Management and tolerance f l lit t fof low quality water for

crops in Andhra Pradeshp

Dr. M. Devender ReddyHead, Water Technology Centre,Head, Water Technology Centre,

ANGRAU, Hyderabad-30

1

Paper presented in "Regional workshop on water use efficiency and water crops in Andhra Pradesh. Hyderabad. March 13-14, 2009

li i d fi dLow-quality water is defined as water with a relatively high content of impurities among which salts are theimpurities, among which salts are the most important factor Inland salinity: Salinity in ground waterInland salinity: Salinity in ground water inland areas is caused due to geogenic sources. Coastal salinity: Problem of ysalinity in groundwater is caused due to excessive exploitation of fresh groundwater in coastal areas and consequent seawater intrusion. 2

Classification of ground water quality for irrigation as CSSRI K lper CSSRI, Karnal

Water Class ECiw(dS\m)

SARiw RSC(meq\l)

A. Good water <2 Upto 10 <2.5B. Saline water

i) Marginally saline 2-4 Upto 10 <2.5ii) Saline >4 Upto 10 <2.5) piii) High SAR saline >4 >10 <2.5C. Alkali water

i) Marginally alkali

<4 <10 2.5-4.0

ii) Alkali <4 <10 >4.0iii) High Alkali Variable >10 >4.0 3

Status of ground water quality in Andhra g q yPradesh

P d ili i i h i 1 30 illi hPresent ground water utilization in the state is 1.30 million ha m and 1.76 million ha m for further utilization. Of this, 54 percent (0.95 million ha m) is available in irrigation

d d th i i 46 t (0 81 illi h )command areas, and the remaining 46 percent (0.81 million ha m) in non command areas. The pH of groundwater is in the range of 6.0-9.0 and meets the

t lit it iwater quality criteria. Conductivity varies from 205 to 10, 940 µmhos/cm except few locations. The concentration of Nitrate (NO3 -) is observed in the range of 0.03-59.10 mg/l and Nitrite (NO2 -) is observed in the range of 0.01-1.37 mg/l (http/www.cpcb.nic.in).

4

RSC is the major problem and exceeded 2.5 me/l in Nellore (53.8%),Ananthapur (54%), Prakasam (44%), Nalgonda (42.2%), Mahaboobnagar(40.6%), Kurnool (25.4%), Khammam (19.1%), Krishna (18.2%), Chittoor(17.9%), Guntur (17.5%), East Godavari (14.3%), West Godavari (7.7%)

About 83% of ground waters were of good quality in West Godavari, 75%in East Godavari, 79.4% in Khammam, 66.7 in Kurnool, 66% in Krishna,64% in Guntur 62% in Prakasam 56% in Mahaboobnagar 52% in64% in Guntur,62% in Prakasam, 56% in Mahaboobnagar, 52% inNalgonda, 45% in Ananthapur, 37% in Prakasam as well as Nelloredistricts while remaining were bad quality waters having both salinity andalkalinity problem.alkalinity problem.

The salinity problem was found mostly in waters, Guntur (18.3%),Prakasam (18.6%), West Godavari (16.8), Krishna (15.8%), East Godavari( ), ( ), ( ),(10.7%), and Nellore (9.4%) districts while it was very low in case ofKhammam (1.5%), Mahaboobnagar (3%), anantapur (1.7%), Nalgonda(5.64%), and Kurnool (6.9%) districts.

5

Classification of under ground irrigation water in different districts of Andhra Pradesh

No. High Margin High % of

different districts of Andhra Pradesh

S.No District of sample

s

Good Marginally saline Saline

High SAR

Saline

Marginally

alkaliAlkali

High

Alkali

% of col8,9 and 10

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )

1 Ananthapur 684 306 (44.7% 8 (1.2%) 1 (0.2%) 2 (0.3%) 148 176 43 50.20%2 Prakasam 166 62 (37.3%) 17 (10.2%) 5 (3.0%) 9 (5.4%) - 73 - 44.00%3 guntur 837 537(64.2% 118 (14.1%) 29 (3.5%)6 (0.7%) 11 124 12 17.50%g ( ( ) ( ) ( )4 East Godavari 140 105 (75.0%) 11 (7.9%) 3 (2.1%) 1 (0.7%) - 20 - 14.30%5 West Godavari 825 685 (83.0%) 69 (8.4%) 7 (0.9%) 62 16 1 7.70%6 Krishna 501 331 (6.0%) 60 (12.0%) 10 (2.0%)9 (1.8%) 68 6 17 18.20%7 Khammam 544 437 (79.4%) 7 (1.3%) - 1 (0.2j%) 60 36 8 19.10%( ) ( ) ( j )8 Kurnool 621 414 (66.7) 36 (5.8%) 5 (0.8%) 8 (1.3%) 89 41 28 25.40%9 Nellore 927 340 (36.8%) 53 (5.7%) 4 (0.4%)30 (3.3%) 195 186 118 53.80%

