Management of salt affected soils

Management of salt affected soils

4. Management of salt affected soils and poor quality waters
Salt related soil and water problems are major limiting factors that invariably reduce the crop yields. The research to overcome salt related problems has progressed in two distinct streams; (i) chemical amelioration and hydro – technical approaches, (ii) biological approaches. It is based on concept that to manage salinity there could be two approaches (a) either change growing environment and make it suitable for the normal growth of plants or (b) select the crop and /or change genetic makeup of the plant so that it could be grown in such areas. There is third approach as well which can be termed as hybrid approach, means combination of both environments modifying approach and biological approach. Now a days major soil reclamation work in Rajasthan involves all the three approaches to combat the salt problem.
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 [Grain yield (q ha-1) and Gross returns (Rs ha-1)]

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)
Mathur et al.(1972) reported that after paddy, mustard , wheat and barley were found to grow successfully and gave higher returns as compared to taramira, gram, pea, lentil,senji or berseem. Growing of mustard were recommended during initial years of reclamation , if water supply condition are erratic and inadequate. Double cropping lowered down salt concentration more effectively as compared to single kharif cropping.
Mehta et al. (1973) suggested one of the two rotations (a) Fallow-wheat, green manuring wheat, bajra-barley and (b) Fallow-wheat, bajra-barley, green manuring- wheat as suitable crop sequence for saline soils and for soil irrigated with waters having EC< 4 dSm-1.
After three years studies on soil irrigated with saline water commonly practiced in western Rajasthan ( EC 4.8 dSm-1 and RSC 7.4 mel-1and SAR 32 ) , Jain et al.(1976) reported that the yields of wheat after fallow , a kharif legume or sesame or pearl millet were at par and the crop rotation would be governed by net profit. Clusterbean – wheat rotation proved more economic for the area.
The best suited crop rotation in treated saline - sodic soil of Udaipur region having pH2 9.27, EC2 3.38 dSm-1, ESP 75.1 and GR 23.8 Mg ha-1 and irrigated with water having pH 8.1, EC 2.1 dSm-1,SAR 13.5 and RSC 8.3 mel-1 was mustard- maize (Qureshi and karan, 1992).
Studies conducted by Babel and Singh (1998) for crop production under high RSC water ( RSC 9.0 mel-1, Adj. SAR 26.5 and EC 2.3 dSm-1) with and without amendments revealed that highest annual gross returns of Rs. 27801 and 32912 ha-1 were obtained from pearl millet-mustard crop rotation both in without as well as in gypsum treated plots , respectively. The lowest annual gross returns of Rs. 13049 ha-1 was recorded with fallow-barley crop rotation in no gypsum applied plots., whereas, it was Rs. 14041 ha-1 in Dhaincha (GM)-barley crop rotation. Gypsum application decreased soil pH (9.38 to 8.44) whereas; it increased EC2 from 0.32 to 0.47 dSm-1. Dhaincha –mustard rotation and Fallow-barley rotation also reduced pH of soil (Table: 4.3).

Table 4.3: Effects of different crop rotations and gypsum levels on annual gross returns (Rs./ ha) and chemical characteristics of soil (Average of 2 years)
Rotations Gross returns (Rs. /ha) Soil characteristics
Without gypsum With gypsum Mean pH EC
Without gypsum With gypsum Without gypsum With gypsum
Pearl millet- barley 20856 25732 23294 9.48 8.42 0.36 0.51
Pearl millet-mustard 27801 32912 30357 9.48 8.47 0.38 0.50
Moong-barley 18456 21017 19737 9.46 8.46 0.34 0.50
Moong-mustard 24152 27995 26073 9.47 8.47 0.34 0.52
Dhaincha (GM)-barley 13978 14041 14009 9.28 8.48 0.34 0.44
Dhaincha (GM) mustard 20794 21267 21040 9.25 8.38 0.32 0.50
Fallow-barley 13049 14352 13700 9.28 8.35 0.33 0.43
Fallow-mustard 19387 20935 20161 9.47 8.53 0.24 0.48
Mean 19809 22770 - 9.38 8.44 0.32 0.47

CD at 5% Gypsum Rotation Interaction
265 136 1932
Source: Babel & Singh (1998)
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 4.4). There was improvement in soil properties also with application of amendments (Table 4.5).
Table4.4: 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)

Table 4.5: 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 4.6). 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 4.6: 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 4.7).



Table 4.7: 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 4.8). 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

Studies conducted on effect of soil amendments on wheat , mustard and their residual effect on pearl millet indicated that maximum grain yield of wheat was obtained with gypsum and sulphur at 0.75 GR equivalent rate, while iron pyrites induced the same with 1.0 GR equivalence. In case of mustard, yield increased significantly with 0.50 GR equivalence of gypsum and iron pyrites, whereas, similar observations were made with 0.25 GR application of sulfur .Farm yard manure in presence of gypsum and sulphur significantly increased the grain yield of both the crops. In residual study, the highest yield of pearl millet, in general, was recorded in plots which were previously treated with gypsum and sulphur @ 0.75 GR equivalence and @ 1.0 GR with iron pyrites (Table 4.12).The order of efficiency after wheat was gypsum> sulphur > iron pyrites (Khurana et al., 1991).

Table 4.12: Effect of different amendments on grain yield (q ha-1) of wheat and mustard and residual effect on pearl millet


Treatments
Gypsum Sulphur Iron pyrite
Wheat Mustard Pearl millet after wheat Wheat Mustard Pearl millet after wheat Wheat Mustard Pearl millet after wheat
Equivalence of GR
0.0 22.57 5.97 11.42 21.82 5.97 10.49 19.50 6.44 4.02
0.25 23.85 6.79 13.54 24.08 7.63 13.15 22.90 6.92 4.63
0.50 26.26 8.38 15.64 26.64 8.36 15.41 24.91 7.50 6.60
0.75 28.96 9.64 19.22 27.20 9.46 19.16 25.86 8.53 7.93
1.00 27.56 8.63 18.63 25.59 8.01 16.82 28.42 7.44 9.91
CD at 5% 1.20 1.12 1.64 2.37 0.93 1.39 2.47 0.85 1.74
FYM ( t ha-1)
0.0 24.98 7..50 14.36 23.52 7.86 13.53 24.10 7.47 5.83
10.0 26.70 8.25 17.03 26.62 7.91 16.50 24.53 7.26 7.41
CD at 5% 0.76 0.71 1.04 1.50 NS 0.88 NS NS 1.10
Source : Khurana et. al. (1991)
Application of gypsum at full and half gypsum requirement increased the grain yield of chickpea by 40.8 and 17.8 % over control in soil having EC2 , pH2, ESP and GR of 0.6 dSm-1 ,8.4 ,15.1 and 4 t ha-1, respectively. The irrigation water used had pH 8.4,EC 2.6 dSm-1, RSC 4.8 mel-1 and SAR 12.9.Increased application of FYM along with gypsum increased the grain yield of chickpea (Khurana et al.1995). Pooled data of three years indicated that successive increased application of gypsum and FYM applied earlier to chickpea increased pearl millet grain yield (Table 4.13).
Table 4.13: Effect of gypsum and organic manure on yield (q ha-1) of chickpea and residual effect on pearl millet (Av. of 3 years)

