Abstract:

【Objective】 Effects of no-tillage (NT), mouldboard plow (MP) and ridge tillage (RT) on the content of soil organic carbon (SOC) in the plow layer (30 cm) of a black soil in Northeast China were studied. 【Method】 The tillage experiment trial was made in Dehui County, Jilin Province in 2001. The effects of the three tillage managements on SOC mineralization were compared using an indicator, least limiting water range (LLWR) under different tillage treatments. 【Result】 NT significantly increased SOC at the top soil (0-5 cm) compared with MP, but SOC content showed a notable reduction at 5-30 cm depth. SOC stratification ratio under NT was higher than that under MP and RT. The values of LLWR under different treatments throughout the study years ranged from 0.129 to 0.170, which were lower under NT than MP, and they went to decrease with the tillage operation. 【Conclusion】 The residue covered on soil surface every year led to a clear effect on SOC accumulation after 7-year field trial. The stratification ratio of SOC under NT was higher than that under MP and RT. Investigating LLWR was helpful to understand SOC fixation related to NT.

Key words: no tillage, soil organic carbon, least limiting water range, stratification ration, black soil