Chloride tolerance of individual crops
In nature, chlorine is found everywhere and is present in aqueous solution as a chloride anion (Cl-). In this form, chlorine is taken up by the plants. The average content in the plant ranges between 2 and 20 mg/g dry matter. For most plant species, however, the requirement for optimal growth is 10 to 100 times lower, so chlorine can be considered a trace element. Since plants receive chlorine from a variety of sources (soil, irrigation water, rainfall, fertilizers, air pollution), there is more risk of chlorine over-supply (toxicity) than chlorine deficiency. Different crops vary considerably in their sensitivity to chloride.
Therefore, four groups are distinguished:
- Chloride-loving plants
- Chloride-tolerant plants
- Conditionally chloride-tolerant plants
- Chloride-sensitive plants
Chloride-loving plants include sugar beet, fodder beet, celery, asparagus, and chard. Chloride-sensitive plants include many fruits and vegetables as well as specialty crops such as hops and tobacco.
Chloride may be present in potassium fertilizers. If the potassium is in the form of potassium chloride, the fertilizer is recommended only for chloride-loving and chloride-tolerant crops. If potassium is present in the form of potassium sulfate, such as in KALISOP®, chloride-sensitive crops can also be fertilized with it. It is advisable to check the information on the chloride content of the fertilizer.
| Demand/Preference | Crops | Products |
|---|---|---|
| Chloride-loving: (chloride fertilizers are preferred) |
sugar beet, fodder beet, celery, chard, coconut | Korn-KALI® 60er Kali® |
| Chloride-tolerant: (chloride fertilizers can be used; however, most vegetables prefer sulfate fertilizers due to sulfur requirements) |
grain, corn, rapeseed, asparagus, coarse cabbage, beet, rhubarb, grassland, clover grass, oil palm, rubber, rice, peanut, cassava, soybean, sugarcane, banana, cotton | 60er Kali® Korn-KALI® Magnesia-Kainit® |
| Conditionally chloride-tolerant: (chloride fertilizers can be used if done in time before the start of vegetation). |
sunflower, grapevine, pome fruit, black currant, seed and table potato, tomato, radish, radish, kohlrabi, fine cabbage, pea, spinach, carrot, leek, horseradish, chicory, pineapple, cucumber, kiwi, coffee, tea. | PatentKALI® KALISOP® Korn-KALI® |
| Chloride-sensitive: (only fertilizers in which potassium is present in sulfate form should be applied). |
starch and grafting potato, tobacco, red currant, gooseberry, raspberry, hops, strawberry, blackberry, blueberry, mango, citrus, pepper, chili, avocado, cashew, almond, cocoa, peach, Pome and stone fruit (especially sweet cherry), bush bean, broad bean, cucumber, melon, onion, lettuce, early vegetables, all greenhouse crops, conifers, flowers and ornamentals, and seedlings and saplings of most plants. | PatentKALI® KALISOP® |
The effect of high chloride concentrations in the soil solution on the yield of various crops is shown in the graphs. The steeper the drop in yield with increasing chloride content in the soil, the more sensitive the crop is to chloride and the better the effect of virtually chloride-free fertilizers, such as KALISOP® and PatentKALI®.
Before these significant yield reductions, the uptake of large quantities of chlorine leads to significant quality problems, such as:
- lower content of organic acids, resulting in a pale taste;
- accumulation of low-molecular organic substances and therefore a lower content of valuable ingredients, such as sugar, starch, and protein;
- increasing water accumulation in plant tissues, resulting in reduced storage and processing properties
The application of virtually chloride-free potassium fertilizers such as KALISOP® and PatentKALI® is recommended to avoid losses in yield, quality, and therefore also income in chloride-sensitive and especially higher-value crops, where quality pays off.
Safeguarding yield and quality with potassium sulfate
Most fruits and vegetables, vines, and table potatoes are sensitive to chloride: yield and quality are affected. Therefore, potassium sulfate should be used instead of potassium chloride for these crops. Information on the chloride content can be found in the declaration of the fertilizers.
