caa a22 4500 477112455 CHVBK 20180405111613.0 cr unu---uuuuu 170330e19960901xx s 000 0 eng 10.1007/BF00011444 doi (NATIONALLICENCE)springer-10.1007/BF00011444 Diurnal cycle of carbon isotope ratio in soil CO2 in various ecosystems [Elektronische Daten] [Andrzej Dudziak, Stanislaw Halas] Our investigations of diurnal variations of the 13C/12C ratio and CO2 content in soil air were carried out in three environments during periods of high biosphere activity. It has been observed that diurnal variation of CO2 concentration is negatively correlated δ13. Particularly great variations occurred at shallow soil depths (10-30 cm) when the plant cover activity was high while the soil temperature was rather low. Under such conditions the δ13 variations had the magnitude of 4‰, while the CO2 concentration varied more than doubly. The maximum of the 13C/12C ratlo and the minimum of the CO2 concentration in a cultivated field with winter wheat took place in the afternoon, whereas in deciduous forest similar patterns were observed at dawn. In these cases soil temperatures at 10 cm depths varied less than 2°C. Hence, under wheat the variation in root respiration rate seem to be the main reason of the recorded varations. In an uncultivated grass-field during the hottest period in summer we did not measure any distinct variations of CO2 properties in spite of the fact that soil temperature varied up to 5°C. This might be due to dominant microbial respiration at the high soil temperature, which exceeded 20°C. Kluwer Academic Publishers, 1996 13C/12C ratio nationallicence CO2 concentration nationallicence diurnal cycle nationallicence microbial respiration nationallicence root respiration nationallicence soil CO2 nationallicence Dudziak Andrzej Department of Physics, Technical University of Lublin, 20-618, Lublin, Poland aut Halas Stanislaw Department of Physics, Technical University of Lublin, 20-618, Lublin, Poland aut Plant and Soil Kluwer Academic Publishers; http://www.wkap.nl 183/2(1996-09-01), 291-299 0032-079X 183:2<291 1996 183 11104 https://doi.org/10.1007/BF00011444 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00011444 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Dudziak Andrzej Department of Physics, Technical University of Lublin, 20-618, Lublin, Poland aut NATIONALLICENCE 700 1- Halas Stanislaw Department of Physics, Technical University of Lublin, 20-618, Lublin, Poland aut NATIONALLICENCE 773 0- Plant and Soil Kluwer Academic Publishers; http://www.wkap.nl 183/2(1996-09-01), 291-299 0032-079X 183:2<291 1996 183 11104 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer