Modern agriculture is a multi-sectoral production, combining, as a rule, livestock and crop production. Depending on soil and climatic, economic and other conditions, as well as the specialization and scale of production in each farm there is a certain structure of sown areas.

The structure of cultivated land – the ratio of areas under crops and bare fallow.

Planning the structure of areas allows the most efficient use of land resources, taking into account the natural, economic and agronomic conditions.

The size of the fields is determined by the cropping pattern, the topography and natural boundaries, and the type of crop rotation. For example, crop rotations with a short rotation allow for larger fields, whereas in multifield crop rotations a long rotation is used. In the steppe and forest-steppe zones, more often, fields are larger than in the forest-meadow zone. It is desirable that the fields in the rotation have approximately equal areas.

Example. On one arable land it is necessary to sow 4 cultures with the following structure of the sown areas: winter wheat – 25%, potatoes – 25%, barley – 25%, mixed crops for green fodder – 25%. For this purpose, the arable area is divided into 4 equal fields, on which one crop is placed. In subsequent years, there may be two ways of placing these crops on the fields.

In the first case, each crop is placed in the same field where it already grew, and thus they will be referred to as a permanent crop.

A permanent crop is a crop that is cultivated for a long time in the same field.

A monoculture is the only perennial crop grown on a farm. Often the term “monoculture” is used as a synonym for “permanent crop”.

Centuries of accumulated farming experience shows: the permanent cultivation of almost all agricultural plants leads to a significant reduction in yields, and in some cases to the death of the crops.

The second option of crop placement from the example assumes their annual replacement on four fields in a predetermined sequence, i.e. in the order of alternation by years.

The most effective and scientifically grounded sequence of alternation for the listed crops is as follows: 1 – forage vicia-oat mixture, 2 – winter wheat, 3 – potatoes, 4 – barley. In this case, each crop is the predecessor of the one that comes next year.

The predecessor is a crop or fallow that occupied the field before the subsequent crop in the rotation.

The given scheme of alternation assumes the following placement by fields and years:

Regardless of the crop that occupies the field in the first year, within 4 years each of them will pass through each field and the rotation of the crop rotation will be completed.

Rotation is the period during which all crops and pairs will pass through each field in the sequence provided by the crop rotation. The rotation chart above is called a rotation table.

The rotation duration in the example is 4 years. The rotation is determined by a rotation schedule with a duration equal to the number of fields. The number of fields in the rotation is determined by the number of crops and their ratio, taking into account the location of land, topography, soil differences and other conditions.

Traditionally, it is customary in crop rotation schemes to designate rotation numbers with Arabic numerals and field numbers with Roman numerals. When a crop rotation is introduced, each field is assigned a permanent number, which is retained in the crop rotation and land management documents, on boundary marks located along the borders of the fields, as long as the crop rotation scheme is used.

After the completion of the first rotation, the subsequent rotation begins with the placement of crops on the same fields on which they were placed in the first rotation. However, during the course of a crop rotation, for many reasons, crop rotation schemes may be altered.

A rotation scheme may include both individual crops and groups of crops, usually with similar properties: cereals (winter or spring), leguminous, row crops, perennial grasses, annual grasses, bare and seeded fallow. For example, the rotation scheme would look as follows: 1 – annual grasses, 2 – winter cereals, 3 – row crops, 4 – spring cereals. This approach allows you to adjust the crop rotation, if necessary, without changing it as a whole. For example, in the above example, crops can be replaced by: 1 – pea-barley mixture green for fodder, 2 – winter rye, 3 – corn for silage, 4 – oats, while keeping the rotation and structure of areas.

As a rule, one crop occupies one field. However, in certain crop rotations, often with a short rotation, it is possible to sow several similar crops in the same field. For example, a field of winter cereals may contain winter rye and winter wheat, a field of row crops may contain potatoes, corn for silage and forage root crops, a field of spring cereals may contain oats and barley, etc. In this case the field will be a combined field.

Prefabricated crop rotation field is a field on which several crops are cultivated.

Repeated crops – crops cultivated on the same field 2-3 or more years in a row with its subsequent replacement until the rotation of the rotation is completed. In some cases, such as perennial forage grasses – legumes, cereals, or their mixtures, which occupy several years one field does not qualify as repeated crops, as the cycle of their development in each year differs from the previous by the composition of the herbage and its use.

Sod-liking crop is a crop that comes after perennial grasses in the rotation. Post-sod-liking crop is a crop that follows the rotational crop after the sod-liking crop.