Water Quality Effects on Plants and Crop Yield

Table 7 gives the expected yield reduction of some crops for various levels of soil salinity as measured by EC under normal growing conditions, and Table 8 gives potential yield reduction due to water salinity levels. Generally forage crops are the most resistant to salinity, followed by field crops, vegetable crops, and fruit crops which are generally the most sensitive.

Table 9 lists the chloride tolerance of a number of agricultural crops. Boron is a major concern in some areas. While a necessary nutrient, high boron levels cause plant toxicity, and concentrations should not exceed those given in Table 10. Some information is available on the susceptibility of crops to foliar injury from spray irrigation with water containing sodium and chloride (Table 11). The tolerance of crops to sodium as measured by the exchangeable sodium percentage (ESP) is given in Table 12.

Table 7. Soil salinity tolerance levels1 for different crops (Adapted from Ayers and Westcot, 1976)



Crop		 Yield Potential, ECe

Maximum ECe
100% 90% 75% 50%
Field Crops

Barleya

Bean (field)

Broad bean

Corn

Cotton

Cowpea

Flax

Groundnut

Rice (paddy)

Safflower

Sesbania

Sorghm

Soybean

Sugar beet

Wheata



8.0

1.0

1.6

1.7

7.7

1.3

1.7

3.2

3.0

5.3

2.3

1.0

5.0

7.0

8.0



10.0

1.5

2.6

2.5

9.6

2.0

2.5

3.5

3.8

6.2

3.7

5.1

5.5

8.7

7.4



13.0

2.3

4.2

3.8

13.0

3.1

3.8

4.1

5.1

7.6

5.9

7.2

6.2

11.0

9.5



18.0

3.6

6.8

5.9

17.0

4.9

5.9

4.9

7.2

9.9

9.4

11.0

7.5

15.3

13.0



28

7

12

10

27

9

10

7

12

15

17

18

10

24

20

Vegetable Crops

Bean

Beetb

Broccoli

Cabbage

Cantaloupe

Carrot

Cucumber

Lettuce

Onion

Pepper

Potato

Radish

Spinach

Sweet Corn

Sweet Potato

Tomato



1.0

4.0

2.8

1.8

2.2

1.0

2.5

1.3

1.2

1.5

1.7

1.2

2.0

1.7

1.5

2.5



1.5

5.1

3.9

2.8

3.6

1.7

3.3

2.1

1.8

2.2

2.5

2.0

3.3

2.5

2.4

3.5



2.3

6.8

5.5

4.4

5.7

2.8

4.4

3.2

2.8

3.3

3.8

3.1

5.3

3.8

3.8

5.0



3.6

9.6

8.2

7.0

9.1

4.6

6.3

5.2

4.3

5.1

5.9

5.0

8.6

5.9

6.0

7.6



7

15

14

12

16

8

10

9

8

9

10

9

15

10

11

13

Forage Crops

Alfalfa

Barley haya

Bermudagrass

Clover, Berseem

Corn (forage)

Harding grass

Orchard grass

Perennial rye

Sudan grass

Tall fescue

Tall wheat grass

Trefoil, big

Trefoil, small

Wheat grass



Fruit Crops

Almond

Apple, Pear

Apricot

Avocado

Date palm

Fig, Olive,

Pomegranate

Grape

Grapefruit

Lemon

Orange

Peach

Plum

Strawberry

Walnut



2.0

6.0

6.9

1.5

1.8

4.6

1.5

5.6

2.8

3.9

7.5

2.3

5.0

7.5



1.5

1.7

1.6

1.3

4.0



2.7

1.5

1.8

1.7

1.7

1.7

1.5

1.0

1.7



3.4

7.4

8.5

3.2

3.2

5.9

3.1

6.9

5.1

5.8

9.9

2.8

6.0

9.0



2.0

2.3

2.0

1.8

6.8



3.8

2.5

2.4

2.3

2.3

2.2

2.1

1.3

2.3



5.4

9.5

10.8

5.9

5.2

7.9

5.5

8.9

8.6

8.61

13.3

3.6

7.5

11.0



2.8

3.3

2.6

2.5

10.9



5.5

4.1

3.4

3.3

3.2

2.9

2.9

1.8

3.3



8.8

13.0

14.7

10.3

8.6

11.1

9.6

12.2

14.4

3.3

19.4

4.9

10.0

15.0



4.1

4.8

3.7

3.7

17.9



8.4

6.7

4.9

4.8

4.8

4.1

1.3

2.5

4.8



16

20

23

19

16

18

18

19

26

23

32

8

15

22



7

8

6

6

32



14

12

8

8

8

7

7

4

8

1Based on the electrical conductivity of the saturated extract taken from a root zone soil sample (ECe) measured in mmhos/cm.

