Chernozem soils in northern Kazakhstan not only sustain crop production in our world, but also store tremendous amount of organic matter, which functions as a huge source and sink of carbon dioxide. In that region, three types Chernozem soils are distributed, i.e. Dark Chestnut (DC; Typic Haplustolls), Southern Chernozem (SC; Typic Haplustolls), and Ordinary Chernozem (OC; Pachic Haplustolls). A 4 or 5-years crop rotation system, including summer fallow and 3 or 4 years continuous cereal (e.g. spring wheat, barely, and oat) cultivation is applied there. The objective of this study was to clarify the influence of land-use on the dynamics of soil organic matter in the above mentioned soils in that region. Surface soil samples were taken from cereal fields, summer fallow fields, and pasture fields in each site. Soil organic carbon was determined by Tyurin method, and Potential Mineralizable organic Carbon (PMC) was determined by incubation method (19 weeks). In the growing season of 2002 (only in SC site), 2004 and 2005, in situ CO₂ emission rate from soils and the amount of plant residues were determined as carbon output and input, respectively. The CO₂ emission within 24 hours was measured by alkaline absorption method, and it was conducted 2 to 3 times per month at each site. At the same time, soil temperature in 5 cm depth was measured. Additionally, precipitation, air temperature, and soil temperature (at 5 cm depth) were monitored by data-logger at each site. Due to the difficulty in monitoring daily soil water content, we introduce dryness factor, which was derived from Potential EvapoTranspiration (PET) and precipitation. Daily PET was estimated by using Hargreaves-Samani equation. And daily dryness factor computed to be precipitation divided by PET. At the OC and SC site, the pattern of CO₂ emission generally corresponded to the one of air temperature and showed considerable increase until July in any land-use. While at the DC site, there was less increase in summer in any land-use. To estimate daily CO₂ emission, prediction equation of CO₂ emission using stepwise multiple regression of Arrehenius model was derived from soil temperature, dryness factor, precipitation, PMC, and soil organic carbon by types of soil and land-use individually. To avoid multicollinearity, precipitation or dryness factor was used in the regression analysis. Soil temperature showed high and positive contribution in all 9 equations. Forty-four to 72 percent of variation of CO₂ emission in summer fallow field at DC and OC site and cereal field at SC site were able to be estimated by using soil temperature and precipitation. And Sixty to 72 percent of total variation in CO₂ emission at pasture fields was explained by soil temperature and dryness factor. PMC factor also contributed to pasture field in DC site and cereal field in SC and OC site. Mean annual CO₂ emission at cereal field was estimated from 0.8 (DC) to 1.3 (OC) Mg C ha^-1. The carbon input as plant residues at cereal field ranged from 0.8 to 2.0 Mg C ha^-1. It was also the highest in OC, followed by SC and DC. Annual carbon budget was calculated by subtracting the annual CO₂ emission from the carbon input as plant residues, and it ranged from -0.03 to 0.8 Mg C ha^-1. However, the carbon budget of summer fallow field was around -0.9 Mg C ha^-1. Thus, the carbon budget on the 4-yr crop rotation system, which calculated by using the result of 2004 and 2005, was estimated from -0.5 (DC) to 0.9 (OC) Mg C ha^-1. It should be noted that carbon budget was negative at DC and SC site, but positive only at OC site. This indicates 4-yr crop rotation system which including summer fallow is resulting in the significant decrease in soil organic carbon at SC and DC sites and increase at OC site. While, carbon budget in pasture field ranged from 0.7 to 1.4 Mg C ha^-1. It is noteworthy that pasture management at all sites contribute to carbon sequestration. Therefore, we recommend pasture management should be introduced as a part of a crop rotation system, especially at SC and DC site, in order to prevent soil organic matter depletion.