Catch crop
As a cover crop is known in agriculture, a crop that between other main use for serving crops as green manure or for use as animal feed is grown.
By intercropping is crop rotation extends and improves.
use
Original usage
Various effects can be achieved by growing cover crops. It can serve to absorb nitrogen from the air and to bind it in the cells of the catch crops. The catch crops are then worked in so that the nitrogen bound in them is available for the next fruit in the crop rotation . Since nitrogen is an important plant nutrient, the cultivation of catch crops can increase the yield .
Other effects consist in stimulating and promoting soil organisms. Compacted soils or soils damaged by leaching can be regenerated with catch crops. There are also crops that should not be grown in immediate succession. Here the catch crop serves as a separating culture in the crop rotation. You can also give soils some rest after infectious diseases such as fungal, virus or bacterial infestation by growing catch crops.
Modern agriculture and water pollution by nitrate
In modern agriculture crops have lost their function as a nitrogen source, because due to the high cattle impurities in the factory farming the quantities present on nitrogen are already very high. Legal regulations (Fertilizer Ordinance) attempt to restrict the use of liquid manure and other animal manure so that the cultivated crops can absorb the nutrients well and overfertilization is avoided. But since z. B. in late summer, when many arable crops no longer need fertilizer and manure is still available, the cultivation of catch crops is interesting. They then absorb nutrients and release them the following spring when the main crop needs them.
In the intensive industrial agriculture of the GDR , nitrogen pollution was reduced by flooding liquid manure on smaller fields and drying it. These were then made plantable again for other types of fruit with high nitrogen-consuming catch crops. However, there are few crops that clearly come with very high concentrations, including various mixture seeds and some grass species that can be burned. In the middle load range can feed corn leach enough the ground.
Harvesting catch crops
Due to the changed purpose of the catch crops, they are seldom plowed today because they would then re-enter the nitrogen they had absorbed. They are therefore often used as feed, such as feed corn . Often they are not collected at the most effective harvest time, but continuously as required or in such a way that the following main crop can hit the ground on time.
Examples of catch crops
Alfalfa and certain types of clover are typical sources of nitrogen. They are also important sources of protein for beef cattle farming. However, alfalfa is not a catch crop.
Other catch crops are:
- Annual ryegrass, such as the Welsche ryegrass
- perennial grass clover
- Alexandrine clover
- Green rye
- Summer and winter rape or white mustard : these cover the ground very quickly due to their rapid emergence and rapid growth. The cultivation protects the soil from erosion and leaching phenomena. The soil fertility is improved by the high amount of organic matter, mustard freezes safely in winter. They can have a nematode-reducing effect. The sowing rate is 20-25 kg / ha. The sowing time is, depending on the variety, from July to September.
- Lupine and other legumes such as field peas or peas have a good ability to acquire nitrates and are fast-growing. The sowing rate is 25 kg / ha, the sowing time is until the end of August.
- Oil radish
- Phacelia is nematode-neutral and freezes safely. It fits into every crop rotation, as there is no relationship with the cereals or other fruits grown here. Phacelia is considered a fruit of recovery. The sowing rate is 10-14 kg / ha, the time of sowing is until the end of September.
- Marrow stem cabbage
- Winter turnips
See also
Individual evidence
- ↑ cf. Definition in Brockhaus in 15 vol., FA Brockhaus, Leipzig / Mannheim, 1999, ISBN 3-7653-2951-7 .