A METHOD TO IMPROVE THE SPRINKLER IRRIGATION UNIFORMITY IN FOREST NURSERIES

The research was carried out in the Iarac forestry nursery in the Iuliu Moldovan Forest District during 2010-2012, on an alluvial soil (the vertical-gleyed subtype). The placement of the sample plots was carried out according to the parcel in two repetitions, and the surface of a parcel was 450 m(2). The present paper displays the results obtained after the sprinkler irrigation, when we determined the quantity of water spread by the 6 sprinklers on a 15-mradius, placed on the direction of the cardinal points. The purpose of the research was to observe the correlation between the qualitative work indexes of the sprinkling devices, by spreading a uniform quantity of water on the entire surface and the maintenance of an ecological balance of cultivation of the saplings in the forestry nursery. In a close connection with the purpose stated, the paper also focuses on the study of the work indexes of the sprinklers used in forestry nurseries, among which the most important is the uniformity of sprinkling. The main means used for the improvement of sprinkling uniformity are the following: the usage of sprinklers with a small radius of sprinkling, having correct pluviometric curves; the correct placement of sprinklers on the terrain, according to the schemes of work recommended; avoiding to water when the speed of the wind surpasses the speed limit established for the sprinklers used. Another major source of non-uniformity of the watering through sprinkling is represented by the influence of the wind. The wind deforms the circular form of the surface sprinkled, which becomes a more or less normal ellipsis and a more or less flattened ellipsis, according to the uniformity and intensity of the wind.