Abstract <p>CO₂ emission from agrochernozems of the dispersed carbonate Tugnui basin and agrochernozems of the quasi-clay Yeravninsky basin of western Transbaikalia were studied. To compare CO₂ emission from soils, the virgin soil variants of the same name are taken. The study aims to quantify and comparatively evaluate the production of carbon dioxide from arable chernozems with contrasting temperature and moisture conditions. The measurement of CO₂ fluxes from the soil was carried out by a closed chamber method with an AZ 7752 portable infrared CO₂ gas analyzer (AZ Instrument Corp., Taiwan). The CO₂ emission was largely dependent on hydrothermal conditions. Its minimum at the beginning of the growing season was associated with the effect of low soil temperatures, while the maximum was more often noted after precipitation. The peaks of CO₂ emission coincided with an increase in temperature and humidity from June to early August, in conditions of a lack of readily available moisture, and were also associated with a humidification regime. The limiting factor of the CO₂ flux for quasi-clay chernozems was the soil temperature, and that for dispersed carbonate chernozems was humidity. It has been established that the total CO₂ emission in arable soils is significantly less than in virgin soils, which is explained by the peculiarities of the agrogenic environment. Arable soil is warmer in summer, and it cools down more and deeper in winter. The transformation of the water regime occurs in the direction of reducing moisture and increasing its contrast during the warm period. The total carbon loss index varies in the following series: dispersed-carbonate chernozem → quasi-clay chernozem, virgin soil → arable soil.</p>