生物炭和菌肥对土壤镉形态和棉花镉吸收的影响

Effects of Biochar and Microbial Fertilizer on Soil Cadmium Forms and Cotton Cadmium Uptake

    摘要
  • 摘要:
      目的  为了明确生物炭和菌肥修复石灰性土壤镉（Cd）污染的效果，探寻适宜石灰性土壤重金属Cd修复技术。
      方法  采用盆栽的试验方法，研究施用3%的生物炭（B3）和1.5%的菌肥（M1.5）对不同外源Cd浓度（0、1、2、4 mg kg−1）石灰性土壤的pH值、Cd形态分布、酶活性以及棉花各器官Cd含量的影响。
      结果  结果表明，生物炭和菌肥均能显著提高土壤的pH，但随着培养时间的延续添加改良剂处理的土壤的pH值呈现出下降的趋势：生物炭和菌肥的施用均能降低土壤可交换态Cd比例，提高土壤残渣态Cd比例，与对照相比，生物炭和菌肥处理下可交换态Cd的含量分别下降了18.42% ~ 48.46%和15.21% ~ 50.19%。生物炭和菌肥的添加显著提高土壤酶活性，其中蔗糖酶、过氧化氢酶、脲酶和碱性磷酸酶的最大增幅分别为89.1%、140.1%、39.7%和38.1%，菌肥处理总体优于生物炭处理。生物炭和菌肥的施用降低了植株各器官Cd含量，其中生物炭处理各器官中Cd含量最大降幅为34.0%，菌肥处理下最大降幅为39.5%。相关性和主成分结果表明，可交换态Cd与土壤酶活性呈显著负相关（P < 0.05），与植株根、茎和叶Cd含量呈现出显著的正相关（P < 0.05）。
      结论  生物炭和菌肥作为土壤重金属钝化剂能够通过影响Cd的形态分布，从而缓解Cd对土壤酶活性的影响，降低棉花对Cd的吸收。总体来看，施加1.5%菌肥较3%生物炭在石灰性土壤Cd污染修复的效果更优。

     

    Abstract:
      Objective  The paper aims to clarify the effect of biochar and microbial fertilizer on the remediation of cadmium (Cd) pollution and to explore the suitable remediation techniques in calcareous soil.
      Method  The pot experiment was conducted to study the effects of 3% biochar (B3) and 1.5% microbial fertilizer ( M1.5 ) on pH value, Cd form distribution, enzyme activities and Cd contents in various organs of cotton in calcareous soil with different added Cd concentrations ( 0, 1, 2, 4 mg kg−1 ).
      Result  The results showed that both biochar and microbial fertilizer could significantly increase soil pH, but with the extension of incubation time, the pH of soil treated with amendments showed a downward trend. The application of biochar and bacterial fertilizer could reduce the proportion of exchangeable Cd in soil and increase the proportion of residual Cd in soil. Compared with the control, the contents of exchangeable Cd in biochar and microbial fertilizer treatments decreased by 18.42% - 48.46% and 15.21% - 50.19%, respectively. The addition of biochar and microbial fertilizer significantly increased soil enzyme activities, and the maximum increase rates of sucrase, catalase, urease and alkaline phosphatase were 89.1%, 140.1%, 39.7% and 38.1%, respectively. The microbial fertilizer treatment was generally superior to biochar treatment. The applications of biochar and microbial fertilizer reduced the Cd content in each organ of the plant, in which the maximum reduction of Cd content in biochar treatment was 34.0%, and that of microbial fertilizer treatment was 39.5%. Correlation and principal component analysis showed that exchangeable Cd was significantly negatively correlated with soil enzyme activities ( P < 0.05 ), and positively correlated with Cd contents in roots, stems and leaves of plants (P < 0.05 ).
      Conclusion  Biochar and microbial manure as soil heavy metal passivators can alleviate the effect of Cd on soil enzyme activities, reduce the absorption of Cd by cotton and affect the form distribution of Cd. Overall, 1.5% bacterial fertilizer is better than 3% biochar in remediation of Cd pollution in calcareous soil.

     

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