Cow manure and cow manure-derived biochar application as a soil amendment for reducing cadmium availability and accumulation by Brassica chinensis L. in acidic red soil

Organic amendment is a promising,in situ phytostabilization approach to alleviate the phytotoxic effects of heavy metal contaminated soils.The aim of this study was to evaluate the feasibility of cow manure（CM）and its derived biochar（CMB）as a soil amendment on cadmium（Cd）availability and accumulation in low and high Cd-accumulating cultivars of Brassica chinensis L.grown in an acidic red soil.CM and CMB were applied to Cd-contaminated acidic red soil at the rates of 0,3.0and 6.0%（w/w）.Application of CMB was significantly more effective than that of CM,as it reduced the availability of Cd in soil by 34.3–69.9%and its bioaccumulation in the low Cd accumulator,Aijiaoheiye 333,by 51.2 and 67.4%,respectively.The addition of CMB significantly increased the extractability and accumulation of trace metals（Zn,Mn,Fe,and Cu）by plants and improved plant biomass production.CMB application,combined with utilizing low Cd accumulating cultivars represents a new,sustainable strategy to alleviate the toxic effects on Cd and improve food safety.