Management of salt affected soils and poor quality water

Management of salt affected soils and poor quality water
4. Management of salt affected soils and poor quality waters
Management of salt affected soil
Germination Studies:
Studies revealed that average germination of cluster bean seeds was around 90% up to EC2 1.50 dSm-1 and was around 80% in soil of EC2 1.94 dSm-1 and beyond this EC the germination decreased significantly. The varieties Durgapura Safed and RGC-986 maintained higher germination up to EC2 2.50 and 3.19 dSm-1, respectively. Average germination of pearl millet seed was 79.3 per cent at EC2 of 1.12 dSm-1 and it was 64% at EC2 of 1.94 dSm-1. The genotype MP-223 showed germination of 76 per cent even at an EC2 of 3.19 dSm-1 as compared to other genotypes (Singhania and Lal, 1993).
Germination studies on clusterbean revealed that at EC2 of about 1.0 to 1.25 dSm-1 there was more than 13% reduction in yield of IGFRI-1019-1, CARG-8 and RG-978 varieties but in case of HG-75 and GAUG-34, the yield reduction varied from 5 to 7per cent only. In HG-75 the yield reduction at EC2 of 1.6 to 2.0 dSm-1 was less than 20 per cent, HG-75 and RGC-936 performed better than others in saline condition (Sharma and Verma, 1997).
Growth Studies:
Studies on growth of cowpea, moong, gram, wheat, cluster bean, cumin under variable soil salinity were undertaken by selecting various sites showing visual variation in soil salinity and in crop growth by correlation regression analysis. The ‘r’ values between EC2 of soil and yields of various crops were calculated and values of EC2 for 25 and 50 per cent reduction in yield of various crops as compared to maximum yield at lowest EC2 are given in table 4.1
The yields of crops decreased linearly as the EC2 of soils increased. Other plant parameters i.e. number of branches, number of pods per plant, heights of plants etc. were correlated negatively and significantly with EC2 of soil. The yields were also negatively and significantly correlated with cations (Ca, Mg, Na) and anions (Cl, CO3) but highest correlation was observed with sodium among cations and chloride among anions.
Table 4.1: ‘r’ values between EC2 and yields of various crops

Crop
Yield
‘r’ Values of EC (dSm-1) for yield reduction
References
25% 50%
Cowpea
Moong
Gram
Clusterbean
Cumin
Sesame Total DM
Total DM
Grain
Grain
Grain
Grain -0.83**
-0.51**
-0.67**
-0.49**
-0.76**
-0.46* 1.03
0.38
0.33
1.00
0.54
0.79 1.75
0.52
0.73
1.81
0.83
1.11 Lal and Singhania (1994)
Lal and Singhania (1994)
Singhania et.al. (1994)
Singhania et.al. (1994)
Verma and Lal (1996)
Lal and Verma (1997)


Cropping pattern:
Experiments conducted during 1984-1989 to find out suitable crop rotation for salt affected soils revealed that Dhaincha-wheat/ barley rotation gave maximum yield and returns (Table 4.2). Incorporation of dhaincha decreased the pH of soil.

Table 4.2: Suitability of crop rotation under salt affected soil

Rotations
Grain yield (qha-1) Gross monetary returns (Rs.ha-1) Soil properties
pH2 EC2
Fallow-Wheat
Daincha-Wheat
Fallow-Barley
Dhaincha-Barley
Fallow-Mustard
Dhaincha-Mustard
CD at 5% 22.19
29.03
28.43
37.85
8.33
12.07 6355
8467
6169
8105
3742
5466
2095 9.3
9.1
9.2
9.1
9.3
9.1 0.80
0.74
0.87
0.86
0.84
0.86
Source: Anonymous (1984-89)
Cultural practices and Amendments:
The low productivity of alkali soils is largely attributed to its poor physical conditions due to high content of sodium on the exchange complex besides some nutritional disorders. Their reclamation essentially require a soluble source of calcium weather mobilized from native calcium carbonate or added from external source. In either way their reclamation require the use of amendments, depending upon the availability, efficiency and overall economics amendments like gypsum, organic materials, pyrites and industrial wastes can be used successfully.
Experiment conducted at Asalpur farm, Jobner during 1981-82 and 1982-83 on soil having pH 8.9 and ESP 31.6 revealed that application of gypsum equivalent to 50% GR is suitable and economical for getting good yields of barley and wheat in sodic soil after incorporation of dhaincha as green manuring (Table 4.3). There was improvement in soil properties also with application of amendments (Table 4.4).
Table 4.3: Effect of different levels of soil amendments on grain yield q ha-1) of wheat and barley after dhaincha green manuring
Treatments Wheat Barley
T1 – Gypsum 25% GR
T2 – Gypsum 50% GR
T3 - FYM (10 t ha-1)
T4 - FYM (20 t ha-1)
T5 - T1 + T3
T6 - T2 + T3
T7 - T1 + T4
T8 - T2 + T4
T9 - control
CD at 5% 39.65
39.91
34.95
36.86
38.85
40.62
42.51
37.62
35.38
6.29 41.91
45.44
42.91
38.67
38.00
47.15
45.01
46.21
31.88
--
Source: Anonymous (1981-82 & 82-83)
Table 4.4: Soil properties as influenced by soil amendments after harvest of crops

Treatment Wheat Barley
1981-82 1982-83 1981-82 1982-83
pH Na+ (mel-1) pH Na+ (mel-1) pH Na+ (mel-1) pH Na+ (mel-1)
T1
T2
T3
T4
T5
T6
T7
T8
T9 8.5
8.4
8.6
8.7
8.5
8.6
8.2
8.6
8.7 3.1
3.1
2.9
3.2
3.0
3.2
2.3
3.0
3.8 8.0
7.8
8.0
8.3
8.0
8.3
8.0
8.4
8.5 2.5
3.4
2.8
3.5
3.3
3.7
4.0
4.3
4.0 8.5
8.5
8.5
8.6
8.4
8.5
8.3
8.6
8.8 3.0
3.4
3.0
3.6
3.2
3.5
2.7
3.4
3.9 8.6
8.0
8.4
8.6
8.5
8.4
8.6
8.3
8.6 3.8
3.6
3.3
4.3
3.6
4.3
3.3
3.4
5.8
Source: Anonymous ( 1981-82 & 1982-83)
Two years studies (1983 and 1984) showed that application of gypsum or pyrite @ 50% GR gave maximum increase in the grain yield of wheat by over 10 q/ha and decreased the pH and ESP of sodic soil as compared to the untreated control (Table 4.5). Addition of FYM @10 t/ha alone increased the wheat yield significantly but the increase was not to the level of chemical amendments. The gypsum or pyrite application proved significantly superior to organic amendments (RSC of irrigation water was 13.0 mel-1 ).
Table 4.5: Effect of addition of amendments on the grain yield of wheat and associated pH and ESP changes
Treatments Grain yield (q ha-1) Soil properties
1983-84 1984-85 Mean pH 2 ESP
Control
Gypsum @25% GR
Gypsum @25% GR+FYM @10 t ha-1
Gypsum @50%GR
Gypsum @50%GR+FYM @10 t ha-1
GM Dhaincha
FYM @10 t ha-1
Pyrites @ 50%GR (4 t ha-1)
Pyrites @50% GR+FYM 10 t ha-1
CD at 5% 14.00
22.00
22.85
27.76
29.82
20.28
20.66
27.32
28.62
3.70 10.00
13.50
13.75
16.75
18.50
12.67
13.75
17.00
18.40
3.30 12.00
17.75
18.30
22.25
24.16
16.97
17.20
22.16
23.50
4.41 9.78
9.24
9.18
9.19
9.14
9.22
9.19
9.22
9.18
0.36 23.76
21.00
20.53
21.00
20.35
20.44
21.75
20.40
20.36
0.96
Source: Anonymous (1983-84 & 1984-85)
Field studies conducted for two years on alkali water (RSC 7.3 mel-1, SAR 15) in Sodic soil (pH 9.2-9.3, ECe 4.8-5.5 dSm-1, and ESP 30-36%)) revealed that wheat and pearlmillet yields were significantly superior in gypsum @ 50% GR treatment as compared to control (Keshwa and Singh, 1988). The highest net returns were obtained with the application of gypsum @ 50% GR and lowest under FYM @ 25 t ha-1 (Table 4.6).

Table 4.6: Effect of amendments on yield and net returns of wheat and pearl millet

Treatments Yield ( t ha-1)
Net return(Rs ha-1)
Wheat Pearlmillet
Control 1.97 0.43 2382
FYM @25 t ha-1 2.40 0.60 2180
Gypsum@25% GR 2.41 0.76 3410
Gypsum @50%GR 2.77 0.84 4072
Pyrite @ 25%GR 1.19 0.73 2925
Pyrite @ 50%GR 2.47 0.82 3330
CD at 5% 0.17 0.09
Source : Keshwa and Singh ( 1988)
Application of gypsum @ 50 % GR proved to be the best treatment followed by pyrite @ 50% GR with respect to grain yield of wheat. Maximum uptake of nitrogen and phosphorus was recorded with gypsum @ 50% GR followed by pyrite @ 50% GR (Keshwa and Singh,1988) ESP and pHs values of soil decreased due to application of amendments (Table 4.7). On the basis of general effect of various amendments in reclaiming the salt affected soils these could be arranged in order of effectiveness as: gypsum 50%GR > pyrite 50%GR > gypsum 25%GR > FYM 25t /ha > pyrite 25%GR > control.
Table 4.8: Effect of amendments on soil characteristics and yield of wheat