Treatment Chickpea Pearl millet
Grain Grain Straw
Gypsum application (GR)
Control 7.91 13.81 52.82
50 % GR 9.46 15.27 58.44
100% GR 11.14 17.03 62.19
CD at 5% 1.35 0.21 1.24
FYM ( t ha-1)
0 8.58 14.10 50.42
10 9.63 14.82 57.35
20 10.29 16.52 65.00
CD at 5% 1.35 0.21 1.24
Source : Khurana et.al.(1995).
Ladda et al. (1997) obtained highest yield of taramira by the application of Gypsum @ 100% GR combined with FYM @ 10 t ha-1.
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)
Studies conducted by Mathur et al. (1971) at Behrore in Anupgarh Shakha of IGNP on saline alkali fine textured soils (ECe 9 dSm-1) revealed that sand application was found to be quite effective in enhancing the leaching of salts from soil profile due to increased infiltration and moisture conservation. Sand covers of 5 to 10 cm thickness significantly increased the yields of seed cotton and subsequently of hybrid Jowar over control. i.e. no sand cover. Ploughing in of sand added benefit in increasing crop yields over no ploughing.
Goyal and Jain (1982) advocated application of gypsum to soils irrigated with saline water (EC 6-12 dSm-1, SAR 20-27) . It reduced the soil dispersion, water stagnation and crust strength, besides lowering the suspension load in pond water. Row application of gypsum was found to be equally effective even at low application rates (1.0 t ha-1) in comparison to broad cast method. The flat bed system of planting performed better than ridge-furrow system.
Mathur et al. (1985) suggested that periodic surface scrapping enhanced the removal of salts as compared to other treatments in fine textured saline - sodic soils of IGNP command. With the application of 51.8 cm of water, salt concentration reduced from 20.2 to 2.3 dSm-1 in surface layer (0-30 cm) . Salt concentration also decreased in sub soil layer (30-60 cm) while its accumulation was observed in lower layers.
Highest yield of paddy was obtained in ridging treatment (15.90 q ha-1 ) followed by ploughing (15.72 q ha-1 ) and tilling (15.53 q ha-1 ) as compared to no tilling operation in fine textured saline- sodic soils of IGNP command (Mathur et. al. 1985)
Mathur and Talati (1987) observed maximum reduction in soluble boron content from 3.4 to 1.1 ppm and 4.2 to 1.5 ppm in surface and sub surface layers, respectively, by treatment of 10 t ha-1 gypsum in combination of 20 t ha-1 FYM. Substantial reduction in salt concentration and ESP values was observed due to leaching and application of soil amendments . Application of 6 cm sand + 20 t ha-1 FYM reduced the salt concentration and ESP to the maximum levels among all the treatments.
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)
Organic amendments improved the availability of native as well as micro nutrients applied to soil. The humic acid and fulvic acid poly electrolytes produced as a consequence of organic matter addition function as a sink for metal ions in the soil. The trace element chelated so formed are fairly stable in the alkali range ( Somani,1990). Green manuring of daincha has been reported to be as effective as use of gypsum in some cases (Somani et al. (1990). The effectiveness of green manuring could be increased by making conjunctive use of organic or inorganic amendments ( Somani,1990). Somani et al. (1992) reported increased infiltration following use of amendments along with fertilizers. Somani et al. (1992) further pointed out that toxicity of fluoride can be reduced by application of amendments.
Somani and Saxena (1981a) reported that sulphur takes a period of 2-3 months for its oxidation and for coming in chemical equilibrium. This suggest that the slowness of sulphur as an alkali ameliorant could be compensated by applying it in advance to permit its oxidation. This led Somani (1980) and Somani and Saxena (1982) to record better ameliorating influence of sulphur as compared to gypsum. The ameliorating efficiency of sulphur is considerably improved if used in conjuction with organic material (Table 4.16) possibly because organic matter fastens the activity of heterotropic sulphur oxidizers in soil besides improving soil physical properties (Somani and Saxena, 1981b).
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.


Table 4.16 : Effect of organic materials and inorganic amendments on some physical and chemical properties of calcareous saline alkali soil and yield of wheat
Treatments pH EC
(dSm-1) Organic Carbon(%) ESP Biological Index Structural Index Wheat Yield (q ha-1)
Control 9.30 12.6 0.18 26.8 31.5 7.3 6.01
Gypsum 8.95 10.9 0.21 21.2 37.7 12.1 11.65
Sulphur 8.80 10.1 0.27 19.5 39.3 15.0 13.21
FYM 9.20 12.2 0.31 24.9 35.1 8.8 8.94
FYM +Gypsum 8.82 10.1 0.39 19.2 40.3 13.8 18.74
FYM + Sulphur 8.70 8.2 0.45 17.7 45.8 16.1 20.86
Dhaincha (DA) 8.85 10.4 0.28 21.4 37.2 12.5 11.45
DA + Gypsum 8.70 9.8 0.30 16.3 45.9 17.9 21.13
DA+ Sulphur 8.40 6.8 0.33 13.8 51.1 23.2 24.13
Poultry Manure(PM) 9.20 11.8 0.30 24.9 34.7 9.6 8.00
PM + Gypsum 8.75 10.6 0.37 18.4 39.2 15.2 16.90
PM + Sulphur 8.60 7.9 0.41 15.7 44.6 17.4 18.69
Rice husk (RH) 9.15 11.7 0.30 24.7 34.1 9.5 7.26
RH + Gypsum 8.80 9.9 0.32 16.7 38.9 14.2 15.05
RH + Sulphur 8.65 7.3 0.38 16.2 43.8 19.5 17.0
CD at 5% 0.20 1.5 0.02 2.6 3.8 0.96 1.46
Source : Somani and Saxena (1981b)

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)
Cassia auriculata (a weed, having pH 5.5, N,P,K and Ca as 1.3 , 0.05, 0.56 and 3.0 per cent respectively ), when applied with gypsum proved to be very good ameliorative agent in reclaiming sodic soil. Combining organic materials like Cassia auriculata, cowdung and FYM could save gypsum equivalent to 25%GR. Significant reduction in pH and ESP of soil was observed whereas hydraulic conductivity increased due to application of gypsum with organic amendments (Karan and Qureshi, 1988) (Table 4.19).

Table 4.19:Effect of amendments on yield of barley and soil properties
Treatments Grain yield
(t ha-1) pH2 ESP HC
(cm hr-1)
Control 3.36 9.2 55.4 Negligible
Gypsum @ 50% GR 12.97 8.3 19.6 2.7
Gypsum @ 25% GR+ Sand 20t/ha 10.18 8.6 37.4 2.3
Gypsum @ 25% GR + Cowdung @ 20 t ha-1 11.07 8.5 28.0 1.4
Gypsum @ 25% GR + FYM 10 t ha-1 15.25 8.5 15.0 2.8
Gypsum @ 25% GR + Cassia auriculata 14.89 8.2 12.7 2.9
CD at 5% 5.66 0.3 13.4 2.2
Source: Karan and Qureshi, (1988)
Babel et al.(2000) observed that addition of organic materials i.e. FYM @ 20 t ha-1 , Dhamasa (Tepherosia purpuria ) and Dhaincha (Sesbenia aculata ) @ 10 t ha-1 increased the grain yield of mustard significantly over control which was irrigated with water having RSC 9.0 mel-1 and Adj. SAR 26.5. Maximum total uptake of N,P and S was recorded in daincha and gypsum 100% RSC neutralization treatment.
For reclamation of sodic soils application of gypsum @ 100 GR + the quantity of gypum equivalent to neutralize RSC in excess of 5 mel-1 was recommended by Joshi and Dhir (1991 &1994) .
Two years studies conducted during 1988-90 in salt affected soil of ARS, Navgoan, with different treatments on barley (RD-2052) revealed the highest response with a treatment combination of Dhaincha green manuring+ soil chiseling up to 30 cm depth +gypsum application @ 2 t ha-1 , giving 38.8 % increase in grain yield of barley over control (Khurana et. al.1991). Application of gypsum decreased ESP of the soil. (Table 4.20)
Table 4.20 Effect of different ameliorative techniques on yield of barley and soil properties
Treatments Barley grain yield (q ha-1) pH2 EC2 (dSm-1)
T1- Control 33.70 8.68 0.72
T2- Dhaicha (gm) 37.61 8.60 0.62
T3- Gypsum @ 50 GR 40.28 8.54 0.77
T4-Gypsum @ 100 GR 41.13 8.51 0.79
T5- Soil chiseling 30 cm depth 41.38 8.60 0.61
T6- FYM @ 10 t ha-1 38.54 8.61 0.70
T7- T5+ T2 +T3 46.47 8.39 0.74
T8- T2 + T3 42.78 8.43 0.76
T9- T5 +T6 44.62 8.46 0.75
CD at 5% 3.56 0.04 0.07
Source: Khurana et. al .(1991)
Jain (1992) reported that gypsum in combination of green manuring of daincha resulted in fastest amelioration of alkali soils of Asalpur Farm Jobner. Incorporation of chemical amendments as well as green manuring decreased pH, ESP and SAR of soil and increased infiltration rate.
An experiment conducted for studying effect of organic and inorganic amendments on pearl millet and mustard crops at ARS, Fatehpur indicated that highest gross returns of Rs. 37479 ha-1 was obtained from the plots where Tepharossia green manuring was followed. Application of gypsum @ 50 % GR gave gross returns of Rs. 32909 ha-1 and it also reduced the soil pH (Babel et. al. 1998) . Application of organic materials increased the organic carbon content of the soil (Table: 4.21).

