Land - use type and slope position effects on soil respiration in black locust plantations in Artvin, Turkey

In this study, influences of aspect, land-use type, and sampling time on soil respiration were investigated in black locust plantation and adjacent grassland sites in Murgul-Artvin, Turkey. Both sites were heavily affected from acid rain produced by a nearby copper smelter. Soil respiration was measured approximately monthly in three sampling plots in each sites from January 2005 to November 2005 using the soda-lime technique. Mean daily soil respiration ranged from 0.22 to 2.37 g C m-2 d-1. Mean soil respiration in black locust plantations and grassland sites were 0.74 and 1.03 g C m-2 d-1, respectively. Soil respiration was significantly higher in grassland sites than in black locust plantation sites. Seasonal changes in soil respiration were related to soil moisture and temperature changes. Mean annual soil respiration rate correlated positively with surface soil (0-15 cm) sand (P < 0.05) and organic matter content (P < 0.1), and correlated negatively with mean surface soil clay and silt contents (P < 0.1). Overall, our results indicate that grassland sites have higher soil biological activity compared to black locust plantation sites.