Treatments ECe
(dSm-1) pHs ESP Yield
(qha-1) Nutrient uptake (kg ha-1)
A* B A B A B A B N P
Control 4.75 5.59 9.3 9.2 30.0 28.9 18.57 20.73 65.3 12.5
FYM @ 25t/ha) 4.53 5.35 8.9 8.9 25.0 23.7 23.09 24.96 73.3 16.3
Gypsum @ 25% GR 4.51 5.30 8.8 8.9 23.4 22.9 23.65 24.46 73.0 16.1
Gypsum @ 50%GR 4.55 5.20 8.7 8.8 21.3 20.4 27.11 28.33 79.5 19.3
Pyrites @ 25% GR 4.56 5.26 8.9 8.9 24.4 24.3 20.97 22.86 69.6 15.5
Pyrites @ 50%GR 4.55 5.28 8.8 8.9 23.4 22.7 24.34 25.05 73.9 16.9
CD at 5% NS NS 0.35 0.23 2.5 1.8 2.27 2.49 6.0 1.6
Source : Keshwa and singh, (1988) * A :1983-84 B : 1984-85
Pearlmillet and wheat yields increased tremendously with addition of 50% GR gypsum along with FYM as compared to FYM and gypsum alone when the crop was irrigated with water having high RSC of 13 mel-1. The residual effect on soil revealed that addition of FYM and gypsum reduced the pH of the soil (Singhania et al, 1991). They concluded that in soil deteriorated with continuous use of high RSC water, gypsum can be successfully used (Table 4.9). Since there is fast decrease in the residual effect as compared to first year, application of gypsum only once is not enough for long effect and definite amount of gypsum need to be added each year or once in two years to maintain the productivity of soil (Table 4.10).
Table 4.9: Direct and residual effect of soil amendments on yield of wheat ( q ha-1)


Treatments Wheat
Residual effect
Pearl millet(Straw)
1987-88 1988-89
Grain Straw Grain Straw
T1 – control
T2 – Gypsum 50% GR
T3 – Gypsum 75% GR
T4 - FYM 10 t ha-1
T5 - FYM 20 t ha-1
T6 - T2 + T4
T7 - T3 + T4
T8 - T2 + T5
T9 - T3 + T5
CD at 5% 3.00
24.50
33.93
4.43
1.43
27.25
33.25
24.12
31.62
7.52 6.40
29.35
37.50
9.30
4.40
37.35
41.75
29.50
38.60
10.86 6.00
17.65
15.30
7.75
8.00
14.75
16.87
12.68
17.18
5.35 15.05
33.40
34.35
16.00
17.10
29.35
31.05
26.90
33.55
12.26 10.00
22.50
30.00
12.50
13.75
33.75
41.25
35.00
48.75
-
Source : Singhania et.al (1991)

Table 4.10: Residual effect of FYM and gypsum on salt status of soil irrigated with high RSC (13.0 mel-1) water after harvesting of wheat
Treatments Soil depth
1987-88 1988-89
0 – 15 15 – 30 0-15 15-30
pH2 EC2 (dSm-1) pH2 EC2
(dSm-1) pH2 EC2
(dSm-1) pH2 EC2
(dSm-1)
T1 – control
T2 -Gypsum 50% GR
T3 -Gypsum 75% GR
T4 - FYM 10 t ha-1
T5 - FYM 20 t ha-1
T6 - T2 + T4
T7 - T3 + T4
T8 - T2 + T5
T9 - T3 + T5 9.1
9.1
8.8
8.9
9.0
9.0
8.8
8.8
9.0 0.50
0.43
0.49
0.47
0.43
0.45
0.48
0.46
0.45 9.1
9.0
8.9
8.9
8.9
8.9
8.9
9.0
9.0 0.40
0.49
0.47
0.43
0.47
0.57
0.50
0.47
0.34 9.9
9.8
9.8
9.8
10.0
9.8
9.7
9.7
9.7 0.79
0.75
0.64
0.64
0.72
0.62
0.62
0.68
0.62 9.7
9.6
9.5
9.6
9.6
9.7
9.6
9.6
9.7 0.62
0.72
0.59
0.65
0.72
0.69
0.65
0.53
0.65
Source: Singhania et.al (1991)
Three years study revealed that application of gypsum @ 50% GR (5 t ha-1) with nitrogen and phosphorus gave significantly higher grain yield and oil content of mustard in soil irrigated with high RSC water as compared to control (without amendments). Pyrite was found superior to gypsum (Table 4.11). The water has a pH 8.7, EC 2.2 dSm-1, SAR 19 and RSC of 10.9 mel-1.
Table 4.11: Effect of gypsum and pyrites on grain yield and oil content of mustard
Treatments Grain yield (q ha-1) Oil content (%)
1985-86 1986-87 1987-88 1985-86 1986-87 1987-88
T1 - Control 7.16 5.05 7.52 34.3 28.0 33.6
T2 - N + P (60+30) 9.13 9.07 10.17 37.4 33.9 36.6
T3 - T2 + Gypsum @ 5 t ha-1 11.13 13.05 14.04 38.0 36.5 40.1
T4 - T2 + Pyrite @ 4 t ha-1 10.63 10.92 11.17 38.3 36.2 39.3
CD at 5% 0.98 2.89 1.87 2.2 2.4 1.7

Comparative performance of different reclamation treatments on yields of different crops is presented in table 4.14
Table 4.14: Comparative performance of different reclamation treatments on yields of different crops (q ha-1)
Treatments Wheat Barley Mustard Maize Sorghum Bajra Paddy
T1- Control 7.82 5.40 1.32 2.03 2.30 3.01 20.25
T2- Gypsum 50% GR 29.42 30.94 9.10 27.10 13.73 15.08 42.80
T3- Gypsum 50 % GR + FYM 10 t ha-1 + Sand 20 t ha-1 31.72 38.60 11.09 41.95 29.10 20.63 45.85
T4- Gypsum 50 % GR + FYM 10 t ha-1 + Sand 10 t ha-1 37.52 35.09 13.34 33.98 22.55 18.95 41.35
CD at 5% 14.00 12.62 5.85 13.80 9.92 10.21 18.69
Source: Minhas et al. (1998)
Deep ploughing and sub soiling are very effective in alkali soil containing compact B-horizon which was obstructing water percolation and root penetration (Somani, 1988).
Plant materials and organic matter:
Efforts have been made to elucidate the possibility of utilizing organic materials from some wild herbs and shurbs on salt affected soils by Gupta and Karan (1984 and 1985). They observed that Tephrosia purpuria a leguminous herb was most effective among six organic materials tested because of its fast decomposing rate . Organic materials increased exchangeable Ca++ + Mg++ and decreased exchangeable Na+, CaCO3, EC and pH of alkali and saline alkali soil. Their results showed progressive reclamation with increasing incorporation of organic material in form of wild herbs and shrubs.(Table 4.15)

Table 4.15: Effect of adding different plant materials to soil on varying chemical properties
Plants Exchangeable
Ca+++Mg++ (me/100g) Exchangeable
Na+(me/100g) CaCO3
( % ) EC (dSm-1) pH
T1 Tephroisia purpuria control
@1.5% 9.3
12.6 15.0
12.0 2.7
1.5 1.7
1.0 8.5
8.1
T2
Crotaleria burhia Control
@1.5% 9.4
12.0 15.0
12.7 2.6
1.7 1.7
1.0 8.5
8.2
T3 Leptadenia pyrotechnica Control
@1.5% 9.6
11.5 15.0
13.2 2.7
1.8 1.7
1.1 8.5
8.2
T4 Vernania cinerea Control
@1.5% 9.4
11.8 15.0
13.0 2.8
2.0 1.7
1.1 8.5
8.2
T5 Aerva pseudotomentosa Control
@1.5% 9.4
11.6 15.0
13.0 2.7
1.8 1.7
1.1 8.5
8.2
T6 Cassia auriculata Control
@1.5% 9.5
12.2 5.0
12.4 2.7
1.9 1.7
1.0 8.5
8.1
C.D.at 5% 0.23 NS 0.08 0.05 NS
Source: Gupta and Karan (1984 & 1985)
Somani et al.(1985) reported results of several field trials which showed that alkali soil treated with Phospogypum @ 10 t ha-1 gave yields at par with that of normal soils.
Soil amendments studies revealed that incorporation of Dhamasa (Tephrosia purpuria) and Subabool (Leucaena leucocephala) to soil showed promising results (Table 4.17) in reducing the deleterious effect of continuous use of saline water (8 dSm-1) on different crops viz., chickpea (11.85 and 11.10 q ha ), methi (20.16 and 19.02 q/ha) and cluster bean (5.24 and 5.68 q ha-1). Incorporation of organic amendments like Dhamasa (N=1.85%, P=0.26%, K=1.7%, Ca=2.6% and O.C=0.36%) and subabool also showed improvement in soil chemical properties (Table 4.18)
Table 4.17 : Effect of organic amendments on grain yield of various crops under saline water irrigation

Treatments Grain Yield (q ha-1 )
C h i c k p e a (3yrs) M e t h i
(2yrs) C l u s t e r b e a n*
(5yrs)
Control
FYM 10 t/ha
Subabbol (leaves) @ 5 t ha-1
N equal to Dhamasa
Dhamasa @ 5 t ha-1
CD at 5% 6.37
8.27
11.10
7.69
11.85
2.80 18.16
18.00
19.02
19.00
20.16
-- 2.96
4.15
5.68
3.66
5.24
1.90
Source :*Vyas et al. (1989)
Table 4.18 : Effect of organic amendments on pH, EC (dSm-1) and soluble sodium (mel-1) of soil after clusterbean and chickpea
Treatments 1985-86 1986-87 Mean
pH EC Na+ pH EC Na+ pH EC Na+
After clusterbean*
Control
FYM
Subabool
N equal to Dhamasa
Dhamasa 8.1
7.9
7.7
7.8
7.7 0.98
0.70
0.65
0.80
0.55 6.2
4.4
4.0
4.2
2.4 8.4
8.2
8.2
8.3
8.2 0.47
0.22
0.32
0.41
0.29 3.5
1.2
2.0
3.0
1.0 8.3
8.1
8.0
8.1
8.0 0.73
0.46
0.49
0.60
0.42 4.9
2.8
3.0
3.6
1.7
After chickpea
Control
FYM
Subabool
N equal to Dhamasa
Dhamasa 8.1
8.0
8.0
8.1
7.8 1.25
1.10
0.98
1.00
0.90 4.0
3.0
3.4
5.0
4.2 8.2
8.2
8.2
8.2
8.1 0.46
0.30
0.26
0.29
0.30 3.0
1.8
1.6
2.2
2.0 8.2
8.1
8.1
8.2
8.0 0.86
0.70
0.62
0.65
0.60 3.5
2.4
2.5
3.6
3.1
Source : *Vyas et. al. (1989)
Saline water: Effects and Management
The quality of ground water in arid and semi arid area of Rajasthan is very poor. The quality of irrigation water has always been recognized as an important factor for the development of salinity and the alkalinity in the soil. However, this effect depends on the texture and the other properties of the soil.
Effect on soil:
When saline irrigation water comes in contact with the soil, both the processes of salinization and alkalization occur simultaneously. As a result of this, excessively saline, sodic or both type of soils may develop, depending upon the soil conditions and quality of water used. As a matter of fact excess of exchangeable sodium influences the physical properties more than its chemical characteristics.
The physical properties of soils are more influenced by the degree of saturation of the exchange complex. However, presence of salt further enhances the deterioration then, depending upon the nature and amounts of salts and the reaction product.
It was observed by several scientists that hydraulic conductivity of soil decreased with an increase in SAR of irrigation water, while, it increased with increasing salt concentration. An increase in clay resulted in reduced hydraulic conductivity ( Lal and Lal, 1988 and Khandelwal and Lal, 1991). The hydraulic conductivity of sandy soil decreased from 9.12 to 8.32 cm hr-1 and of clay loam ( medium black soil) decreased from 1.18 to 1.05 cm hr-1 under irrigation with water having SAR values of 21.

