摘要
为揭示秸秆还田措施下沼液替代化学氮肥施用对土壤中重金属环境风险的影响,本文以江苏滨海典型围垦农田(稻麦轮作)为对象,设置不加沼液和不加秸秆(CK)、加沼液但不加秸秆(B)、加秸秆但不加沼液(S)和沼液秸秆联用(BS)这4个处理的田间小区试验,观测不同土层中土壤Cu、Zn、Cd和Pb的迁移及形态变化特征,并评估其环境风险.结果表明:(1)BS处理下稻麦田表层(0~20 cm)土壤中Zn和Pb的总量显著下降(P<0.05).稻田土壤中4种重金属由表层向中下层(20~60 cm)相对迁移6%~11%,麦田土壤中Cu、Cd和Pb从表层向下迁移25%~33%.这表明,沼液秸秆联用加速了表层土壤中重金属的垂向下移.(2)BS处理下,稻田表层土壤中Cu的弱酸提取态所占质量分数下降8.8%,Zn、Cd和Pb的残渣态降低7.0%~14.2%.这表明Cu被钝化,但Zn、Cd和Pb有活化趋势.相比较而言,麦田表层土壤中Cu的残渣态降幅为弱酸提取态的2.8倍,表明Cu被活化.与此同时,Cd的残渣态升高,Pb的弱酸提取态降低,Cd和Pb被钝化.(3)重金属生态风险评估表明,BS处理下稻麦田土壤均未发现重金属生态风险,并且,其风险指数明显低于B和S处理(P<0.05).因此,沼液秸秆联用有助于显著降低滨海围垦田土壤重金属污染风险.
In order to reveal the impact of the application of biogas slurry instead of chemical nitrogen fertilizer on the environmental risk of heavy metals in the soil by returning straw to the field,four treatments,without biogas slurry and without straw applications(CK),biogas slurry application without straw(B),straw application without biogas slurry(S),and biogas slurry combined with straw applications(BS),were applied in a typical coastal reclaimed farmland(rice-wheat rotation)in Jiangsu province.The migration and morphological characteristics of Cu,Zn,Cd,and Pb in different soil layers were observed,and the potential environmental risks were estimated.The results showed that:①The total amounts of Zn and Pb in the surface soils(0-20 cm)in the rice and wheat fields under the BS treatment decreased significantly(P<0.05).The four heavy metals in the paddy soils migrated 6%-11%from the surface to the middle and lower layers(20-60 cm),and Cu,Cd,and Pb in the wheat soils migrate down from the surface by 25%to 33%.This indicated that the combined use of biogas slurry and straw accelerates the vertical downward movement of heavy metals in the surface soil.②Under the BS treatment,the contents of the weak acid extraction of Cu in the surface soil of the paddy field decreased by 8.8%,and the residual state of Zn,Cd,and Pb decreased by 7.0%to 14.2%.This revealed that Cu was passivated,but Zn,Cd,and Pb tended to be activated.In comparison,the reduction in Cu residues in wheat field surface soil was 2.8 times that of the weak acid extraction,indicating that Cu was activated.Furthermore,the residue state of Cd increased,the weak acid extraction state of Pb decreased,and Cd and Pb were passivated.③The ecological risk assessment of heavy metals showed that there is no ecological risk in the soils under the BS treatment,and the risk indices were significantly lower than those of the B and S treatments(P<0.05).Therefore,the combined use of biogas slurry and straw helps to significantly reduce the risk of heavy metal pollution in
作者
王伟
周珺楠
汤逸帆
申建华
韩建刚
WANG Wei;ZHOU Jun-nan;TANG Yi-fan;SHEN Jian-hua;HAN Jian-gang(College of Biology and Environment,Nanjing Forestry University,Nanjing 210037,China;Collaborative Innovation Center of Sustainable Forestry in Southern China of Jiangsu Province,Nanjing Forestry University,Nanjing 210037,China;COFCO Meat(Jiangsu)Co.,Ltd.,Dongtai 224200,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2021年第4期1979-1988,共10页
Environmental Science
基金
国家重点研发计划项目(2017YFC0505803)
国家自然科学基金项目(41977354)。
关键词
沼液
秸秆
稻麦两熟田
土壤
重金属
biogas slurry
straw
rice-wheat double cropping field
soil
heavy metal