10 Nalgonda 815 425 (52.15%) 41 (5.03%) 5 (0.61%) - 199 105 40 42.21%11 Mahaboobnaga 1131 637 (56.40%) 31 (2.74%) 3 (0.27%) - 215 208 37 40.59%g ( ) ( ) ( )12 Chittoor 335 262 (78.2%) 13 (3.9%) 0 0 36 22 2 17.90%

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Status of Ground water quality in Andhra Pradesh:

The quality of groundwater along the coastline is generally poorThe quality of groundwater along the coastline is generally poor due to the intrusion of seawater into the coastal aquifers. Chloride concentrations are generally found to be in the range of 85 to 845 ppm (Lakshmi, 2007). Groundwaters of rural Guntur district are alkaline, very hard and mostly brackish. Possible sources of fluoride (F-) are weathering and leaching of F--bearing minerals under the alkaline environment (Subba Rao 2005)environment (Subba Rao, 2005). A high rate of evapotranspiration, longer residence time of waters in the aquifer zone, intensive and longterm irrigation, and heavy use of fertilizers are the supplementary factors to further increaseuse of fertilizers are the supplementary factors to further increase the F- content in the groundwaters.

7

GUNTUR DITRICT

8

Ground water quality in Krishna District

Ground waterSurface water

Place Chloride

TDS*(ppm

Hardness

Place Chloride

TDS(ppm

Hardnesse

(ppm)(ppm)

s(ppm)

e(ppm)

(ppm)

s(ppm)

Tenali 145 879 210 Tenali 55 625 65

Duggirala 140 916 160 Duggirala 55 631 55Duggirala 140 916 160 Duggirala 55 631 55

Pedavadlapudi

130 1346 175 Pedavadlapudi

55 597 55

Nidumolu 85 842 135 Nidumolu 60 677 130

Gudur 60 1044 300 Gudur 55 783 125

Pamarru 845 4916 730 Pamarru 50 759 139

Eluru 240 1253 210 Eluru 60 704 90u u 40 53 0 u u 60 04 90

Gudlavallaru 70 1160 145 Gudlavallaru

50 669 115

Mudinepalli 250 941 150 Mudinepalli 50 652 135

* Total Dissolved SolidsSource: Lakshmi, 2007

9

KRISHNA DISTRICT

Good

Marginally saline

S liSaline

Marginally Alkali-I

Marginally Alkali-II

Alkali

High SAR Saline

Under Canal Irrigation

10

WEST GODAVARI

11

Quality map of Nellore district 12

The higher values of certain parameters pH, conductance, total dissolved solids, alkalinity, hardness, chloride, sulfate, nitrate, sodium, , , , , ,potassium, calcium and magnesium at various locations of Kakinada town in the East Godavari District indicate the influence of sea water and make the water unsuitable forwater and make the water unsuitable for domestic applications. The values of sodium adsorption ratio indicate that majority of samples fall under thethat majority of samples fall under the category of low to high sodium hazards (Jain et al, 1997).

13

Groundwater samples from the Anantapurdistrict, analyzed for chemical constituentsindicated it is brackish and very hard with anindicated it is brackish and very hard, with anexcess alkalinity, and is not fit for drinking andirrigation (Subba Rao et al, 2006).Acoording to the WHO standards theAcoording to the WHO standards, thegroundwater quality of water samples collectedfrom the existing wells in the Niva River basin,Chittoor district, reveal that, in general, the, , g ,groundwater is suitable for both agricultural anddomestic uses, exept in a few locations (SrinivasaRao et al, 1997). High concentration of nitrates

b d i f th ll (b thwas observed in some of the wells (bothagricultural and domestic) that are affected bythe impact of industrial effluents.

