Summary:

Effects of three different irrigation systems (sprinkler irrigation, micro-jet sprinkling and drip irrigation) on the one-year old verrucose birch production under conditions of zoomelioration, are compared in the paper. Zoomelioration measures consisted in introduction of living edaphon with organic matter of forest soil to the nursery soil. Two-year (2003-2004) field experiments were carried out in forest nursery at Białe Błota, Forest Inspectorate of Bydgoszcz. Investigations were conducted on a brown podzolic soil formed from loose sandy soil. Experiment was established as one-factorial trial in randomized block method with four replications. Studied pressure irrigation systems significantly increased the height and diameter of verrucose birch seedlings grown under conditions of zoomelioration. Increased height of verrucose birch seedlings obtained thanks to irrigation ranged from 76 to 100%. Diameter of seedlings was increased by irrigation in the range 67 – 84%. The lowest relative increases of studied biometric features were found under drip irrigation. On the other hand, this irrigation system was characterized by the most economical of water use as compared to micro-jet sprinkling and sprinkler irrigation. Micro-jet sprinkling was the most advantageous in consideration of both the studied growing vigour features of seedlings. This irrigation method simultaneously secured slightly lower seasonal irrigation rates in comparison to sprinkler irrigation Zoomelioration measures connected with microirrigation caused a manifold increase of concentration and the numer of saprophagous oribatd mites as well as their domination in gatherings of mites, that is typical for forest soils. Gatherings of Oribatida on a plot with traditional methods of seedling production (sprinkler irrigation, without mulching) were characterized by domination of Tectocepheus velatus. Oribatula tibialis was the most numerous oribatid mite on all the other plots. Results obtained in the experiment indicated that microirrigation (especially micro-jet sprinkling) can be recognized as an alternative way of watering in forest nurseries instead of sprinkler irrigation, and zoomelioration (amelioration with soil animals) can positively influence on biological balance of nursery soils.