Table 4.21: Effect of different amendments on grain yield of pearl millet and mustard, gross returns ha-1 and soil properties

Treatments Yield q ha-1 Gross returns ha-1 Soil characteristics
Pearlmillet Mustard pH2 EC2 0.C.( %)
Control 9.20 15.25 23089 9.30 0.36 0.12
Gypsum @ 50 GR 15.79 21.21 32909 8.69 0.31 0.13
FYM @ 20 t ha-1 18.58 21.33 34813 8.92 0.26 0.18
Tepharossia @ 8 t ha-1 19.68 29.96 37479 8.81 0.32 0.20
Manuring of cluster bean straw @ 8t ha-1 11.75 17.03 28972 9.02 0.33 0.17
Rain water ponding 12.28 15.71 29571 9.22 0.31 0.13
CD at 5 % 8.28 1.65. -
Source: Babel et al. 1998
Based on three years studies it was observed that gypsum application recorded 15% increase in annual gross returns. Maximum returns with gypsum applied plots were under pearl millet- mustard, moong-mustard and daincha-barley rotations Babel et al. (1999).
Maximum yield and oil content in mustard with addition of gypsum in soil was reported by Kothari and Deo (1990), while, maximum yield, uptake of N and S by taramira with application of organic and inorganic amendments was recorded by Jain (1992).
Afforestation and horticultural crops:
Salt affected soil generally has high concentration of salt through out the profile. The solumn is compact with columnar structure and highly calcareous strata. However, this land can also be put under silvi-pasture land use. For management of these salt affected soils, shrubs, grasses and trees tolerant to salinity have been identified (Table 4.22). Ridge and furrow technique of planting is recommended on such land (Jain, 1964).
Table 4.22: Salt tolerant species recommended for Arid zone

Vegetation Soil salinity ( EC dSm-1)
Low Medium High Very high
4 8 8-16 >16
Trees Cassia siamea Azadirachta indica Eucalyptus
camaldulensis Prosopis juliflora,
Albizzia lebbek Acacia aneura, Colophospermum mopane Eucalyptus, hybrid,
Dichrostachys glomerala Tamarix articulata, Chenopodium sp.
Grasses/ shrubs Eragrostis ciliaris, Heteropogon tortus, Eremopogon faveolatus, Sporobolus marginatus,
Eleusine compressa,
Dichanthium annulatum Zizyphus nummularia. Cenchrus setigerus Daotyloctenium
sindicum,
Source: Jain ( 1964 )
Jain et. al. (1983) observed that survival and growth of Eucalyptus hybrid was adversely affected by water of 6.0 dSm-1 and Cassia siamea even with waters of 2.7 EC. Survival and growth of Prosopis juliflora , Acacia aneura and Chenopodium species were not adversely affected even with waters of 9.0 dSm-1. High salinity in irrigation waters caused increase in salinity levels of soils by 3-5 times and SAR values by 1.5 to 2 times. Salt concentrations and SAR values were lowered during rainy season.
Jain et. al. (1983) reported that Prosopis juliflora and Tamarix articulata can be planted in soils of very high salinity (33.5 dSm-1 ), Eucalyptus camaldulensis and Acacia tortilis in medium and high salinity levels (22.5 dSm-1 ) and Azadirachta indica could be planted in soils of medium salinity levels (11.5 dSm-1 ). Albizzia lebbek was found to be most sensitive to salinity.
Suwalaka and Qureshi (1995) observed that out of nine tree species planted on sodic soil (Typic Natrustalf having pH2-9.0 to 9.6 EC2 1.7 to 2.2 dSm-1 , ESP 48 to 56 and O.C. 0.23 to 0.48 % and clay loam texture) , Prosopis juliflora, Casuarina equisetifolia, Eucalyptus sp. and Acacia tortilis thrived better. Other promising species survived were Inga dulge, Acacia arabica and Dalbergia sissoo. However, Leucaena leucocephala and Azadirachta indica failed to survive. Prosopis juliflora ameliorated effectively the sodic soil by reducing pH and ESP and increasing hydraulic conductivity (HC). The Casuarina equisetifolia , Acacia tortilis and , Eucalyptus tree species also exerted ameliorative effect to lower down the sodicity of their respective plots but, a very meager effect was observed due to Azadirachta indica, Leucaena leucocephala and Dalbergia sissoo. (Table 4.23).
Table 4.23 : Performance of different tree species on Typic Natrustalf after two years of plantation


Tree species Survival % Plant height (m) Collar girth (m) pH ESP HC
(ms-1x107 )
A B A B A B
Azadirachta indica 13.5 0.24 0.81 9.2 9.0 47 45.4 3.3 6.4
Dulberia sissoo 65.0 1.25 4.58 9.2 8.8 50 46.2 2.8 6.7
Eucalyptus sp 90.4 1.76 2.45 9.3 8.8 48 42.8 3.0 10.0
Inga dulge 80.0 2.03 3.20 9.5 8.9 48 40.9 2.2 10.6
Prosopis juliflora 94.2 2.06 3.16 9.4 8.5 51 39.8 2.8 14.0
Casurarina quistifolia 92.3 3.33 8.41 9.3 8.6 50 40.6 2.5 12.8
Leucaciana eucaitfala 11.0 1.80 6.82 9.4 8.9 48 45.2 3.6 7.8
Acacia tortilis 90.0 1.82 4.10 9.3 8.7 48 41.0 3.3 11.7
Acacia arabica 70.0 1.65 3.32 9.2 8.6 47 40.0 3.3 9.5
CD at 5% 18.4 0.12 1.23 - 0.24 - 1.8 - 5.8
Source : Suwalaka and Qureshi (1995) A- At time of planting B- after two years of planting.