14

Ananthapur district

15

Groundwater in Chittoor district is alkaline and sodium andGroundwater in Chittoor district is alkaline, and sodium and bicarbonate are the dominant cation and anion, respectively (Srinivasarao, 2007). Gibbs variation diagram shows that the control of the h i t f d t i th t d i th th ichemistry of groundwater in the study area is the weathering

of granitic gneisses and also the leaching of evaporated and crystallized ions from the topsoil of the irrigated areas and improperly treated industrial effluent ponds. It was observed that 30.06% of the area is with suitable, 67.45% of the area is with moderately suitable and 2.45% of the area is with unsuitable quality of groundwater for domestic purpose. Further, 46% of the area is with suitable, p p , ,53.36% of the area is with moderately suitable and 0.64% of the area is with unsuitable quality of groundwater for irrigation purpose.

16

Mulakalacheruvu

Ananthpur Distric

t

Tirupathi urban

Tirupathi ruralMadana palle Jemmana palle

Renugunta

R F Forest

Srikalahasti

Kovanur

Chandragiri

Yerrava

Vayalapad Piler

GurramkondaKalakada

Chinnagottigallu

Kothakota

BNKandriga

YerapeduTottampedu

Nagari

VedurukuppamSomala Pakala

Madana palle p

Pottuur

R.F ForestChandragiri

Varadapalem

Pungamur

BNKandriga

SatyaveeduKarvetinagar

Narayanavanam

ChittoorGangavaram

Pedda PanjaKarnataka

du

Bangarupalem

Vijayapuram

BaireddypalleYadamarri

GNpalem

Good

Marginally alkali

Alkali

Kuppam

Santhapuram

Tamil NaduVenkatagiri Kota

Ramakuppam

Marginally saline

High alkali

1. BN Kandriga 2. Chandragiri 3. Karveti Nagar 4. KVB Puram 5. Narayanavanam 6. Pakala 7. Pulicherla 8Puttur 9. RC Puram 10. Renigunta 11. Satyavedu 12. Srikalahasti 13.Thottambedu 14. Tirupati ( R ) 15.Tirupati (Urban) 16 Vadamalpet 17 Varadaiahpalem 18 Vyedurukuppam 19 YerpeduTirupati (Urban) 16. Vadamalpet 17. Varadaiahpalem 18. Vyedurukuppam 19.Yerpedu

Quality map of under ground water in parts of chittoor district17

KURNOOL DISTRICT

18

G d f M h b b h di bi bGroundwater of Mahaboobnagar have sodium bicarbonate, sodium chloride, mixed cationic-mixed anionic, mixed cationic Na dominating bicarbonate, and mixed cationic Ca dominating bicarbonate types (Raju and Goud, 2005). Of them sodium bicarbonate and mixed cationic Mg dominatingOf them, sodium bicarbonate and mixed cationic Mg dominating bicarbonate types of waters are more prevalent. Graphical treatment of chemical data reveals that, in general, the area has basic water, whereas the left flank canal area is dominated by secondary alkaline water and Pallamarri and Peddadominated by secondary alkaline water, and Pallamarri and Pedda Rajmur villages have strongly acidic waters. Ion-exchange studies show that cation-anion exchanges exist all over the area except for two places, which have a base exchange hardened type of water. Graphical representation further shows that most of the area has medium salinity-low sodium (C2S1) water useful for irrigation purposes. High salinity-low sodium (C3S1) and high salinity-medium sodium g y ( ) g y(C3S2) waters are present in some areas, which need adequate drainage to overcome the salinity problem.

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Groundwater quality of Mahaboobnagar and Chittor

S.N Name of the No. of sampleso district

Total

Good

Marginally saline

Saline

HighSARSalin

Marginally alkali

Alkali High Alkali

Saline

1 Mahaboobnagar

1131

637 31 3 0 215 208 37

2 Chittoor 712 511 65 2 7 79 38 10

Source: Lakshmi, 2007)

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In Telangana region especially in NalgondaIn Telangana region, especially in Nalgonda and Mahaboobnagar districts, alkali soils have come to exist due to irrigation with poor quality waters, which are loaded with residualquality waters, which are loaded with residual sodium carbonate (RSC). Continuous and unabated use of saline ground water are affecting the soil structure, saltwater are affecting the soil structure, salt balance, microflora and microfauna (Sudarshana, 1999). The overall increase in saline area is nearly 5% ypercent from the 1980 baseline value. This has happened despite increase in total annual recharge by nearly half.

