Conjunctive Use of Poor Quality Groundwater

Groundwater depletion will be the main challenge for
India’s agricultural and rural development in the
coming decades.
-IWMI,2004

 In India, the rapid expansion in the use of surface
and ground water, primarily for irrigation, has
contributed significantly to its agricultural &
economical development
 The irrigation potential created from the surface and
ground water has increased nearly 8 to 9 times in the
last 60 years

The net area irrigated by different sources in the country
has increased from 20.85 million ha during 1950-51 to
about 63.20 million ha during 2008-09
 The average area irrigated from surface water has
decreased from about 70% during 1956-65 to about 40% in
1996-2005, whereas corresponding underground water
irrigation has registered an increase from 30% to about
60% during the period
The extent of poor quality water range from 32 to 84 %
whereas the average extent of sodic and saline waters are
approximately 37 to 43 % respectively

0
10
20
30
40
50
60
70
1956-65 1966-75 1976-85 1986-95 1996-05
PercentArea
Decadal average area irrigated by surface and groundwater
resource in India 1956-2005
surface water
groundwater

 Municipal
 municipal waste land
spreading
 landfills
 leaky sewer lines
 Industrial
 chemicals: storage & spills
 fuels: storage & spills
 mine tailing piles
 underground storage tanks
 Agricultural
 fertilizers
 Pesticides
 livestock waste storage
facilities & land spreading
 wells: poorly constructed or
abandoned
 Individual
 detergents
 motor oil

Management of Poor Quality Groundwater
Conjunctive use of canal water with poor quality ground water
Technology provides sustainability and high yields compared
to rain fed agriculture. Helps to control water logging and soil
salinization
Number of amendments and bye-products such as gypsum,
pyrites, distillery spent wash and press mud identified

INTRODUCTION
 Conjunctive use refers to simultaneous use of surface water
and groundwater to meet crop water requirements

Primary Source Secondary Source Selected Examples
Canal water Groundwater
Groundwater + Rainfall
Western Indo-Gangetic Plain (Rabi)
Western Indo-Gangetic Plain (Kharif)
Groundwater Canal water
Drainage + Rainfall
Tail End of Many Systems
Deltas in Eastern And Southern India,
Bangladesh
Rainfall Canal water
Groundwater
Drainage
Sri Lanka and Southern India
Eastern Gangetic Plain (Kharif)
Bangladesh, Eastern India
Drainage Groundwater
Canal Water
Deltas in Eastern and Southern India,
Bangladesh
Deltas in Eastern and Southern India,
Bangladesh

 Simultaneous use of water from different sources is
mixed before application to the crop
 Separate use of water from the different sources, relying
for a single source of water for each water application

 Use of groundwater helps to reduce peak demand for
irrigation, size of canals and hence construction cost
 Increases and ensures water resources supply to tail
end areas
 It keeps the water table deep enough to avoid danger
of water logging or other hazards arising out of
shallow water table depth
 It provides security against any irregularity in supply
of water and ensures crop productivity

Threat Main Causes
Groundwater
depletion
Unregulated growth of shallow tube wells in areas of
fresh groundwater
Soil salinization Excessive recycling of shallow groundwater leading
to salt accumulation in upper layers of soil
Pumping of poor quality groundwater to compensate
for deficiencies in surface water supplies
Deterioration of
groundwater quality
Leaching of salt accumulation into groundwater
Depletion of shallow freshwater overlying saline
groundwater

Influence of Conjunctive Use of Canal and Sodic Water
on Performance of Crops in Rice Based Cropping
System
(Vaiyapuri et al.,2002)
Journal of Agriculture Biological Sciences, 2(6):498-502, 2006

Objective:
 To find out the effect of conjunctive use of canal water and
sodic water in rice based cropping systems on the growth
and yield of crops
Material and methods:
 Soil with pH 7.8, EC 0.13d S/m and ESP15.8
 Canal water with pH 7.5, EC 0.5 d S/m
 Alkali water with pH 8.4, EC 1.9 d S/m
 Four treatments with different irrigations viz., continuous use of
alkali water (AW), canal water (CW) alone, conjunctive use of
canal and alkali water in 1:1 and 1:2 ratio for rice were fitted in
the main plot
 The sub plot treatment consisted of four rice based cropping
systems viz., rice - fallow, rice - green gram, rice - sunflower and
rice - cotton

