Improved characteristics of Populus sp. ecosystems by agroforestry practices

Sa？etak Agroforestry is a multifunctional, environmentally-friendly and modern system of land use by which we can reach economic, environmental and social benefits for the society. This is confirmed by this study on poplar plantations along the Danube River in the region of Vidin (Bulgaria) where agroforestry was practiced by intercropping cultivation of vegetable crops. Productivity of poplars is improving by applying agroforestry. The average diameters and the average heights of trees in the areas with agroforestry are high for the correspondent age. Thus the 10 yеаrs old plantation with agroforestry has DBH = 9.9 cm and Hav = 7.44 m whereas the same aged control has worse dendrometric characteristics (DBH = 8.7 cm ; Hav = 7.04 m). The other sample plot (SP1) near Novo selo village with 2 years old plantation where are currently planted corn has DBH = 2.7 cm and Hav = 2.67 m. The sample plot (SP3) near Vidin with 3 years old plantation where before 1 year has been planted corn has DBH = 1.6 cm and Hav = 2.55 m. The creation of agroforestry systems also leads to improvement of soil properties. Total soil humus content is higher in poplar ecosystems with agroforestry (varied from 4.3% to 2.5%) in comparison with the control (2%). Regarding the composition of organic matter, the control has the smallest content of stable humic acids (0.20%) in comparison with the other three agroforestry systems which have humic acids contents from 0.78% to 0.49%. At the same time control has the highest content of fulvic acids (0.62%) which is more mobile and less stable in comparison with humic acids. The content of fulvic acids in the other plots (with agroforestry) varied from 0.46% to 0.05%. At the same time the control has the highest content of “aggressive” fulvic acids (0.05%). This gives as reason to recommend agroforestry systems as appropriate in growing Populus sp. in Vidin region on Fluvisol