21

Good Medium alkaliGood Medium alkali

Alkali High alkali4241 11

810

69

5

12 1314

1.Koyalkonda 2. Mahaboobnagar 3. Nawabpet4. Hanwad 5. Jedcherla 6. Balanagar 7.Boothpur 8. Shadnagar 9. Keshampet 10.K tt 11 K d 12 T l k d lli 13

2

716

17

14

3435

5

7 25

7

18

17

16

1520

Kottur 11. Kondurgu 12. Talakondapalli 13.Amangal 14. Madugula 15. Vangoor 16.Veldonda 17. Kalvakurthy 18. Midjel 19.Nagarkurnool 20. Tadoor 21. Telkapally 22.Pedakothapalli 23. Gopalpet 24. Pebbair 25.Wanaparthy 26. Pedamandadi 27. Ghanpur 28.

1 3

4

5

68

9

10

1213

1415

3332

31

28

30 26

23

22

2160

61 62

Wanaparthy 26. Pedamandadi 27. Ghanpur 28.Kothakota 29. Atmakur 30. Narva 31. CCKunta 32. Devarakadra 33. Dhanwada 34.Dharoor 35. Ghuttu 36. Ieeja 37. Gadwal 38.Maldakal 39. Timmajipet 40. Bijinepalli 41.Bommarasipeta 42. Kodangal 43.

11

1820

2122

31

3836

3940

29

52

56

2457

22

58 59

Doulathabad 44. Damargidda 45. Maddur 46.Narayanpet 47. Utkur 48. Makthal 49.Maganoor 50. Vaddapalli 51. Manopad 52.Itikyala 53. Alampur 54. Weepangandla 55.Kollapur 56. Pangal 57. Kodair 58. Lingal 59.Balmoor 60 Uppununthala 61 Achampet 6219

3750

52

51

53

54Balmoor 60. Uppununthala 61. Achampet 62.Amrabad 63. Kosigi

Quality map of under ground irrigation water in parts of Mahaboobnagar district 22

Warangal Dt.

Medak Dt. 1

23

46

Hyderabad Dt.4

57

89

10

1112

13 14

15

16

1734

Rangareddy Dt.

18

192021

22

2324 29

30 31 32 3335

36

37

38394042

Mahaboob Nagar Dt.

2526

27

284041

42

43

444547

50 51

52

53

54 5556

57

58

59

Krishna Dt.

Krishna RiverNagarjuna Sagar Dam

Guntur DtMahaboobnagar

4648

49

52

Guntur Dt.g

Names

Good Marginally Saline Saline

Marginally Alkali High AlkaliAlkali

Ground Water Quality Map of Nalgonda District23

Khammam district

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A systematic ground water survey carried out in various districts of Andhra Pradesh indicated presence of high Residual Sodium Carbonate (RSC) water in Anantapur, es dua Sod u Ca bo ate ( SC) ate a tapu ,Prakasam, Nellore and Mahaboobnagar. The crop yields were adversely affected due to use of these waters. The soil properties also deteriorated There was 50% yieldThe soil properties also deteriorated. There was 50% yield increment with RSC waters in paddy when treated with 2.5 t ha-1 of gypsum+ 2.5 t ha-1 of green manures over no amendments. Th t ti d t k f t i t l i d iThe concentration and uptake of nutrients also increased in rice crop with use of the amendments (Rajendra Prasad et al 2002). Besides, a reduction in soil pH, EC and increase in contents of available N and P2O5was observed. In case, th d t i f t l lit d tthe ground water is of extremely poor quality and cannot be recommended even for blending.

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Management for saline waterSelection of crop:

For successful utilization of saline water, crops which are semi tolerant to tolerant such aswhich are semi-tolerant to tolerant such as mustards, wheat and cotton as well as those with low water requirement are recommendedrecommended. Crops such as rice, sugarcane and berseem, which require liberal water use, should be

id d I l i f ll ( 40avoided. In low rainfall areas (<40 cm/annum), mono–cropping is recommended for maintaining salt balances. Salt tolerance li i f l il d bl dlimits of cereals, oil seeds, vegetables, and pulses developed in different ecological regions of India are available. 26

Salinity limits of irrigation water for agriculture crops

Crops Soil texture Previous

cropECiw (dS\m) for yield (%)p p ( )

Cereals 90 75

Wheat Silty clay loam Sorghum 3.4 7.0

Sandy loam Bajra 6.6 10.4

Loamy sand Fallow 8.3 11.7

Sand Fallow 14.0 16.1

Barley Sandy loam Fallow 7.2 11.3y y

Rice Sility clay loam Rice 2.2 3.9

Maize Clay loam Wheat 2.2 4.7

Pearl-millet Sandy loam Wheat 5.4 9.0

Italian-millet Sand Sunflower 2.4 4.6

sorghum sandy loam Mustard 7.0 11.2

Sorghum fodder Sandy loam Berseem 5.2 10.2

Oilseeds

Mustard Sandy loam Sorghum 6.6 8.8 27

Crops Soil Previous crop ECiw (dS\m) forCrops Soil texture

Previous crop ECiw (dS\m) for yield (%)

