Soil salinity and sodicity - global problem, exists in six continents and nearly 100 countries including Pakistan. Major countries - Argentina, Australia,

• Soil salinity and sodicity - global problem, exists in six continents and nearly 100 countries including Pakistan.

• Major countries - Argentina, Australia, Egypt, Iran, Pakistan, USA, Russia, India, China, Thailand and South Africa.

GLOBAL SCENARIO OF THE PROBLOM

Statistical information regarding area

Area Pakistan Punjab

(m ha)

Geographical area 80 21

Total cropped area 22 16

Surveyed area 69 21

Irrigated area 18 14

Saline and saline-sodic soil 6.68 2.68

Source: Agricultural statistics of Pakistan 2006

SOIL SALINITY/SODICITY PROBLEM IN PROVINCES OF PAKISTAN(m ha)

Punjab 2.68

Sind 2.11

Baluchistan 2.31

N.W.F.P. 0.04

Salt-Affected Area (m ha) of Punjab, Pakistan Year Area

surveyedSalt-Affected

Uncult. Cultiv. Total %

1945-46 4.84 0.42 0.49 0.91 18.80

1955-56 5.96 0.05 0.69 1.20 20.64

1965-66 6.88 0.44 0.68 1.12 16.28

1975-76 7.34 0.37 0.61 0.98 13.35

1985-86 7.57 0.30 0.58 0.88 11.62

2000-01 7.92 1.16 1.51 2.67 33.71

Source: Ahmad & Chaudhry, 2004

TUBE WELLS IN THE PUNJAB

0

200000

400000

600000

800000

1000000

1200000

1979 orbefore

1985 orbefore

1986 to1990

2002-2003 2006-2007

year

No

. of t

ub

e w

ells

Source: Punjab Development Statistics, 2006

Source: Punjab Development Statistics, 2011

No. of Tubewells in Punjab

300000

400000

500000

600000

700000

800000

900000

1000000

1999-00 2000-01 2001-02 2002-03 2003-04 2004-05 2005-06 2006-07 2007-08 2008-09

Years

No.

of T

ubew

ells

No. of Tubewells

Salinity/sodicity: 6.68 m haSalinity/sodicity: 6.68 m ha

60 % are saline-sodic in Pakistan,60 % are saline-sodic in Pakistan,

84 % are saline-sodic in Punjab84 % are saline-sodic in Punjab

(Khan, 1998)(Khan, 1998)

CROPS / PLANTS TOLERANCE WITH RESPECT TO SALINITY AND SODICITY

Field crops

S.No. English name/Common name

Botanical name 50% reduction in yield

ECe ESP

1 Millet Panicum miliaceum 19.5 20-25

2 Sorghum Sorghum bicolor 16.0 15-40

3 Sesbania Sesbenia microcarpa

15.4 50-60

4 Soybean Glycine max 7.5 16-20

5 Maize Zea mays 8.6 <15

6 Sunflower Halianthus annus 6.3 30-50

7 Cotton Gossypium hirsutum

17.1 30-50

8 Mash Vigna mungo 10.0 10-15

9 Rice Oryza sativa 7.4 60-70

S.No.

English name/ Common name

Botanical name

50% reduction in yield

ECe ESP

10 Barley Hordium vulgare

15.7 50-60

11 Sugar beet Beta vulgaris 15.0 >40

12 Lentil Lens culinaris 12.0 10-15

13 Oat Avena sativa 11.7 30-50

14 Berseem Trifolium alexandrium

10.3 20-25

15 Safflower Cathamus tinctorium

9.9 10-15

S.No.

English name/ Common name

Botanical name 50% reduction in yield

ECe ESP

16 Wheat Triticum aestivum 9.9 30-50

17 Sugarcane Saccharum officinarum

9.9 15-40

18 Canola Brassica napus 8.16 30-50

19 Alfalfa Medicago sativa 8.8 >40

20 Flax Linum ustiatissimum

5.9 25-30

21 Mustard Brassica compastis (CS-52)

Salinity/Sodicity tolerant

30-50

22 Kharchia-65 Triticum aestivum Salinity/Sodicity tolerant

30-50

Forages

S.No.

