退化设施蔬菜地修复过程中土壤可溶性有机碳与无机氮动态

土壤强还原处理(reductive soil disinfestation,RSD)可以有效修复退化设施蔬菜地土壤,但实施过程中亦会存在可溶性有机碳(DOC)与无机氮(NO3--N和NH4+-N)的淋溶风险。本研究选用水稻秸秆及其制备的生物质炭(biochar,BC)作为修复材料,采用BC、RSD以及RSD+BC三种方法修复退化蔬菜地土壤,探究修复过程中土壤基本性质、DOC与无机氮的动态变化。结果表明,与对照土壤相比,BC处理显著提高了土壤pH、EC和DOC含量(P<0.05),但对土壤NO3--N和NH4+-N无显著影响。对于RSD和RSD+BC处理,土壤NO3--N含量在1~3 d内快速下降,之后维持在较低水平;土壤DOC含量呈先上升后下降趋势,在整个培养时段均显著高于对照处理(P<0.05)。方差分析表明,BC与RSD处理对土壤DOC、全碳(TC)、全氮(TN)和C/N存在交互作用。可见,RSD和RSD+BC处理能有效去除NO3--N,但DOC含量大幅度增加,存在淋溶风险。

Dynamics of soil dissolved organic carbon and inorganic nitrogen during remediation of degraded facility vegetable soil.

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.