Abstract. Elderberry (Sambucusnigra L.) is a common species belonging to the Adoxaceae family native to most of Europe and North America. For centuries, elderberry has been used as a medicinal plant. This species is also a popular ornamental plant often grown in the gardens and city parks. However, the seedling survival rate of elderberry depends mainly on the suitable soil water conditions that can be controlled using a properly designed and operated microirrigation system. Firstly, it is necessary to determine the water needs of Sambucusnigra L., especially in the first period of growth, which determines the seedling survival rate of the plants introduced into the gardens or parks. A commonly accepted measure of the plant water requirements is the potential evapotranspiration of this plant. The purpose of the research was to assess the water needs of Sambucusnigra L. during the first three years of its growing in five different regions of Poland. Potential evapotranspiration of the elderberry was calculated using modified by Żakowicz for Polish conditions the Blaney-Criddle's method, to which the crop coefficients were adjusted. The study was carried out for thirty years, from 1981 to 2010, in five different agro-climatic regions of Poland.The largest water needs in the period of increased demand for water in elderberry (June-July) occurred in the central-north-western (232 mm) and central-eastern (230 mm) regions. The lowest water needs were found in the south-eastern region (214 mm). The highest rainfall deficit in the central-north-west region (102 mm), smaller rainfall deficit in the central-eastern and south-western regions, amounted to 82 mm and 72 mm, respectively. The lowest rainfall deficit (40 mm) was found in the south-eastern region.In the central-north-west and central-eastern regions, precipitation deficiency occurred in 28 out of 30 considered years (93 % years). In the south-eastern region, precipitation deficiency occurred in 21 years (70 % of years).Keywords : irrigation, evapotranspiration, reclamation, seedling survival, water requirements.
IntroductionElderberry (also called medicinal lilac) is a popular plant used for centuries for medicinal purposes [1; 2]. Sometimes it is cultivated -as an ornamental shrub -also in parks and home gardens. High Elderberry planting -on the surface of the park or within a given garden -depends primarily on optimal water conditions that can be effectively shaped using properly programmed and operated microirrigation. However, this requires the necessary prior determination of the needs of water plants, especially in the first -decisive for the success of the plantings carried out -the period of growth of plants introduced into the area of a given park or garden.The objective of the present research was to estimate of the water needs of elderberry (Sambucusnigra L.) at the first three years of growing on reclaimed land in different regions of Poland.