Productivity of Populus nigra L. in two different soils over five rotations

Abstract

This study describes growth performance and productivity of poplars (Populus nigra L.) on a 5-year rotation in two soil types. Two adjacent and even-aged stands of poplar (PS1 and PS2) with different productivity were selected in poplar plantations of Tehran, Iran. On a 5-year rotation, growth parameters of poplar trees were measured and productivity was computed. A transect sampling method with 10% intensity was used for measurement of the growth parameters. A composite soil sample was taken for all transects, and soil physico-chemical properties were determined. Texture, EC, organic matter percent, the contents of some macro and micro nutrients and some heavy metal concentrations of soil had significant differences between two stands; as a consequence growth performance and productivity of poplars were significantly difference between PS1 and PS2. In PS1, productivity of 5-year trees was 2.5 times higher than in PS2. Soil with Clay Loam texture, more contents of organic matter and nutrients, lower EC and lower contents of Ca, Mg, S and heavy metals provided more suitable conditions for growth of poplars. The growth parameters were positively correlated with the contents of nutrients, clay and organic matter in the soil, but they were negatively related to EC and the contents of silt, Ca, Mg, S and heavy metals of soil. Careful selecting sites based on soil properties before planting can be useful for increasing productivity of poplars.