Ecological Indicators (Feb 2023)
Soil respiration may be reduced by wind via the suppressing of root respiration: Field observation in maize farmland in the agro-pastoral transitional zone, northeastern China
Abstract
Soil respiration is a major source of atmospheric carbon dioxide (CO2). Intensive exploring on soil respiration in farmland may provide important information for controlling CO2 emissions. However, some important meteorological factors, especially for the wind, have been neglected previously. In this two-season field observation, we measured soil total respiration (Rt) in maize farmland in an agro-pastoral transitional zone in northeastern China, including autotrophic (root) respiration (Ra) and heterotrophic respiration (Rh), using the root-exclusion method. The mean Rt was 4.0 ± 0.8 and 6.1 ± 1.4 μmol·m−2·s−1 in the two growing seasons. The root contribution to the total soil respiration rate (Rc) was 55.5 and 44.1 %, respectively, and both followed an approximately unimodal curve as a function of day of year. Ra and Rh were both positively correlated with the soil temperature. Ra decreased with increasing wind speed, but Rh was not significantly affected; thus, Rc was negatively correlated with the wind speed. The decrease of Rc caused by increased wind speed differed among the growth stages. Significant suppression of Rc was detected at the jointing stage and at maturity. Responses of Rt and its components to meteorological factors differed significantly in magnitude between the day and night. However, Rc decreased with increasing wind speed both during the day and at night. In summary, the decrease of farmland soil respiration by the wind resulted from decreased root respiration and could be regulated by the modifying of artificial windbreaks or by the expanding of row space of the maize planting, thereby reducing carbon dioxide emission. Indeed, this study is only the observation and analysis of some traditional factors, more intensive observations, especially evidence from physiological traits, morphological anatomy and other perspectives are required to confirm this relationship in further studies.