English name /Common name

Botanical name

50% reduction in yield

ECe ESP

1 Kallar grass Leptochloa fusca

22.0 >70

2 Sudan grass Sorghum sudanense

14.4 -

3 Tall fescue Festuca elatior 13.3 <15

4 Garden cress Lepedium sativum

10.0 -

5 Rhodes grass Chloris gayana 8.0 >70

6 Australian grass

Diplachne fusca

22.0 -

7 Fodder beet Beta vulgaris 19.0 <55

S.No.

Englishname /Common name

Botanical name 50% reduction in yield

ECe ESP

8 Guar Cyamopsis tetragonoloba

Salinity/Sodicity tolerant

25-30

9 Tall wheat grass

Agropyron elongatum

19.4 >40

10 Bermuda grass

Cynodon dactylon

14.7 70

11 Triticale Secole cereale X Triticum durum

13.5 -

12 Wild rye Elymus triticoides

11.0 5-15

13 Mott grass Pennisetum purporium

14 Para Grass

Brachiaria mutica 11.0 60-70

Vegetables

S.No.

English name/Common name

Botanical name

50% reduction in yield

ECe ESP

1 Asparagus Asparagus officinnalis

13.0 5-15

2 Cantaloupe

Cucumis melo 9.1 5-15

3 Pumpkin Cucurbita pepo 7.9 5-15

4 Okra Abelmoschus esculentus

Salinity tolerant -

5 Bringal Solanum melongena

Salinity tolerant -

6 Cauliflower Brassica oleracea

10.1 5-15

7 Broccoli Brassica oleraceaitalica

8.2 5-15

S.No.

English name/Common name

Botanical name

50% reduction in yield

ECe ESP

8 Spinach Spinacia oleracea

8.6 15-40

9 Tomato Lycopersicum esculentum

7.6 30-50

10 Cabbage Brassica oleracea

7.0 5-15

11 Onion Allium cepa 4.3 20-25

12 Coriander

Coriandrum sativum

Salinity tolerant

5-15

13 Garlic Allium sativum Salinity tolerant

25-30

Medicinal plantsS.No.

English name/Common name

Botanical name

50% reduction in yield

1 Hina Lasonia spp. Salinity tolerant

2 Sweet basil Ocimum basilicum

Salinity tolerant

3 Parslane Portulaca oleracea

Salinity tolerant

4 Mint Mentha veridis Salinity tolerant

5 Liquorice Glycerrhiza glabra

Salinity tolerant

6 Fenugreek Tigonella foenumgraceum

Salinity tolerant

NUTRITIONAL ASPECTS OF SALT AFFECTED SOILS

Availability of plant nutrients is affected adversely in salt affected soils and their productivity is decreased resultantly.

The main reasons for depletion in fertility of such soils are as under:-

1. Excess of certain ions like Na, CO3 and HCO3 suppress the availability of other like Ca, K, P, Zn, Mn, Fe and B. technically, it is called antagonistic effect.

2. An increase in soil pH, especially in sodic soils decreases the overall availability of phosphorus and micronutrients.

3. In salt affected soils microbiological activity is curtailed to a great extent.

4. During the reclamation process, leaching of salts is also accompanied by leaching of nutrients.

5. Nutrient uptake by plants in salt affected soils is also reduced due to decreased water uptake because of physiological unavailability of the latter.

NITROGEN

Nitrogenous fertilizer play important role in utilizing the salt affected soils for improving crop yield because

1. These soils are deficient in nitrogen.2. Low N and organic matter contents 3. Reduced microbial population4. Rate of mineralization of nitrogen is slow down. Salinity level (ECe)

above 10 dS m-1 is harmful5. Nitrogen absorption by plants increase up to moderate salinity value

(6 dS m-1) and then decreases at higher salinity values and ESP of soil.

