Abstract
As a metal immobilizer, biochar can be used to remediate contaminated soil. Biochar’s effect on the phytoremediation process in flooded conditions under a scenario of increasing flooding frequency as global climate change is not well understood. This study investigated bamboo biochar (BBC) effects on growth and metal accumulation of Salix in multi-metal contaminated soil under non-flooded versus flooded conditions. Salix cuttings were cultivated in pots with severely contaminated soil by Cd and Zn, for 120 days, with four treatments including non-flooded treatment, flooded treatment, non-flooded with 3% BBC application (BBC/soil, w/w), and flooded with 3% BBC addition. BBC, flooding, and BBC× flooding significantly decreased the bioavailability of metals in soils (P < 0.05). The BBC addition markedly stimulated Cd concentration in leaves under non-flooded (94.20%) and flooded conditions (32.73%) but showed little effect on roots. The BBC significantly boosted Cd and Zn transport from roots to aboveground parts by 68.85% and 102.27% compared with no BBC amendment under non-flooded treatment, while showing insignificant changes under flooded treatment. Although the plant biomass was little affected, BBC significantly increased Cd and Zn accumulation in the whole plant by 52.53% and 28.52% under non-flooded while showing an insignificant impact under flooded conditions. Taken together, BBC enhanced the phytoremediation efficiency of Salix to Cd and Zn in severely polluted non-flooded soil, while flooding offset this effect. The results indicated the effects of BBC varied under different soil moisture, which should be considered in the biochar-assisted phytoremediation to variable and complex environments.Graphical abstract
Highlights
Soil contamination caused by heavy metals (HMs) is a global environmental issue that seriously threatens the ecology, human health, and social sustainability (Ali et al 2013; Murtaza et al 2017; Xia et al 2019)
We investigated plant growth and HMs accumulation of Salix psammophila grown in heavily contaminated soil by Cd and Zn, with 3% bamboo biochar (BBC) addition according to previous results (Li et al 2021), under non-flooded or flooded conditions
The BBC amendment markedly increased soil organic matter (SOM) by 33.46%, and AK by 156.02% in NF-3% than in NF-0 treatment, increased SOM by 22.19%, and AK by 57.10% in F-3% treatment compared to those treated with F-0 treatment, respectively
Summary
Soil contamination caused by heavy metals (HMs) is a global environmental issue that seriously threatens the ecology, human health, and social sustainability (Ali et al 2013; Murtaza et al 2017; Xia et al 2019). Salix plants have been studied as a potential candidate for phytoremediation/dendroremediation due to their unique characteristics, including fast growth, deep and extensive roots, short rotation, coppice systems, high antioxidant enzyme activity in the leaves, efficient transpiration, and high nutrient uptake capacity (Marmiroli et al 2011; Mcbride et al 2017). Salix plants exhibit the ability to cope with several adverse environmental stresses, including HMs, floods, salt, alkali, and drought (Liu et al 2011b; Tlustoš et al 2007). Flooding could alter the soil properties such as soil pH, organic matter, and oxygen content (Chen et al 2012). The Salix showed marked tolerance to oxygen shortage in flooded soils with the trait of the presence of adventitious roots (Jackson and Attwood 1996). Yang et al (2020) reported that Salix showed phytostabilization potentials of Cu/Zn under flooded conditions, and the fertile lenticels/adventitious roots of Salix conferred the tolerance to
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
