不同氮磷钾肥对海泡石钝化修复镉污染土壤的稳定性研究

    Effects of Nitrogen, Phosphate and Potassium Fertilizer on In-situ Remediation of Cd Polluted Paddy Soil With Sepiolete

    • 摘要: 选取尿素、碳铵、普钙、钙镁磷肥、KCl和K2SO4为典型化肥,以海泡石为钝化材料,通过连续2 a水稻盆栽试验研究了施用不同化肥对海泡石钝化修复镉污染土壤稳定性的影响。结果表明,添加海泡石后水稻糙米中w(Cd)显著降低,第1年和第2年的降幅分别为41.4%和32.7%。在海泡石钝化的基础上施碳铵和钙镁磷肥在连续2 a试验内均降低了糙米中w(Cd);第1年的降幅分别为28.4%和26.9%;第2年的降幅分别为2.1%和11.4%。KCl和普钙在2 a内均增加了糙米中w(Cd),其增幅分别为31.6%、39.3%(第1年)和9.24%、53.8%(第2年)。施尿素第1年使水稻糙米中w(Cd)降低了49.93%;第2年使水稻糙米中w(Cd)增加了23.51%。施K2SO4第1年使水稻糙米中w(Cd)增加了36.57%;第2年降低了3.29%。此外,第1年海泡石对Cd的稳定效率远远大于第2年。但2 a均能对Cd污染土壤起到良好的钝化修复效果,第1年试验结果显示,添加不同肥料均降低了Cd的稳定性,其中钙镁磷肥的降低幅度最小,KCl的降低幅度最大;第2年尿素和碳铵使Cd的稳定率分别降低了4.54%和10.2%;而钙镁磷肥、普钙、KCl和K2SO4使Cd的稳定效率均有所增加。综合考虑不同肥料对水稻糙米中Cd的富集以及不同肥料对海泡石钝化能力的稳定性的影响,在海泡石钝化修复Cd污染土壤过程氮磷钾肥分别推荐使用碳铵、钙镁磷肥和K2SO4

       

      Abstract: A two-year pot experiment was conducted to investigate effects of application of urea, NH4HCO3, SSP, CMP, KCl or K2SO4, (six common types of fertilizer) on Cd immobilization in remediation of Cd polluted soil with sepiolite. Results show that Cd concentration in brown rice decreased by 41.4% in the first year and 32.7% in the second. The application of NH4HCO3 and CMP decreased the Cd concentration in brown rice by 28.4% and 26.9% in the first year and by 2.1% and 11.4% in the second, respectively, while the pa of SSP and KCl increased the Cd concentration in brown rice in both years by 31.6% and 39.3%, and by 9.24% and 53.8%, respectively. The application of Urea decreased the Cd concentration in brown rice by 49.93% in the first year, but increased it by 23.51% in the second. The application of K2SO4 increased the Cd concentration in brown rice by 36.57% in the first year, but decreased it by 3.29% in the second. Besides, the effect of sepiolite immobilizing Cd was much higher in the first year than in the second, but was still good in the second in remedying the polluted soil. However, its effect was affected by application of fertilizers. In the first year its Cd immobilization coefficient dropped the least in the treatment of CMP and the most in the treatment of KCl, while in the second year, it dropped by 4.54% and 10.2%, respectively, in the treatment of urea and NH4HCO3. Nonetheless, CMP, SSP, KCl and K2SO4 all increased the Cd immobilization coefficient to a varying extent. Considering the effects of different fertilizers on Cd concentration in brown rice and sepiolite immobilization of Cd, it is highly recommended to use NH4HCO3, CMP and K2SO4 in the process of remedying Cd contaminated soil with sepiolite.

       

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