施用沼液对土壤和玉米重金属累积的影响

Effect of Biogas Slurry on Heavy Metal Accumulation of Soil and Maize

为研究沼液不同施用量对土壤和植物重金属累积的影响,以玉米为供试材料,设计小区试验,通过施用不同量的沼液,分析不同沼液施用量对玉米产量的影响、土壤和玉米籽粒中的Cd、Cr、Pb、As、Hg等重金属含量的影响。结果表明:(1)施用沼液及常规化肥处理均能显著增加玉米的产量,增幅为5.56%～13.19%,当沼液施用量控制在5 000～7 000kg/(667m2)的范围内时,玉米能获得较高的产量;(2)玉米种植后,土壤中Cd、Cr、Hg含量与清水对照相比略有增加,而Pb和As变化不大,但均符合GB 15618-1995《国家土壤环境质量二级标准》;(3)随着沼液施用量的增加,玉米籽粒中Cd、Cr、Pb的含量略有增加,而As含量变化不大,Hg未检测出,但均符合食品限量标准(GB 2762-2005)。表明适量沼液的添加能有效实现沼液的资源化利用,同时不会对土壤和植物造成重金属污染风险。

A field study was conducted by mesuring the variation of production maize grain and contents of Cd,Cr,Pb,As and Hg in the soil and maize grain in order to investigate the influence of biogas supplementation on the accumulation of heavy metals in the soil and plant.The results showed that：（1）The application of biogas slurry as well as the chemical fertilizer significantly increased the maize production by 5.56%～13.19% and the higher maize production was obtained when the slurry application were controlled at 5 000～7 000 kg/（667 m2）.（2）Although contents of Cd,Cr and Hg in soil added with biogas slurry were slightly increased,no difference was detected in contents of Pb and As in soil when compared with control,contents of all of the tested heavy metals were lower than the corresponding limitations in the National Soil Environmental Quality Standards（GB 15618-1995）.（3）Caused by the biogas slurry,contents of Cd,Cr and Pb in maize grain were slightly increased,contents of As were not changed significantly,Hg was not detected,however,contents of all the mentioned heavy metals were below the limit of the National Food Safety standard（GB 2762-2005）.It indicated that an appropriate application of biogas slurry in soil-plant system achieved the resource utilization while no heavy metal contamination was pressured to soil and plant.