Effect of culturing temperatures on cadmium phytotoxicity alleviation by biochar
Biochar produced from rice straw at 400 °C (RS400) was prepared to determine its alleviating effect on Cd phytotoxicity to wheat seedlings under different cultivation temperatures and pH. A hydroponic system (pH 4.3) and a loam soil slurry system were designed to respectively simulate acidic and neutral soil condition, and cultivation at increasing temperatures (20, 25, and 30 °C) were performed to evaluate the greenhouse effect. The root and shoot elongation and the Cd concentration in root and solution were measured; furthermore, batch experiments for Cd adsorption were undertaken. An increasing inhibition of the root by Cd addition was observed at increasing temperatures. The inhibition rate was 50.50 and 20.80% in hydroponic system and slurry system at 25 °C, respectively; however, the corresponding inhibition rates of root were significantly decreased to 25.5 and 3.5% with addition of RS400. This is mainly attributed to the reduction of Cd migration into the roots by RS400, which decreased Cd bioavailability. The mechanism behind the reduced Cd bioavailability is attributed to the Cd adsorption and the strong buffering capacity of acidity by RS400. Therefore, biochar could be a potential amendment for the remediation of Cd-contaminated soil even at increasing culturing temperatures.
KeywordsRice straw Biochar Cadmium Culture temperatures Phytotoxicity
This article is financially supported by the National Key Research and Development Program of China (2017YFA0207002); the National Natural Science Foundation of China (Grants No. 21507138 and 51309214); the Natural Science Foundation of Jiangsu Province, China (Grants No. SBK2015041561); the Frontier Fields during the Thirteenth 5-Year Plan Period of the Institute of Soil Science, Chinese Academy of Sciences (Grants No. ISSASIP1656); and the National Science Foundation for Distinguished Young Scholars of China (Grants No. 21425730).
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