Salinity hazard:
Deo and Lal (1982) observed that ECe of soil increased with an increase in the EC of irrigation water. Thus, the salt accumulation in soil is closely related to the salt concentration of the irrigation water because a water of higher EC adds more salts in soil. Lal and Lal (1988) observed that the ECe of soil was less than the EC of irrigation water. On an average, ECe of loamy sand soil was 83 per cent of the EC of irrigation water (Table 4.24).This may be attributed to high hydraulic conductivity and sandy nature of the soil, where every irrigation leaches the soil.
Table 4.24:Average effect of EC and SAR of irrigation water on ECe, SAR, ESP, pH and HC of soil

Treatments ECe ( dSm-1) SAR ESP pH HC (cm hr -1 )
A B A B A B A B A B
Control 1.17 1.19 6.4 6.5 9.8 9.6 8.21 8.22 7.1 7.1
E1S1 3.34 3.35 19.2 18.4 19.2 19.7 8.57 8.61 6.5 6.3
E1S2 5.58 3.54 24.7 24.5 24.6 25.0 8.66 8.69 6.2 6.1
E2S1 6.21 6.57 22.7 22.3 20.4 20.8 8.51 8.54 7.0 7.0
E2S2 6.62 6.68 28.7 28.5 28.5 28.3 8.57 8.60 6.8 6.7
CD at 5% 0.40 0.41 1.6 1.6 1.8 1.5 0.28 0.29 0.3 0.3
E1 3.45 3.46 22.0 21.9 21.9 22.3 8.61 8.65 6.4 6.9
E2 6.41 6.47 25.7 24.4 24.4 24.6 8.54 8.57 6.9 0.2
CD at 5% 0.28 0.29 1.1 1.3 1.3 1.1 NS NS 0.2 6.6
S1 4.77 4.82 20.9 20.3 19.8 20.3 8.54 8.58 6.2 6.4
S2 5.20 5.11 26.7 26.5 26.6 26.6 8.61 8.60 6.5 0.2
CD at 5% 0.28 0.29 1.1 1.1 1.3 1.3 NS NS 0.2 0.2
Source: Lal and Lal (1988) A: 1980-81 B: 1981-82 E1 & E2 are EC of irrigation water -4 and 8 dSm-1, respectively whereas, S1 & S2 are SAR of irrigation water - 18 and 26, respectively.
Sodium Hazard:
The adsorption of sodium on soil surface increases with its concentration in irrigation water and is also influenced by the relative concentration of other cations. Highly saline water are dominated by sodium ions. Calcium forms hardly 10 to 20 per cent of the total salt concentration.
Lal and Lal (1988) reported that SAR, ESP and pH values of soil increased with an increase in the SAR of the irrigation water, while, hydraulic conductivity decreased. This may be attributed to the increase in the proportion of sodium in the soil solution with the application of waters of higher SAR values. As a result of the rise in the SAR of soil, the ESP increased, resulting in an increase in pH and decrease in hydraulic conductivity. The ESP values of the soil treated with waters having SAR values of 16 and 26 were 20.0 and 26.6, respectively.
Studies on six representative sites irrigated with saline waters in Bilara tract of south-eastern part of Jodhpur district of Rajasthan revealed that irrigation waters were the source of soluble salt in these soils. EC and pH of irrigation water varied from 2.0 to 13.5 dSm-1 7.3 to 8.1, respectively, whereas, SAR and RSC varied between 19.5 to 43.2 and nil to 13.3 mel-1. The more or less uniform ionic concentrations in the pedons showed that their distribution has attained equilibrium for the depths studied (upto 120 cm). The presence of greater amount of soluble sodium has provided high SSP to the soil (Table 4.27)as also reflected with pH value of 8.5 and more. Soils being low in CEC (1.8 to 10.0 me/100g) attained higher average ESP values of 23.8 and above. EC of soil is significantly related with soluble salts and SAR in irrigation water (Table 4.28). Vyas et. al., (1982) observed that criteria used to classify soils as well as the irrigation waters as having high salinity hazard are not tenable for well drained light textured soils and need modification.
Table 4.27: Soil reaction, salinity, SAR, SSP, CEC and ESP of soils
Soil depth (cm) pH EC (dSm-1) SAR SSP CEC (me/100g) ESP
0-24 8.5
1.0-7.3
(3.8) 9.8-43.9
(26.9) 66.3-95.2
(87.8) 2.0-5.9
(4.2) 13.7-34.8
(23.8)
24-48 8.8 1.8-5.6
(3.2) 11.9-47.0
(29.5) 80.8-95.9
(91.2) 2.7-10.0
(6.3) 13.8-35.0
(24.1)
48.72 8.7 1.3-6.0
(3.4) 12.4-60.7
(37.3) 85.4-98.8
(92.7) 3.9-9.5
(6.9) 14.9-33.9
(24.0)
72.96 8.6 2.0-6.8
(3.7) 11.3-57.0
(31.3) 74.1-96.5
(90.2) 2.5-9.0
(5.8) 11.6-42.2
(24.9)
96-120 8.6 2.0-8.6
(4.2) 18.7-70.0
(39.5) 73.1-98.1
(88.1) 1.8-9.0
(5.3) 16.3-42.2
(26.3)
Source: Vyas et. al. (1982) *Figures in parentheses are average values.

Table 4.28: Relationship between irrigation water and soil properties

Parameters Depth (cm)
0-24 24-48 48-72 72-96 96-120
ECiw X Ece soil +0.915* +0.839 +0.770 +0.881* +0.895*
SARIW X ESP Soil +0.557 +0.805 +0.736 +0.604 +0.566
SARiw X SARe +0.983** 0.987** +0.670 +0.985** +0.806
SSPiw X ESP +0.808 +0.822* +0.788 +0.791 +0.706
Source: Vyas et. al. (1982) *, ** Significant at 5 % and 1% respectively.
Effect on crops:
An experiment conducted during 1985-88 with three salinity levels (EC-2, 4 & 6 dSm-1) and four growth stages (germination, flower initiation, pod formation and all above) on clusterbean in kharif and fenugreek (1986-87 and 1987-88) crops in rabi showed that there was practically no effect of salinity of irrigation water and the growth stages on yield of clusterbean and fenugreek in all the three years. Yields of both the crops decreased when saline water was applied at all the growth stages (Table 4.30).
Table 4.30: Effect of saline water irrigation and different stages of growth on grain yield (q ha-1) and soil properties
Treatments Clusterbeean (Av. 3 Yrs) Fenugreek (Av. 2 Yrs)
Yield pH EC Grain pH EC
EC of water (dSm-1)
2
4
6
CD at 5% 4.57
4.73
4.21
NS 7.98
8.10
8.02 0.40
0.35
0.37 23.79
24.87
23.81
NS 7.85
7.93
8.07 0.49
0.58
0.61
Growth Stages
Germination
Flower initiation
Pod formation
All the above
CD at 5% 4.70
4.50
4.70
4.29
NS 7.93
7.98
8.04
8.05 0.30
0.29
0.34
0.37 25.13
24.07
24.50
22.72
NS 7.84
8.24
8.03
7.92 0.44
0.50
0.51
0.64
Source: Anonymous (1982)
Wheat yield significantly decreased with increasing salinity of water from 8 to 12 dSm-1, whereas ,there was no effect of SAR even up to 80 on crop yields indicating resistance of crop to higher sodicity. Increasing EC and SAR levels of irrigation water increased EC of soil (Table 4.31).

Table 4.31: Effect of EC and SAR of irrigation water on yield of wheat and soil properties

Treatments Grain yield (q ha-1) Soil properties
1985-86 1986-87 Mean pH EC
Salinity levels 0-15 15-30 0-15 15-30
E1 - 8 dSm-1
E2 -12 dSm-1
CD at 5% 29.92
26.24
2.96 28.37
23.37
3.81 29.15
24.81
-- 8.12
8.25 8.45
8.60 0.91
1.00 1.11
1.10

SAR levels
S1 -20
S2 -40
S3 -60
S4 -80
CD at 5% 29.60
28.48
27.59
26.72
NS 29.78
26.02
25.28
22.00
NS 29.69
27.25
26.44
24.36
-- 8.22
8.03
8.15
8.15 8.75
8.56
8.81
8.81 0.94
1.21
1.21
1.53 1.08
1.15
1.15
1.24
Source: Anonymous (1985-86 & 86-87 )
Chhipa and Lal (1985) reported a decrease in phosphorus content with increase in EC and SAR of irrigation water. Further, they observed a decrease in potassium content of wheat grain and straw with increasing salinity and sodicity (EC and SAR).
During studies on screening of varities of wheat under salt affected soils (ECe ranging from 4.2 to 18.1dSm-1) Chhipa and Lal (1985) reported that plant height , effective tillers, grain and straw yields of wheat decreased with increasing salinity above ECe 8.1 dSm-1 . Kharchia was the most salt tolerant followed by HD 2009 > Kalyan Sona > Raj 1114 > Raj 821 > Raj 911.Grain and straw P and K contents increased and N, Ca and Na contents ecreased with increasing salinity.
Lal and Lal (1990) conducted a field experiment on wheat (Triticum aestivum L.) variety Kalyan Sona to determine its yield potential under irrigation with five types of water viz. EC 0.90 dSm-1 and SAR 3.67 (control water) and other four waters consisting of the combination of two EC levels i.e. 4.0 (E1) and 8.0 (E2) dSm-1 and two SAR levels i.e. 16 (S1) and 26 (S2). Although the grain and straw yield decreased at higher level of EC and SAR of irrigation water as compared to their corresponding lower levels, the extent of reduction was more conspicuous at higher level of salinity than at higher level of sodicity of irrigation water. On an average, a reduction in grain yield to the extent of 13.58 per cent was observed at an ECe of 6.44 dSm-1 as compared to its yield at ECe of 3.46 dSm-1 (Table 4.32). Due to an increase in SAR of irrigation water, the ESP and pH of the soil increased and nutritional disturbances occur which have affected the growth and yield of wheat.

Table 4.32: Effect of different qualities of irrigation water, EC of irrigation water and SAR of irrigation water on grain and straw yield of wheat (q ha-1)

Treatments Grain yield Straw yield
1980 – 81 1981 – 82 1980 – 81 1981 – 82
Control 39.95 39.24 78.67 77.63
E1S1 38.05 38.40 74.75 74.28
E1S2 36.02 36.88 71.14 70.43
E2S1 33.18 34.53 66.43 66.15
E2S2 30.20 31.15 62.47 62.28
CD at 5 % 1.774 1.673 3.007 3.075
E1 37.03 37.64 72.94 72.35
E2 31.69 32.84 64.45 64.21
CD at 5 % 1.255 1.182 2.126 2.175
S1 35.61 36.46 70.60 70.21
S2 33.11 34.01 66.81 66.35
CD at 5 % 1.225 1.182 2.126 2.175
Source : Lal and Lal (1990)
Studies on crop response to phosphorus under chloride dominated waters revealed that there was significant reduction in grain and straw yields of pearl millet with increasing salinity of irrigation water. Ratio of Cl: SO4 and different doses of P had no significant effect on crop yields. Almost similar results were obtained in second year also except that there was significant effect of salinity levels on pearl millet yield.Further, two years studies on effect of phosphorus under different chloride dominated waters indicated that salinity of irrigation water and phosphorus levels had recorded significant effect on grain and straw yield of wheat. Increasing salinity levels recorded a gradual decrease in the grain and straw yield of wheat with maximum yield under control and the minimum being under salinity levels of 12 dSm-1 (Table 4.33). Ratio of anions did not influence the grain and straw yield significantly. Regarding the effect of phosphorus on grain and straw yield of wheat, it was clear that maximum yield was recorded at P1 followed by P3 and minimum under P2. In 1987-88 grain and straw yields decreased with increasing salinity and increasing Cl: SO4 ratio. However, the effects of treatments were non-significant.

Table 4.33: Response of pearl millet and wheat under chloride dominated irrigation water to phosphorus


Treatments G r a i n y i e l d (qha-1)
Pearl millet Wheat
1987-88 1988-89 Mean 1987-88 1988-89 Mean
Salinity levels
S1 -_ 2 dSm-1
S2 - 8 dSm-1
S3 - 12 dSm-1
CD at 5% 6.61
6.04
6.25
NS 10.80
8.64
7.45
2.19 8.71
7.34
6.85
-- 21.86
20.10
18.40
NS 19.49
17.91
16.96
1.21 20.68
19.00
17.68
--
Ratio of anions (Cl: SO4)
C1 (70 : 30) **
C2 (90 : 10)
CD at 5% 6.33
6.38
NS 9.05
8.87
NS 7.69
7.63
-- 19.29
21.00
NS 16.84
19.39
NS 18.07
19.54
--
Levels of phosphorus
P1 (control)
P2 100% R.D. *
P3 150% R.D.
CD at 5% 5.82
6.89
6.18
NS 9.02
9.05
8.82
NS 7.42
7.97
7.50
-- 18.98
20.45
21.02
NS 19.15
17.00
18.21
1.40 19.07
18.73
19.62
--
Source: Anonymous (1984 – 1989) * R D. - Recommended dose, ** Cl : SO4
Results of experiments conducted at Jobner on loamy sand to sandy loam soils to find out tolerance of wheat, barley, clusterbean, fenugreek, mustard, spinach, coriander and chilli to saline water irrigations, are summarized in (Table 4.35). Results indicate that most crops tolerated higher levels of salinity in irrigation waters because of the coarse texture (loamy sand) of the soil. Wheat and barley yields were reduced only by 15 and 26% at the highest level of ECiw (14 dSm-1) tested (Vyas et al., 1986). Legume crops of clusterbean and fenugreek produced 50% of their potential yields at ECiw,8 dSm-1. (The annual rainfall received at the centre is about 500mm, more than 80% of which is received during July-August).
Table 4.35 : Yield of different crops (q ha-1) under saline water irrigation
ECiw (dSm-1)
Wheat Barley Cluster bean Methi Mustard Spinach Coriander Chillies
*5 5 2 3 2 2 2 2
2.1 18.7 32.0 4.9 11.4 24.7 624 15.7 91.2
3.3 17.2 27.7 -- -- -- 594 14.3 82.9
4.7 16.7 29.2 4.0 8.6 22.2 561 14.6 83.8
6.1 -- -- -- -- -- 489 -- 76.7
7.8 -- -- 2.7 5.7 22.0 -- 12.3 --
9.2 17.0 28.3 -- 2.4 -- 488 -- 63.0
11.6 -- -- 1.4 -- 20.7 -- 11.2 --
14..0 15.7 23.6 -- -- -- 450 -- 54.9
15.6 -- -- 1.0 0.9 18.0 -- -- --
Source: Minhas et al. (1998) * No. of years
Experiments were conducted at SKN College , Jobner to establish saline water tolerance of crops. The tolerance limits are given in (Table 4.36) and same have been recommended to the farmers.
Table 4.36: Salt tolerance of crop varieties
Crop Variety ECiw (dSm-1) Yield(q ha-1)
Wheat K.Sona 12 21.1
Barley RD-31 12 33.5
Clusterbean Durgapura safed 6 4.0
Methi Nagauri local 6 9.6
Mustard T-59 10 17.0
Spinach Jobner green 6 560
Chillies(green) Local 6 83.8
Corriander UD-41 8 10.4
Source: Anonymous (1984 – 1989)
Table 4.38 : Promising cultivars suitable for cultivation under poor quality water(screened at ARS, Bikaner)
S.No. Crop Genotypes/Varieties
1. Pearl millet HHB-60, MH-419, RHB-90
2. Ground nut SB- XI, K-3
3. Mustard RBT-1, RBT-2, Kranti, SLT-2, CSCN-17,CSCN-19
PCR-10, PCR-15, PCR-27, PCR-9302
4. Cumin UC-208, UC-209, RZ-19
5. Isabgol RI-49
6. Fennel RF-125
7. Coriander RCR-20, RCR-446
8. Castor RCH-1
9 Wheat Raj-3077. KRL 1-4 , K-65, Raj.2918, Raj.2991,Raj.1114,
10 Barley RS-6, RS-17
11 Cluster bean HG-75, RGC-978,GAUG-34
12 Paddy Getu , BK-190
Source: Anonymous (1990 – 2001)
Variety Raj.1972 and Raj .3077 gave significantly higher yield than Lok-1 and Kh-65 (Table 4.42). Variety BL-2 gave significantly higher yield (33.88 q ha-1) as compared to RD-1635, RD-2182, RD-2259 and RD-2423.

Table 4.39 : Performance of different varieties of crops under high RSC water (8.2 me l-1)
Pearlmillet Barley Wheat
Varieties Yield (q/ha) Varieties Yield (q/ha) Varieties Yield (q/ha)
MH-36 16.12 RD-1635 15.48 Raj.3077 25.79
MH-169 23.73 RD-2182 20.48 Raj 1972 26.29
MH-179 20.42 RD-2259 18.07 Raj.1482 23.56
RCB-2 22.07 RD-2423 27.52 Raj.1114 24.37
WCC-75 19.29 BL-2 33.88 Lok-1 20.82
Kharchia 18.62
CD at 5% 1.67 2.58 3.85
Source: Anonymous (1989-90)
Studies on the performance of different varieties of wheat and barley under saline sodic condition (ECe 8.86 and ESP 30.78 ) revealed that Variety Kh-65 of wheat and RS-6, RS-17 of barley performed better under saline sodic soils as compared to other varieties (Table 4.40).

Table 4.40: Performance of different verities of wheat and barley under saline sodic condition
Wheat Barley
Varieties Grain yield Varieties Grain yield
Kh-65 23.77 RS-6 30.77
Raj-2996 14.88 RS-17 26.44
Raj.2934 11.33 BL-2 11.99
Raj 3062 11.22 Karan-19 6.88
Raj.3027 11.11 Karan-15 6.66
Raj.3030 11.88
CD at 5% 2.16 CD at 5% 2.91
Source: Anonymous (1984 – 1989)
On the basis of yield reduction in pooled analysis at higher level of soil salinity (ECe = 16 dSm-1) varieties Kharchia–65, Job -666, KRL-1-4 and Raj 3077 were reported as salt tolerant varieties and Raj 1482, Lok–1, HD–4030 and Raj.-3777 as salt sensitive varieties of wheat (Lal, 2001).
Table: Performance of barley varieties under saline and non –saline conditions
Varieties Grain yield (q ha-1) Varieties Grain yield (q ha-1)
Saline Non-saline Saline Non-saline
RS-6 30.77 32.66 Karan-16 2.99 7.44
RS-17 26.44 30.66 Karan-163 6.88 10.99
BL-2 11.99 19.21 Karan-264 6.33 9.55
Karan-15 6.66 9.77 CD at 5 % 2.85 2.91

Management:
Mixing and conjunctive use :
A field experiment conducted during 1997-99 on sandy soil at AICRP on use of saline water, Agricultural Research Station, Bikaner (Rajasthan), to find out the most suitable cyclic and mixing modes of canal ( EC 0.25 dSm-1) and saline water (EC 8.0 dSm-1) irrigation for pearl millet- wheat rotation in IGNP Command area, revealed that maximum grain yield of pearl millet was recorded with canal water and saline water by cyclic mode of 2CW - 1SW and 1CW - 1SW, whereas, in case of wheat maximum grain yield was recorded when only canal water was used (Table 4.41). Further, the yields obtained in cyclic modes were at par with mixing mode of irrigation (Verma et al. 2003). The lowest yield and yield attributes of both the crops were recorded when only saline water was used. ECe and pHe of soil increased with the use of saline water (Table 4.42). These findings indicated that in case of inadequate supply of canal water and where perched or under ground saline water is also available, initial one to two irrigations with good quality water followed by saline water may be used .
Table 4.41: Influence of different modes of Saline tube well waters on grain yields of pearl millet and wheat (qha-1).
Treatments Pearl millet Wheat
1997 1998 Mean 1997 1998 Mean
T1 –Canal water (CW) 8.79 9.50 9.15 14.92 19.20 17.05
T2-1CW- Saline water (SW) 6.80 5.44 6.12 11.92 15.08 13.50
T3 –Saline water (SW) 4.54 2.64 3.54 10.22 4.10 7.16
T4 -1CW – 1SW 8.61 7.50 8.06 12.78 13.80 13.29
T5 -Mixing 1SW :2 CW 7.20 6.20 6.70 12.64 11.00 11.82
T6 – Mixing 2SW :1 CW 6.40 4.44 5.42 10.69 15.80 13.25
T7 - 2CW - 1SW 8.25 7.91 8.08 13.19 14.60 13.90
T8 - 1SW - 1CW 6.37 4.69 5.53 11.10 9.20 10.15
CD at 5% 1.49 0.57 2.28 2.40
Source: Verma et al. (2003)

Table 4.42: Effect of different proportion of saline and canal water irrigation on pHe and ECe of soil before sowing and after harvesting of crops
Treatment pHe ECe (dSm-1)
Oct.
97 March
98 July
98 Oct.
98 April
99 Oct.
97 March
98 July
98 Oct.
98 April
99
T1 -Canal water (CW) 8.4 8.5 8.4 8.4 8.4 0.72 0.81 0.70 0.78 1.00
T2- 1CW – Saline
water (RSW) 8.5 8.6 8.4 8.5 8.5 0.90 1.16 0.84 1.35 1.76
T3 -Saline water (SW) 8.7 8.6 8.5 8.7 8.7 1.21 2.25 1.18 2.70 3.44
T4 -1CW – 1SW 8.6 8.6 8.5 8.6 8.6 0.90 1.03 0.92 1.26 1.90
T5 -Mixing 1 SW : 2 CW 8.7 8.6 8.5 8.7 8.7 0.90 1.58 0.90 1.83 2.08
T6 - Mixing 2SW : 1CW 8.7 8.7 8.5 8.7 8.7 0.99 1.80 0.96 1.95 2.30
T7 - 2CW – 1SW 8.5 8.5 8.4 8.5 8.5 0.72 0.74 0.66 1.12 1.44
T8 - 1SW – 1CW 8.5 8.6 8.4 8.5 8.5 0.86 1.22 0.81 1.35 1.68
Initial 8.4 0.61
Source: Verma et al. (2003)
Studies conducted by Sharma, et al., 2003 for three years to find out the effect of mixing of saline ( EC 7.5dSm-1) and BAW ( EC 2.5 dSm-1) irrigation on groundnut -wheat rotation indicated that there was about 18.3, 51.1, 59.7 and 79.3 per cent reduction in pod yield of ground nut at EC of mixed water 3.75, 5.0, 6.25 and 7.5 dSm-1, respectively, as compared to BAW, whereas, corresponding reduction in wheat grain yields were 12.5, 22.9, 35.5 and 46.7 per cent, respectively (Table 4.43). EC2 of soil also increased from 0.16 to 1.26 dSm-1 with an increase in salinity of irrigation water after three year's rotation of experimentation, whereas, there was little increase in pH2 (Table 4.44). They recommended that if two sources of water of variable quality are available , they may be in such a proportion that EC of mixed water is around 3.75 and 5.0 dSm-1 for reasonably good yield of ground nut and wheat , respectively.
Table 4.43 : Effect of mixed saline and BAW irrigation water on the yield of groundnut and wheat (q ha-1)
Treatments EC of
Mixed water Groundnut Wheat
Pod yield % reduction w.r.t BAW Grain yield % reduction w.r.t BAW
T1 100 % canal water 0.25 42.22 - 36.04 -
T2 100 % best available water (BAW) 2.50 34.03 - 33.78 -
T3 25% Saline water + 75 % BAW 3.75 27.81 18.3 29.55 12.5
T4 50% Saline water + 50 % BAW 5.00 16.64 51.1 26.04 22.9
T5 75% Saline water + 25 % BAW 6.25 13.69 59.7 21.80 35.5
T6 100% Saline water 7.50 6.87 79.3 18.00 46.7
C.D. at 5% 4.97 2.71
Source: Sharma, et. al. (2003)
Table 4.44: Soil characteristics after harvesting of crops (0-30 cm)
ECiw
(dSm-1) 1999-2000 2000-2001 2001-2002
After groundnut After wheat After Groundnut After Wheat After Groundnut Afterwheat
pH2 EC2 (dSm-1) pH2 EC2 (dSm-1) pH2 EC2 (dSm-1-) pH2 EC2
(dSm-1) pH2 EC2 (dSm-1) pH2 EC2 (dSm-1)
0.25 8.4 0.18 8.4 0.20 8.5 0.21 8.5 0.22 8.5 0.21 8.5 0.22
2.5 8.6 0.42 8.7 0.54 8.7 0.58 8.7 0.60 8.8 0.63 8.8 0.68
3.75 8.6 0.50 8.7 0.62 8.8 0.63 8.8 0.66 8.8 0.66 8.8 0.76
5.00 8.7 0.56 8.8 0.71 8.8 0.73 8.8 0.75 8.8 0.72 8.8 0.89
6.25 8.8 0.65 8.9 0.82 8.9 0.86 8.9 0.90 8.9 0.92 8.9 1.00
7.5 8.9 0.76 8.9 0.94 9.0 1.02 9.0 1.06 9.1 1.06 9.1 1.26
Initial 8.5 0.16
Source: Sharma, et al. (2003)
Grasses:
Forage grasses found to perform well under saline water /soil conditions. An experiment carried out by growing forage grasses viz: para grass (Brachiaria mutica), guttan panic (panicum maximum), blue panic (p. antidotale), Rhodes grass (chloris gayana) with best available water (EC 2 dSm-1) and saline water for four years revealed that Rhodes grass gave the highest green forage yield followed by blue panic ( Singhania et.al. ,1997 ). There was little effect of saline water on grass yields. The pH of soil under guttan panic was the lowest, while pH and EC was the highest under Rhodes grass and blue panic. Addition of saline water increased the EC of soil from 0.44 to 0.62 dSm-1 (Table 4.46).
Table: 4.46: Effect of best available and saline water on green forage yield and soil characteristics
Treatments Green Forage yield (q ha-1) Soil characteristics
1986-87 1987-88 1988-89 1989-90 Mean pH2 EC 2 (dSm-1)
Grass
Para grasss 350.7 82.1 99.54 70.6 150.7 9.85 0.50
Guttan panic 189.5 41.7 31.6 65.6 82.1 9.77 0.52
Blue panic 594.1 163.2 223.2 343.5 331.0 9.95 0.56
Rhodes grass 814.1 250.6 243.4 353.1 415.3 9.95 0.55
Sewan grass - 26.6 58.3 112.2 65.7 9.87 0.50
CD at 5% 402.2 20.0 62.4 26.2
ECiw (dSm-1)
2 507.9 117.8 278.0 191.7 191.7 9.96 0.44
12 457.9 108.6 282.9 186.2 186.2 9.85 0.62
CD at 5% NS 3.4 NS NS
Source: Singhania et al. (1997)
Use of RSC water:
High RSC water is characterized by low total salts concentration. The relative proportion of calcium and magnesium is much smaller as compared to sodium. Such waters have carbonates and bicarbonates predominant anions. The prolonged use of such water immobilizes soluble calcium and magnesium in soil by precipitating them as carbonates , consequently the concentration of sodium in soil solution and exchangeable complex increases and leads to development of alkali or sodic condition. High RSC water is the severe problem in Nagaur, Jaipur, Sikar, Sirohi, Jodhpur, Bhilwara , Tonk and Pali districts of Rajasthan.
In arid and semi arid regions agriculture may involve the use of irrigation water containing higher amount of residual sodium carbonate (RSC). The magnitude of adverse effect is variable depending upon the content of RSC in irrigation water, soil texture, calcium carbonate and calcium sulphate in the soil, SAR of water, source of RSC and effect of leaching and mean annual rainfall. High sodicity in soil induced by irrigation with alkali water reduced soil water availability to plants, not for osmotic reasons but due to lack of infiltration of water into the root zone. Additionally, high pH leads to reduction in availability of micro-nutrients and some macro nutrients viz. .Calcium and potassium. Inadequate calcium adversely affects membrane functions and finally plant growth. Deficiency of calcium can also be caused due to irrigation with water of high Mg/Ca ratio. Irrigation with water containing more than 2.5 mel-1 RSC is considered hazardous.Increased bacterial activity accompanied by organic matter addition, especially wide C: N ratio materials decrease volatilization losses of nitrogen in alkali soils because a considerable fraction of native and synthesized into the body tissue of bacteria and released slowly upon their death ( Somani ,1980).
Addition of gypsum to soil @ 50 % GR had increased grain yield of pearl millet and mustard and at 100 % GR the yields did not increased further (Table 4.47). Neutralization of RSC of irrigation water had significantly increased the grain yield of pearl millet and mustard up to 6 mel-1 ( Verma et al. 2003). The increase in yield was higher at first two-milli equivalent neutralization as compared to higher neutralization. There was no adverse effect of remaining RSC of water up to 4.0 mel-1 on pearl millet and mustard yields. Addition of gypsum not only reduced the alkalinity of soil but also prevented further degradation of soil with the use of high RSC water (Table 4.48).
Table 4.47: Effect of different quantities of added gypsum on the yield (q ha-1) of pearl millet and mustard (average of three years)
Soil Application (% GR) RSC neutralization of irrigation water (mel-1)
0 2 4 6 Mean
Pearl millet
0 20.87 23.23 24.79 26.77 23.94
50 22.61 24.85 27.96 28.06 25.87
100 23.20 25.22 26.20 25.72 25.09
Mean 22.23 24.47 26.31 26.85
CD (P=0.05) GR 1.52 RSCN 1.77 GR X RSCN 3.06
Mustard
0 16.06 18.57 20.25 21.14 19.01
50 20.16 20.90 22.44 23.12 21.66
100 20.99 22.38 24.72 24.77 23.22
Mean 19.07 20.61 22.47 23.01
CD (P=0.05) GR 1.68 RSCN 2.10 GR X RSCN 3.26
Source: Verma et al. (2003)
Table 4.48: Effect of neutralization of alkalinity of soil and water on pH2 and EC2 of soil after harvesting of crops



