生物炭对污泥混合基质性质和植物生长的影响

Effects of biochar types on properties of sludge-soil mixture and plant growth

为探讨不同原料生物炭对污泥-土壤混合基质理化性质和在该基质中种植的园林植物生长的影响,采用盆栽试验,以污泥和土壤(质量比1∶1)混合物为栽培基质(CK),研究污泥生物炭(SB)、凋落物生物炭(LB)和水稻秸秆生物炭(RB)添加(按照基质质量的4.5%添加)对基质理化性质、有效态重金属含量以及蓝花草(Ruellia simplex)生长的影响。结果表明:与CK(基质中不添加生物炭)相比,3种生物炭均降低基质容重,提高总孔隙度和毛管持水量,对基质pH影响不显著。SB显著增加基质全P含量,降低速效P含量,LB显著提高有机质、全N、全P、碱解N、速效K含量,降低速效P含量,RB显著提高全P、全K、速效P、速效K含量。对于有效态重金属,SB显著降低有效态Cd、Pb、Cu、Zn、Ni含量,而LB和RB仅显著降低有效态Cu含量。3种生物炭均显著促进蓝花草根系生长及对N、K的吸收,SB还显著提高蓝花草地上部生物量及对P的吸收。模糊隶属函数显示,对基质改良和植物生长影响的综合评价排序为SB>LB>RB>CK。综上,在污泥园林利用中添加污泥生物炭、凋落物生物炭和水稻秸秆生物炭均可有效提升土壤质量,促进园林植物生长,其中污泥生物炭的综合改良效果最佳。

This study aims to investigate the effects of three biochar types on the physicochemical properties of sludge-soil mixed substrate(mass ratio 1∶1)and the growth of garden plants grown in the substrate and explore the potential of biochar application in sludge utilization.A pot experiment was conducted to quantify the effects of three biochar types(added at 4.5%of the substrate mass),including sludge biochar(SB),tree litter biochar(LB),and rice straw biochar(RB),on the physicochemical properties of the substrate,availability of heavy metals,and the growth of Ruellia simplex.Results showed that all the biochar types decreased the bulk density and raised the total porosity and capillary capacity of the substrate compared with that of the control(substrate without biochar addition,CK),with no significant effect on pH.These biochars differently enhanced substrate nutrient levels.SB only significantly increased total P content,whereas LB increased the contents of organic matter,total N,total P,alkaline solubilized N,and available K,and RB promoted the total P,total K,available P,and available K contents.The addition of SB and LB decreased the available P content,while SB reduced the contents of available Cd,Pb,Cu,Zn,and Ni.LB and RB only reduced the available Cu content.These biochars remarkably promoted root biomass and the uptake of N and K by R.simplex,while only SB enhanced the aboveground biomass and the uptake of P by R.simplex.The membership function values showed that the overall effect of the three treatments on substrate improvement and plant growth exhibited the following order:SB>LB>RB>CK.This study shows that the addition of SB,LB,and RB to the sludge-soil mixture effectively improved the substrate quality and promoted the growth of garden plants,with the sludge biochar outperforming the others.