The Content Of The Article:
- Origin of calcium cyanamide
- Chemical composition of lime nitrogen
- Long-term effect by nitrification inhibitors
- fertilizing effect
- Effective fungus and pest control
- Calcium cyanamide as a herbicide
- Health hazards of calcium cyanamide
- Use in the garden
- Dosage of calcium cyanamide
Origin of calcium cyanamide
Calcium cyanamide has been industrially produced for over 100 years and used both in agriculture and in private gardens. In 1895, for the first time, chemists succeeded in binding the abundant atmospheric nitrogen to calcium carbide, which is produced from coal and limestone. These carbon shares are also what give the lime nitrogen its typical color - it is almost black.
Since the 1950s, lime nitrogen as a nitrogen source has mostly been replaced by more nutritious fertilizers. Despite health risks, however, it is still very popular - because although lime nitrogen is approved as a fertilizer and not as a pesticide, it is usually appreciated because of its herbicidal side effect.
Chemical composition of lime nitrogen
Calcium cyanamide is often offered as a "perlka" and contains 19.8 percent nitrogen in the form of calcium cyanamide (CaCN2), some nitrate and a calcium content of more than 55 percent. At first, the plants can not do anything with calcium cyanamide, but they only reach the required nitrogen by way of detours.
Calcium cyanamide is converted into plant-available substances in the soil in interaction with water and certain micro-organisms. First, slaked lime and water-soluble, toxic cyanamide are produced, which is responsible for the herbicidal effect. After two weeks cyanamide loses its poisonous effect, as the microorganisms make it harmless urea, ammonium and ultimately nitrate, which the plants can use directly. There are no toxic residues left.
Long-term effect by nitrification inhibitors
As long as ammonium does not turn into nitrate, the nitrogen remains in the soil. The microorganisms take some time until the nitrogen is completely processed for the plants. To slow down this transformation even more, the calcium cyanamide dicyandiamide (DCD) is added, a so-called nitrification inhibitor, which also arises again as a by-product in the degradation of cyanamide. The DCD slows down the bacteria that convert ammonium into nitrate. This is the basis of the long-term effect of calcium cyanamide.
The nitrate content of lime nitrogen is immediately available to the plants, the remaining nitrogen supplies them for another four to eight weeks. The duration of action varies according to soil moisture and temperature. Lime is also a plant nutrient, but stabilizes above all the pH of the soil and makes it permeable. Overcalculation is due to the concentration is not to be feared, but you should consider the amount in any subsequent liming. In the compost heap, lime nitrogen acts as a composting agent that neutralizes, among other things, the acids that are formed.
Effective fungus and pest control
The fungicidal and insecticidal effect of the use of calcium cyanamide is due to the action of cyanamide. This kills germinating (weed) seeds, seedlings, pests, but also other animals in the soil. Therefore, lime nitrogen is often used in the basic fertilization of empty seed and plant beds.
The Kohlhernie is probably the most persistent fungal disease that can occur in cabbage. She can hardly fight. However, lime nitrogen prevents the permanent pores in the soil from germinating, so that the infestation pressure drops significantly. The same happens with the spores of apple scab, which do not survive in calcium-treated fall foliage.
Snails can become a real plague in the garden. Lime nitrogen kills both existing stocks and their eggs radically. It can also be used against wireworm or Tipula larvae.
Calcium cyanamide as a herbicide
Calcium cyanamide acts as a weed agent in the first few days after application and penetrates two to three centimeters deep into the soil. He is almost too efficient and destroys there all flatroots, seedlings and young plants to the training of the fourth leaf.
Health hazards of calcium cyanamide
Human health hazards threatened by incorrect or negligent use, especially by the toxic cyanamide. On contact with the mucous membranes or damp skin, lime nitrogen is corrosive and extremely harmful to health. The cyanamide must not be inhaled in any way. Wearing protective gloves is essential! It is not for nothing that lime nitrogen has a hazard identification that is otherwise only found in pesticides. However, cyanamide does not form any rising vapors in the soil, but the surface should still rest after use.
Use in the garden
Calcium cyanamide is commercially available as granules - as a dust-fine powder, it is no longer available for safety reasons. It can be spread in the garden from March to September and worked into the soil. In spring two weeks, in summer a week before planned planting or sowing. That's how long it usually takes until the toxic phase is over. During this time, the bed should not be entered and also be inaccessible to pets.In cool weather, we recommend to wait a few days longer with the planting.
When spreading, make sure that the calcium cyanamide grains do not end up on other crops or neighboring crops. The use in the garden is in principle limited to new plantings of lawns or beds, to fill up the nitrogen reserves or the "floor cleaning" after a culture. In existing cultures, the application, especially for inexperienced gardeners, not recommended.
Although calcium cyanamide has proven very successful as a lawn fertilizer, it can only be recommended to advanced gardeners or specialists. For the inexperienced a proper and safe handling is hardly practicable. A burnt lawn due to overdose, uneven distribution or damp weather too likely. If you remove the lime nitrogen with the spreader, the slightest overlapping of the lanes will also cause burns.
Dosage of calcium cyanamide
The dosage is adapted to the needs of the crops: starvation feeders such as cauliflower or broccoli receive 30 to 90 grams per square meter, depending on the amount of nitrogen in the soil. Salads, potatoes, Brussels sprouts or cucumbers 30 to 50 grams. Important: potatoes are placed before fertilizing. To create a new lawn you spread 50 grams per square meter, for existing lawn 20 grams are recommended. With compost, 150 grams of calcium cyanamide are added to one square meter of compost surface. Between the individual grit should be at least 30 centimeters thick layer of raw material (kitchen and garden waste).