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 Singh, 1974 ; 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. However, with the increase in salinity of irrigation water (EC 2.6 to 6.3 dSm-1) the hydraulic conductivity of soil increased from 4.51 to 4.87 cm hr-1 (Sharma and Lal, 1975)
Salinity hazard:
Soil salinization depends upon the composition of the water, soil type, salt balance of the irrigated soil, annual rainfall and annual evaporation. Several researchers(Gupta and Abichandani, 1970; Lal and Singh, 1973 and Jain, 1976) reported that rainfall, if not unduly below average, is appreciable and effective in desalinizing and de-alkalinising the saline water irrigated soils in the semi-arid zone in Western Rajasthan.
Shankarnarayana and Ganu (1963) and Gupta and Abichandani (1968) found that soils under irrigation with saline water of SAR 15 to 40 turned saline sodic with exchangeable sodium percentage value of 15 to 49.
According to Paliwal and Maliwal (1971) in sandy to sandy clay loam soils of Jodhpur, Pali and Bhilwara, the EC of the saturation extracts ranged from 1.03 to 7.0 times of the EC of irrigation waters, with an average of 2.79, whereas, Lal and Singh (1973) reported that in a field experiment conducted for two years on the loamy sand soil, ECe of the irrigated soils was less than that of the water used for irrigation. After the rainy season, there was a drastic reduction in the ECe and marked decrease in SAR, ESP and pH of the soils.
Gupta and Abichandani (1970) observed that after rains (35-45 cm) salt concentration were reduced so that top 40 cm of soil was completely non – saline. The hydrolysis of Na –clay was of small significance and leaching did not result in high alkalinity. In calcareous soils exchangeable Na was also reduced . Surface soil of the type Na-Mg-Ca-SO4 became Na-Ca-CL-HCO3 after rainfall.
Gupta et al. (1971) reported that correlations of cations and anions in general was most significant with ECe followed by EC2 and SSP .
Sharma (1972) reported that accumulation of salt in clay loam soil was 1.8 times more that in sandy soil. The application of water of EC 2.55 dSm-1 could not make the sandy and clay loam soil saline if the water is applied @ 4 cm and 6 cm above the field capacity, respectively.
Gupta and Abichandani (1973) examined one season effect of irrigation with saline water on several soils in Western Rajasthan. They found that the ECe of soil after irrigation increased by three to seven times as compared to before irrigation but it is interesting to observe that ECe of the soil after irrigation was less than EC of the waters used for irrigation. The lower values of ECe as compared to EC of irrigation waters were because of the light and medium texture of the soils with good drainage.
Saline ground water (EC 3.4-11.3 dSm-1) is commonly used for irrigation in desert region. These waters predominantly contain chlorides and sulphate of sodium, calcium and magnesium with low carbonates and bicarbonates and 18 to 20 SAR. Irrigation with such saline water results in development of high salinity, which gets reduced upto complete leaching in loamy sand, 80 per cent in sandy loam and 50 to 80 percent in heavier soils by fallowing in one rainy season. In heavier textured soils, two rainy seasons fallowing is required (Dhir, 1977).
Lal and Lal (1977) found significant positive correlations between both EC and potential salinity of irrigation water and ECe of irrigated soils. Similarly significant positive correlations were obtained between SAR and RSC of water and ESP of irrigated soils as well as the boron content of waters and water soluble boron in respective soils.
Jain (1978) observed that salinity hazards of water increased with the increase in the content of silt + clay and was predominant in the surface soil layers. Sodic hazards were lowered with increase in silt + clay content.
Paliwal and Deo (1978) reported that ECe of irrigated soils of Bhilwara district varied from 1.72 to 42.0dSm-1. ECe / ECiw varied from 0.34 to 5.60 with an average of 1.6. These values were 0.41, 1.50 and 2.11 in sandy, loamy sand and sandy clay loam soils, respectively.
Lal and Lal (1980) and 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.
Jain (1978) observed that for similar values of EC, SAR of irrigation water and silt + clay in soil there was increase in the total salt concentration, however, relative Na concentration was lower. In the soil having high silt and clay content salinity effects were more pronounced in surface layers as compared to lower depths (Table 4.25).
Table 4.25: Salinity and sodicity build up in soil in different silt + clay group
Silt + clay grouping
0-20 cm depth 20-40 cm depth
<20 20-40 >40 <20 20-40 >40
ECe dSm-1 12.5 13.9 19.1 13.3 9.8 13.4
SAR 32.6 25.2 21.9 28.0 23.5 26.8
ECe/ECiw 1.21 1.46 1.54 1.20 1.18 1.10
SARe/ SARiw 1.21 1.33 1.11 1.79 0.93 1.21
ESP/ SARiw 1.73 2.05 1.80 1.93 1.74 1.91
Source: Jain (1978)
Jain (1981) while studying the salt balance in saline water irrigated soils observed that with the application of saline water (2.7-12.0 dSm-1) there was an over all increase in soil salinity. Average EC2 values of 2.59 dSm-1 was observed with water of 12 .0 dSm-1. After leaching during rainy season the average EC value decrease from 0.5 to 0.8 dSm-1. The salt concentration during the irrigation cycle was 2.5 to 5 times higher as compared to that after leaching during the rains.
Balai (1993) reported that increasing level of SAR of irrigation water increased the ECe, SAR and pH of soil significantly. The exchangeable K content of soil decreased with increasing levels of SAR
Khandelwal and Lal (1991), Deo et al. (1993) and Lal et al. (1998) investigated that increasing levels of EC of irrigation water increased EC of soil and pH increased with increase in SAR of irrigation water.

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 effect of different levels of ECiw and adj SAR on the properties of different soils indicated that increase in the level of adj. SAR in irrigation water increased ECe, pH and SAR of soil (Table 4.26).The adverse effect of EC and Adj. SAR was more in fine textured, slowly permeable clay soil and it was less on the coarse textured highly permeable loamy sand soil.
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 4.26: Average effect of ECiw, Adj. SARiw and soil type on ECe (dSm-1), SAR & pH of soil
Treatments ECe (dSm-1) SAR pH
ECiw (dSm-1)
2.0
4.0
6.0
CD at 5%
Adj. SAR
10
20
30
40
50
CD at 5%
Soil types
Loamy sand
Loam
Clay
CD at 5%
2.0
3.6
6.0
0.27

