The phenomenon of the disappearance of loosening, that is, subsidence, creates a lot of trouble in practice, because it very often causes the surface of the lawn to ripple. The consequences of this phenomenon can be very clear, if the lawn is set up on high embankments that are not sufficiently compacted. Therefore, before setting up a lawn on an embankment, it must be carefully compacted, and often leave for a period of 2–3 lat, during which subsidence will occur.
A clear uneven soil subsidence occurs after it has been loosened even by several centimeters. Greater uneven subsidence always occurs on heavier soils, because the cultivation of these soils increases the loosening. The degree of loosening is also influenced by soil moistening.
Very dry sandy soils undergo the smallest loosening, on the other hand, clay soils in a dry state obtain the greatest loosening during cultivation.
Knowledge of these regularities is of great practical importance, because it allows you to perform certain cultivation treatments (np. mixing soil with sand, with peat and fertilizers) without causing excessive loosening, by carrying out treatments in conditions of appropriate soil moisture. Exercising deep to 30 cm of plowing soil under the lawn should be justified only in partially sodded or contaminated areas. The plowed soil should be loosened at least twice with a cultivator and left for the winter, that subsidence can occur.
Only the following year can the surface be finally leveled.
On previously cultivated soils, it is enough to loosen the soil twice with a cultivator to the depth 20 cm, thorough harrowing and smoothing with a drag or mesh harrow. These treatments should not be performed, when the soil is excessively moist or very dry.
Before carrying out the treatments consisting in mixing the soil, fertilizers must be added, especially phosphorus and lime, if required by the results of the pH measurement, and organic materials, like peat, compost, etc..