绿肥秆秸和玉米秆秸配施钝化剂对土壤理化性质及镉有效性的影响

Effects of Green Manure and Straw Application with Passivators on Soil Physicochemical Properties and Cadmium Availability

  • 摘要:
    目的 绿肥秆秸和玉米秆秸作为有机物料不仅可以提高土壤肥力和作物产量,也存在增加土壤活性镉(Cd)含量的可能性。通过研究绿肥秆秸和玉米秆秸配施钝化剂,准确评估两种秸秆与钝化剂配施体系对土壤重金属Cd有效性的影响。
    方法 本文采用盆栽试验方法研究豆科绿肥光叶苕子(Vicia villosa var.)秸秆和玉米秸秆配施不同钝化剂(生物炭、硅肥、钙镁磷肥)后,土壤理化性质及Cd有效性的变化。
    结果 单施绿肥秸秆可显著增加土壤有机质和脲酶含量,降低土壤pH值;单独施用玉米秸秆可显著降低土壤有机质、脲酶和pH值。而用绿肥秸秆、玉米秸秆和钝化剂配施处理土壤,与单独用有机材料处理的土壤相比,绿肥秸秆配施生物炭、硅肥、钙镁磷肥处理可显著降低土壤有机质、脲酶和pH值;而玉米秸秆配施生物炭、硅肥、钙镁磷肥处理可显著增加土壤有机质、脲酶和pH值。单独施用绿肥秸秆可以显著降低土壤中有效镉的含量(23.20%,P < 0.05),而单施玉米秸秆处理对土壤有效Cd无显著影响。与单施绿肥秸秆处理的土壤相比,绿肥秸秆与生物炭复合处理的土壤钝化效率最高(26.88%);与单施玉米秸秆相比,玉米秸秆与钙镁磷肥复合处理的钝化效率最高(为25.17%)。在土壤环境因子与Cd生物有效性的相关性分析中,土壤有效Cd与土壤碱解氮、速效钾、有机质、脲酶和碱性磷酸酶呈显著负相关。冗余分析表明,在土壤性质中,有机质对土壤Cd有效性影响较大;在所有处理中,绿肥秸秆配施生物炭对土壤有效Cd钝化效率最高(43.93%)。
    结论 在绿肥秸秆和钝化剂配施体系中,绿肥秸秆和生物炭配施对土壤Cd钝化效果最佳;在玉米秸秆和钝化剂配施体系中,玉米秸秆配施钙镁磷肥对土壤Cd钝化效果最佳。因此,推荐绿肥秸秆配施生物炭或者玉米秸秆配施钙镁磷肥来降低Cd污染地区土壤Cd活性,有利于Cd污染土壤的修复。

     

    Abstract:
    Objective Green manure straw and corn stalks as organic materials can not only improve crop yield and soil fertility, but also increase soil cadmium (Cd) availability. The aims were to clarify the effects of green manure straw and corn stalks application with passivator on the soil physicochemical properties and Cd availabilities.
    Method The effects of leguminous green manure light-leaved camas (Vicia villosa var.) straw and maize straw with different passivators (biochar, silica fertilizer, and Ca-Mg-P fertilizer) on soil physicochemical properties and Cd effectiveness were investigated by using a pot test method.
    Result The application of green manure straw alone significantly increased soil organic matter and urease content, and decreased soil pH values. The application of corn straw alone significantly decreased soil organic matter, urease and pH values. The treatments of green manure straw with biochar, silicon fertilizer, Ca-Mg-P fertilizer could significantly reduce soil organic matter, urease and pH compared with the treatment of organic material alone. The treatments of corn straw with biochar, silicon fertilizer, Ca-Mg-P fertilizer could significantly increase soil organic matter, urease and pH values. The application of green manure alone could significantly reduce the content of effective Cd (23.20%, P < 0.05). Whereas the treatment of corn straw alone did not have a significant effect on the effective Cd. The green manure straw with biochar was the highest of passivation efficiency (26.88%), and the passivation efficiency was 25.17% in the treatment of corn straw with Ca-Mg-P fertilizer. The correlation analysis among soil environmental factors and Cd availabilities showed that soil effective Cd was significantly negatively correlated with Alkaline hydrolysis nitrogen, available potassium, organic matter, urease and alkaline phosphatase. Redundancy analysis showed that soil organic matter had a greater effect on soil Cd effectiveness. The green manure straw with biochar application had the best effect on soil Cd passivation efficiency (43.93%).
    Conclusion The application of green manure straw with biochar had the best effectiveness on soil Cd passivation, next is the treatment of corn straw with Ca-Mg-P fertilizer. Therefore, green manure straw with biochar or corn straw with Ca-Mg-P fertilizer was recommended to reduce soil Cd activity in Cd-polluted areas, which was conducive to the remediation of Cd-polluted soil.

     

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