3.4
3.6
3.9
4.2
4.4
0.28

2.7
4.0
4.9
0.27
20.8
21.7
22.4
0.87

10.7
15.2
21.6
25.2
35.6
1.12

22.7
21.4
20.8
0.87
8.7
8.6
8.5
NS

8.4
8.5
8.6
8.6
8.8
0.20

8.7
8.5
8.6
NS
Source : Pathan et.al.(1991)
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.
Goyal and Jain (1982) observed that irrigation with high EC and SAR waters resulted in the increased salinity and ESP in the soil (Table 4.29).
Table 4.29: EC and ESP levels attained by soil after irrigation
Irrigation water Soil
EC ( dSm-1) SAR EC ( dSm-1) ESP
6 20 1.5-2.5 25-35
9 25 3.5-4.0 33-45
12 26 4.5-5.0 41-45
Source : Goyal and Jain (1982)
According to Gupta (1979) the SAR criteria works reliable for waters with EC<5 dSm-1 and Mg/ Ca ratio <1, whereas, it under–estimates the sodium hazards for water of higher EC and Mg/Ca ratio.
Studies on the effect of different quality of irrigation water on pure lime and three calcareous soils revealed that calcium carbonate is precipitated in soil below a pHc value of 7.44, while above pHc value of 7.52 calcium carbonate starts dissolving. Precipitation of calcium carbonate enhances the sodium hazard in soil, while, its dissolution decreased the sodium hazard. High salinity favorably influences the release of Ca and Mg ( Paliwal and Deo, 1988)
Yadav (1993) reported that irrigation water increased EC, SAR and ESP of soil and decreased pH of soil.
Boron hazard:
Boron may be found to the extent of 10 ppm in salt affected soils while in normal soils it is generally 2 ppm. It is an essential micro-nutrient for plants but it may produce toxicity symptoms at concentration slightly above optimum.
Baser and Saxena (1967) observed that most of the soils of Mewar region of Rajasthan are adequate in water soluble boron content. Uptake of boron was more in wheat plant than in gram plants.
The soils of three different textures ( clay loam, loam , sandy loam ) were equilibrated with six levels of boron (2,5,10,20,40 and 100 ppm) at four levels of NaCl (0,40,100 and 250 mel-1 ).Sudies revealed that adsorption of boron increased with the fineness of texture of soil but was unaffected by NaCl concentration ( Mehta et al. ,1977)
Greater adsorption of boron occurred in heavy soil than in light soil , with irrigation water containing high concentration of boron (4.5mg L-1) . Lack of drainage was considerd as the factor responsible for high boron accumulation. Khandelwal and Lal (1991) reported that boron content of soil decreased with an increase in EC, SAR, and boron content of irrigation water but decreased with an increase in clay percentage of the soil. Water-soluble boron is positively correlated with the organic matter and negatively with CaCO3.
Studies carried out in IGNP command by Bhatnagar et al. (1979) revealed that adsorption of boron was found to depend upon texure of soils. There exists always an equilibrium between adsorbed and soil solution boron. Fredudlich adsorption isotherm was valid for wider range of boron concentrations than Langmuir adsorption isotherm.
Lal and Lal (1979) observed that in two loamy and saline sodic soils (ECe 5.3 dSm-1 &ESP 15 ; ECe 8.0 dSm-1 & ESP 25) and having 10 .0 mel-1of Ca and 200 ppm boron in their saturation extract and Ca/B ratio lower than 100 reduced the grain and stover yields of pearl millet. Two ppm boron did not cause adverse effect in treatments where Ca/B ratio in the soil was above 100.
Lal and Lal (1980) reported significant increase in grain and straw yields of wheat upto 1.7 ppm boron in water. Above this level decrease in yield was observed. The yields with 4.7 ppm were almost equal to those observed with 0.7 ppm boron. In case of barley the grain and straw yields increased upto 2.7 ppm boron in irrigation water. The boron content in leaves and hot water soluble boron of the soil increased with an increase in level of boron. The results indicated that the wheat and barley can be safely grown on loamy sand soil deficient in boron with water containing boron content upto 4.7 and 6.7 ppm., respectively.
Gupta (1988) indicated that injury may develop in the more sensitive plants when irrigated with water containing in excess of 3 ppm . The injury may appear as burning of leaf top followed by yellowing of margins. There is no effect of excess boron on soil properties. The sensitive crops which are affected most are lemon, grapes and oranges. Lemon, cotton, grapes, potato, beans and peas show marginal burning and cupping of the leaves that results the restriction of the growth .
Kumar (1992) reportd water having EC upto 8 dSm-1 and boron content up to 4.0 ppm can be used for bajra fodder.
Deo et al. (1993) reported that increasing levels of EC and SAR of irrigation water increased the ECe, SAR,ESP and boron content of soil. The pH of soil increased with increasing SAR while it decreased with increasing levels of EC of irrigation water.
Sharma (2003) reported that soil applied gypsum was found effective in reducing toxic effects of SAR and boron of irrigation water. Application of gypsum @75 % GR was found sufficient for reducing toxic effects of 15 SAR and 3 ppm boron water for wheat. While application of gypsum @ 100 % GR was found suitable for reducing toxic effect of water having 30 SAR and 6 to 9 ppm boron of irrigation water.
Panwar (2000) reported that harmful effect of sodicity of soil and boron in irrigation water on growth yield and nutrient absorption of wheat can be reduced to some extent by applying gypsum @ of 75% GR. Increasing levels of gypsum application increased N, P, K, Ca and S content of grain and straw, whereas, sodium and boron content of grain and straw decreased. Increased level of gypsum application increased the availability of Ca and S in soil where as ECe, ESP and pH and availability of boron in soil decreased. Irrigation water having 7.5, 10.0 and 12.5 ppm boron decreased grain yield of wheat to the extent of 14.2, 17.5 and 22.6 per cent, respectively as compared to normal irrigated water having 0.5 ppm boron.
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 (1978) observed an increase in nitrogen content in grain and straw of wheat with increase in EC and SAR of irrigation water.
Studies on effects of equal concentrations ( 3,6 and 9 dSm-1) of Na2CO3 and NaHCO3 on metabolic indices of maize revealed that both the salts suppressed root and shoot growth. Salt treatments reduced the contents of chlrophyll, protein, RNA,DNA and free amino acids. NaHCO3 proved more deleterious than Na2CO3 (Garg and Garg, 1982)
Garg et. al. (1983) reported that under similar concentration (EC dSm-1) of different salts , maximum adverse effects on growth and yield of wheat (Kharchiya 65) were brought about by Na2CO3 , NaHCO3 and NaCl while Na2SO4 and KCl caused negligible effects.
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.
Totawat and Mehta (1985) observed that irrigation water of higher salinity levels led to significant decrease in dry matter yield, leaf area, height and nutrient uptake of maize and sorghum genotypes. The maize genotypes Ganga- 5 and Ganga-2 and sorghum genotype CSH-5 recorded significantly higher leaf area, higher dry matter yield and nutrient uptake. These genotypes showed higher Na/ K ratio too.
Studies on effects of equal concentrations ( 0,15, 30 and 45 mel-1) of Na2CO3 and NaHCO3 on metabolic indices of green gram revealed that both the salts suppressed root and shoot growth and the reduction was significant at and above 30 mel-1. the salt treatments enhanced RNA concentration but reduced the contents of chlrophyll, protein and free amino acids. NaHCO3 proved more deleterious than Na2CO3 (Garg,1985).
Garg and Garg (1985) reported that NaHCO3 had a suppressive effect on root and shoot growth as well as pod yield of pea. . At 60 mel-1 concentration the reduction in root, shoot growth and pod yield was 70,76 and 85 percent, respectively.
Kumawat (1989) indicated that water having EC upto 9.0 dSm-1 and adj.SAR upto 60 can be used for supplemental irrigations of Pearl millet variety MLBH-10. Levels of EC and Adj. SAR for MH-169 and MBH-130 were 6.0 dSm-1& 60 and 6.0 dSm-1 & 45, respectively.
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)
Khandelwal and Lal (1991) reported that grain and straw yield of wheat decreased with increase in EC and SAR of irrigation water. Moolchandani (1997) observed considerable decrease in yield of bajra fodder at ECiw of 10 dsm-1 in sandy soil of Bikaner.
Netwal (2003) reported that adverse effect of salinity can be mitigated to some extent with application of vermi - compost @ 5 t/ha. The application of FYM @ 10 t ha-1 and vermin-compost @ 5 t ha-1 increased seed yield of cowpea by 27.3 and 32.3 per cent respectively.
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

Studies conducted with five varieties of green gram to evaluate the specific anion effect and varietal difference on germination percent in salt tolerance revealed that green gram could tolerate sodium salt up to 5 mel-1. The general order of specific anion effect at low level of salinity (5-10 me l-1) was HCO3- > CO3-->NO3->Cl->SO4--. In general SO4-- is least toxic, CO3-- and HCO3- are most toxic and Cl- & NO3- are intermediate. Hybrid-45 and GC-140 were most sensitive to carbonate. GC-139 was maximum tolerant to sulphate (Table 4.34).
Table 4.34: Effect of different anions and increasing salt concentration on the germination percentage of some varieties of green gram
Salts Hybrid-45 Krishna-11 GC-153 GC-140 GC-139
5 10 20 5 10 20 5 10 20 5 10 20 5 10 20
Na2CO3 54 45 20 57 47 20 75 70 30 47 32 21 58 54 35
NaCl 70 48 33 88 72 52 68 56 42 88 67 52 95 82 59
Na2SO4 80 65 38 91 79 45 84 61 50 68 51 38 95 84 72
NaHCO3 45 37 24 38 27 22 55 45 38 42 30 23 53 45 39
NaNO3 78 63 31 66 54 49 67 50 40 72 54 41 78 63 58
CD at 5 % 7.5 9.1 8.3 7.7 8.2
Source: Somani et al,1989
Lahiri et al. (1987) observed that Malosan and HFG-182 varieties of clusterbean showed almost 20 % reduction in dry matter and grain yield whereas, the sensitive varieties Durga Jaya and FS-277 showed almost 40-50% reduction in grain yield at ECe level of 10.0 dSm-1Tolerant genotypes of clusterbean had lower Na and Cl ions in their shoot tissues and had a wider K: Na ratio than in susceptible genotypes (Lahiri et al.,1996)
Types of salts may show varied effects on seed yield . For instance , at ECe 10 dSm-1 reduction in grain yield of clusterbean was 53.2,48.7 and 45.0 with NaHCO3 , Na2SO4 and NaCl type salts, respectively compared to control (Garg et al. ,1997)
Somani (1977) reported that there was no significant effect of fluorine on growth of wheat at concentration up to 10.0 mgl-1.
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 -- 82.9
4.7 16.7 29.2 4.0 8.6 22.2 561 14.3 83.8
6.1 -- -- -- -- -- 489 14.6 76.7
7.8 -- -- 2.7 5.7 22.0 -- -- --
9.2 17.0 28.3 -- 2.4 -- 488 12.3 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)
With the increase in salinity and SAR there is restriction on the choice of crops. Jain (1984) reported that under saline water irrigation in rabi barley , wheat and raya are most suitable crops . In subsequent kharif sorghum performed better compared to sesamum and pearl millet (Table 4.37). Studies at CAZRI indicate that crops can be raised with saline water having EC of 12 dSm-1. However a better choice of crop in particular saline water coupled with management practices is key to the success. Under moderately saline water up to 5 dSm-1 cumine, plantago and lucern can be grown with fairly good success, whereas at higher salinity(5-10 dSm-1) barley, cotton, sugarbeet, wheat, sorghum, sunflower and soyabean can be successfully grown ( Dhir,1977).

