Effect of vegetation change from native broadleaf forest to coniferous plantation on selected soil properties.

The objective of this study was to examine the effects of vegetation change from a native broadleaf forest to a coniferous plantation on selected soil properties, including soil texture, pH, organic matter, total nitrogen (N), total phosphorus (P), exchangeable cations (Ca(2+), K(+), Na(+)), and cation exchange capacity (CEC). Results showed that the amount of clay particles, Ca(2+), and K(+) values significantly increased, whereas Na(+), total N, and organic matter and soil pH values decreased on the treatment plot after vegetation change. Soil acidity also increased and soil textural group changed from moderately fine-textured soils (clay loam) to medium-textured soils (loam) under both control and treatment plots. Organic matter, total N, and Na(+) values increased, whereas Ca(2+) concentration decreased through time on the control plot. Soil pH, total P, K(+), and CEC did not show significant changes through time on the control plot.

Response of understory vegetation to exclosure in a heavily compacted forest recreational site.

Objectives of this study were to investigate effect of exclosure on understory vegetation recovery and determine the time required for understory vegetation recovery in a forest recreational site. Recovery of understory vegetation in an exclosure was monitored for three growing seasons and plant density and vegetation cover were determined for each plant species. Exclosure was compared with control plot for the Shannon index of diversity. Results showed that a total of 33 (18 woody, 15 herbaceous) plant taxa were established in the exclosure while 42 (16 woody, 26 herbaceous) were encountered in the forest plot. Quercus petraea (Mattuschka) Liebl. subsp. iberica (Steven ex Bieb.) Krassiln. had the highest density both in the exclosure (30.37 plants m(-2)) and forest plot (25.75 plants m(-2)) and followed by Hedera helix L. (28.44 plants m(-2)) in the exclosure, 23.33 plants m(-2) in the forest plot). Plant species recovered in the exclosure did not survive very long as growing season progressed, top soil dried, and canopy closure increased. H. helix L. was the major dominant plant species for vegetation cover in both exclosure (45.23 %) and forest plot (45.08 %). There was a significant difference between plots for species diversity and forest plot had diversity index of 1.01 while exclosure had a diversity index of 0.741.

Impacts of land use conversion on soil properties and soil erodibility.

Land use conversion can affect natural ecological processes such as surface runoff and erosion. Therefore, it has potential to change soil stability To investigate this process in depth, Iskalan creek catchment in the Black sea region, where excessive land use applications and erosion events have often occured, was selected as the study area. The objective was to determine the effects of land use conversion on soil properties, soil erodibility and the relationships among soil properties and some erodibility indices. Duplicate topsoil samples were taken by using steel cylinders at 100 different sampling points from three different land use types; 34 of them are in farmlands, 34 in rangelands and 32 in forestlands. Soil particle size distribution, loss of ignition, pH, electrical conductivity skeleton percentage and three erodibility indices were determined. Data were analysed by using Pearson correlation analysis (at 95% and 99% significance level), ANOVA and Tukey's test at 95 % significance level. According to study results, land use conversion affects some properties of soils significantly Loss of ignition of soils in forests was significantly higher than soils in farmlands and rangelands. Soil skeleton percentage in rangelands and farmlands were significantly different. The study results showed that there was significant difference between pH of soils in forests and farmlands (p < 0.05). Pearson correlation analysis results showed significant correlations among erodibility indices and certain soil properties such as clay and sand fraction of soils (p < 0.05 and p < 0.01). Topsoils of the study area were sensitive to erosion according to all three erodibility indices. The most sensitive soils were in farmlands.