Lawns are perennial crops that are kept on a certain substrate, and often even a dozen or so years, therefore, particular attention should be paid to the selection and preparation of this substrate.
Composition, mechanical. The value of the soil is usually proportional to the degree of fragmentation of the parent rock that makes up the soil minerals. The degree of fragmentation of these components varies in different soils. Mechanical composition, that is, the relationship between the skeletal parts present in the soil in the form of stones and gravel and the earth parts in the form of sand, Dust, silt, is very important in assessing the suitability of soil not only for lawns, but also for many other crops.
The breakdown of soil minerals into fractions is presented in the table. Based on the mechanical composition, a preliminary assessment of the physical and chemical properties of the soil can be made.
The mechanical composition has a very significant influence on many soil properties. Generally known, for example, that the high content of gravel and stones in the soil deteriorates its water properties. Then there is too much water permeability and excessive airiness, as a result of which such soils are most often too dry. On the other hand, soils consist largely of finely divided material, generally called clay, having much smaller pores, they keep the water very well, but they are not very airy.
From the point of view of the needs of plants, such soils are considered the most appropriate (or just their top layers in thickness 20-30 cm), in which the sand fraction predominates. The content of sand in the soil, depending on other factors, np. permeability and moisture content of the substrate, (should be 60-90%, and the dust and clay parts (cops) — 40-10%. For high-quality lawns that are well-cared for, soils with an upper limit of content are used, that is 90% ,sand and only 10% cops. The mixture can be modified mainly by the use of various additives of organic materials. Keeping the mineral parts in such proportions facilitates the creation and maintenance of permanent soil physical properties suitable for lawn plants, and therefore, above all, a suitable structure, water capacity and air permeability. Please note, that in the soil under the lawn very difficult or, it is impossible to obtain adequate porosity, which is suitable in other areas through annual cultivation treatments, In the lawn soil, this porosity must be created permanently precisely by maintaining the appropriate grain size ratio.