【摘要】 为研究椰壳炭(coconut shell biochar,简称"CSB")及铁锰改性椰壳炭(Fe-Mn modified coconut shell biochar,简称"FM-CSB")对土壤中Cd的钝化效果及对水稻吸收积累Cd的影响,采用室外水稻盆栽试验,比较了施加质量比为0. 5%的CSB与质量比为0. 05%、0. 1%、0. 2%、0. 5%的FM-CSB对南方酸性污染稻田土壤pH、Cd的形态变化及水稻各部位吸收积累Cd的差异性.结果表明:与CK相比,施加CSB与FM-CSB均能提升土壤pH,当FM-CSB施加量高于0. 1%时效果显著(P<0. 05),施加0. 5%FM-CSB处理效果最好,且优于添加0. 5%的未改性CSB处理.相比于CK处理,施加CSB与FM-CSB处理均可使土壤中w(弱酸可溶态Cd)随着水稻的生长而逐渐降低,而w(可还原态Cd)、w(可氧化态Cd)与w(残渣态Cd)则呈升高趋势,其中0. 5%FM-CSB处理对土壤中w(弱酸可溶态Cd)的降低效果最佳.随着FM-CSB添加量的增加,水稻各部位及稻米中w(Cd)均逐渐降低,施加0. 5%FM-CSB时的降Cd效果最佳,可使水稻根、茎、叶、壳与糙米中w(Cd)比CK分别下降48. 66%、54. 64%、45. 11%、31. 64%与48. 94%,并增产39. 33%,而施加量同为0. 5%时的FM-CSB处理下的降Cd效果显著高于未改性的CSB.研究显示,施加0. 5%CSB与0. 05%～0. 5%的FM-CSB均可钝化土壤中Cd并降低水稻对Cd的吸收,且施加相同量的FM-CSB对Cd的钝化效果优于CSB.可见,FM-CSB可钝化土壤中Cd、降低其生物有效性,并减少Cd在水稻各部位的积累.更多还原

【Abstract】 In order to study the effect of coconut shell biochar(CSB) and Fe-Mn modified coconut shell biochar(FM-CSB) on passivation and accumulation of Cd by rice in Cd contaminated soil,an outdoor rice pot experiment was conducted by addition of 0. 5%CSB and 0. 05%,0. 1%,0. 2%,0. 5% Fe-Mn modified coconut shell biochar(FM-CSB) to the southern acid-contaminated paddy soil.The changes in soil pH,Cd speciation and content in various parts of rice in the treatment group and control group were compared. The results showed that addition of CSB and FM-CSB could increase soil pH,especially at applied amount of FM-CSB higher than 0. 1%(P<0. 05). And the best treatment was achieved when 0. 5% FM-CSB was added. Compared with CK,application of both CSB and FM-CSB could reduce the content of weak acid soluble Cd in soil along with the prolongation of rice growth period,but increase the content of reducible Cd,oxidizable Cd and residual Cd. The addition of 0. 5% FM-CSB resulted in the highest acid-soluble Cd reduction in soil. Cd content in various parts of rice was gradually decreased with the increase of FM-CSB content and the application of 0. 5% FM-CSB resulted in the highest Cd reduction in soil with 48. 66%,54. 64%,45. 11%,31. 64% and 48. 94% decrease in Cd content in rice root,stem,leaf,shell and brown rice,respectively,along with 39. 33% increases in rice yield. When CSB and FM-CSB were applied at the same amount of 0. 5%,FM-CSB resulted in significant lower Cd content than that of CSB in the rice. Our studies show that the application of0. 5% CSB and 0. 05%-0. 5% FM-CSB can passivate Cd in soil and reduce the absorption of Cd in rice,and FM-CSB has better passivation effect than CSB on Cd. The research results indicate that FM-CSB could stabilize Cd in soil and reduce the accumulation of Cd in various parts of rice.更多还原