Research Seminar Christophe Loix
Apr 28, 2017 16.00 uur - 18.00 uur
Potential of different biochars for Cd stabilization and improved plant yield
Large parts of Europe deal with severe historic Cd pollution, including the Northern Campine region in Belgium. Such marginal lands are not suitable for food- or feed-orientated agriculture due to threats to human, animal and plant health. To render these lands arable again, they must be remediated or stabilized. A novel approach of phytostabilization is the use of biochar, produced from waste streams of agriculture. Biochar has the potential to stabilize metals, promote plant growth and close the loop within the industry. Because of the many interactions of biochar with different elements in the soil and the wide variety of waste streams that serve as input for biochar, effects may however be complex and variable.
Biochar from different animal (pig manure and chicken manure) and plant sources (oak and rice husks) were tested for their Cd stabilization and plant growth promoting properties. Sand and soil were used as substrates to illustrate the important differences that can arise from biochar-substrate interactions. Arabidopsis thaliana were grown on biochar-amended substrate to analyze the in planta effects on the level of biomass, metal uptake and gene expression.
Biochar effectively and strongly reduced Cd bioavailability. Pig manure derived biochar alleviated Cd-induced growth inhibition but induced signs of Cu toxicity on sand at the gene expression level. Comparison with plants grown on biochar-amended soil, where Cu toxicity was not observed, highlights the importance of biochar-substrate interactions. Chicken manure derived biochar reduced Cd in the shoot, increased shoot biomass and did not exert Cu toxicity. Oak derived biochar stabilized Cd effectively as well, but did not promote plant growth and strongly affected substrate pH. Alkalization is the main mechanism of biochar metal stabilization but the increased pH can render essential nutrients less bioavailable. Chicken manure derived biochar had minimal effects on the pH yet strongly reduced Cd bioavailability, making it a good candidate for further and more applied research.