6. The rate of conversion of one form of nitrogen to other forms is quite slow e.g. hydrolysis of urea to ammonium N was much slow down with increase in soil pH.

7. Low enzymatic activity in saline soils.8. Chloride reduces the rate of nitrification when present between 0.5- 1.0 percent.9. Ammonium volatilization loss from applied nitrogen increases with increase in pH/alkalinity of soil10. 20-25 percent over dose of nitrogen fertilizers

PHOSPHORUS

Chemistry of phosphorus is more complex in salt affected as compared to normal soils.1. The availability of P is decreased in sodic soil during reclamation.2. The availability of P in saline soil may decrease, increase or remain

unchanged depending on the nature and degree of salinity.3. Salts which change pH show more changes in the solubility of

phosphates in soils. 4. Barren sodic soils have high amounts of Olsen extractable P and

categorized as adequate in available P. 5. Amount of water soluble P increase with soil pH above 9.0.6. The availability of phosphorus increases up to moderate salinity (ECe 6

dS m-1)

7. In sodic soils, there is a tendency for increase of Ca-P form with increase in ESP and decrease in Al-P 8. In highly saline sodic soils about 10-15 percent more P is to be added and special care is to be taken for calcareous soils.9.Phosphorus absorption by plants is generally reduced with increase in salinity and ESP of soil. 10. P uptake by plants increases up to moderate salinity (ECe 6 dS m-1) and ESP (30-35) levels.

Potassium1. Increase in soil salinity depresses the K uptake by plant while Na

uptake increases.2. In sodic soil Na increases and those of Ca, Mg and K decreases.

MICRONUTRIENTSHigh pH, high CaCO3, high ESP, low organic matter content and high amount of soluble salts are the major factors responsible for micronutrients deficiencies in salt affected soils. Among the micronutrients, Zn deficiency is wide spread in sodic soils. Other micronutrients like Fe, Mn and Cu are also precipitated as their hydroxides or carbonates in highly alkaline range and may show their deficiency. In many areas particularly under poorly drained condition in medium and fine textured soil B has been reported to be present in toxic amounts.

Low nutrient use efficiency

Nutrient Efficiency (%)

Cause of low efficiency

Nitrogen 30-50 Immobilization, volatilization, denitrification, Leaching

Phosphorus 15-20 Fixation in soils Al – P, Fe – P, Ca – P

Potassium 70-80 Fixation in clay - lattices

Sulphur 8-10 Immobilization, Leaching with water

Micro nutrients (Zn, Fe, Cu, Mn, B)

1-2 Fixation in soils

Field experiments Results

RESPONSE OF RICE LINE PB-95 TO DIFFERENT NPK LEVELS

Original soil analysespHs 8.60

ECe (dS m-1) 4.72

SAR (mmol L-1)1/2 26.28O.M. (%) 0.42Available P (mg kg-1) 5.18Extractable K (mg kg-1) 86.0

Effect of different NPK rates on rice yield (t ha-1)

NPK (kg ha-1) Paddy yield Straw yield

T1 0-0-0 1.02 F 1.16 F

T2 0-75-75 2.41 DE 2.74 DE

T3 60-75-75 2.54 D 2.88 D

T4 120-75-75 3.52 AB 4.00 AB

T5 180-75-75 3.41 B 3.88 B

T6 120-0-75 2.35 E 2.67 E

T7 120-50-75 3.12 C 3.55 C

T8 120-100-75 3.63 A 4.13 A

T9 120-75-0 3.41 B 3.88 B

T10 120-75-50 3.55 AB 4.04 AB

T11 120-75-100 3.52 AB 4.00 AB

LSD 0.1714 0.2041

Nutrients Use Efficiency (%)Treatments NPK (kg ha-1)

