Some site conditions in the protected part of the alluvial plain of the central Danube Basin and their effect on the plantation productivity of two varieties of eastern cottonwood and one variety of Euramerican black poplar were researched on three different soil systematic units. It was determined that the study soil systematic units had different physical characteristics. The high content of the fraction silt + clay and the low air capacity had an unfavourable effect on the productivity of I-214 plantation on humofluvisol. The sandy form of fluvisol had a low capacity of readily available water, which could affect the reduced productivity of the plantation. The volumes of the plantations of the clones 618 and 450, depending on the contentof the silt + clay fraction, had a positive linear tendency, i.e. the increase of the above fraction content leads to the increase of plantation volume. This tendency of the clone I-214 is in the form of the parable.