Treatment 1999-2000 2000-2001 2001-2002
Pearl millet Mustard Pearl millet Mustard Pearl millet Mustard
pH2 EC2 (dSm-1) pH2 EC2 (dSm-1) pH2 EC2 (dSm-1) pH2 EC2 (dSm-1) pH2 EC2 (dSm-1) pH2 EC2 (dSm-1)
Gypsum application (%) G R
G0 9.7 0.35 9.4 0.36 9.3 0.29 9.4 0.35 9.0 0.25 8.9 0.32
G50 9.5 0.38 9.0 0.38 8.9 0.26 8.8 0.36 8.7 0.22 8.6 0.33
G100 9.4 0.39 8.9 0.40 8.7 0.25 8.6 0.37 8.6 0.21 8.5 0.34
RSCN*(mel-1)
0 9.6 0.34 9.5 0.36 9.4 0.29 9.4 0.34 9.0 0.24 8.9 0.31
2 9.6 0.36 9.3 0.37 9.1 0.27 9.0 0.36 8.9 0.23 8.8 0.32
4 9.5 0.37 9.0 0.39 8.8 0.26 8.6 0.37 8.8 0.22 8.6 0.34
6 9.5 0.38 8.7 0.39 8.6 0.26 8.5 0.37 8.6 0.22 8.4 0.34
Source:Verma et. al. (2003) *RSCN- RSC Neutralization
An experiment was conducted by Yogesh et al. (2005) to find out the effect of use of agro-chemicals for minimizing the alkalinity hazards and sustaining crop yields on alkali water irrigated calcareous soils on cluster bean and mustard indicated that Maximum seed yield was obtained with addition of pyrite as per 50 per cent GR in soil followed by partial neutralization of RSC + Spray of 2% FeSO4 + 0.1% Citric acid (Table 4.49).

Table 4.49 : Effect of different methods of RSC neutralization of water on yield of Cluster bean and mustard
Treatments Seed yield clusterbean
(q ha-1) Seed yield mustard
(q ha-1)
2002 2003 Av. 2001-02 2002-03 2003-04 Av.
T1 {Partial RSC Neutralization (2mel-1) in irrigation water (Control) 11.45 11.05 10.75 14.13 13.50 17.5 15.04
T2 (T1 + Gypsum @ 50 % GR) 13.05 11.60 12.33 16.93 17.66 22.3 18.96
T3 (T1 + Pyrite @ 50 % GR) 15.90 14.05 14.98 18.25 20.66 25.0 21.30
T4 (T1 + Spray of 2% FeSO4 + 0.1% Citric acid) 14.65 12.35 13.50 17.41 19.33 24.2 20.31
T5 (T1 + Spray of 0.1% Citric acid) 11.65 10.15 10.90 15.25 14.50 18.2 15.98
T6 (T1 + Gypsum @ 25 % GR) 12.15 11.10 11.63 16.11 15.91 20.7 17.57
CD (P = 0.05) 1.69 1.57 1.67 1.73 2.68 3.5 2.72
Source: Yogesh et al. (2005)
Addition of pyrite or gypsum in soil as per GR reduced the pH2 of soil (9.40 to 8.71), while EC2 of soil had shown little increase up to IInd year of rabi but in kharif after IInd year harvesting of cluster bean decline was observed in EC (Table 4.50) . It might be due to good monsoonal rains received during the period. There was little variation in EC2 of soil.
Table 4.50 : Chemical characteristics of soil after harvesting of crops

Treatments Ist year IInd year IIIrd year
After mustard After cluster bean After mustard After cluster bean After mustard
pH2 EC2 pH2 EC2 pH2 EC2 pH2 EC2 pH2 EC2
T1 9.31 0.40 9.35 0.44 9.21 0.48 9.05 0.35 8.97 0.42
T2 9.19 0.41 9.22 0.45 9.14 0.42 9.00 0.31 8.85 0.38
T3 9.10 0.40 9.15 0.41 9.06 0.48 8.95 0.28 8.71 0.37
T4 9.38 0.39 9.39 0.45 9.29 0.54 9.11 0.34 9.05 0.44
T5 9.38 0.39 9.38 0.43 9.38 0.52 9.20 0.32 9.11 0.41
T6 9.24 0.40 9.28 0.43 9.27 0.49 8.99 0.30 8.90 0.40
Initial 9.40 0.38
Source: Yogesh et al. (2005)
An experiment on irrigation with high RSC water conducted at K.V.K. Sardarshahar indicated that grain and straw yield of wheat were significantly influenced by the application of FYM. There was significant increase in the yields with the application of FYM @ 5 t ha-1 as compared to control; further increase in dose of FYM @10 t ha-1 did not increase the yield further. Application of gypsum at RSC neutralization of 7.5 mel-1 increased the yield of wheat significantly as compared to control. There was decrease in pH2 with addition of FYM and gypsum application. A slight increase in EC2 with application of gypsum was also observed (Table 4.51).
Table 4.51: Effect of organic manure and RSC neutralization of water on yield of wheat.
Treatment Grain yield
(q ha-1) Straw yield (q ha-1) Soil Characteristics
pH2 EC2
Manuers
Control
FYM 5 t ha-1
FYM 10t ha-1 6.50
8.61
9.38 9.88
12.16
12.50 9.27
9.05
8.97 0.41
0.40
0.40
CD at 5% 1.09 1.97
RSC Neutralization (mel-1)
0 7.30 10.59 9.16 0.38
2.5 8.00 10.74 9.16 0.39
5.0 8.29 12.00 9.10 0.42
7.5 9.07 12.74 8.97 0.42
CD at 5% 1.52 2.28
Source : Annonymous (2001-02)
Irrigation management:
The distribution of water and salts in soils vary with the method of irrigation, therefore, the methods followed should create and maintain favorable salt and water regimes in the root zones such that water is readily available to the plants. In poor quality waters, methods of irrigations have pronounced effect on crop growth.
A field study conducted on sandy loam soil of low fertility revealed that yield of wheat reduced with increased salinity of irrigation water beyond 6 dSm-1 . Maximum yield of wheat was recorded at the irrigation schedule of 43mm CPE at EC of 2 dSm-1 (Vyas et al. 1986) (Table 4.52).
Table 4.52: Combined effect of irrigation frequency and salinity of irrigation water on grain yield of wheat (q/ha)


ECiw(dSm-1) Irrigation frequency (CPE in mm)
I0(60) I2(50) I3(43)
1981-82 1982-83 1981-82 1982-83 1981-82 1982-83
2 24.50 20.80 22.81 22.00 32.17 24.80
6 24.60 18.40 26.80 19.54 28.49 19.66
10 17.24 13.40 21.02 13.40 21.02 15.39
14 14.29 10.40 14.40 7.80 16.71 7.80
CD at 5% 4.76 2.99
Source: Vyas et al. 1986
The experiments conducted on barley and wheat for 4-6 years with two levels of irrigation at IW/CPE ratio 1.0 and 1.15 and four levels of salinity (viz. BAW, ECiw 4.0, 8.0 and 12.0 dSm-1) revealed that increasing depth of irrigation IW/CPE 1.0 to 1.15 enhanced the wheat crop yield up to moderate salinity (8 dSm-1) compared to non saline water. While in barley crop increased IW/CPE was not found useful (Table 4.53)
Table 4.53 : Wheat and Barley yield (q ha-1) with varying IW/CPE ratio under saline irrigation

IW/CPE ratio ECiw (dSm-1)
BAW 4 8 12
Fallow wheat (Mean of 6 years)
1.0 24.1 22.7 23.7 22.3
1.15 25.8 25.8 25.5 22.6
Fallow barley(mean of 6 years)
1.0 50.8 42.3 44.4 43.1
1.15 49.7 44.4 41.1 41.0
Source: Minhas et al. (1998)
Use of drip and pitcher irrigation has been found useful, as suction or drip irrigation helps to keep the soil moist. Crops are able to tolerate more saline condition if moisture levels are maintained around field capacity. In drip irrigation, the water is added to the soil in drops, whereas in suction irrigation system, as the name suggests, soil suction is used to extract the water contained in porous emitters placed near the plant roots (Yadav et al. 1986).
Basin and pitcher irrigation:
Studies conducted on pitcher and conventional method of irrigation revealed that the maximum mean vegetable yield (9306 kg/ha) was recorded with normal water under pitcher irrigation method (Table 4.54). Salinity of water reduced the yield slightly under both the methods of irrigation. Pitcher irrigation with normal water was found to be significantly superior over rest of the treatments in first year but it was significantly inferior to check basin irrigation in second year. Pitcher irrigation with saline water was also significantly superior to check basin method in first year while a reverse trend was observed in the second year of study this might be due to reduced rate of water suction as a consequence of salt deposition on the pitcher surface in the form of insoluble compounds. Average conjunctive use of water in check basin method was 2800 mm as compared to 635 mm in pitcher irrigation indicating a saving of about 80% water (Singh et al., 1987).
Table 4.54: Vegetable yield and economics of knol khol cultivation on sandy soils as affected by method of irrigation


Treatments Vegetable yield (qha-1) Net returns (Rs ha-1)
1985-86 1986-87 Mean 1985-86 1986-87 Mean
I1 – Check basin Normal water 7340 6656 6998 7526 6460 6993
I2 –Check basin with saline water 7320 5920 6620 7496 5356 6426
I3 –Pitcher method with normal water 14720 3893 9306 20407 3935 12021
T4 –Pitcher method with saline water 10940 3080 7010 14337 2616 8526
CD at 5% 1904 2636 -- -- -- --
Source: Singh et al. (1987)
Suction irrigation system:
The suction irrigation system developed by the center has given very good results and it can be adopted to cultivate vegetables, fruits, medicinal plants, flowers etc. in salt affected soils with or without saline water irrigation (Yadav, 1986). The general features of the emitters are shown in Fig. 9. The emitters are embedded in the soil at about 5 cm depth below the ground surface. These are connected to a tank by plastic tubes and initially air is removed through the system by circulating water. When filled with water, it will be sucked out of these emitters by the soil, which is at a higher suction than the water contained in the emitters.

Fig. 9 : General features of suction emitters made of cow-dung and potter’s earth
Several auto-irrigators were developed to replace factory made costly and sophisticated auto-irrigators. The gulli and dumb-bell shaped emitters were developed to irrigate economically any seasonal crop and vegetable sown in rows. The gulli-shaped emitters were modified and developed to irrigate sugarcane. Bulb, ball and emitter battery were developed to irrigate annual and biannual plants including fruit plants. These auto-irrigators require clayey soils (Potter’s soil) and cow dung replacing synthetic materials adopted in factories. Ordinary potters or farmers can develop them after undergoing little training. The prototype auto-irrigators are simple, low cost, easy to fabricate and low in running cost. The operation is easy. This saves about 90% irrigation water than applied to furrow irrigation.

Data in table 4.55 showed that suction irrigation system increased the vegetable yield of bottle gourd, brinjal, cabbage, cauliflower, knolkhol and water melon by 4.72, 11.11, 47.05, 45.91, 68.57 and 40.92 per cent over punched hole dripper system respectively. Clay drip system of irrigation was more eight times more economical than any drip system developed then.

Table 4.55: Yields of crops under different methods of irrigation

Vegetable crop Yield (q/ha)
Clay drip system Punched hole dripper
Water applied (cm) Yield (q/ha) Water applied (cm) Yield q/ha)
Bottle gourd 8.0 310 19.0 296
Brinjal 4.0 250 9.6 225
Cabbage 5.3 500 13.3 340
Cauliflower 4.6 518 11.6 344
Knol-khol 3.9 590 10.1 350
Watermelon 72.3 730 84.5 518
Source: Yadav (1983)
During 1988-89 a study was carried out for evaluation of the effect of quality of irrigation water on different vegetables with suction and pitcher method of irrigation. The water requirment of all the vegetables was lower in the plots irrigated by suction than in pitcher (Table 4.56). By adopting suction method of irrigation, about 33.3 to 48.4 per cent of irrigation water may be saved. It was observed that in the suction method, the crop yield was about 3.8 to 4.4% more at 2 dSm-1 and 3.2 to 7.0% at 12 dSm-1 besides saving in water.
The suction irrigation was found better than the pitcher irrigarion as far as water saving and yield of the vegetables were concerned.
Table 4.56: Water applied (cm) and yield (q/ha) of different vegetables
Vegetables Quantity of water (cm) Yield (q/ha)
Suction Pitcher Suction Pitcher
2 12 2 12 2 12 2 12
Kundru
Bottle gourd
Ridge gourd
Bitter gourd --
6.5
5.1
4.9 --
6.8
5.1
4.9 --
10.2
9.8
9.7 --
10.2
9.8
9.7 --
315
334
196 --
304
320
185 --
302
321
188 --
2
3
1
Source: Yadav (1983)
Drip irrigation:
A field syudy conducted at AICRP on use of saline water ARS, Bikaner on drip irrigation system with saline water irrigation having ECiw 3.0 and 6.0 dSm-1 revealed that tomato and bottle gourd can be grown successfully upto ECiw 3.0 dSm-1 (Table 4.57).

Table: 4.57 Effect of different salinity levels of water under drip irrigation on yield (q ha-1) of tomato and bottle gourd
ECiw
(dSm-1) Bottle gourd Tomato
Mulch Without mulch Average Mulch Without mulch Average
0.25 122.0 209.3 165.6 344.8 354.6 349.7
3.0 139.8 258.3 199.0 392.7 415.8 404.3
6.0 113.7 167.4 140.6 143.8 178.8 161.0
ECiw Mulch EC X M ECiw Mulch EC X M
CD at 5% 39.8 32.7 56.3 24.9 20.4 NS
Source: Anonymous (2004)
Effect of nitrate rich saline water on the performance of wheat
Studies on nitrate rich saline water conducted during 1997-98 on wheat in pots. The treatments comprised of four levels of saline water ( BAW, 4.0,8.0 and 12.0 dS/m ) and four levels of nitrate ( BAW, 20 ppm, 40 ppm and 80 ppm ). The data presented in table SW 35.1 indicate that dry matter yield of wheat was significantly influenced by salinity of irrigation water . Dry matter yield decreased by 4.0,11.8 and 43.5 per cent at ECiw 4.0,8.0 and12.0 dSm-1 as compared to BAW(0.25 dSm-1). Similar trend was also observed in case of plant height and ear length. Effect of nitrate levels in irrigation water was observed to be non significant on yield and yield attributes of wheat.
Table 35.1: Effect of different levels of ECiw and nitrate on yield and yield attributes of wheat
Treatments Dry matter (g/plant) Plant height (cm) Ear length (cm)
ECiw (dSm-1)
BAW(0.25 dSm-1) 0.825 36.3 6.7
4.0 0.792 34.8 6.4
8.0 0.728 33.0 6.0
12.0 0.466 26.0 5.2
SEm + 0.021 0.9 0.2
C.D. at 5% 0.059 2.7 0.6
Nitrate levels
BAW 0.661 31.4 5.9
20 ppm 0.669 32.4 6.1
40 ppm 0.727 33.1 6.3
80 ppm 0.725 33.1 6.1
SEm + 0.021 0.9 0.2
C.D. at 5% NS NS NS

Data on chemical characteristics of soil (Table SW 35.2) indicated that pH2, EC2 and ionic composition of soil increased with increase in salinity of water. Applications of nitrates as potassium nitrate increase pH2, EC2 and potassium of the soil.
Table 35.2: Effect of different levels of ECiw and nitrates on chemical characteristics of soil after harvesting of wheat

Treatments pH2 EC2
(dSm-1) Ionic composition (meL-1)
Ca++ Mg++ Na+ K+ CO3--+HCO3- Cl- SO4--
ECiw (dSm-1)
BAW(0.25 ) 8.57 0.26 0.8 0.5 0.6 0.66 1.1 1.2 0.26
4.0 8.65 0.53 1.9 1.2 1.3 0.94 2.0 2.6 0.74
8.0 8.75 0.72 2.3 1.7 2.1 1.0 2.6 3.7 0.80
12.0 8.83 0.89 3.4 2.3 2.6 1.0 3.2 5.0 1.10
Nitrate levels
BAW 8.65 0.55 2.0 1.4 1.7 0.63 2.2 3.1 0.43
20 ppm 8.70 0.58 1.9 1.4 1.7 0.79 2.2 3.0 0.59
40 ppm 8.75 0.62 2.0 1.4 1.7 1.04 2.2 3.1 0.84
80 ppm 8.78 0.66 2.1 1.4 1.7 1.36 2.2 3.2 1.16

Effect of sewage water on soil properties and nutrient status of crops.

Range of chemical composition of sewage water (Table SW 42.1) Indicated that pH and EC of water samples ranged between 8.0 to 8.3 and 2.0 to 2.1 dSm-1, respectively. Sodium is the dominant cation and chloride is the dominant anion which varied between 12.6 to 14.1 and 10.9 to 12.1 meL-1 , NO3-N and phosphate contents varied between 12.0 to 12.5 and 2.1 to 2.8 mgL-1, respectively. Adj. SAR of the water samples ranged between 9.21 to 18.19. As regarding micro nutrients composition, Zinc, Copper, Iron and Manganese contents of the water samples ranged from 252.5 to 259.3, 215.9 to 231.6, 444.3 to 485.4 and 303.2 to 311.0 mgL-1, respectively for different months of the year. BOD and TSS of water samples ranged between 314.2 to 388.0 and 312.5 to 347.2 mgL-1,respectively.
Data on the chemical characteristics of the soil of different profiles located in the area indicated that pH2 and EC2 of surface soil (0-15cm) ranged from 7.7 to 8.0 and 0.6 to 1.24 dSm-1. The values of pH2 increase with depth but EC2 of soil profiles decreased with increase in depth (Table SW 42.2)
The surface soil of experimental sites are sandy loam in texture and are rich in organic carbon (9.5 -10.7 gKg-1 ), available nitrogen (284 - 300 Kgha-1 ), phosphorus (204 - 244 Kgha-1) and potash (446 - 502 Kgha-1). CEC and CaCO3 in the surface soil varied between 10.4 to 13.4 [cmol (P+)kg-1] and 46.5 to 65.5 g kg-1, respectively. Available nutrients and organic carbon contents in the profiles decreased with increase in depth. (Table SW 42.3).
Data on DTPA extractable micro nutrients status( Table SW 42.4) revealed that zinc, copper, iron and manganese contents surface soil (0-15 cm ) varied between 11.3 to 13.9, 9.1 to 15.1, 17.8 to 20.7 and 3.9 to 6.0 mgKg-1 , respectively. DTPA extractable micro nutrients contents in the soil profiles decreased with depth.
Correlation studies table SW 42.5 indicated that DTPA extractable metallic cations are negatively and significantly correlated with pH2 of soil. Whereas, correlation between EC2 and DTPA extractable metallic cations are found to be significantly positive. Correlation between Organic carbon and metallic cations are also positively significant.
Chemical analysis of plant samples collected from the fields receiving sewage water for irrigation is under progress.
Table 42.1 : Chemical composition of sewage water of Bikaner city .
Chemical characteristics Range of different constituents Chemical characteristics
Range of different constituents
PH 8.0 - 8.3 NO3-N (mgL-1) 12.0 - 12.5
EC (dSm-1) 2.0 - 2.1 Phosphates(mgL-1) 2.1 - 2.8
Ca+2 (meL-1) 3.2 - 3.4 Adj. SAR 9.21 - 18.19
Mg+2 (meL-1) 3.5 - 3.7 Total Suspended Solids (mgL-1) 312.5 - 347.2
Na+(meL-1) 12.6 -14.1 Biochemical Oxygen Demand (mgL-1) 314.2 - 388.0
K+(meL-1) 0.7 - 0.8 Zinc(µgL-1) 252.5 - 259.3
Cl-(meL-1) 10.9 -12.1 Copper(µgL-1) 215.9 -- 231.6
CO3-2(meL-1) 0.8 - 0.9 Iron(µgL-1) 444.3 - 485.4
HCO3-(meL-1) 3.3 - 3.8 Manganese(µgL-1) 303.2 - 311.0
SO4-2(meL-1) 4.5 - 5.2

