生物质炭对根际土壤中镉形态转化及水稻镉累积的影响

Effects of Straw Biochar on Rhizosphere Soil Cd Forms Transformation and Cd Accumulation in Rice

采用盆栽试验和Tessier连续形态分析方法,研究了不同镉污染水平下(1.0、2.5、5.0 mg·kg-1),施入不同量的生物质炭(0.0、2.5、5.0、10.0 g·kg-1)对根际与非根际土壤中镉形态转化及水稻镉累积的影响。结果表明,(1)施入生物质炭后,根际与非根际土壤中镉的有效性降低。施入生物质炭后,根际与非根际土壤可交换态、碳酸盐结合态、铁锰氧化物结合态以及有机物结合态镉最大可分别降低34.64%和28.15%、49.27%和63.82%、34.58%和24.59%、60.04%和49.00%,残渣态镉最大可分别增加14.79%和16.57%。10.0 g·kg-1生物质炭处理影响效果最显著。在不同处理下,镉形态变化显著且根际与非根际之间的变化呈显著性差异。中低镉污染水平下,施入生物质炭,根际与非根际土壤中镉形态变化趋于一致但镉形态含量存在差异。高镉污染水平下,生物质炭引起根际与非根际土壤中镉形态变化但不显著。(2)施入生物质炭可显著降低水稻各部分镉含量且水稻根部镉含量大于地上部镉含量。在不同镉污染程度下,不同施入量生物质炭处理与对照相比,地上部、根部镉含量最大可分别降低42.51%、22.86%;根部镉含量最大是地上部的2.63倍。10.0 g·kg-1生物质炭对水稻各部分镉含量降低效果最明显。

A pot experiment and Tessier continuous shape analysis method was conducted to study effect of rhizosphere and nonrhizosphere soil forms transformation of Cd and accumulation of Cd in rice by applying different amount (0.0, 2.5, 5.0, 10.0 g·kg-1)of biochar, under different levels (1.0, 2.5, 5.0 mg·kg-1) of Cd-contaminated. The results showed that, (1) The application of biocharcould effectively reduce the availability of Cd in rhizosphere and non rhizosphere soil.Application of biochar reduced the content ofex-changeable, carbonate bound, Fe Mn oxide bound and organic bound Cd in rhizosphere and non rhizosphere soil by as high as34.64% and 28.15%, 49.27% and 63.82%, 34.58% and 24.59%, 60.04% and 49%, respectively, and increased the content of residualCd by as high as 14.79% and 16.57%, respectively. The treatment of 10.0 g·kg-1 biochar had the most significant effect. Underdifferent treatments, forms transformation of Cd had significant change and there were differences between the rhizosphere and nonrhizosphere. Under the low and middle levels of Cd-contaminated, the forms transformation of Cd tended to be consistent inrhizosphere and non rhizosphere soil, but the content of Cd was different. Under the high level of Cd-contaminated, the biochar couldcause forms transformation of Cd in rhizosphere and non rhizosphere, but it was not significant. (2) The application of biochar couldsignificantly decrease the Cd content in rice aerial part and root, and the accumulation of Cd in rice root was higher than that of in theaerial part. Under different levels of Cd-contaminated, compared with B0, applying different amount of biochar reduced the contentof Cd in rice aerial part and root by as high as 42.51% and 22.86%, respectively. The maximum content of Cd in root was 2.63 timeshigher than that in the aerial part. Treatment of amendment of 10.0 g·kg-1 biochar is the most effective in the rice.