1, A2 and A3 classes, respectively. In both pre and post monsoon seasons majority of
the samples found under A1 class i.e. RSC<1.25 me L-1
.
As per CSSRI classification 60.7, 8.8, 2.3, 5.3, 9.1, 8.4 and 5.3 per cent of water
samples in west Godavari district during pre-monsoon season were classified under
good, marginally saline, saline, high SAR saline, marginally alkali, alkali and high
alkali categories, respectively. Likewise during the post-monsoon 64.2, 9.8, 2.3, 4.7,
6.5, 7.2 and 5.3 per cent of waters were classified under good, marginally saline, saline,
high SAR saline, marginally alkali, alkali and high alkali categories, respectively. In
both pre and post monsoon seasons majority of the samples were recorded under good
category. As per USSL (1954) classification 22.6, 40.9, 12.1, 12.3, 5.9 and 6.5 per cent
of waters in West Godavari district during pre-monsoon season were classified under
C2-S1, C3-S1, C3-S2, C4-S2, C4-S3 and C4-S4 categories, respectively. Likewise during
the post-monsoon 25.3, 45.1, 11.2, 10.0, 3.7 and 4.7 per cent of water samples were
classified under C2-S1, C3-S1, C3-S2, C4-S2, C4-S3 and C4-S4 categories, respectively. In
both pre and post monsoon seasons majority of the samples recorded under C3-S1
category i.e. high salinity-low sodium hazard class.
The yield of rice crop was negatively correlated with pH, K+
, HCO3
-
and SO4
-2
but not at significant level whereas, it was negatively correlated with EC, Na+
, Ca2+
,
Cland
Boron at one per cent level of significance.
Description
D5454
Keywords
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