Safflower Silty clay loam

Maize 3.3 6.8

Sunflower Sandy loam

Mustard 3.5 7.2

Groundnut Sand Italian-millet 1.8 3.1

Soyabeen Silty clay loam

Mustard 2.0 3.1

Pulses\Legumesmes

Pigeon pea Sandy loam

Onion 1.3 2.3

Clusterbean Sandy Variable 3 2 4 5Clusterbean Sandy loam

Variable 3.2 4.5

Cowpea Loamy sand

Variable 8.2 13.1

Source: Sharma and Minhas, 2005

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Growth stages:All crops do not tolerate salinity equally well at different stages of their growth. For example, different stages of their growth. For example, germination and early seedling establishment are the most critical stages followed by the phase changes from vegetative to reproductivephase changes from vegetative to reproductive i.e. heading and flowering to fruit setting. Therefore, the use of saline water should be avoided during initial stages of crop growth.avoided during initial stages of crop growth.

Crop cultivar:In addition to inter genic variations, crop c lti a s also a in thei tole ance to salinitcultivars also vary in their tolerance to salinity. Such cultivars have been identified on their rating for high yield potential, salt tolerance

d t bilit d li i tand stability under saline environments

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Water ManagementThe distribution of water and salts in soils vary with the method ofThe distribution of water and salts in soils vary with the method of irrigation. A shift towards micro-irrigation systems such as drip and sprinklers, where a better control on salt and water distributions can be achieved, hold promise for enhancing the use efficiency of saline water especially for high value crops.water especially for high value crops. Application of the two waters separately, if available on demand, can be done either to different fields, seasons or crop growth stages so that the higher salinity water is avoided at sensitive growth stages of the crops Cyclic uses i e irrigating with water of different qualitiesthe crops. Cyclic uses i.e. irrigating with water of different qualities separately offers both operational and performance advantages over mixing. For skimming of fresh water floating over seawater in coastal sandy soils, conventional “Dorouv” system has been improved with specially designed subsurface water harvestingimproved with specially designed subsurface water harvesting system that can irrigate up to 3-5 ha land (Raghu- Babu, 1999).

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Nutrient ManagementNutrient Management

Green manuring, with sesbania every year or at least once in two years, to raise organic matter status and to overcome the nitrogen deficiency problem is necessary. In Krishna Western Delta, application of Zinc oneproblem is necessary. In Krishna Western Delta, application of Zinc one day before sowing of black gram in rice fallow pulse cropping system significantly increased the black gram yields in saline soils. Of the nineteen released and pre released black gram cultivars, highest yield recorded by LBG 726 (13.89 q ha-1) followed by LBG 685 (11.79 q ha-1), LBG 727 (10 98 h 1) d LBG 20 (10 44 h 1) t B t A il blLBG 727 (10.98 q ha-1) and LBG 20 (10.44 q ha-1) at Best Available water (BAW).Response to applied nitrogen is rather reduced under saline irrigation. Thus, additional doses of nitrogenous fertilisers are recommended to compensate volatilisation lossescompensate volatilisation losses. Soils irrigated with chloride rich water respond to higher phosphate application, because the chloride ions reduce availability of soil phosphorus to plants. The requirement of the crop for phosphoric fertilizers is, therefore, enhanced and nearly 50 per cent more phosphorusfertilizers is, therefore, enhanced and nearly 50 per cent more phosphorus than the recommended dose under normal conditions should be added,

31

Farmyard Manure (FYM)FYM and other organic manures not only have the

t iti l th l l i t t l inutritive value, they also play an important role in structural improvements. This further influences leaching of salts and reduce their accumulation in the root zone The other advantage of FYM in salineroot zone. The other advantage of FYM in saline water irrigated soils are in terms of reducing the volatilization losses and enhancing the nitrogen-use efficiency. Retention of nutrients in organic forms for y glonger periods also guards against leaching and other losses. In the context of the advantages of FYM and other organic manure, they should be applied to the

i ibl li itmaximum possible limit.

