Soil compaction assumes volume compression of the soil under the action of external factors. As solid particles can not be compressed, the air pockets between them reduce and therefore through compaction the dimensions of the pores is modified, their distribution and also the soil durability. The degree of compaction of the soil can be estimated thru apparent density, total porosity and degree of settling . The ground compaction in the forestry nurseries is characterized by the increase of the apparent density, the reduction of the total porosity, of the hydraulic conductivity and of the air permeability. These modifications influence the air and water mobility in the soil. The processing of the soil can produce or avoid the soil compaction. The excessive processing can favour the pulverization of the structure of the soil with effects on the compaction at the surface. The repeated tillage with a disc harrow at the same depth can lead, on certain soils, to the formation of compacted strata under the working depth. In general, the capacity of the soil to resist to compaction reduces itself while its humidity increases. When the soil is too humid, its plasticity and adherence are high and thus, the structural aggregates can be easily deteriorated. The result is the soil compaction. The research in cause has as a purpose the identification of the technical means of optimal mechanisation used in the forest nurseries, which are meant to lead to an decrease degree of compaction, a rise of the qualitative level of the processing. The purpose of the research is scientifically motivated through the necessity of introducing new tools for the execution of the works implied for soil preparation about activity settlement . The research has been carried out in three forest nurseries Forestry Department Arad, during 2006-2008, on different soil types. In the present paper, we display the results obtained after the working of the soil in the classical tillage system and minimum tillage system on the physical and mechanical properties. The work systems applied have been: classical tillage system (plough + disc 2X) and minimum tillage system (paraplow+ harrow). The usefulness of this paper lays in the research data gathered, processed, analyzed and exploited in order to provide a pertinent study material, which could be effectively used by the specialists in the design of obtaining saplings in the forestry nurseries and the choice of the tillage system for the optimal soil.

compaction, technical work, compression degree

Presentation: oral