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