小龙虾壳炭和细叶榕枝条炭对土壤养分及镉和铅生物有效性的影响

Effects of biochar from Procambarus clarkii shells and Ficus microcarpa branches on soil nutrients and bioavailability of Cd and Pb

【目的】探讨施用小龙虾Procambarus clarkii壳炭(CSB)和细叶榕Ficus microcarpa炭(FMB)对复合污染土壤理化性质及作物生长的影响。【方法】在650℃限氧条件下热解制备厨余废弃物小龙虾壳炭和园林废弃物细叶榕炭。以不同质量比(0、1%、3%)施入小红萝卜Raphanus sativus盆栽土壤,测定和分析施用小龙虾壳炭和细叶榕炭对土壤中镉和铅有效性、养分转化、土壤酶活性及小红萝卜生长的影响。【结果】3%FMB处理对土壤有机碳、有效磷和速效钾质量分数提升效果最显著(P<0.05),较对照的增幅分别为135.8%、35.4%和173.7%。除1%CSB处理外,其余生物质炭处理下土壤中有效态镉和铅质量分数较对照均显著降低(P<0.05),降幅分别为60.7%~91.1%和21.0%~26.1%。3%CSB处理对土壤β-葡萄糖苷酶、亮氨酸氨基肽酶和β-N-乙酰基氨基葡萄糖苷酶活性提升效果最显著(P<0.05),较对照分别提高79.7%、30.3%和1668.5%。不同比例CSB和FMB的施用均显著(P<0.05)提高了小红萝卜可食部分的生物量,且3%CSB处理的提升效果最显著(P<0.05),较对照提高了171.5%。【结论】与细叶榕炭相比,小龙虾壳炭在提高土壤酶活性,降低土壤中镉和铅生物有效性以及提升作物品质和产量方面效果更为优越,更适合作为镉-铅复合污染土壤修复的潜在应用材料。

[Objective]This study aims to investigate the effects of biochar derived from Procambarus clarkii shells(CSB)and Ficus microcarpa(FMB)on physicochemical properties of contaminated soil and plant growth.[Method]The biochar was prepared by pyrolysis of both typical kitchen and garden wastes at 650℃with limited oxygen supply.A pot trial was conducted using Raphanus sativus with different mass ratios(0,1%,3%)to investigate the effects of different doses of CSB and FMB on cadmium(Cd)and lead(Pb)bioavailability in soil,nutrient transformation,soil enzyme activity,and R.sativus growth.[Result]3%FMB treatment had the most significant effect on improving contents of soil organic carbon,available phosphorus and available potassium(P<0.05),which increased by 135.8%,35.4%,and 173.7%respectively compared with the control.Except 1%CSB treatment,other biochar treatments significantly(P<0.05)decreased the concentrations of available Cd by 60.7%−91.1%and Pb by 21.0%−26.1%.3%CSB treatment showed significant increase in soil enzyme activities such asβ-glucosidase,leucine aminopeptidase andβ-N-acetylglucosamine(P<0.05),which were 79.7%,30.3%and 1668.5%higher than that of the control,respectively.All biochar treatments significantly(P<0.05)increased the biomass of the edible part of R.sativus.3%CSB treatment had the most significant improvement effect(P<0.05),which increased by 171.5%compared with the control.[Conclusion]The CSB is more effective than the FMB in improving soil enzyme activity,reducing Cd and Pb bioavailability in soil,and improving crop quality and yield.It is more suitable as a potential material for the remediation of soils co-contaminated with Cd and Pb.