Table 4.37: Average yields (q ha-1) of different crops as affected by different salinity in irrigation water
ECiw
(dSm-1) Kharif crops Rabi crops
Sorghum Sun flower Seasamum Pearl millet wheat Barley Raya
2.7 24.0 8.9 7.6 17.0 17.2 21.5 15.7
6.0 25.1 7.4 6.2 13.9 13.8 22.2 15.0
9.0 22.7 5.7 5.3 11.8 7.5 17.5 12.2
12.0 21.4 6.5 3.5 13.2 5.9 18.5 11.1
CD at 5% 3.0 2.0 2.1 2.8 5.0 7.2 4.3
Source: Jain (1984)
Screening of Varieties:
Reliable screening is an integral part of salt related management programme . The varieties screened under poor quality water at AICRP centre Bikaner are given in Table 4.38.
Garg et al.(2004) observed that HG-75 displayed higher salt tolerance whereas cv. FS-277 was most sensitive with 48.7% reduction in seed yield at 15 dSm-1 of NaCl . HFG-182 displayed an intermediate tolerance to soil salinity. Salt induced changes in the levels of total chlorophyll , soluble protein, free amino acids and activities of nitrate reductage , glutamine synthase and glutamate synthase and glutamate dehydrogenase were considerably less in tolerant genotype HG-75 as compared to moderately tolerant HFG-182.
Table 4.38 : Promising cultivars suitable for cultivation under poor
quality water
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 Cluster bean HG-75, RGC-978,GAUG-34
11. Barley BL-2, RS-17 and RS-6


Two years study during 1989 and 1990 in sodic soil (pH 9.2, EC 0.65 dS m-1) irrigated with high RSC water (8.2 me l-1) at farmer’s field revealed that variety MH-169 and RCB-2 gave higher yield (23.73 and 22.07 q ha-1) as compared to MH-179 , WCC-75 and MH-36.
Variety BL-2 gave significantly higher yield (33.88 q ha-1) as compared to RD-1635, RD-2182, RD-2259 and RD-2423.
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

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

Studies on screening of four varieties HB-1, HB-2, HB-3 and HB-4 of pearl millet under six levels of saline water (0-20 dSm-1) indicated that variety HB-1 was comparatively better and also suitable for salt affected soils ( Marwaha and Vyas, 1972).
Maliwal et al. ( 1976 ) reported that wheat can be grown successfully upto ECiw 8.0 dSm-1.The relative yield potential of varieties in saline water was K-68 > Kharchia > Sonalika> RS 31-1> Kalyansona..
Kumar et al. (1986) observed 56.9 per cent decrease in seed yield of Raya with irrigation of water having EC 10 dSm-1.
Yadav (1993) reported that irrigation water increased EC, SAR and ESP of soil and decreased pH of soil. Order of tolerance were Kharchia-65 > Raj 3077 > Raj 1114> WT-133 and Kalyan sona. Kharchia -65 accumulated higher amount of N, P, K, and Ca content and lower amount of Na as compared to Raj 3077, Raj 1114, WT-133.
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).
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 Grain yield of pearl millet(q ha -1) Grain yield of Wheat (q ha -1)
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 : 1
CW 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)
Studies carried out in Balotra- Siwana area of Barmer district revealed that irrigation with water of 12 to 15 mel-1 RSC and 26.2 to 46.6 SAR turned the soil highly sodic. After two to three years of fallowing farmers are able to take wheat crop (Joshi and Dhir, 1991). However, the crop was patchy, stunted and yield were very low (11.5 to 27.8 q ha-1).Wide variation in grain yield were mainly due to different stages of reclamation in field situation and plant stand.
Algalization of sorghum and wheat for two crop seasons, each on saline-sodic soils followed with saline water (EC 2.7 to12.0 dSm-1)irrigation has shown beneficial effect in economizing on nitrogen application. Algalization decreased soluble Na / (Ca+Mg) ratio and soluble sodium in sandy clay loam Calciorthid soils .
Horticultural crops:
In arid region the high ground water salinity coupled with low and erratic rainfall limit the choice of fruit plants to be cultivated. Ber, Pomegranate, Date palm are some of the plants which could be grown under this harsh climate. Jain and Das (1988 a) observed that Zizyphus rotundifolia commonly used for root stock for ber was tolerant to irrigation water salinity upto 4.5 dSm-1 and 6.5 dSm-1 EC at germination and seedling growth stages , respectively. Z. spinachisti and Z. maurtiana were moderately tolerant upto 2.5 dSm-1 EC, while, Z. nummularia was sensitive to salinity.
Jain and Das (1988 b) further observed that tolerance to salinity levels (Table 4.45)in irrigation water was more in ber variety of Jujubee than in Gola and Mundia and more in Khog variety of pomegranate than in Jalore seedless. Irrigation of Sev (variety of ber) with 6.5 dSm-1water and Gola and Mundia with 4.5 dSm-1 for 8 to 10 months at the initial establishment stage in nursery did not show any adverse effect on its survival. However, pomegranate cultivar Jalore seedless could tolerate upto 4.5 dSm-1. The level of salinity upto 4.5 dSm-1 did not affect the survival of Indian cherry but higher level caused mortality.

