Effect of pine afforestation on soil physicochemical properties compared to pasture land: A case study in Kosovo

This study investigates the long-term effects ofpine (<i>Pinus nigra</i>) afforestation onsoil characteristics incomparison toadjacent pastureland incentral Kosovo. Soil samples (<i>n</i>=24) were collected from two land-use types, pine plantations and grassland, over three topographic positions (lower, medium, upper) and two depths (0–10 cm and 10–20 cm). Standard laboratory techniques were used todetermine soil organic matter (SOM), organic carbon (SOC), total nitrogen (TN), pH (H₂O and CaCl₂), available phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and bulk density (<i>BD</i>). The data were analysed using principal component analysis (PCA) and correlation matrices. The top soils (0–10 cm) beneath pine had higher soil organic matter (mean 2.45%) compared tothe pasture lane (1.59%). The SOC and TN levels increased by43% and 36%, respectively. Soil pH was lower under pine (mean pH_H₂O =6.3) than under pasture land (pH_H₂O =6.81), particularly onmiddle and lower slopes. Exchangeable calcium and magnesium declined byupto20% under pine plantations, and bulk density also decreased (for example, 1.15 g·cm^–3 under pine land compared to1.29 g·cm^–3 under pasture land), signifying reduced compaction. Phosphorus concentrations were slightly higher under pasture atadepth of0–10 cm (mean 12.4 mg·100 g^–1), but under pine, they increased atadepth of10–20 cm ontop slopes. PCA showed differentiation based onland use, with the initial two components representing 70.1% ofthe overall variance.