ADuring germination and seeding stage ECe should not exceed 4 to 5 mmhos/cm except for certain semi-dwarf varieties.

BDuring germination ECe should not exceed 3 mmhos/cm.



Table 8. Irrigation water salinity tolerances1 for different crops. (Adapted from Ayers and Westcot, 1976)



Crop		 Yield Potential, ECe
100% 90% 75% 50%
Field Crops

Barley

Bean (Field

Broad bean

Corn

Cotton

Cowpea

Flax

Groundut

Rice (paddy)

Safflower

Sesbania

Sorghum

Soybean

Sugar beet

Wheat



Vegetable Crops

Bean

Beet

Broccoli

Cabbage

Cantaloupe

Carrot

Cucumber

Lettuce

Onion

Pepper

Potato

Radish

Spinach

Sweet corn

Sweet potato



5.0

0.7

1.1

1.1

5.1

0.9

1.1

2.1

2.0

3.5

1.5

2.7

3.3

4.7

4.0



0.7

2.7

1.9

1.2

1.5

0.7

1.7

0.9

0.8

1.0

1.1

0.8

1.3

1.1

1.0

1.7



6.7

1.0

1.8

1.7

6.4

1.3

1.7

2.4

2.6

4.1

2.5

3.4

3.7

5.8

4.9





1.0

3.4

2.6

1.9

2.4

1.1

2.2

1.4

1.2

1.5

1.7

1.3

2.2

1.7

1.6



8.7

1.5

2.0

2.5

8.4

2.1

2.5

2.7

3.4

5.0

3.9

4.8

4.2

7.5

6.4



1.5

4.5

3.7

2.9

3.8

1.9

2.9

2.1

1.8

2.2

2.5

2.1

3.5

2.5

2.5

3.4



12.0

2.4

4.5

3.9

12.0

3.2

3.9

3.3

4.8

6.6

6.3

7.2

5.0

10.0

8.7





2.4

6.4

5.5

4.6

6.1

3.1

4.2

3.4

2.9

3.4

3.9

3.4

5.7

3.9

4.0

Forage Crops

Alfalfa

Barley hay

Bermudagrass

Clover, Berseem

Corn (Forage)

Harding grass

Orchard grass

Perennial rye

Sudan grass

Tall fescue

Tall wehat grass

Trefoil, big

Trefoil, small

Wheat grass



1.3

4.0

4.6

1.0

1.2

3.1

1.0

3.7

1.9

2.6

5.0

1.5

3.3

5.0



2.2

4.9

5.7

2.1

2.1

3.9

2.1

4.6

3.4

3.9

6.6

1.9

4.0

6.0



3.6

6.3

7.2

3.9

3.5

5.3

3.7

5.9

5.7

5.7

9.0

2.4

5.0

7.4



5.9

8.7

9.8

6.8

5.7

7.4

6.4

8.1

9.6

8.9

13.0

3.3

6.7

9.8

Fruit Crops

Almond

Apple, Pear

Apricot

Avocado

Date palm

Fig, Olive

Pomegranate

Grape

Grapefruit

Lemon

Orange

Peach

Plum

Strawberry

Walnut



1.0

1.0

1.1

0.9

2.7



1.8

1.0

1.2

1.1

1.1

1.1

1.0

0.7

1.1



1.4

1.6

1.3

1.2

4.5



2.6

1.7

1.6

1.6

1.6

1.4

1.4

0.9

1.6



1.9

2.2

1.8

1.7

7.3



3.7

2.7

2.2

2.2

2.2

1.9

1.9

1.2

2.2



2.7

3.2

2.5

2.4

12.0



5.6

4.5

3.3

3.2

3.2

2.7

2.8

1.7

3.2

1Based on the electrical conductivity of theirrigation water (ECe) measured in mmhos/cm.





Table 9. Chloride tolerance of agricultural crops. Listed in order of tolerance.a (Adapted from Tanji, 1990).