Table 4.45 : Effect of saline water on survival (%) and salt tolerance of fruit crops

Fruit
Variety EC iw (dSm-1) Mean
survival (%) Mean
Survival Index
0.5 2.5 4.5 6.5
Jujubee Sev 90 90 80 90 87 96
Gola 90 90 80 60 80 85
Mundia 60 70 70 30 57 94
Pomegranate Jalor seedless 70 60 50 30 52 67
Khog 100 100 70 70 85 80
Indian Cherry Local 80 70 70 30 62 71
Source: Jain and Das (1988 b)
Gupta et al. (1989) observed that ber was more tolerant to bicarbonate waters at seedling stage than at germination stage. In case of chloride the seedling stage was more critical than germination stage. At higher level of salinity both chloride and carbonate waters were harmful for survival of seedling. With increase in salinity from ECiw 5-10 dSm-1 specific ion toxicity effect determines the overall effect.
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 (Eaten 1950;). However, in the rainfall zone of 650 – 700 mm per year, Gupta (1980), even with 10 mel-1 RSC water, could not observe adverse effects. In areas receiving 400 mm rainfall, Manchanda et al. (1982) recommended that water containing 4.5 to 13.8 mel-1 RSC could be used on a loamy sand soil for growing tolerant crops like wheat and barley. In arid region of Rajasthan (200 – 500 mm rainfall) irrigation with water containing more than 5 mel-1 RSC has been found hazardous (Joshi and Dhir 1989).
By using high RSC water ESP of soil increases, high exchangeable sodium causes dispersion, surface crusting, poor physical conditions and poor permeability hampering leaching of salts. Crop yield declines drastically and lands are abandoned for cultivation. In the arid region of Rajasthan, Joshi (1992) observed that irrigation with RSC water (12 – 24 mel-1) developed high sodicity (pH2 9.2 to 9.9). The soils were low in salinity but the ESP ranged between 50 and 70.
As a result of irrigation with sodic water the soils acquire unusual hardness, even the loamy sand soil, which are otherwise quite friable and loose becomes very hard and compact. The soil clod attains close packing leaving little pore space for air and water movement.. The water infiltration was greatly reduced (Joshi and Dhir, 1989). Penetration of plant roots is equally difficult.
The bad effect of such waters could be eliminated to a considerable extent by mixing some cheap source of soluble calcium in the soil or by treating the water with such a source. Talati et al. (1966) observed that the RSC of irrigation water was completely eliminated and sodium concentration, SAR and Mg:Ca were reduced to 50% by mixing of gypsum, however, EC of water increased.
Paliwal and Gandhi (1970) reported that gypsum has no benefit in Vallab Nagar soil and negative effect on Sareri soil. Puntambkar et al.(1972) harvested good yields of wheat from a poorly drained sandy clay loam (pH 8.9 and ESP 35) irrigated with HCO3 rich water (EC 3.1 dSm-1, SAR 25.7 and RSC 12.4 mel-1) by applying 15-30 t ha-1 of gypsum and the higher yields were obtained with 20 t ha-1 of gypsum.
Gupta and Abichandani (1977) suggested that application of gypsum on the surface of soils in May and June, before the onset of monsoon plays an important role in the effective desalinization of saline water irrigated soils.
Gupta (1980) pointed out that application of gypsum prevented rise of pH and SAR values of soils under irrigation with high RSC waters. Gypsum was added @ 4 q ha-1 in soil to neutralize RSC equal to 1 mel-1. It was top dressed after pre-sowing irrigation. However, there was no response on growth of wheat. Improved humus build up, water stable aggregates and hydraulic conductivity of soils as a consequence of addition of fertilizers along with amendments led to high yield of wheat ( Somani and Saxena,1980).
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).
Increasing levels of SCAR (Sodium to Calcium Activity Ratio) from 7 to 10 and RSC from 0 to 10 mel-1 in irrigation water decreased the EC, hydraulic conductivity, water holding capacity, organic carbon , soluble cations and anions and increased the pH and ESP of soil. The reduction in plant growth, dry matter yield and nutrient uptake in wheat was more pronounced at SCAR value of 10 in irrigation water and in soil finer in texture, indicating SCAR to be a suitable index for judging the suitability of irrigation water than that of SAR (Singh and Totawat, 1994).
Ladda et.al. (1997) obtained highest yield of taramira by the application of Gypsum @ 100% GR combined with FYM @ 10 t ha-1.
Babel (1998) observed that FYM, dhamasa, bui and dhaincha @ 10 t ha-1 and gypsum (100 % GR) resulted in improvement in growth, yield and nutrients content of bajra and mustard irrigated with high RSC water. These amendements improved physical and chemical properties of soil. Dhamasa amongst organic amendements and gypsum (100 % GR) resulted in faster amerolation of alkali soils of ARS, Fetehpur.
Yadav (1999) observed that grain and straw yield of wheat, P, K, Ca, Mg and Zn content decreased with increasing levels of RSC of water, while N and Na content increase. Application of Zn increase the yield of crop and N, K, and Zn contents but P and Na content decreased.
Babel et al.(2000) reported that incorporation of organic materials and gypsum increased the grain yield of both pearl millet and mustard. Addition of organic materials decreased soil ESP and SAR over control. The magnitude of decrease in these parameters was observed maximum with dhaincha.
Increasing levels of RSC in irrigation water decreased the ECe , soluble calcium, magnesium and sodium and exchangeable calcium and magnesium content of the soil. However, an increase in pH , soluble carbonates and bicarbonates and exchangeable sodium was recorded as a consequence of rise of RSC levels of irrigation water (Saini and Totawat, 2001) .A higher dry matter accumulation , root weight and low Na/K ratio were recorded in plants of foxtail genotype SR-16 and Arjuna as compared to other genotypes. Further, deterioration to higher degree in physico- chemical properties of the soil and reduction in growth and uptake of nutrients by foxtail millet plants were apparent on clay loam soil as compared to sandy loam soil.
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.
Dahiya (1979) reported that with waters of high salinity, barley should be irrigated at 50% available soil moisture in heavy textured soils. The ECe, SAR and ESP of soil increased with EC and SAR of irrigation water.
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: Anonymous (1980 – 1985)
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)
Gupta et al. (1988) have innovated a novel device (Jal tripti) for early establishment of saplings with limited water. Longitudinal section of double walled earthen pots is shown in Fig. 10 this device is a boon for sandy soil s in desert areas where water is scarce e and more than 90 per cent is wasted due to deep percolation.
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)

