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[目的]对沼液养分和重金属农用安全风险进行分析,以期为沼液的安全农用提供科学依据。[方法]对秸秆及粪便中温厌氧消化的沼液进行重金属养分分析,并利用不同类型和浓度的沼液进行种子发芽试验。[结果]物料的类型及配比、碱液预处理均对沼液的成分和性质产生影响。碱液预处理可降低沼液中的重金属含量,可提高氮、磷、有机质以及速效成分的含量。沼液中重金属的最高含量分别为镉 8.76 μg/kg,铬 52 μg/kg,铅 210 μg/kg,汞 0.512 μg/kg,砷 140 μg/kg,铜、锌的含量较高,分别可达 279 和 680 μg/kg,但均低于城镇垃圾农用限定标准值。种子在沼液中的发芽试验验证了 5%以下低浓度沼液的催芽作用,但盐胁迫作用使幼苗在沼液中的长期生长受到抑制。[结论]以粪便作为沼液发酵原料时应适当的控制其在进料中的比例或做重金属预去除;当沼液用作液肥以灌溉方式施入农田时,应经稀释或做除盐处理。
[Objective] The research aimed to analyze the nutrient safety of biogas slurry and the safety risk of heavy metal agricultural use, in order to provide a scientific basis for safe agricultural use of biogas slurry. [Method] The heavy metal nutrient of the biogas slurry digested at moderate temperature in straw and excrement was analyzed, and the seed germination experiment was conducted by using different types and concentrations of biogas slurry. [Result] The types and proportions of materials, and the pretreatment of lye all had an impact on the composition and properties of biogas slurry. Lye pretreatment can reduce the content of heavy metals in biogas slurry and increase the content of nitrogen, phosphorus, organic matter and quick-acting ingredients. The highest concentrations of heavy metals in biogas slurry were 8.76 μg / kg cadmium, 52 μg / kg chromium, 210 μg / kg lead, 0.512 μg / kg mercury and 140 μg / kg arsenic, respectively. Copper and zinc contents were higher 279 and 680 μg / kg, respectively, but lower than the limit value of urban garbage for agriculture. Germination test of seed in biogas slurry verified the germination of low concentration biogas slurry below 5%, but the salt stress inhibited the long-term growth of seedling in biogas slurry. [Conclusion] When using manure as feedstock for biogas slurry fermentation, the ratio of feed to feed or the pre-removal of heavy metals should be properly controlled. When biogas slurry is applied as liquid fertilizer to farmland by irrigation, it should be diluted or desalted .