32

Cultural PracticesOwing to reduced germination, often a poor crop stands in

fields irrigated with saline water. Thus, to ensure better populations following measures are suggested:Reduce inter/intra row spaces and use 20-30% extraReduce inter/intra row spaces and use 20 30% extra seed than under normal conditions. Dry seeding and keeping the surface soil moist through sprinkler or post sowing saline irrigation helps in better establishment of cropsestablishment of crops. Modifications in seedbed e.g. sowing near the bottom of the furrows on both sides of the ridges, applying irrigation in alternate row, and to seed on the north-east id f th id i d dside of the ridges, is recommended.

For the larger seeded crops, the seeds can be planted in the furrows. The furrow irrigation and bed planting system (FIRB)The furrow irrigation and bed planting system (FIRB) has been found better than conventional planting in cotton / pearl millet –wheat rotations. Adoption of measures for better intake of rainwater (tillage to open up soil) and its conservation in soil via(tillage to open up soil) and its conservation in soil via checking unproductive evaporation losses (soil/straw mulching) is recommended during monsoon season.

33

Land levelling and rain water conservation:

Proper land levelling and provision of 30-40 cm high strong bunds for capturing and retaining rainwater are the essential prerequisites for managing the land irrigated with sodic water. Th f il h ld b t t d i t b ti ti fThe surface soil should be protected against beating action of raindrops, which can be achieved through ploughing the field in between rains.

34

Management for alkali waterCrop Selection

The guiding principle for choosing the right kind of crops and cropping patterns suitable for particular sodic water is to select only those crops whose sodicity tolerance limits are lower thanonly those crops whose sodicity tolerance limits are lower than the expected soil sodicity (ESP) to be developed by the use of that water.

Use of AmendmentsSodic water can be safely and economically used after treating them with calcium bearing amendment such as gypsum. The agricultural grade gypsum can either be added to soil or applied in water through specially designed gypsum beds. Both methods g p y g gypare equally effective in neutralizing the RSC of water and its adverse effects. Acidic amendment like pyrites can also be used for amending the deleterious effect of high RSC water both as soil application and as pyrite bed. pp py

35

Irrigation ManagementConventional irrigation practices such as basin irrigation could be adopted to manage alkali water.irrigation could be adopted to manage alkali water. Emphasis should be to minimize the irrigation with alkali water as deterioration of soil directly depends on the quantities of irrigation water. The ‘alkali h d’ i d d id bl if th t i dhazard’ is reduced considerably, if the water is used alternatively or mixed with canal water. Besides reducing the gypsum requirement of soil, conjunctive use of alkali and canal water also helps in bringinguse of alkali and canal water also helps in bringing more area under protective irrigation and also in controlling rise in ground water table and associated problems.problems.

36

Nutrient ManagementSince sodic water cause a rise in soil pH that leads to greater nitrogen losses through volatilization and denitrification, extra nitrogen may have to be added to meet the requirement of thenitrogen may have to be added to meet the requirement of the crops. Similarly, the availability of zinc and iron is also low due to their precipitation as hydroxides and carbonates. Some beneficial tips as regards fertilizer use are:A li ti f 25% t it i d d d t thApplication of 25% extra nitrogen is needed as compared to the normal conditions. Zinc sulphate @ 25 kg per ha should be added, particularly for the rabi crops. Phosphorus, potassium and other limiting nutrients may also be applied on the basis of

il t t l S di t b i h i t i t hsoil test values. Some sodic water may be rich in nutrients such as nitrogen, potassium and sulphur. Water should be analyzed and the fertiliser dose of concerned nutrient reduced accordingly.

37

Addition of Organic MaterialsIt is generally accepted that addition of organic materials improve sodic soils through mobilization ofmaterials improve sodic soils through mobilization of inherent Ca2+ from CaCO3 (Calcium Carbonate) and other minerals by organic acids and increased pCO2 in soils The solublized Ca2+ in soil replaces Na+ fromin soils. The solublized Ca2+ in soil replaces Na+ from the exchange complex. Reclamation of barren alkali soils by addition of organic materials has been widely reported However for soils undergoing sodicationreported. However for soils undergoing sodication, some disagreement exist in literature regarding the short– term effects of organic matter on the dispersion of sodic soil particles (Gupta et al 1984)dispersion of sodic soil particles (Gupta et.al, 1984).

