The release of carbon (C) in the biogeochemical cycle of grassland vegetation, soil, and the atmosphere mainly results from metabolism and respiration in roots, soil mineralization, and microbial activities. Soil temperature, soil moisture, above-ground biomass, below-ground biomass, soil nutrition, and microbiological composition can all affect soil respiration in grassland ecosystems. Fire has been identified as one of the most important factors controlling ecosystem processes and the C cycle. Soil nitrogen (N) availability influences plant growth, net primary productivity, and litter decomposition, all of which can affect the supply of C substrate for plant roots and soil microorganisms. Mowing, contrary to grazing, non-selectively affects all plants in a community by removing their above-ground biomass, traditionally only once or twice a year. Rainfall can affect the mineral composition of grasses. Correctly evaluating the effects of different disturbances on the grassland C cycle has contributed to understanding the effects of various management practices on grasslands. Soil net respiration plays an important role in regulating the responses of ecosystems and global C cycling to natural and anthropogenic disturbances. When total soil respiration is investigated, the net soil respiration flux is usually taken as a basis for measuring the net C release from grasslands to the atmosphere. Therefore, research on the quantitative distinction between net soil respiration and total soil respiration and quantitative descriptions of the C cycle processes of grassland ecosystems has imperfections. To address this, a grassland in the Hebei Guyuan national grassland ecosystem field scientific observation station was used as to investigate soil net respiration dynamics by the root exclusion method under irrigation, N fertilization, mowing, and burning, and in an undisturbed grassland from April 2011 to October 2012. The results showed consistent and obvious seasonal changes in soil net respiration under the different disturbances. Soil net respiration under all disturbance types was higher in late spring than in summer and lower in early spring and autumn. The soil net respiration rate under burning, irrigation, and mowing was decreased by 28.93%, 16.25%, 36.82%, respectively, compared with undisturbed grassland. The soil temperature and soil moisture were exponentially correlated with soil net respiration rate (P <0.01). Regression analysis of the seasonal mean soil net respiration with above-ground biomass, below-ground biomass, soil organic C content, and soil total N contents demonstrated that soil organic C and total N content were the main influences on soil net respiration. Therefore, it was concluded that in the north temperate grassland area, soil temperature can better explain the inter-annual variability of soil net respiration than can soil moisture. The regulating action of soil moisture on soil net respiration should consider not only climate characteristics but also intra-zone water distribution. Soil organic C and total N content are crucial factors for soil net respiration. Under certain time-space conditions, soil net respiration under the disturbances was significantly different than in undisturbed grassland. Irrigation, N fertilization, mowing, and burning can all increase the C sequestration ability of grassland ecosystems. The different mechanisms by which irrigation, burning, mowing, and N fertilization were found to influence soil net respiration will facilitate the simulation and projection of ecosystem C cycling in the semi-arid grassland of northern China.