No abstract

Forests, grasslands, and agricultural areas are the primary deposits of carbon. Forests have an enormous storage capacity of carbon compared to other terrestrial ecosystems. The vast majority of carbon stocked in soil component for each land use/land cover classes. Special attention should be paid for soil carbon studies. Negative effects of climate change can be reversed by proper forest management.

Aboveground biomass (AGB) and belowground biomass (BGB) of grasslands are important parameters for characterizing regional and global carbon cycles in grassland ecosystems. Compared with the relatively detailed information acquired for AGB, data regarding the BGB has been poorly reported at the regional scales. In this study, AGB, BGB, and soil samples for their organic matter, texture and pH level were collected from the 49-plots across the grasslands of the four different sub-watersheds (Bicakcilar, Kilickaya, Oltu and Uzundere) within the Coruh River Basin to compare the differences in AGB, BGB, total biomass (TB) and the ratio of below to aboveground biomass (B/A) in those sub-watersheds. The relationships among parameters including AGB, BGB, TB, B/A, climate and soil were also examined. It was found that AGB, BGB and TB differed significantly among the grasslands of four subwatersheds while B/A did not differ. Structural equation model (SEM) analyses indicated that mean annual precipitation (MAP) and mean annual temperature (MAT) were the strongest positive driver for the allocation of AGB, BGB and TB. AGB and TB were positively correlated with soil organic matter and negatively related with pH, whereas BGB and B/A were positively related with pH and negatively correlated with soil organic matter. Climatic variables, MAP and MAT, were negatively correlated. The results demonstrated that BGB and TB were positively correlated to MAP (p<0.01) and were negatively related to MAT. B/A was negatively related to AGB (p<0.01). With all data pooled, TB and MAP were strongly correlated, as the relationship between MAP and TB (R 2 =0.72). These results indicated that increase in precipitation positively influence grassland biomass production in Coruh River Basin grasslands. In addition to these, precipitation and temperature had strong control on AGB, BGB and TB in semi-arid grassland ecosystems.

Vegetation on earth surface is the integral part of the world ecosystems in functioning for varying spatial and temporal scales. Along with other benefits, land-use as a forest can dramatically reduce the soil erosion and water pollution by protecting the soil surface from erosive effects of rainfall. The objective of this study was to determine rill/interrill (surface) erosion risk by using the RUSLE equation for Velikoy sub-watershed (417 km 2) which has rich forest-resources within the Coruh River Basin located at northeastern Turkey. Land use and cover (C factor), rainfall and runoff (R factor), soil erodibility (K factor), slope length and steepness (LS factor), and management support practice (P factor) were identified as the sub-factors for the RUSLE equation and were multiplied to estimate soil loss by rill/interrill erosion. Results showed that the mean surface soil erosion from the sub-watershed was around 3.9 t ha-1 yr-1. Of the total study area, 8.2% was estimated as the areas of high and very high risk for the potential surface soil erosion that also indicates prioritization for the implementation of the erosion conservation measures.