Abstarct: Total soil organic carbon is an indicator of soil quality. This index responds to changes in soil management slowly, studying the more unstable components of soil organic carbon may lead to a better diagnosis of the effect of changes in fertilizer management on soil quality. One of the components of organic carbon used for this purpose is activated or unstable carbon. Various researches have shown that two soils with similar (total) organic carbon content have different amounts of active carbon. In the present research, changes in total organic carbon and forms of organic carbon in different soils and in different managements of organic and chemical fertilizers were investigated. An experiment was carried out in fixed plots and in the research farm of the Soil and Water Research Institute located in Mashkindasht, Karaj, on two crops, corn and rapeseed in 1399-1400 and wheat crop in the spring of 1401. The following nine treatments were implemented in an incomplete (randomized) block format, in three replications. 1) Planting; 2) control without fertilizer consumption; 3) the use of nitrogen, phosphorus and potassium chemical fertilizers; 4) application of 20 tons of cow manure every two years + application of 75% of the recommended amount of nitrogen + application of 50% of the recommended amount of phosphorus and potassium; 5) application of 20 tons of waste compost every two years + application of 75% of the recommended amount of nitrogen + application of 50% of the recommended amount of phosphorus and potassium; 6) annual application of 20 tons of cow manure + application of 75% of the recommended amount of nitrogen; 7) annual application of 20 tons of waste compost + application of 75% of the recommended amount of nitrogen; 8) annual use of 20 tons of cow manure (10 tons in the first crop and 10 tons in the second crop); 9) Annual use of 20 tons of waste compost (10 tons in the first crop and 10 tons in the second crop) + biological stimulants. After each cultivation and necessary care, a composite sample was prepared from two depths of 0-15 and 15-30 cm from the soil surface and the amount of total soil organic carbon and active organic carbon was measured. Using the indices of active (unstable) organic carbon and total soil organic carbon, the index of soil organic carbon management was calculated. Finally, the results were statistically analyzed using SAS software. The results showed that with the application of organic fertilizers, the amount of soil organic carbon and its components (CMI, LI, CPI) increased due to the increase in microbial and enzyme activity. As CPI (Total Organic Carbon Index) and LI (Carbon Instability Index) increased, CMI (Carbon Management Index), which is calculated from the product of these two indices, also increased accordingly. According to the results of this experiment, it can be stated that; The combined use of organic fertilizers with other chemical and mineral fertilizers effectively in the long term can be one of the most important influencing factors in increasing the qualitative and quantitative level of soil organic matter and carbon content and other carbon components of the soil and finally CMI. baxsed on the obtained results, the annual application of 20 tons of municipal waste compost + application of 75% of the recommended amount of nitrogen at the recommended depth of 0 to 15 cm had the most positive effect on increasing the soil organic carbon management index.