Effects and Mechanism of Continuous Liming on Cadmium Immobilization and Uptake by Rice Grown on Acid Paddy Soils
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ORIGINAL PAPER
Effects and Mechanism of Continuous Liming on Cadmium Immobilization and Uptake by Rice Grown on Acid Paddy Soils Zhaobing Liu 1,2 & Ying Huang 1 & Xionghui Ji 2 & Yunhe Xie 2 & Jianwei Peng 1 Ahmed E. Fahmy 4,5 & Salah F. Abou-Elwafa 6
&
Mamdouh A. Eissa 3 &
Received: 21 April 2020 / Accepted: 7 July 2020 # Sociedad Chilena de la Ciencia del Suelo 2020
Abstract Lime application is the most effective agricultural practice for the reduction of cadmium (Cd) bioavailability in acid soils. This study was conducted to investigate the impact of continuous liming across five consecutive growing seasons on the remediation of Cd in acid paddy soils, as well as rice yield. Two rice cultivars, i.e., Zhuliangyou 819 and Xiangwanxian 12, were cultivated in Cd-contaminated paddy soil for five consecutive growing seasons from 2014 to 2018. The investigated lime levels were 0, 450, 900, 1350, 1800, 2250, 3000, and 3750 kg ha−1. Lime application significantly increased rice yield, soil pH, exchangeable soil Ca2+, and rice calcium (Ca) contents; besides, it reduced soil and rice Cd contents. The application of lime at the rate of 1350– 2250 kg ha−1 significantly increased rice yield. Under continuous liming, rice yield obviously increased first and then decreased with the cumulative application of lime. The application of a cumulative lime amount of 18,000 kg ha−1 was identified as the critical transition point of soil pH, soil Cd, and rice Cd content. Application of lime up to or above 3000 kg ha−1 per season reduced Cd content in brown rice below 0.20 mg kg−1. The results suggest that the reduction in effective Cd content might be a result of the combined action of exchangeable soil Ca2+ and soil pH rather than being a direct effect of Ca2+. Therefore, acid Cdcontaminated paddy fields can realize the safe production of rice by the continuous application of an appropriate amount of lime. Keywords Rice . Lime application . Cadmium . Heavy metals . Paddy soils
1 Introduction Rice (Oryza sativa L.) is one of the most globally important food crops, especially in Asia and the Pacific region (Li et al. 2017). The continuously growing world population and the adverse impacts of climate changes necessitate carrying out
research aimed at ensuring the sustainable production of such a staple crop and food security through agro-ecological managerial practices (El-Mahdy et al. 2018; Eissa and Negim 2018; Abou-Elwafa et al. 2019). Acid soil is identified as the soil with a pH < 5.50 in its surface horizon (0–20 cm). About 30% of the global land area,
Zhaobing Liu and Ying Huang contributed equally to this work. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s42729-020-00297-9) contains supplementary material, which is available to authorized users. * Jianwei Peng [email protected] 1
College of Resources and Environment, Hunan Agricultural University, Changsha 410128, Hunan, China
2
Ministry of Agriculture Key Laboratory of Agriculture Environment in Middle Reach Plain of Yan
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