38

Effect of different amendments on mitigating adverse effect ofEffect of different amendments on mitigating adverse effect of RSC waters on grain and straw yields of rice crop

2000Yr 2001Yr 2000 Yr 2001 YrT1 Control i e Well water without any amendment 3000 0 2812 3 5211 0 4032 0

Treatments Yield( kg ha-1)Grain Straw

T1 Control i.e Well water without any amendment 3000.0 2812.3 5211.0 4032.0

T2 Gypsum Application to soil @ 5t ha-1 3866.7 3625.0 7208.3 5164.3

T3 FYM @ 10 t ha-1 4725.0 4188.0 7481.7 6161.0

T4 Gypsum 50%+ 50% FYM (2.5 t ha-1Gypsum +5 t ha-1 FYM) 4675.0 4688.0 7485.0 6637.0T5 passing of gypsum through irrigation water (@1/2 bag per 4575.0 4675.0 7223.3 6732.0

T6 Green manure @ 5 t ha-1 5456.7 4500.0 7826.7 6512.3

T7 Green manure @ 2.5 t ha-1 + Gypsum @ 2.5 t ha-1 5481.7 4775.0 7880.0 6843.7Mean 4540.0 4180.5 7188.0 6011.8S.Em( + ) 94.1 141.0 48.6 218.8C.D (0.05) 205.0 307.2 105.9 476.7C.V % 2.5 4.1 0.8 4.5

39

An experiment on conjunctive use of saline drain water and good quality water was conducted at SWS, Bapatla in RBD experiment with three replications using maize, var; DHM-103 as test crop in a soil having pH 8 2 and ECvar; DHM 103 as test crop in a soil having pH 8.2 and EC 0.32 dSm-1 (Lakshmi, 2007). The EC and pH of groundwater and Surface Drainage Water (SDW) used for irrigation during crop growth of both the seasons varied from 0.64 to 0.82; 7.02 to 7.52 and 2.80 to 4.00varied from 0.64 to 0.82; 7.02 to 7.52 and 2.80 to 4.00 dS m-1; 7.08 to 8.80, respectively. Seed and stover yields obtained by irrigation at all stages with SDW and at all stages with SDW but pre-sowing with GW resulted in lower yields compared to SDW given at flowering, atin lower yields compared to SDW given at flowering, at silking and milking and at pre-sowing, silking and milking. In the areas of limited availability of good water for irrigation, saline drain water could be used efficiently when used for irrigation at silking and milkingefficiently when used for irrigation at silking and milking stages by maize.

40

Crop Variety Season

Soil type

Eciw dS/m for relative yield

Experimental results incorporated with the package of practices

n typeCereals 90% 75% 50%

RP-4-14 (Prakash)IET-1444(Rasi)

Wheat Raj-3077, SW-2560 Sl 3.8 7.8 16.7Fingermillet Godavari S 1.7 3.7 7.6

yield

paddy Rabi Scl 1.8 2.9 4.8

Bajra Vijaya composite S 4.6 6.2 7.3PulsesBlackgram LBG-17 Sl 2.7 4.8 6.9Greengram LGG-127 Sl 2.2 4.3 5.9Oil-Seeds

Girnar 1 Sel 7 3 1 5 3Groundnut Sl 1 8Girnar-1,Sel-79-1, ICGV-87189 &86309ICGS-1, 5 & 44And TMV-2

Mustard Local C 3.8 7.9 14.7

3.1 5.3Groundnut Sl 1.8

Mustard Local C 3.8 7.9 14.7Sunflower EC-68415 Sl 3.5 7.2 13.4Gingelly Gowri Red

loam2.3 4.6 7.3

Castor SHB-18 & 48-1 Red loam

6.6 7.6 14.6

Safflower Hima & HUS-305 Sl 5.1 7.6 13.9VegetablesTomato Pusa ruby Sl 2.4 4.1 6.9Onion Local Sl 5.1 6 7.5Bittergourd Coimbatore white Sl 2 3.4 5.8Bottlegourd Summer prolific Sl 3.2 4.5 6.8

X-235, 3.2 4.5 6.8Ca-960 2.5 4.3 5.8G-4 2.6 4.4 5.8

Coriander CS-4 C 2.9 5.8 10.7

Chillies Sl

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These guidelines identify special consideration for li t hsaline water such as:

