Effects of wheat straw derived biochar on cadmium availability in a paddy soil and its accumulation in rice. (February 2020)

• Record Type: Journal Article
• Authors: Jing, Feng; Chen, Can; Chen, Xiaomin; Liu, Wei; Wen, Xin; Hu, Shimin; Yang, Zhijiang; Guo, Bilin; Xu, Yanling; Yu, Qingxin
• Is Part Of: Environmental pollution. Volume 257(2020)
• Publication Date: 2020-02
• Subjects: Biochar -- Cd distribution -- Soil profile -- Aggregates -- Rice; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2019.113592
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: This study was carried out to investigate the effect of biochar amendment on cadmium (Cd) availability in a paddy soil with biochar amendment and its effect on the accumulation in rice. Biochar was applied once at rates of 0 (A0), 10 (A10), 20 (A20), 30 (A30), and 40 (A40) t ha −1 on the soil surface layer (0–17 cm). Results showed that the soil organic matter (SOM) content and pH in 0–17 cm soil layer increased as biochar application rate increased, whereas the content of dissolved organic carbon (DOC), and available iron (Fe), manganese (Mn), aluminum (Al) in diethylenetriamine pentaacetic acid (DTPA) extracts declined with biochar added. Available Cd in DTPA extracts in the 0–17 and 17–29 cm soil layer of A40 treatments was significantly lower (p < 0.05) by 49.4 and 51.7% than that in A0. Compared with A0, the distribution factor (DF) of DTPA extracted Cd in the 0.053–0.25 mm and <0.053 mm aggregates of A40 treatments increased by 136 and 269%, respectively, and the DF values in these micro-aggregates of A40 treatments were greater than 1.0. Based on European Community Bureau of Reference (BCR) sequential extraction results, 40 t ha −1 rate of applied biochar reduced the proportion of acid extractable Cd fractions in both 0–17 and 17–29 cm soil layers, but increased the Cd in the oxidizable and residual fractions. The Cd concentration in the rice plants of different biochar treatments was in the order of A0>A10 > A20 > A30 > A40. DTPA extractable Cd concentration in soil was the key factor affecting the Cd uptake by rice roots. In conclusion, biochar application at 40 t ha −1 can effectively reduce the availability of Cd in soil profile, enhance the available Cd enrichment in micro-aggregates, and thus limit the Cd uptake by rice. Graphical abstract: Image 1 Highlights: Biochar at 40 t ha −1 increased pH and thus immobilized Cd in soil subsurface layer. Biochar amendment enhanced the available Cd enrichment in micro-aggregates. Biochar transformed acid extractable Cd into oxidizable and residual fractions. The Cd uptake by roots was primarily affected by the variation of DTPA-Cd in soil. Abstract : Wheat straw biochar addition reduced the availability of Cd in soil surface and subsurface layers, enriched the available Cd in micro-aggregates, and thus limited the Cd uptake by rice.