N-Use Efficiency P-Use Efficiency K-Use Efficiency

T1 0-0-0 0.00 F 0.00 D 0.00 H

T2 0-75-75 0.00 F 7.88 BC 26.99 G

T3 60-75-75 38.99 A 9.75 B 33.65 F

T4 120-75-75 38.20 A 15.88 A 57.38 C

T5 180-75-75 27.27 D 15.72 A 54.89 C

T6 120-0-75 17.77 E 0.00 D 32.30 F

T7 120-50-75 28.93 D 5.72 C 49.82 D

T8 120-100-75 38.24 A 15.08 A 62.47 B

T9 120-75-0 32.88 C 14.93 A 0.00 H

T10 120-75-50 35.71 BC 16.41 A 70.66 A

T11 120-75-100 35.81 ABC 17.01 A 43.50 E

LSD 3.2008 2.1755 3.8113

NPK concentration in PaddyTreatments NPK (kg ha-1)

N-Concentration (%)

P- Concentration (%)

K- Concentration (%)

T1 0-0-0 1.04 F 0.13 D 0.11 F

T2 0-75-75 1.07 EF 0.26 BC 0.21 E

T3 60-75-75 1.13 DE 0.27 BC 0.27 CD

T4 120-75-75 1.28 AB 0.28 B 0.29 BC

T5 180-75-75 1.35 A 0.28 B 0.30 BC

T6 120-0-75 1.14 DE 0.15 D 0.25 D

T7 120-50-75 1.18 CD 0.26 BC 0.29 BC

T8 120-100-75 1.25 BC 0.34 A 0.32 AB

T9 120-75-0 1.19 CD 0.27 BC 0.12 F

T10 120-75-50 1.21BC 0.29 B 0.21 E

T11 120-75-100 1.22 BC 0.30 A 0.35 A

LSD 0.0720 0.0546 0.0348

NPK concentration in rice strawTreatments NPK (kg ha-1)

N-Concentration (%)

P- Concentration (%)

K- Concentration (%)

T1 0-0-0 0.31 E 0.09 E 0.79 E

T2 0-75-75 0.32 E 0.11 DE 1.05 D

T3 60-75-75 0.44 D 0.14 BC 1.14 C

T4 120-75-75 0.56 B 0.16 AB 1.25 AB

T5 180-75-75 0.65 A 0.17 A 1.24 B

T6 120-0-75 0.46 CD 0.10 DE 1.22 B

T7 120-50-75 0.50 BCD 0.12 CD 1.26 AB

T8 120-100-75 0.54 B 0.18 A 1.29 A

T9 120-75-0 0.50 BC 0.16 AB 0.74 E

T10 120-75-50 0.52 BC 0.16 AB 1.09 CD

T11 120-75-100 0.53 B 0.17 A 1.21 B

LSD 0.003 0.0294 0.0523

RESPONSE OF WHEAT TO POTASSIUM

APPLICATION IN SALT AFFECTED SOILS.

Treatments:T1: 140-110-0 kg NPK ha-1

T2: 140-110-30 kg NPK ha-1

T3: 140-110-60 kg NPK ha-1

T4: 140-110-90 kg NPK ha-1

T5: 140-110-120 kg NPK ha-1

Pre-sowing Soil Analysis:

ECe: 5.28 d Sm-1

pHs: 8.57SAR: 29.80OM: 0.36%Avail. P: 5.32 mg kg-1

Ex. K: 114 mg kg-1

Treatments

NPK kg ha-1

Grain Yield

(t ha-1)

Straw yield

(t ha-1)

K-use Efficiency

140-110-0 2.54 b 3.06 d 0.0 c

140-110-30 2.88 c 3.55 c 36.17 a

140-110-60 3.19 b 3.98 b 34.57 a

140-110-90 3.31 a 4.29 a 29.30 b

140-110-120 3.28 a 4.24 a 20.87 b

LSD 0.08 0.093 7.43

RESPONSE OF RICE TO POTASSIUMAPPLICATION IN SALT AFFECTED

SOILS.

