Summary:

The influence of fertilization with the compost prepared from forest humus and mulching with the fresh ectohumus on the soil properties, the growth of one-year old Scots pine seedlings as well as on the biological activity of soils in the forest nursery was studied in the work. The biological activity was estimated with the usage of bioindicatory method - mites (Acari), especially saprophage oribatid mites (Oribatida) were used as biological indices.
On the base of the study it was stated that the ground surface horizon was characterized by acid reaction. Fertilization with the compost from forest humus increased significantly the height of Scots pine seedlings - plants cultivated on plots fertilized with compost were by 46% higher than those fertilized by mineral fertilizers only. Organic fertilization increased also significantly the fresh mass of the above-ground parts of Scots pine seedlings. Effect of mulching - which was carried out in September - on the investigated parameters was not detected. In the spring - before the measure of mulching - the density of mites on the studied ground was low. Among these arthropods the most numerous were Actinedida which constituted from 91 to 100% of all mites. After the measure of fresh ectohu-mus mulching, the number of saprophage oribatid mites was distinctly increased - they constituted 51 to 82% of all Acari. On these stands there were 11-19 taxa of oribatid mites, and Tectocepheus velatus was the predominant representative of this order of mites.