Supplementary irrigation at container nursery

Abstract. For the period from the 1st of May to the 30th of October 2014, the water balance for Scots pine, Norway spruce, Pedunculate oak and European beech seedlings in a plantation setting was analysed. The experiment was conducted at the container nursery in the Rudy Raciborskie Forest District, Poland. Water was supplied by natural rainfall as well as a by small-droplet irrigation system and two automatic weather stations combined with 32 rain collectors were used to monitor rainfall throughout this research. Rain gauges were located 25 cm above the metal pallets and 10 cm below the nursery containers. An average of 987 mm∙m-2 of water reached the plantation, of which 53% were provided by the irrigation system. Most water was supplied to the oak field, whereas least was given to the spruce plantations and the irrigation water amounted to 535 liters and 422 liters per square meter, respectively. The amount of water percolating through the substrate was approximately 50–65%, depending on the tree species. An average sum of evapotranspiration at the container nursery was estimated to amount to 520 mm∙m-2 during the growth season leading to a total water balance of +463 mm.