Use gypsum when saline water (having SAR > 20 and/or Mg/Ca ratio > 3 & rich in silica) induces water stagnation during rainy season and crops grown are sensitive to it. Fallowing during rainy season is helpful when SAR > 20 andare sensitive to it. Fallowing during rainy season is helpful when SAR > 20 and water of higher salinity are used in low rainfall areas. Additional phosphatic fertilization is beneficial, especially when C1/SO4 ratio in water is > 2.0. C l t f bl i d t l th t i l di iCanal water preferably is used at early growth stages including pre-sowing irrigation for conjunctive use with saline water. Putting 20% extra seed rate and a quick post-sowing irrigation (within 2-3 days) will help better germination. y ) p gWhen ECiw < ECe (0-45 cm soil at harvest of rabi crops), saline water irrigation just before the onset of monsoon will lower soil salinity and will raise the antecedent soil moisture for greater salt removal by rains. Use of organic materials in saline environment improves crop yieldsUse of organic materials in saline environment improves crop yields. Accumulation of B, F, NO3, Fe, Si, Se and heavy metals beyond critical limits proves toxic. Expert advice prior to the use of such water may be obtained. For soils having (i) shallow water table (within 1.5 m in kharif) and (ii) hard g ( ) ( ) ( )sub-soil layers, the next lower ECiw/alternate mode of irrigation (canal/saline) is applicable.

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Due to high sodium and high pH in RSC water irrigated soils, it is necessary to apply Zn, Fe and other micronutrients. Gypsum application suggested when high RSC waters are used for irrigationirrigation. The Water with RSC less than 2.5 meq l-1 is safe for irrigation and Water with RSC between 2.5 to 4.0 meq l-1 needs occasional gypsum application to improve crop yields. The best time for gypsum application is after summer showersThe best time for gypsum application is after summer showers followed by ploughing to a shallow depth. Passing sodic Water through gypsum beds is equally good and labour saving. Tolerant or semi tolerant crops having low Water requirement such as sorghum and pearlmillet, etc should be grown andsuch as sorghum and pearlmillet, etc should be grown and crops with high Water requirement such as rice, sugarcane etc can be avoided. Sodic waters should not be used for growing summer crops. Occasional gypsum application along with FYM will improve rice yield. Application of 25 per cent extra

it i d d d t l diti F thnitrogen is needed as compared to normal condition. Further, application of Zinc sulphate@ 25 kg ha-1 to the rabi crops grown with alkali water.

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Crop rotation improves the yield and soil physico-chemical properties under sodic water condition. Ridge sowing is better than other methods. The Vegetable crops like Brinjal, tomato, Cabbage andThe Vegetable crops like Brinjal, tomato, Cabbage and Cucumber etc can be grown successfully with application of FYM 10 t ha-1 and passing RSC water through gypsum bed. The Marginally saline water can be used for irrigation in light textured soils without any problem either on crop yield or on y p p ysoil properties. The marginally saline water can also be used in heavy textured soils with few precautions such as selection of crops requiring less number of irrigations and with no requirement of summer i i tiirrigation. Application of FYM@ 5-10 t ha-1 will mitigate the adverse effect of marginally saline/saline water irrigation. Waters with ECiw less than 3 dS m-1, SAR less than 10 and RSC less than 4 meq l 1 do not pose any serious problem in different soilsmeq l-1 do not pose any serious problem in different soils under wide range of climate

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Minimization of adverse effects of RSC waters with gypsum and FYMamendments

Presence of high Residual Sodium Carbonate (RSC) water in Anantapur,Prakasam, Nellore and Mahaboobnagar.

Th i d d d i 2000 d 2001 f fi ldThe experiment was conducted during 2000 and 2001 at farmers field,Vippaguntla village, Prakasam district using gypsum, FYM and green manauresand their combination to reduce ill effect of RSC waters on crop (rice) yields.Results indicated nearly 50% yield increase when treated with 2 5 t ha-1 of gypsumResults indicated nearly 50% yield increase when treated with 2.5 t ha 1 of gypsum+ 2.5 t ha-1 of green manures than that of control (no amendments).

Reduction in soil pH, EC and increase in available N and P2O5 contents after theReduction in soil pH, EC and increase in available N and P2O5 contents after theharvest of crop even after crop removal (Table 1 & 2).

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Gypsum to be applied Kgs/ha

No of RSC of RSC to Heavy Light Sandy SandyNo. of irrigati

ons

RSC of water (me/L)

RSC to be

neutralized

Heavy textured soils Kg/ha

Light textured soils Kg/ha

Sandy loams

Sandy soils

5 5678

5-4=16-4=27-4=38-4=4

300600900

1200

200400600800

100200300400

Occasional gypsum applicati8 8 4 4 1200 800 400 application is sufficient to improve crop yield.

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