Understanding of soil carbon dynamics after establishment of alley-cropping systems is crucial for mitigation of greenhouse CO 2 gas. This study investigates soil CO 2 fluxes in an alley-cropping system composed of tree strips of black locust ( Robinia pseudoacacia L.) and poplar ( Populus nigra * P. maximowiczii, Max 1) trees and adjacent to them crop strips ( Lupinus/Solarigol). Soil CO 2 flux was measured monthly over a period from March to November 2012, using a LI-COR LI-8100A automated device. Concurrently with CO 2 flux measurements, soil and air temperature, soil moisture, microbial C and hot water-extractable C were determined for the soils nearby soil collars. Root biomass was determined to a depth of 15 cm. In all sampling areas, soil CO 2 flux increased from May to July, showing a significant positive correlation with air and soil temperature, which can be a reflection of increase in photosynthesis, and therefore supply of carbohydrates from leaves to rhizosphere, over the warm summer months. A positive correlation between CO 2 flux and soil moisture over the warm period indicates an enhancing role of soil moisture on microbial mineralization and root respiration. Average CO 2 flux values observed over March-November period did not differ significantly between sampling areas, showing 2.5, 3.2, and 2.9 mol m -2 s -1 values for black locust, poplar and crops, respectively. Significantly higher CO 2 flux values over the summer period in trees could be attributed to the higher photosynthetic activity and higher root density compared to crops.
