Respond of Populus deltoides Bartr. ex Marsh seedlings to various soil moisture regimes in Guilan province

Current study was carried out by the aim of investigating the effect of different degrees of irrigation on some quantitative characteristics of eastern cottonwood (Populus deltoides Bartr. ex Marsh) seedlings in Guilan province. The cuttings were planted in a completely randomized design with four treatments and five replications. Three irrigation levels including 20%, 40% and 60% of soil saturated moisture content in each pot including 187.5, 375 and 570 ml water for 2.5 kg soil and control treatment (without manual irrigation) every three days applied on seedlings form the beginning of spring to end of summer. At the end of the period, height of seedlings using ruler, collar diameter using caliper, stem and root fresh weight by scale, stem and root biomass by drying in oven, root length using graph paper, the number of leaves by counting were measured for all treatments and examined by one-way analysis of variance (ANOVA) test. The results showed that the highest mean of seedlings height (with 89 cm), maximum mean of collar diameter (with 8.28 mm), highest mean of stem fresh weight (with 37 g), highest mean of root length (462 80 cm), the highest mean of leaf number (with 10.23) was related to 60% treatment. The highest mean of root fresh weight and the highest stem and root biomass were observed at 40% with 4.26, 14.05 and 1.62 grams, respectively. The optimum amount of poplar seedlings irrigation was also determined by 40%.