engleski

Soil erosion in 85-year old black pine forest in Croatian Mediterranean region

Soil erosion has a destructive effect on soil quality, structure, stability and texture, plant diversity, water dynamics and can degrade downstream water quality. Climatic, hydrological, topographic, geological and vegetation conditions, as well as the land use management are basic natural and anthropogenic factors largely responsible for erosion occurrence. Soil erosion processes caused by rain are large environmental problem throughout the Mediterranean region because of rainfall seasonal variability and intensity. To reduce runoff and soil loss and to increase vegetation structure, forest management policies in Croatia encourage afforestation. In the sub- Mediterranean region of southeast Croatia, in the hilly part of Dalmatian hinterland, black pine forests were established for their conservation purpose. The aim of this study was to evaluate effect of precipitation on soil erosion, runoff and sediment in black pine forest. In order to quantify runoff and soil loss caused by rain, experimental plots (20.0 x 2.5 m) were set up in 85 years old black pine (Pinus nigra Arn.) forest at an altitude of 550 m a.s.l. at western exposition and inclination of 32°. Collector was set up at the lowest point of each erosion plot and it was designed for suspension volume measurement and collection. Suspension (sediment yield and runoff) was collected after each rainfall event. Rainfall data from meteorological station near experimental plots was provided by Croatian Meteorological and Hydrological Service. During the study period (1 year) 76 rainy days were observed, 21 of them caused runoff and soil erosion. The results showed that runoff coefficient in black pine forest was less than 3% of precipitation volume. Annual value of runoff was 28, 21mm m-2 and erosion loss was 2, 115 g m-2, while the size of most eroded sediment particles were ranging from 5 to 80 µm. Therefore, the afforestation with black pine in sub- Mediterranean karst region of Croatia is useful for the reduction of the erosion process.

precipitation, runoff, runoff coefficient, sediment particles, soil loss

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