|
High levels of chloride in the soil solution will result in chloride toxicity in the plant (Table 1) (Libro Azul, 2002). A number of crops are known for being sensitive to chloride: fruit crops (almond, apricot, avocado, banana, citrus, grapes, mango, peach), berries (incl. strawberry), vegetables (lettuce, onions, sweet pepper), field crops (potato, tobacco), coffee and flowers.
Elevated chloride levels, when allowed to exist, may directly result in plant toxicity, or reduce the quality of the harvested part of the plant. Examples of reduced quality are: reduction in the dry matter content of potato tubers, reduced combustibility and “Wet dog” symptoms in tobacco (tobacco becomes dark and smelly after packing), and a reduced percentage of extractable sucrose in sugar cane. Furthermore, plants may tolerate chloride well, but not the associated increase in soil salinity (e.g. banana).
| Table 1. |
Tolerance of fruit and other crops to different chloride levels in the saturated soil extract. |
|
Fruit crops
|
Chloride level in the saturated soil extract
|
|
mmol/litre
|
ppm
|
|
Citrus
|
10-25
|
350-875
|
|
Stone fruit
|
7-25
|
245-875
|
|
Avocado
|
5-8
|
175-280
|
|
Grape
|
10-25
|
350-875
|
|
Berries
|
10
|
350
|
|
Strawberry
|
5-8
|
175-280
|
|
Other crops
|
|
Sugar beet
|
90
|
3.150
|
|
Tomato
|
39
|
1.365
|
|
Geranium
|
30
|
1.050
|
Table 2 shows the risk of chloride toxicity in plants at different chloride levels in the irrigation water (Libro Azul, 2002).
| Table 2. |
Risk of chloride toxicity in plants at different chloride levels in the irrigation water. |
|
Chloride in water
|
Comments
|
|
mmol/l
|
ppm
|
|
<2
|
<70
|
In general, safe for all plants
|
|
2-4
|
70-140
|
Sensitive plants usually show light to moderate toxicity effects
|
|
4-10
|
140-350
|
Moderately tolerant plants show light to substantial toxicity effects
|
|
>10
|
>350
|
May cause severe problems
|
Reference:
Libro Azul. 2002. Manual de fertirriego de SQM. 3 ed. Ed. by Samuel Román C.
|
PRODUCT FEATURES & BENEFITS 
