Evaluation of Soil Physical and Chemical Properties in Poplar Plantations in North of Iran

Soil physical and chemical properties and some quantitative characteristics of Populus deltoides Marsh (clone 79.51) plantations and relationships between them were evaluated in Guilan plain of north of Iran. Two same aged poplar plantations with low and high qualities were selected. In each poplar plantation, fifteen sample plots with systematic sampling method were selected. In each sample plot diameter at breast height (DBH) as well as height of all trees within them was determined. Soil samples were taken from 0-20cm in each plot and soil texture, water holding capacity (WHC), bulk density (B.D) and particle density (P.D) as well as soil porosity, O.C, N, available P and exchangeable K were determined for each soil sample in laboratory. Tree data and soil properties between two plantations were analysed using independent samples t-test (Student's t test at p < 0.05). The results showed that among soil physical properties, percentage of clay, sand, B.D and WHC and amongst soil chemical properties O.C, N, available P and exchangeable K were significantly different between two plantations. Heavy textured soils with high B.D are undesirable for growing of populus deltoides in study area. The results also indicated that poor quality plantations has negative effect on soil nutrient and reduces its fertility. Reduction of nutrient availability had negative effects on quantity and quality of poplar trees.