Fate and transfer of heavy metals following repeated biogas slurry application in a rice-wheat crop rotation

A - Papers appearing in refereed journals

Tang, Y., Wang, L., Carswell, A. M., Misselbrook, T. H., Shen, J. and Han, J. 2020. Fate and transfer of heavy metals following repeated biogas slurry application in a rice-wheat crop rotation. Journal of Environmental Management. 270, p. 110938. https://doi.org/10.1016/j.jenvman.2020.110938

AuthorsTang, Y., Wang, L., Carswell, A. M., Misselbrook, T. H., Shen, J. and Han, J.

The application of biogas slurry, from anaerobic digestion of livestock excreta, to cropland has proven to be an effective mechanism for recycling nutrients within farms. However, the potential pollution of heavy metals from repeated biogas slurry fertilization has not received much attention. Here we present the results of a field experiment under rice-wheat rotation demonstrating the accumulation, speciation distribution and plant uptake of heavy metals (Cu, Zn, Pb and Cd) in soil following biogas slurry application. The treatments were: zero biogas slurry application (BS0), and biogas slurry application for three (BS3) and five (BS5) years, at a rate of 450 m3 ha−1 y−1. Our findings show that biogas slurry fertilization resulted in accumulation of Cu and Zn in the soil. The concentrations of soil Cu and Zn under BS5 were, respectively, 38 and 29% greater in the wheat season and 35 and 35% greater in the rice season relative to BS0 (p < 0.05). The bioavailability of soil Cu and Zn increased following biogas slurry application. Plant uptake of Cu and Zn to all parts of wheat and rice plants (excluding Cu in wheat straw) increased with the years of biogas slurry application (p < 0.05), and the concentration of Cd in wheat grain was significantly greater in BS5 relative to BS0 (p < 0.05). After five years of biogas slurry fertilization, concentrations of Cu, Zn, Pb and Cd in wheat grains were 3.28, 25.19, 0.11 and 0.053 mg kg−1 and 4.24, 33.78, 0.12 and 0.035 mg kg−1 for rice grains, respectively, all within the safety limits. Our results demonstrate that repeated biogas slurry fertilization for five years has a relatively low pollution risk of heavy metals. However, long-term field monitoring and co-application with metal-immobilizing materials are required to ensure the safety of its application to cropland.

KeywordsDigestate; Potentially toxic metal; Bioavailability; BCR sequential extraction; Coastal reclaimed farmland
Year of Publication2020
JournalJournal of Environmental Management
Journal citation270, p. 110938
Digital Object Identifier (DOI)https://doi.org/10.1016/j.jenvman.2020.110938
Web address (URL)https://www.sciencedirect.com/science/article/pii/S0301479720308677?via%3Dihub
Open accessPublished as non-open access
FunderBiotechnology and Biological Sciences Research Council
BBSRC Newton funding
Funder project or codeS2N - Soil to Nutrition - Work package 2 (WP2) - Adaptive management systems for improved efficiency and nutritional quality
UK - China Virtual Joint Centre for Improved Nitrogen Agronomy (CINAG)
Output statusPublished
Publication dates
Online13 Jun 2020
Publication process dates
Accepted06 Jun 2020
PublisherAcademic Press Ltd- Elsevier Science Ltd

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