改性生物质炭对原油污染土壤中苏丹草萌发的影响

Effect of modified biochar on germination of sorghum-sudangrass in crude oil contaminated soil

为探究原油胁迫下改性生物质炭对苏丹草种子萌发和幼苗生长的影响,在土壤含油率4%的原油污染土壤中分别添加硝酸和芬顿试剂改性的棉花秸秆生物质炭,采用土培发芽试验研究两种改性生物质炭不同添加量(炭土质量比为2%和4%)对苏丹草发芽率、胚芽长、胚根长、生物量和土壤总石油烃降解率的影响。结果表明:施用生物质炭和改性生物质炭均能显著提高土壤有机质含量(P<0.05),未改性生物质炭添加会提升土壤pH值,硝酸和芬顿试剂改性生物质炭添加会降低土壤pH值。相比于未加生物质炭处理,添加生物质炭可以显著提高苏丹草发芽率、胚芽长和植株生物量,改性生物质炭对种子生长的促进效果更好,4%硝酸改性生物质炭处理的胚芽长和生物量比对照组分别增加了67.83%和80.26%。生物质炭和改性生物质炭添加均能显著提高土壤中总石油烃降解率,与未加生物质炭处理相比,添加4%生物质炭和4%芬顿改性生物质炭处理的总石油烃降解率分别增加了23.86、20.89个百分点。研究表明,在原油胁迫下,添加改性生物质炭有助于减缓原油污染对苏丹草种子萌发的负面效应,生物质炭的改性方法和添加量会影响苏丹草与生物质炭共同作用下土壤中石油烃的短期降解效果。

To explore the effects of modified biochar on seed germination and seedling growth of sudangrass under crude oil stress,cotton straw biochar modified by nitric acid and Fenton reagent was added to the contaminated soil with 4%oil content.The effects of the two kinds of modified biochar on germination rate,germ length,radicle length,biomass,and total petroleum hydrocarbon degradation rate of sudangrass were studied by soil culture germination test.The results showed that both biochar and modified biochar significantly increased soil organic matter content(P<0.05).The addition of unmodified biochar increased soil pH,while the addition of biochar modified by nitric acid and Fenton reagent decreased soil pH.Compared with the treatment without biochar,the addition of biochar significantly increased the germination rate,germ length,and plant biomass accumulation of sudangrass.Modified biochar promoted seed growth.The germ length and biomass in treatments with 4%biochar modified with nitric acid increased by 67.83%and 80.26%,respectively,compared with the control group.The addition of biochar and modified biochar could significantly improve the degradation rate of total petroleum hydrocarbons in soil.Compared with the treatment without biochar,the degradation rate of total petroleum hydrocarbons in treatments with 4%biochar and 4%Fenton-modified biochar increased by 23.86 and 20.89 percentage points,respectively.Therefore,under crude oil stress,the addition of modified biochar mitigates the negative effects of crude oil pollution on seed germination of sudangrass.The modification method and the amount of added biochar will affect the short-term degradation effect of petroleum hydrocarbons in soil under the joint action of sudangrass and biochar.