作者：Wu, P (Wu, Ping) ; Cui, PX (Cui, Pei-Xin) ; Fang, GD (Fang, Guo-Dong) ; Wang, Y (Wang, Yu) ; Wang, SQ (Wang, Shen-Qiang); Zhou, DM (Zhou, Dong-Mei); Zhang, W (Zhang, Wei) ; Wang, YJ (Wang, Yu-Jun)

题目：Biochar decreased the bioavailability of Zn to rice and wheat grains: Insights from microscopic to macroscopic scales

刊物：SCIENCE OF THE TOTAL ENVIRONMENT，卷: 621 页: 160-167

DOI: 10.1016/j.scitotenv.2017.11.236

出版年: APR 15 2018

文章下载：https://ac.els-cdn.com/S0048969717332953/1-s2.0-S0048969717332953-main.pdf?_tid=25766c89-7283-4d62-8e40-7789532bd0e7&acdnat=1521421417_06bab43d429a57cbc2af052bd6ad5f07

摘要：

Zn deficiency is a critical problem for many crops and human populations worldwide. Soil biochar amendment has recently been promoted as a sustainable agricultural practice. However, its effect on the bioavailability of micronutrients (especially Zn) to crops has not been fully addressed. This study investigated the impact of long-term biochar application in soils on Zn bioavailability to rice and wheat, using field experiments, and batch sorption/desorption experiments, in combination with extended X-ray absorption fine structure spectroscopy (EXAFS). In field soils biochar amendment increased total Zn content, but significantly decreased CaCl2-extractable Zn concentrations. Intriguingly, the uptake of Zn to wheat and rice grains was decreased. At high biochar application rates of 124 and 270 t/ha the Zn concentrations in wheat grains (36.6 and 37.5 mg/kg) reached a deficient level, lower than the recommended concentration of 45 mg/kg. The batch experiments showed that biochar application at a cumulative rate of 10.5, 15.8, 31.5, 124, and 270 t/ha significantly increased soil pH and soil organic matter (SOM) content, resulting in greater sorption and lower desorption of Zn. The EXAFS results demonstrated that the main forms of sorbed Zn were outer-sphere Zn complexes, Zn-illite, Zn-kaolinite and Zn-OM. The proportion of Zn-OM increased with increasing biochar application rates, suggesting that higher SOM might be more effective in immobilizing Zn and thus decreasing the Zn bioavailability. These results on the microscopic and macroscopic scales improved our understanding of the Zn bioavailability to crops, and raised potential concerns on the Zn deficiency in agricultural soils with long-termbiochar application. (C) 2017 Elsevier B.V. All rights reserved.