Crop		 Maximum CL- concentrationb without loss in yield
mol/m3 ppm
Strawberry

Bean

Onion

Carrot

Radish

Lettuce

Turnip

Rice, paddyc

Pepper

Clover, strawberry

Clover, red

Clover, alsike

Clover, ladino

Corn

Flax

Potato

Sweet potato

Broad bean

Cabbage

Foxtail, meadow

Celery

Clover, berseem,

Orchardgrass

Sugarcane

Trefoil, big

Lovegrass

Spinach

Alfalfa

Sesbaniac

Cucumber

Tomato

Broccoli

10

10

10

10

10

10

10

30d

15

15

15

15

15

15

15

15

15

15

15

15

15

15

15

15

20

20

20

20

20

25

25

25

350

350

350

350

350

350

350

1,050

525

525

525

525

525

525

525

525

525

525

525

525

525

525

525

525

700

700

700

700

700

875

875

875

aThese data serve only as a guideline to relative tolerance among crops. Absolute tolerances vary, depending upon climate, soil

conditions and cultural practices.

BCl- concentrations in saturated-soil extracts sampled in the rootzone.

CLess tolerance during emergence and seeding stage.

DValues for paddy rice refer to the Cl- concentration in the soil water during the flooded growing conditions.



Table 10. Limits of boron in irrigation water. (Adapted from Rowe and Adbel-Magid, 1995)

A. Permissible Limits (Boron in parts per million)


Class of Water		 Crop Group
Sensitive Semitolerant Tolerant
Excellent

Good

Permissible

Doubtful

Unsuitable

 < 0.33

0.33 to 0.67

0.67 to 1.00

1.00 to 1.25

> 1.25

 < 0.67

0.67 to 1.33

1.33 to 2.00

2.00 to 2.50

> 2.50

 < 1.00

1.00 to 2.00

2.00 to 3.00

3.00 to 3.75

> 3.75

B. Crop groups of boron tolerance (in each plant group, the first names are considered as being more tolerant; the last names, more sensitive
Sensitive

(1.0 mg/L of boron)

 Semitolerant

(2.0 mg/L of boron)

 Tolerant

(4.0 mg/L of boron)

Pecan

Walnut (Black, Persian, or English)

Jerusalem artichoke

Navy bean

American elm

Plum

Pear

Apple

Grape (Sultania and Malaga)

Kadota fig

Persimmon

Cherry

Peach

Apricot

Thornless blackberry

Orange

Avocado

Grapefruit

Lemon

(0.3 mg/L of boron)

 Sunflower (native)

Potato

Cotton (Acala and Pima)

Tomato

Sweetpea

Radish

Field pea

Ragged Robin rose

Olive

barley

Wheat

Corn

Milo

Oat

Zinnia

Pumpkin

Bell pepper

Sweet potato

Lima bean

(1.0 mg/L of boron)

 Athel (Tamarix aphylla)

Asparagus

Palm (Phoenix canariensis)

Date palm (P. dactylifera)

Sugar beet

Mangel

Garden beet

Alfalfa

Gladiolus

Broad bean

Onion

Turnip

Cabbage

Lettuce

Carrot









(2.0 mg/L of boron)



Table 11. Relative susceptibility of crops to foliar injury from saline sprinkling waters. (Tanji, 1990)

Na or Cl concentration (mol/m3) causing foliar injury8
< 5 5 - 10 10 - 20 > 20
Almond

Apricot

Citrus

Plum

 Grape

Pepper

Potato

Tomato

 Alfalfa

Barley

Corn

Cucumber

Safflower

Sesame

Sorghum

 Cauliflower

Cotton

Sugar beet

Sunflower

aFoliar injury is influenced by cultural and environmental conditions. These data are presented only as general

guidelines for daytime sprinkling.



Table 12. Tolerance of Various Crops to Exchangeable-Sodium Percentage. (James et. al., 1982)

Tolerance to ESP

(range at which affected)



Crop		 Growth Responsible

Under Field Conditions

Extremely sensitive

(ESP = 2-10)

 Deciduous fruits

Nuts

Citrus

Avocado

 Sodium toxicity symptoms even at low ESP values
Sensitive

(ESP = 20-40)

 Beans Stunted growth at low ESP values even though the physical condition of the soil may be good
Moderately tolerant

(ESP = 20-40)

 Clover

Oats

Tall fescue

Rice

Dallisgrass

 Stunted growth due to both nutritional factors and adverse soil conditions
Tolerant

(ESP - 40-60)

 Wheat

Cotton

Alfalfa

Barley

Tomatoes

Beets

 Stunted growth usually due to adverse physical conditions of soil
Most tolerant

(ESP > 60)

 Crested and fairway wheatgrass

Tall wheatgrass

Rhodes grass

 Stunted growth usually due to adverse physical conditions of soil