The influence of irrigation on the growth of Paulownia trees at the first year of cultivation in a light soil

eISSN 2345-0916; eISBN 9786094491283The field experiment was carried out in 2016 on sandy soil in the forest nursery Białe-Błota (Bydgoszcz Forest Division, Poland). The effect of sprinkler irrigation on the growth Paulownia Shan Tong trees was investigated. The experiment was established as one factorial. The variability factor was the irrigation: S-sprinkler irrigation and C- without irrigation (control). The process included the controls of growth parameters: tree height, trunk diameter, number and surface of leaves. It was found that the sprinkled seedlings of Paulownia Shan Tong were significantly higher than those growing in the non-irrigated plots. The sprinkler irrigation applied in the experiment resulted in an increase in the number of leaves of the Paulownia and their surface area, which resulted in an increase in biomass yield. By analysing the results of the study on trunk diameter, leaf number and surface, it may be stated that irrigation watering significantly influenced the tested parameters. Irrigation significantly increased the height of Paulownia trees. The positive effect of the usage of sprinkler irrigation may indicate the possibility of effective application of this method in the field cultivation of Paulownia Shan TongVytauto Didžiojo universitetasŽemės ūkio akademij

Effect of expected climate changes on the water needs of forest nursery in the region of central Poland

eISSN 2345-0916; eISBN 9786094491283The aim of the study was to estimate the water needs of forest nursery in 2021-2050 in the region of Bydgoszcz (central Poland) basing on the predicted changes of air temperature. The forecast of average monthly air temperature for the Bydgoszcz region in 2011-2050, according to the expected climate change in Poland (SRES: A1B), was applied. The water requirements of forest nursery were determined basing on the daily water consumption for plant transpiration and field evaporation. The water needs were estimated for two types of the soil: sandy and clay, in the period from April to September for each year from 2021 to 2050. The reference period was 30 years from 1981 to 2010. According to the calculations, during 2021-2050 in the Bydgoszcz region, the forecasted water needs of forest nurseries will increase by 12-15%. In relation to the reference period and according to the expected climate changes, the water needs of forest nurseries in 2021-2050 will raise during the growing period from 427 to 489 mm on clay and from 498 to 560 mm on sandy soil. The greatest water needs, occurred in July, were 110 and 137 mm on the clay and sandy soil, respectively. Correlation and regression analysis showed that the water needs of forest nurseries in 2021-2050 will significantly increase in April by 3.3 and 3.8 mm·decade-1, and in August by 5.4 and by 6.0 mm·decade-1 on the clay and sandy soils, respectivelyVytauto Didžiojo universitetasŽemės ūkio akademij