Effects of biochar amendment on root traits and contaminant availability of maize plants in a copper and arsenic impacted soil

Abstract

Biochar has been proposed as a tool to enhance phytostabilisation of contaminated soils but little data are available to illustrate the direct effect on roots in contaminated soils. This work aimed to investigate specific root traits and to assess the effect of biochar amendment on contaminant availability. Amendment with two different types of biochar, pine woodchip and olive tree pruning, was assessed in a rhizobox experiment with maize planted in a soil contaminated with significant levels of copper and arsenic. Amendment was found to significantly improve root traits compared to the control soil, particularly root mass density and root length density. Copper uptake to plants and ammonium sulphate extractable copper was significantly less in the biochar amended soils. Arsenic uptake and extractability varied with type of biochar used but was not considered to be the limiting factor affecting root and shoot development. Root establishment in contaminated soils can be enhanced by biochar amendment but choice of biochar is key to maximising soil improvement and controlling contaminant availability

Biochar application to a contaminated soil reduces the availability and plant uptake of zinc, lead and cadmium

“…In the higher doses of BC plants showed more developed and distributed roots (data not shown). Phytoremediation combined with BC addition to soil can enhance soil biological activity (Lu et al, 2015) because BC amendment promotes root growth (Brennan et al, 2014).…”

Application of Biochar for Soil Remediation

“…Brennan et al (2014b) showed an increase in maize (Zea mays) biomass and chlorophyll content after biochar produced form pine woodchip and maize stubble was added to soils contaminated with PAHs, As, Cu, and Zn. Furthermore, biochar promoted the development of fine maize roots, crucial to water and nutrient uptake in Cu-and As-contaminated soil (Brennan et al, 2014a). Houben et al (2013a) found that the availability of Cd, Zn, and Pb to Brassica napus decreased with increasing biochar applications.…”

Effect of biochar on leaching of organic carbon, nitrogen, and phosphorus from compost in bioretention systems

“…Biochar potentially can prevent leaching of pollutants from compost. The addition of biochar can reduce leaching of nitrate from soil (Knowles et al, 2011;Clough et al, 2013) and reduce pore water concentrations of metals (Brennan et al, 2014;Meng et al, 2014). Dissolved organic matter, however, can negate the increased sorption of metals by biochar (Beesley et al, 2014).…”