Abstract: 【Objective】Dissolved organic carbon(DOC)and other components of soil organic matter can be transformed into other forms of organic matter. Although the proportion of DOC in soil organic matter is relatively small, it is the most active organic carbon pool in the terrestrial ecosystem and it influences the dynamic balance of soil organic carbon components. In order to provide a reference for the effective management of soil carbon pools in poplar plantations under different management models, a sequential batch equilibrium experiment was conducted with poplar litter as the source material of DOC.【Method】In this study, soil samples were collected from three different management models(agro-poplar pattern, poplar-alder mixed pattern and poplar plantation pattern)in the Chenwei Forest Farm in Sihong County, Jiangsu Province. Five sampling points were selected for each sample plot. Soil from 0-10, ≥10-20 and ≥20-30 cm soil layers were collected by soil drills. Collected soil was evenly air-dried and passed through a 2 mm sieve. These soil samples were then used for the adsorption test. Meanwhile, DOC initial liquor was prepared from poplar leaf litter collected in the forest farm. DOC adsorption and its effects on poplar plantation soil under different management patterns were investigated with a batch equilibrium experiment and described by the initial mass isotherm equation(IM equation). For the batch equilibrium experiment, whole soils(5 g)were placed in 50 mL glass centrifuge tubes. Twenty milliliters of a DOC solution(solid-liquid mass ratio is 1:4. Concentration is 0, 50, 100, 200 and 400 mg/L)were then added to the tubes. A NaN₃ solution was added(but fumigated soil was not added)and a KCl solution was used to adjust the ionic strength. Samples were kept at constant temperature(25 ℃, 15 ℃)and oscillated for 2 hours on a 200 r/min horizontal oscillator, centrifuged for 20 minutes at low temperature(4 ℃)in a 12 000 r/min high-speed centrifuge, filtrated with a 0.45 μm membrane, and analyzed for filtrate DOC content using a TOC instrument.【Result】 Results showed that adsorption in the soils could be fitted by an IM equation and R² ranged from 0.810 9 to 0.999 3. The trend of DOC adsorption in different soil layers was the same under different modes. When no exogenous DOC was added, there was a net release of DOC in the soil. However, the amount of DOC adsorbed showed a significant positive linear relationship with the amount of DOC added. DOC adsorption amounts were significantly different(P<0.05, F_2,6=73.789)for different management patterns and adsorption amounts were influenced by initial concentrations of DOC added into the soil. When initial concentrations of DOC were ≤200 mg/L, adsorbed amounts of DOC showed the following trend: poplar plantation pattern>agro-poplar pattern>poplar-alder mixed pattern. When initial concentrations of DOC were between 200 and 400 mg/L, adsorbed amounts of DOC were highest for the agro-poplar pattern and lowest for the poplar-alder mixed pattern. The adsorption capacity of soil in the 0-10 cm layer was significantly different from soil at the ≥10-20 cm or ≥20-30 cm layers(P<0.05, F_2,6=2.713)in the agro-poplar pattern, while there were no significant differences between the three soil layers(P>0.05, F_{mix, 2, 6}=1.198, F_{poplar, 2, 6}=1.483)in the poplar plantation and poplar-alder mixed patterns. In addition, temperature had no significant effect on the ability of soil to adsorb DOC, while fumigation did have a significant influence on DOC adsorption in soil. There was no significant difference in DOC adsorption capacity among the three management patterns at two different temperatures(15 ℃ and 25 ℃). However, after soils were fumigated by chloroform, DOC adsorption amounts increased and the values of m and K_d were higher than for the unfumigated soil(0.128 9 to 0.199 0 and 1.64 to 1.87, respectively). The term m is the regression coefficient in the IM equation, K_d is the partition coefficient of DOC in soil, both of which can be used to measure affinity of DOC to soil.【Conclusion】There was a significant linear relationship between the amount of DOC adsorbed and DOC added. Thus, these parameters of adsorption can reflect the soil's ability to adsorb DOC. The adsorption of DOC in the soil was significantly different(P<0.05)under different management patterns. In this study, temperature had no significant effect on the ability of soil to adsorb DOC. However, future studies need to examine the effect of temperature on DOC adsorption in soil.