Abstract: Reductive soil disinfestation (RSD) is an effective method to restore degraded facility vegetable soil. However, RSD may cause the leaching of dissolved organic carbon (DOC) and inorganic nitrogen (NO₃^--N and NH₄⁺-N). In this study, we used rice straw and biochar (BC) as remediation materials to investigate the dynamics of soil basic properties, the contents of DOC and inorganic nitrogen during the remediation process in an experiment with BC, RSD and RSD+BC treatments. Compared with control, BC treatment significantly increased soil pH, EC and DOC content (P<0.05), and did not affect soil NO₃^--N and NH₄⁺-N contents. Soil NO₃^--N content decreased rapidly in RSD and RSD+BC treatments within 1-3 days, and then maintained at a low level. Furthermore, the contents of DOC in the RSD and RSD+BC treatments increased firstly and then decreased, and were significantly higher than those in the control during the whole incubation period (P<0.05). BC and RSD significantly interacted to affect soil DOC, TC, TN and C/N. In summary, RSD and RSD+BC treatments can effectively remove NO₃^--N, but with a risk of leaching due to the increases of DOC.

Key words: anisohydry, sap flow density, isohydry, Pinus tabuliformis, Hippophae rhamnoides.