Fig. 10 : Double walled earthen pot
Chauhan (1992) recommended pitcher method of irrigation was most suitable for Jobner tract to utilize under ground water to obtain maximum water use efficiency. In this method, water loss through leaching, percolation and evaporation was negligible. Vegetable crops like chillies, tomato, cucumber, cauliflower, brinjal etc. can be grown. Accumulation of salt at surface was more and decreased with increasing depth and horizontal distance, deep rooted crops should be taken near to the pitcher wall and relatively shallow rooted crops should be grown away from the pitcher.
Alleviation of salt injury:
Several workers reported the inducement of salt tolerance in crop plants by chemical, physical and agro physical treatments of seeds and seedlings. Darra et. al. (1970) reported that presoaking of seeds with NaCl and KH2PO4 salts increased the germination of wheat under high salinity, SAR and boron levels. Puntamkar et al. (1971) obtained highest yield of wheat on saline soil (pH 8.4, ECe 12.6 dSm-1) when the seeds were presoaked in 3 per cent Na2SO4 solution, 351.0 and 217.3 per cent higher yields were obtained in cv. S-227 and cv. Kharchia-65, respectively, as compared to control. Presoaking of pearl millet seeds for 10 hours in 1 per cent MgCl¬2 has been reported to increase fodder yield of pearl millet under saline, saline sodic and sodic conditions, (Chhipa and Lal, 1976).
Chhipa and Lal (1978, 1988) reported that presoaking of wheat seed with 3 % Na¬2SO4 , Ca(NO3)2 3% and Pyridoxine 0.3%) tended to mitigate the adverse effect of higher salinity by increasing effective tillers , grain and straw yields and increased the absorption of essential nutrients like N,P , K and Ca in grain and straw while decreased Na+ content as compared to control .
Chhipa and Lal (1978) observed that suitable Na/K ratio (260.1,51:1, 10.4:1) in irrigation water induced the salt tolerance in wheat (Var.S227).They also reported that effective tillers , plant height , grain and straw yield, and N, P and K content increased while content of Na decreased with decrease of Na/K ratio in the irrigation water . Higher dose of K (24.9kg/ha) has been reported to increase the germination and fodder yield of pearl millet under saline , sodic and saline sodic conditions by Chhipa and Lal (1976)
Mehta et al. (1980) pointed out that the soaking of barley seeds in various salt solutions resulted in increased yield and more uptake of Na, K, Ca, Mg and phosphorus .
Plant Growth Regulator:
PGRs also have been found to protect the plant against salt injury. Among naturally occurring PGRs, IAA, GA and CK have been studied. IAA antagonizes Na2SO4 induced decrease of root growth in wheat (Sarin and Rao 1961, Sarin 1961, 1962) and decreased sodium uptake in maize (Darra and Saxena1973). Synthetic PGRs and amino acids also have been reported to decrease salt injury e.g. Phosfon-D in aerial parts of pea (Sarin1975, 1976). Presoaking of seeds with growth regulators and salts had significant effects on germination of wheat (Darra et al., 1970).
Darra and Saxena (1971) reported that under low salinity regimes, beneficial effects of presoaking of seeds in gibberllic acid may be achieved up to 100 ppm., while under moderate to high salinity levels in combination of high SAR and boron contents, 200 ppm could be more useful.
Increase in EC levels increased the content of sodium in cowpea, moong and groundnut plants, whereas, increase in SAR values of irrigation water markedly decreased the content of Ca+Mg but no appreciable effect on sodium in plants. A rise in SAR value significantly increased the content of phosphorus but decreased the synthesis of crude protein. An increase in Boron content in irrigation waters decreased the content of Ca+ Mg in moong, iron in cowpea and water soluble carbohydrates in cowpea and moong. Cowpea stands hardier to increasing levels of EC and SAR values of irrigation water. IAA pre soaking seed treatment activated the protein metabolism and ion uptake.
A marked decrease in the content of amino acids was observed in phaseolus aureus when the boron concentration was increased from 0.5 to 2.0 ppm particularly at low value of SAR and low value of EC of of water . At medium value of EC along with low value of boron increase in value of SAR suppressed the content of lycine, arginin+ histidin, aspartic acid + glutamin, threonine + alanine, proline and cysteine in plants(Totawat and Saxena, 1971).
Increase in concentration in vigna catjung at low SAR, or vice versa, irrespective of EC levels of applied irrigation water, produced a marked decrease in contents of various amino acids , pointing to a definite relationship between sodium and boron with respect to plant nutrition. . Increase in boron level at high SAR resulted in increased synthesis of lycine, arginin + histidin, aspartic a cid+ glutamin, threonine + alanine, proline, cysteine, tyrosine, tryptophane, valine, methionine and leucine (Totawat and Saxena,1974).
Increasing levels of EC, SAR and boron concentration in water tended to increase the amino acid levels, while, treatment with IAA depressed the levels of some amino acid in Arachis hypogea (Totawat and Saxena,1975).
Chhipa and Lal (1985) observed that presoaking of wheat seed with IAA and IBA (200ppm) and 3% Na2SO4 increased boron tolerance of wheat by way of decreasing P/Ca ratios in grain and Na/P, Na /Ca and Na/K ratios in grain and straw and increasing K/P of grain and K/B and Ca/B ratios in straw . Response of plant growth regulators as well as salt solutions was observed at low level of salinity, sodicity and boron and while at higher levels beneficial effects were not perceptible.
Several workers have reported the salt tolerance characters of crop plant on the basis of certain ionic ratios. Chhipa and Lal (1991) reported that presoaking of wheat seeds (var.Raj.911) with IAA (200ppm) increased the salt tolerance by way of increasing N / Na ratio in grain and straw of wheat. It was also observed that salt tolerance varieties have higher N/P, N/Na, K/P and K/Ca ratios as compared to sensitive varieties. The presoaking of wheat seeds with plant growth regulators (IAA of 200ppm, IBA of 200ppm and 3% Na2SO4 salt solution) increased the salt tolerance by way of increasing K/P in grain and N/Na in grain and straw of wheat. They further predicted the sodicity tolerance behavior of wheat genotype on the basis of certain ionic ratios. The presoaking wheat seed with IAA and IBA (200ppm) and 3% Na2SO4 have been found to increase sodicity tolerance by decreasing the P/Ca, N/P, N/K, Na/Ca, Na/P, Na/K and Na/Ca ratios in grain and straw of wheat.
A marked decrease in biosynthesis of various amino acids in cowpea was observed by presoaking treatment of IAA. An increase in boron concentration at low value of SAR and low boron concentration with higher SAR value in irrigation water irrespective of the EC levels resulted in decrease in synthesis of various amino acids. Increase in EC of irrigation water led to accumulation of free amino acids in plants (Totawat and Saxena, 1992).

5. Future Areas of Research
About 11 lakh hectares of land in Rajastan is affected with salinity and sodicity . Farmers of the salt affected land to some extent use the recommendations given by the scientists and are able to raise a reasonable good crop. However, these research recommendations are not followed as such by the farmers as there may be some constraints on the part of farmer or on the part of technology. Most of the technologies are specific but many a times they are generalized at extension level, thus desired results are not obtained.
There is a scarcity of good quality water in Northwestern Rajasthan but with the introduction of sprinklers large number of wells are being dug in undulating lands and farmers have been raising the crops. The EC of the water ranging between 2 to 6 dSm-1. The farmers of the area is totally ignorant about irrigated agriculture in general and the use of poor quality water in particular. Moreover, the technologies so far developed for the use of poor quality water use relates mainly to flood system of irrigation whereas there is tremendous increase in area under pressurized irrigation system particularly the sprinklers.
Due to extension of irrigation facilities the problematic area in IGNP is increasing day by day. The major reasons for development of salt affected soils are the excessive use of irrigation water, seepage from canal, presence of hard pan near the surface in the soil profile, lack of proper drainage and presence of natural depressions at some locations. The water table in IGNP command area is rising at alarming rate resulting into water logging and development of soil salinity in the area. Large area in phase II of IGNP command has hard pan very close to surface. If proper water management and agronomic practices are not followed, this area will be converted into water logged/ salt affected soils. So there is great need to conduct experiments for standardization of practices, suitable for the area.
Though lot of work has been done to solve most of the problems of soil and water salinity, however, there is great scope for further work in Rajasthan on following areas.
Areas of Research
 Management of poor quality waters for drip and sprinkler irrigation of plants.
 Effect of irrigation frequency and depth of irrigation with saline water on crops and soils.
 Agronomic practices most suitable for salinity/alkali resistant non-conventional crops grown on gypsiferous / calcareous soils.
 Integrated nutrient management for salt affected gypsiferous/ calcareous soils.
 Studies on mineralization of added organic-N in salt affected soils.
 Studies on reclamation of salt affected soils of IGNP area having high water table.
 Rate of soil salinization under varying cropping sequences and water table conditions.
 Standardization of rapid diagnostic criteria for identification of salt affected soils.
 Standardization of methods for determining gypsum content in gypsiferous soils
 Detailed studies on the effect of specific ions / ionic ratios on soil and plant
 Investigations on salt balance studies in different cropping systems.
 Identification of best cropping sequence for sustainable agriculture in salt affected soil of IGNP area
 Indices for salinity/alkalinity/boron tolerance for crops.
 Plant based reclamation approach based on molecular marker.
 Screening of Horticultural crops for salinity and alkalinity tolerance.
 Effect of forest trees on salt affected soil.
 Conjunctive use of saline and good water for grain and forage production and afforestation
 Performance of forest trees in water-logged salt affected soils or under irrigation with poor quality waters.
 Drainage systems under different soil types in irrigation projects for controlling water table and soil salinity.
 Use of drainage effluents for irrigation or growing fish in disposal ponds or for salt production
 Reclamative capacities of different halophytes
 Quality criteria for sewage water for irrigation.
 Studies on socio-economic viability of reclamation of waterlogged soils at farmers field.
 Development of regional hydro-salinity models.
 Studies on management of Nitrate/fluoride rich waters for their profitable utilization.
 Induction of salt resistence in different crops through soma-clonal techniques.
 Development of regional hydro-salinity models. Studies on management of Nitrate/fluoride rich waters for their profitable utilization. Induction of salt resistence in different crops through soma-clonal techniques

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