Table 42.2 : Range of Chemical characteristics of soils of different profiles located in the area receiving sewage water for irrigation.
Characteristics Depth
0-15 15-30 30-45 45-60
PH2 7.7-8.0 8.1-8.4 8.4-8.6 8.6-8.7
EC2 (dSm-1) 0.62-1.24 0.45-0.73 0.35-0.55 0.30-0.44
Ca+2 (meL-1) 1.1-6.6 0.7-3.1 0.4-1.9 0.3-1.4
Mg+2 (meL-1) 0.8-6.1 0.4-2.7 0.2-1.7 0.2-1.2
Na+(meL-1) 2.5-5.3 2.2-3.9 1.6-3.2 1.5-2.9
K+(meL-1) 0.3-1.5 0.2-0.8 0.1-0.4 0.1-0.4
Cl-(meL-1) 2.1-10.2 1.4-5.1 0.5-3.5 0.4-2.4
CO3-2 + HCO3- (meL-1) 0.8-1.2 1.0-1.2 1.2-1.6 1.3-1.8
SO4-2(meL-1) 1.7-8.4 0.8-4.4 0.2-2.5 0.2-2.2
SAR 2.2 - 2.6 2.4 - 2.6 2.5 - 2.8 2.6 - 2.9


Table 42.3 : Range of Physico-chemical characteristics of soils of different profiles located in the area receiving sewage water for irrigation.
Characteristics Depth
0-15 15-30 30-45 45-60
Organic Carbon(gKg-1) 9.5-10.70 4.85-6.85 3.05-3.90 1.15-1.75
Available Nitrogen (Kgha-1) 284-300 173-211 139-150 122-130
Available P2O5 (Kgha-1) 204-244 103-121 43-60 21-33
Available K2O (Kgha-1) 446-502 374-429 327-380 267-308
CEC [cmol(P+)Kg-1] 10.44-13.36 7.38-10.81 5.41-7.89 4.39-5.58
CaCO3 (gKg-1) 46.45-65.50 71.25-109.85 86.80-124.8 105.15-141.05
Sand (%) 70.98-72.96 71.66-73.21 72.65-75.53 78.73-80.60
Silt (%) 14.15-15.16 13.75-14.66 12.90-14.28 9.55-11.06
Clay (%) 11.11-12.06 10.95-11.83 9.88-11.45 7.88-8.55



Table 42.4 : Range of DTPA extractable metallic cation of soils of different profiles located in the area receiving sewage water for irrigation.
Characteristics Depth
0-15 15-30 30-45 45-60
Zinc (mgKg-1) 11.3 -13.9 5.3 - 8.1 2.9 - 4.7 2.6 - 3.2
Copper(mgKg-1) 9.1 -15.1 6.3 - 9.5 3.7 - 5.4 2.3 - 3.4
Iron(mgKg-1) 17.8 -20.7 13.7 -15.7 12.8 -14.5 11.9 -13.2
Manganese(mgKg-1) 3.9 - 6.0 1.6 - 2.9 0.9 -1.7 0.3 - 0.7



Studies on Rate of salinization

For the studies on rate of salinization of soil, three sites were selected at RD 276, RD 277 and RD 305 in Loonkaransar tehsil falling under IGNP command having water table varying from 0.6 to 1.8 m. Three years studies ( 1996-97 to 1998-99 ) showed that the water tables were shallow during October to February as compared to other period of the year (Table SW 26.1). Within a certain range of water table depths, EC of perched water was more responsible for higher rate of salinization than water table depth, for example average perched water table depth and EC of perched water of 276 RD was 108 cm and 2.07 dSm-1 and that of 277 RD it was 117cm and 5.21dSm-1, respectively. The rate of salinization in RD276 and RD 277 was 0.017 and 0.037 mg/cm2/d, respectively. Though the perched water table was deeper and perched water was more saline in RD 277 than RD 276, the rate of salinization in RD 277 was high (Table SW 26.2). This indicated that the EC of perched water was more responsible for higher rate of salinization. It was further observed that if water table were beyond 125cm there would be no contribution towards salinization through perched water table.


Table : Chemical characteristics of perched water and soil at different period of time



S. No.

Site

Date Perched water
Water table
depth (m) pH EC
(dSm -1) RSC (meL-1) SAR Surface soil
pH Surface soil
EC (dSm-1) Profile
Average pH Profile average
EC
(dSm-1)
1 RD276 22.5.98 121 8.9 2.18 9.1 31.2 8.6 0.11 8.6 0.13
2 17.6.98 106 8.5 1.28 5.4 20.3 8.5 0.16 8.6 0.17
3 21.7.98 117 8.8 1.37 5.8 22.2 8.9 0.14 9.3 0.17
4 21.8.98 132 8.9 2.25 9.6 30.6 8.3 0.13 8.7 0.18
5 22.9.98 103 8.4 1.97 8.1 24.2 8.6 0.11 8.9 0.13
6 27.10.98 109 8.2 1.58 5.5 22.2 8.6 0.13 9.1 0.19
7 13.11.98 74 7.9 2.40 8.9 20.9 8.4 0.20 8.8 0.26
8 21.12.98 92 8.2 1.96 8.4 18.6 8.4 0.26 8.6 0.30
9 18.1.99 85 8.3 2.43 8.5 21.1 8.5 0.34 8.9 0.38
10 28.2.99 92 8.5 2.63 8.1 18.5 8.5 0.36 8.8 0.37
11 24.3.99 124 8.6 2.78 6.5 18.4 8.5 0.33 8.8 0.36
12 26.4.99 136 8.3 1.95 7.8 18.4 8.6 0.35 8.7 0.36
Mean 107.6 8.45 2.07 8.53 0.22 8.82 0.28
1 RD277 22.5.98 120 8.9 2.20 7.8 29.7 9.2 0.60 9.4 0.66
2 17.6.98 110 8.9 3.66 9.9 46.2 9.7 1.44 9.8 1.16
3 21.7.98 129 8.9 2.39 8.2 32.6 9.6 1.54 9.7 1.07
4 21.8.98 136 8.6 2.94 8.3 38.2 9.1 0.32 9.6 0.62
5 22.9.98 124 8.7 5.53 11.6 65.4 8.7 0.12 9.5 0.50
6 27.10.98 116 8.7 3.24 9.3 40.4 9.2 0.19 9.5 0.87
7 13.11.98 114 8.2 6.98 12.4 64.0 9.0 0.28 9.3 0.86
8 21.12.98 105 8.3 6.98 9.2 60.6 8.7 0.11 9.4 1.01
9 18.1.99 92 8.6 5.37 10.3 56.8 8.7 0.31 9.3 0.54
10 28.2.99 105 8.8 7.42 10.1 56.6 8.8 0.36 9.4 0.69
11 24.3.99 120 8.7 7.54 8.3 55.1 8.5 0.28 9.3 0.72
12 26.4.99 130 8.9 8.33 9.3 53.9 8.8 0.32 9.5 1.00
Mean 116.8 8.66 5.21 9.0 0.51 9.48 0.81
1 RD305 22.5.98 127 8.4 0.42 1.6 5.6 8.4 0.32 8.8 0.54
2 17.6.98 109 8.8 1.42 4.5 12.4 9.1 0.16 9.5 0.62
3 21.7.98 136 8.6 0.77 3.0 10.0 9.0 0.10 9.1 0.17
4 21.8.98 149 8.7 1.02 4.4 12.2 8.8 0.12 9.0 0.24
5 22.9.98 143 8.7 1.12 4.8 7.6 8.8 0.09 9.2 0.28
6 27.10.98 149 8.6 1.35 4.6 10.8 8.8 0.12 9.0 0.25
7 13.11.98 118 8.0 1.28 4.5 11.1 8.7 0.17 9.0 0.31
8 21.12.98 98 8.1 1.88 5.1 13.0 8.7 0.22 9.0 0.33
9 18.1.99 111 8.2 1.58 5.1 14.8 8.8 0.16 9.2 0.32
10 28.2.99 98 8.5 2.02 4.9 13.2 8.9 0.12 9.3 0.29
11 24.3.99 127 8.4 1.84 5.3 14.2 8.7 0.30 9.0 0.44
12 26.4.99 143 8.6 2.52 7.4 17.8 8.9 0.15 9.3 0.35
Mean 122 8.47 1.44 8.8 0.17 9.1 0.35

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