The determination of the changes in soil properties of the stone pine (Pinus pinea L.) plantations in the Turan Emeksiz sand dune area

The aim of this study is to determine the effect of stone pine (Pinus pinea L.) residues on the "initial soil formation" of the sand dunes covered with plantations of different periods. For this purpose were researched litter and soil properties under the stone pine canopy. Thus, analyses on pH, EC, CaCO3, cation exchange capacity, organic matter, humin compounds, available P fractions, total N, available micronutrients (Fe, Mn, Zn and Cu), and mycorrhizae potential were undertaken on soils of each plot. Undisturbed soil aggregate samples were also collected from all plantation plots for SEM/microprobe studies.While, the weight of organic litter formed by dead leaves, decomposed material and humus, determined under the stone pine canopy is increasing with depth, the oxidisable organic matter amounts are decreasing. The maximum organic litter amount was determined in the oldest plantation (1961) zone. Surface horizons (Ah) of all plot sites were determined to contain higher organic matter, available micronutrients and available P, total N, than the subsurface horizons with the highest values in the 1961 plot. Humin compounds contents were highest in the 1981 plantation plot soils. Undisturbed soil aggregate samples revealed the in-situ humification of plant residues together with the development of fungal hyphae (mycelia) binding mineral surfaces. Thus, the increase of the organic matter and humin substances reveal the "initial development of the soils" on the sand dunes covered with stone pine plantations for mitigation wind erosion .