Irrigating digestate to improve cadmium phytoremediation potential of Pennisetum hybridum. (September 2021)

• Record Type: Journal Article
• Authors: He, Lin; Zhu, Qili; Wang, Yanwei; Chen, Chenghan; He, Mingxiong; Tan, Furong
• Is Part Of: Chemosphere. Volume 279(2021)
• Publication Date: 2021-09
• Subjects: Digestate -- Pennisetum hybridum -- Cd bioavailability -- Phytoremediation; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2021.130592
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The bioavailability of heavy metal and growth of hyperaccumulator are key factors controlling the phytoextraction of heavy metal from soil. In this study, the efficacy and potential microbial mechanisms of digestate application in enhancing Cd extraction from soil by Pennisetum hybridum were investigated. The results showed that digestate application significantly promoted the height, tiller number, and biomass yield of Pennisetum hybridum . The application also increased the activities of urease, sucrase, dehydrogenase, available Cd contents of rhizosphere soils (from 2.21 to 2.46 mg kg −1 ), and the transfer factors of Cd from root to shoot and leaf. Assuming three annual harvests, digestate application would substantially reduce time needed for Pennisetum hybridum to completely absorb Cd from soil—from 15-16 yr–10 yr. Furthermore, the results of microbial community diversity analysis showed that digestate irrigation was more facilitated for the growth of the predominant bacteria, which were Actinobacteria and Chloroflexi at phylum level, and Sphingomonas and Nitrospira at genus level, which mainly have the functions of promoted plant growth and metal resistance. The results suggested that the enhanced phytoextraction of Cd by Pennisetum hybridum with digestate application might mainly attributed to the increased Cd bio-availability and the enhanced plant growth, indicating that an approach combining digestate and Pennisetum hybridum could be a promising strategy for remediating Cd-contaminated soils. Graphical abstract: Image 1 Highlights: Digestate application promoted the growth of Pennisetum hydridum. Digestate increased some enzyme activities and available Cd of rhizosphere soils. Digestate promoted Cd transfer from underground to above ground. Digestate irrigation increased the relative abundance of beneficial bacteria. Combining digestate and Pennisetum hydridum could be a promising candidate method.