Treatments:T1: 110-90-0 kg NPK ha-1

T2: 110-90-25 kg NPK ha-1

T3: 110-90-50 kg NPK ha-1

T4: 110-90-75 kg NPK ha-1

T5: 110-90-100 kg NPK ha-1

Pre-sowing Soil Analysis:

ECe: 6.10 d Sm-1

pHs: 8.75SAR: 37.56OM: 0.28%Avail. P: 5.90 mg kg-1

Ex. K: 110 mg kg-1

Treatments

(NPK kg ha-1)

Paddy Yield

(t ha-1)

Straw yield

(t ha-1)

K-use Efficiency

110-90-0 2.46 c 2.95 d 0.0 c

110-90-25 2.61bc 3.13 c 19.61 b

110-90-50 2.86 b 3.43 b 24.97 a

110-90-75 3.17 a 3.80 a 25.36 a

110-90-100 3.22 a 3.86 a 20.87 b

LSD 0.255 0.1593 4.510

RESPONSE OF WHEAT TO BORON APPLICATION IN SALT AFFECTED SOIL

PRE-SOWING SOIL ANALYSIS

ECe (dS m-1) 4.74-4.90

pHs 8.60-8.72

SAR(m mol L-1)1/2 24.98-28.66

O.M.(%) 0.65

Available P ( mg kg-1) 8.30

Extractable K (mg kg-1) 115.0

Available B ( mg kg-1) 0.306

Effect of different rates of boron on grain and straw yield of wheat

Treatments Grain yield ( t. ha-1)

Straw yield (t. ha-1)

T1 140-110-60 kg ha-1 3.21 E 3.32 E

T2 140-110-60 kg ha-1 +B @ 0.25 kg ha-1 3.36 D 3.41 DE

T3 140-110-60 kg ha-1 +B @ 0.50 kg ha-1 3.44 CD 3.52 CD

T4 140-110-60 kg ha-1 +B @ 1.00 kg ha-1 3.74 A 3.88 A

T5 140-110-60 kg ha-1 +B @ 1.50 kg ha-1 3.62 AB 3.69 B

T6 140-110-60 kg ha-1 +B @ 2.00 kg ha-1 3.57 BC 3.63 BC

LSD 0.1409 0.1522

Treatments Boron conc. in grain (mgkg-1)

Boron conc. in straw (mgkg-1)

Boron Use Efficiency(%)

T1 140-110-60 kg ha-1 1.24 C 1.54 C 0.00

T2 140-110-60 kg ha-1+B @ 0.25 kg ha-1 1.24 C 1.56 BC 1.39 AB

T3 140-110-60 kg ha-1+B @ 0.50 kg ha-1 1.28 BC 1.59 ABC 1.59 AB

T4 140-110-60 kg ha-1+B @ 1.00 kg ha-1 1.30 ABC 1.62 ABC 1.82 A

T5 140-110-60 kg ha-1+B @ 1.50 kg ha-1 1.34 AB 1.67 AB 1.13 AB

T6 140-110-60 kg ha-1+B @ 2.00 kg ha-1 1.36 A 1.70 A 0.86 B

LSD 0.0630 0.1165 0.8307

Post Harvest soil analysis

Treatments pHs ECe

(dS m-1)

SAR(m mol L-1)1/2

Available B(mg kg-1)

T1 140-110-60 kg ha-1

8.65 4.83 25.77 0.288

T2 140-110-60+B @ 0.25 kg ha-1

8.64 4.76 23.10 0.314

T3 140-110-60+B @ 0.50 kg ha-1

8.62 4.74 22.65 0.351

T4 140-110-60+B @ 1.00 kg ha-1

8.60 4.72 22.54 0.483

T5 140-110-60+B @ 1.50 kg ha-1

8.60 4.71 22.57 0.634

T6 140-110-60+B @ 2.0 kg ha-1

8.61 4.72 22.69 0.766

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