Catch crop cultivation and plowing
Catch crops, which are sown to green the soil before winter, play a crucial role in keeping it healthy. They contribute to humus enrichment and thus create the basis for high-yield agriculture.
What catch crops are there?
Catch crops are diverse and can offer many advantages due to their different properties. Their selection should be adapted to climatic and site-specific conditions as well as the crop rotation. Their later use, e.g. as fodder crops or green manure, can also be a selection criterion. With his selective choice of catch crop, the farmer can decide which advantages of catch crop cultivation he wants to use.
Some of the most common catch crops are:
- Legumes such as red clover (Trifolium pratense), white clover (Trifolium repens), alfalfa (Medicago sativa) and winter vetches (Vicia villosa) improve the soil structure through intensive rooting and their root residues increase the nitrogen balance in the soil. They can also bind nitrogen from the air with the help of nodule bacteria and are a good source of animal feed.
- Cruciferous plants such as mustard (Sinapis alba), oil radish (Raphanus sativus var. oleiformis) and turnip rape (Brassica rapa) can effectively suppress the growth of weeds and help to reduce soil pests thanks to their very rapid growth. The deep roots of oilseed radish break through compacted soil layers and absorb excess nutrients. Its cultivation has become particularly important as a preceding crop before mulch sowing.
- Grasses such as rye (Secale cereale), oats (Avena sativa) and ryegrass (Lolium perenne) are cold-tolerant, suppress weeds through their rapid growth and improve the soil structure. They are also suitable as fodder in spring.
- Other catch crops such as phacelia (Phacelia tanacetifolia) or sunflowers (Helianthus annuus) protect the soil from erosion, break through it with deep roots and provide nectar for pollinators.
Mixtures of different catch crops combine the advantages of the individual plants.
What are the advantages of growing catch crops?
- Soil improvement: catch crops loosen the soil and increase the permeability for water and air, which increases soil fertility.
- Nutrient supply: After dying, catch crops release nutrients that are available to the main crops, reducing the need for synthetic fertilizers.
- Erosion protection: The plants form a dense cover of vegetation that protects the soil from wind and water and thus minimizes erosion.
- Weed suppression: catch crops reduce weed growth by competing for light and space, which minimizes the use of herbicides.
- Promoting biodiversity: They provide habitats and food for insects, birds and other animals.
- Economic aspects: Improved soil fertility and structure leads to higher yields. In addition, catch crops can provide feed for animals or be used as energy crops.
What happens to the catch crop after the winter?
The post-winter treatment of catch crops is an essential part of their use and depends on the cultivation objectives, the stage of development of the plants, the soil and climatic conditions and operational requirements.
Incorporation can be done mechanically by repeated tillage. On the one hand as deeper incorporation using a plow. On the other hand, as shallow incorporation with a cultivator, tiller or harrow, which mixes the plants with the top layer of soil. As a result, the soil is initially uncovered again and more susceptible to heavy rainfall and sunlight. Shallow incorporation is only possible with frost-sensitive catch crops that die completely in winter. Winter-hardy catch crops such as rye or winter vetch survive the winter and must be treated in spring. However, mild winters can also cause frost-sensitive plants such as oil radish or mustard to sprout again and cause weed problems.
Catch crops can be left on the soil surface as mulch. This regulates the soil temperature, retains moisture and suppresses weeds. Later main crops can be sown directly into the mulch, for which special seed drills are required.
Both in systems with minimum tillage and in direct sowing, the chemical killing of catch crops is usually unavoidable. This is done with glyphosate. An alternative to this is the killing of catch crop residues with the Volt.apply system. This technology is based on the pre-treatment of plants with a conductive liquid, followed by an electrical application that destroys the cells and water-conducting bundles of the plants, leading to ripening and drying.