Irrigation Mode Crops following rice
Rice Follow up
crops
Fallow Green
gram
Sunflower Cotton Mean
AW AW 4100 3985 3906 3707 3924
CW AW 5750 5417 5033 4705 5226
1CW:1AW AW 4601 4247 4194 3930 4243
1CW:2AW AW 4328 4211 4054 3830 4106
Mean 4695 4465 4297 4043

Rice Follow up
crops
Green
gram
sunflower cotton Mean
AW AW 1716(429) 513(308) 1503(451) 1244
CW AW 3860(965) 711(427) 2793(838) 2445
1CW:1AW AW 2904(726) 648(389) 1993(598) 1848
1CW:2AW AW 2628(657) 587(352) 1877(563) 1697
Mean 2777 615 2042

Rice Follow
up crop
Fallow Green
gram
AW AW 9.12 9.23 9.33 9.42 9.28
CW AW 8.07 8.40 8.51 8.62 8.40
1CW:1AW AW 8.70 8.75 8.83 8.85 8.78
1CW:2AW AW 8.96 9.08 9.22 9.25 9.13
Mean 8.72 8.87 8.97 9.03

Rice Follow
up crop
Fallow Green
gram
AW AW 0.36 0.39 0.45 0.84 0.51
CW AW 0.12 0.14 0.15 0.16 0.14
1CW:1AW AW 0.17 0.19 0.20 0.20 0.19
1CW:2AW AW 0.24 0.25 0.28 0.31 0.27
Mean 0.22 0.24 0.27 0.27

 The conjunctive use of canal water for rice and alkali
water for green gram recorded the highest rice grain
equivalent yield
 Continuous use of alkali water for rice and follow up
crops resulted in yield decline of 18–35% of rice and
35–50% of follow up crops
 An increase in soil ESP from initial 15.8 to a range of
39-42 depending on cropping system

Managing Soil Salinity Through Conjunctive Use of
Surface And Groundwater
(Qureshi et al., 2002)
Acting Regional Director and Research Officer, IWMI

Objective:
To evaluate the long-term effects of different quality irrigation
water (obtained through mixing of poor quality groundwater in
different ratios with the good quality surface water)
Source of Water :
Canal Water, Groundwater.
Water quality standard for irrigation based on electrical
conductivity:
Category ECe(dS/m)
Fresh <1.5
Marginal 1.5-2.7
saline >2.7

 Conjunctive water management in fresh groundwater
areas
 Conjunctive water management in marginal groundwater
areas
 Conjunctive water management in saline groundwater
areas

0
2
4
6
8
10
12
30 60 90 120
ECe(dS/m)
Soil Depth(cm)
FGW_100% FGW_75% FGW_50% FGW_25%

0
2
4
6
8
10
12
14
30 60 90 120
ECe(dS/m)
Soil Depth(cm)
MGW_100% MGW_75% MGW_50% MGW_25%

0
5
10
15
20
25
30 60 90 120
ECe(dS/m)
Soil Depth(cm)
SGW_100% SGW_75% SGW_50% SGW_25%

 In fresh groundwater areas (EC=1.0dS/m), FGW_100% and FGW_75%
scenarios showed an increasing trend in root zone salinity, which can
effect crop transpiration in below average rainfall (about 780mm) in a
year
 In marginal groundwater areas (EC=1.5dS/m), the risk of salinization
would be much more higher than fresh groundwater areas
 The results of long term simulations reveal that irrigation applications
with MGW_100% and MGW_75% scenarios would take 4-5 years to
built up root zone salinity to the level where it will start affecting crop
transpiration

 In saline groundwater (EC=3dS/m), for irrigation either in
isolation or in conjunction with the canal water (by any ratio)
would be a complete disaster and land would become salinized
in just 3-4 years

 To optimize conjunctive use of water, the best way is to
concentrate on capacity building of irrigation system managers
to improve system management and reshape hydraulic
infrastructure of large and small-surface systems
 By conjunctive use of groundwater, we can reduce about 50
percent conveyance losses in canals
 In present era, the amount of surface water is inadequate to meet
crop water requirements and directly use of poor quality
groundwater is unfit for irrigation so, conjunctive use of water
is adequate for irrigation

 Poor quality groundwater can be better utilized through its
cyclic use i.e. alternate irrigation of canal and tubewell water
which causes less built of salts in soil profile
 Utilize poor quality groundwater in conjunction with canal
water to enhance the crop productivity, crop intensity and
multiple use of irrigation water than single use of water

Conjunctive Use of Poor Quality Groundwater

Conjunctive Use of Poor Quality Groundwater

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