Siderat (green fertilizers) are plants grown for the purpose of subsequent incorporation into the soil to improve its structure, enrichment with nitrogen, and suppress the growth of weeds.
Usually, siderat is plowed before or shortly after the beginning of flowering as a green fertilizer rich in nitrogen, proteins, starch, sugars, microelements; at the same time, compost is formed on the surface, the soil is protected from erosion and blowing. Plant roots improve the mechanical structure of the soil: a system of root canals is created, worms and microbes that accumulate nitrogen feed on dead roots.
Siderat quickly develops dense foliage that creates shade and inhibits weed growth. In addition, some types of green manure ( cereals ) secrete substances that retard seed germination, which also reduces the number of weeds. A well-developed root system of green manure helps to improve the structure and water permeability of the soil: penetrating deep inside, it loosens and enriches heavy clay soils with air, and supports light, sandy soils from crumbling. Green manure roots also deliver nutrients from deeper layers to the top, closer to the roots of useful crops, between which “green fertilizer” is grown. Siderat planted among vegetable crops partially distract garden pests to themselves. Some green manures can repel pests, such as radishes suppresses nematodes, mustard – scabs. In addition, most have bright and nectar-filled flowers that attract bees and bumblebees, which simultaneously pollinate neighboring plantings, which contributes to higher yields. Siderat of the legume family is in symbiosis with nitrogen-fixing bacteria, which convert atmospheric nitrogen into a bound state, which makes it available for consumption by plants. When using green manures, the amount of nitrogen available for further crops is usually 40-60% of the total amount of nitrogen contained in the green manure.
Siderat usually performs several functions, improving and protecting the soil:
- Siderat increases the percentage of organic matter (biomass) in the soil. Leguminous green manures bind atmospheric nitrogen into a form suitable for plant consumption. Embedding green manure in the soil causes the accelerated formation of humus available for subsequent plants. The increased microbial activity in the soil also leads to the formation of mycelium, improving the structure of the soil. The level of aeration and water penetration is improved.
- The root systems of some types of green manure effectively and deeply penetrate into the dense soil, causing additional aeration of the soil and extract upward substances that are inaccessible to plants with a shallow root system ( alfalfa ).
- Siderat is also useful for preventing erosion, controlling weeds, insect pests, and diseases. The deep root system of many green manures and their rapid growth make them effective weed control agents.
- Some green manure restrains plant diseases, such as Vertitsillioznoe withering (Verticillium wilt) potatoes.
- During flowering, green manures additionally attract both beneficial pollinating insects and predatory insects, which increases the yield of the main crops and reduces the use of insecticides.
Also, green manure can be used to reduce the pH of alkaline soils.
Types of siderat
It is believed that about four hundred cultures can act as siderat.
Primarily for siderat using bean: it peas, vetch, annual lupine, sainfoin, clover, chickpeas, alfalfa, beans, kidney beans, soybeans, lentils, goat’s rue, sweet clover, peas, cowpeas ( Vigna ), field pea ( pelyushka ), rank, seradella, etc. Legumes contain colonies of bacteria on their roots – nitrogen fixers – and greatly enrich the soil with nitrogen. Three crops of legumes are the same as a full dose of manure. All of them are cold-resistant, emerge early, and their roots powerfully loosen the ground.
From cereals, winter wheat, triticale, and rye, spring barley and oats, sugar and grain sorghum, Sudanese grass, paiza, hedgehog combined, chumiza (Italian millet), ryegrass, fescue, field grass, timothy grass, gray (non-sprawling) are used as green manure wheatgrass.
Cruciferous plants are also used: white mustard (English), gray mustard (Sarepta), winter rape, winter and spring rape, oil radish.
Plants of other families are also popular as siderat: phacelia, mallow, buckwheat, amaranth, etc.
Application of siderat
Limitations in the use of green manure are associated with the time, energy, and resources (monetary and material) required for their successful use. The choice of green manure should be determined by the nature of the region and the amount of precipitation – to ensure their effective use.
Ways to use green manure:
- In row spacing between vegetable or ornamental crops
- As an early ripening culture among long-ripening (parsnips, root celery, leeks, etc.)
- In the off-season, at the end of summer, or in autumn before winter
- During the rest of the soil from intensive use for the whole year