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    Crop rotations and soil

Crop rotation effects on soil and crop

The combination of different types of crops with individual root systems and root lengths promotes different microorganisms in different soil layers. Here, catch crops are an helpful addition to the rotation.

Cultures with different deep roots can break up unfavorable structures, so that air, water, nutrients and soil organisms can collect in the space in between. New connections can be created between the soil layers. In addition, soil organisms like earthworms consolidate the structure of the soil.

Topsoil, subsoil, cover crops

The topsoil should, if possible, consist of a fine crumb structure and be interspersed with harvest residues and fine roots. A single grain or aggregate structure with macropores without damaging compaction should be aimed for in the subsoil.

If such structures exist, it is important to maintain them, among other things, by cultivating cover crop mixtures.

What is more: In all operations, care must be taken to ensure that the floor is protected and that the structure of the floor is not destroyed but improved. The workability and navigability must be checked regularly.

Above-ground biomass reduces wind and water erosion, protects the soil from drying out and prevents weed formation through shading. The binding of soil nutrients in the biomass prevents leaching into the groundwater or erosion into surface waters.

At the end of the growing season, the catch crops can be harvested and used as animal feed or biogas substrate. In most cases, however, the organic matter is returned to the soil as nutrient humus after the growing season.

Many cover crop mixtures contain a mix of plant species with tap and tuft roots, which means that various soil horizons are deeply rooted underground. The fine and main root fractions loosen the soil by creating a branched system of pipes and ducts, crumbling soil aggregates and promoting the fermentation.

The different species in a mixture root through the soil at different depths. The roots give off exudates and enrich the soil with humus. The soil life is stimulated considerably - literally "fed". Due to the higher biological activity in the soil and the excretions of the plant roots themselves, nutrients are mobilized and are available in a plant-available form for the subsequent crop.

Cover crops with special properties

Some species have special properties that also have a positive effect on the soil. Legumes, for example, live in a symbiosis with nodule bacteria and, in exchange with organic carbon compounds, can bind nitrogen from the air - so the soil nitrogen is not only stored in the plant, but even reproduced naturally. Other species, in turn, are able to make certain nutrients available to the plants through their root excretions in the soil.

The ideal state of fertile soil is known as soil tare and is created by favorable physical, chemical and biological conditions.

In fertile soil, the mineral primary particles (e.g. clay, sand or silt) combine with organic soil components (humus) to form so-called aggregates. Pores are formed between the aggregates, which are ventilated and can hold water against gravity for a certain period of time - this creates a fertile habitat for microorganisms and other beneficial organisms such as earthworms.

A neutral to slightly acidic soil pH value plays an important role for the availability of nutrients, the life activity of the microorganisms and plant growth, depending on the type of soil it is between 5.5 and 7. Regular soil limescale can reduce the pH value, which changes over the course of the year, lowering, raising and improving the soil structure. To ensure that the plants are supplied with all the important nutrients and that soil fertility is maintained, needs-based fertilization is carried out according to good professional practice. It compensates for the erosion of nutrients by the harvest.

Some influencing factors for a cooked soil, such as the type of soil or the weather, cannot be influenced. Nevertheless, the farmer has many agricultural tools at his disposal for maintaining healthy soil, including, for example, soil-conserving cultivation systems, a site-specific nutrient supply, and liming or crop rotations.

The rooting of the soil is significantly involved in the formation of the Gare. On the one hand, root growth results in mechanical crumbling of the aggregates, on the other hand root exudates serve as food for microorganisms and as an adhesive substance for new aggregates. The sequence or combination of different types of crops with individual root systems and root lengths promotes different microorganisms in different soil layers.

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