基施钢渣及生物炭结合水分管理阻控水稻镉砷吸收研究

采用土柱实验和田间实验,研究了不同水分管理、基施钢渣及生物炭对稻田-水稻系统中镉砷污染同时阻控的效果。土柱实验结果表明,持续性淹水(CF)降低了Cd的生物有效性,但显著提高了As在土壤中的溶出,钢渣显著提高了土壤p H,降低了土壤Eh,并同时降低了Fe和Cd的溶解,增加了土壤溶液中Mn和As的含量。田间实验结果表明,糙米中Cd和As的含量呈显著负相关(R=-0.838,P0.05)。好氧环境下,基施钢渣及生物炭(A+SS、A+SS+BC)无法抑制Cd在稻米中的积累,而持续性淹水环境下基施钢渣和生物炭(CF+SS+BC)对水稻Cd和As具有同时阻控的效果,这或可成为水稻镉砷同时阻控的配套技术。

Mitigation of cadmium and arsenic in rice plant by soil application of steel slag and/or biochar with water management

Simultaneous mitigation of cadmium(Cd) and arsenic(As) in rice grain has been a great challenge, in contaminated paddy soilrice system. Here, a soil column experiment and a field experiment were conducted to investigate the optimal mitigation strategies on Cd and As contaminated paddy soil by soil application of steel slag and/or biochar with water managements. Soil column experimental results showed that continuous flooding(CF) decreased Cd but increased As concentrations in soil solutions. Soil application of steel slag(SS) significantly increased soil pH but decreased soil Eh. Meanwhile, SS treatment reduced the Fe/Cd concentrations but increased Mn/As concentrations in soil solutions. The field trial data showed that there was a significant negative correlation(R=-0.838, P<0.05) between brown rice Cd and brown rice As. The results indicate that aerobic condition could not reduce Cd accumulation in rice grain. However, soil application of steel slag and biochar with continuous flooding condition(CF+SS+BC) had the best mitigation effect on both Cd and As concentrations(rice Cd reduced by 80% and rice As kept unchanged) in rice grain simultaneously. Hence it could be one of the effective strategies to mitigate Cd and As accumulation in rice plant.