【摘要】 研究赤泥对中轻度Cd污染的酸性潮泥田稻谷产量和Cd污染修复机理的影响。结果表明,稻谷产量随赤泥施用量的增加呈先增加后下降的变化趋势。早稻以施4 500 kg/hm2赤泥的产量最高,晚稻以施3 000 kg/hm2赤泥的产量最高,分别比不施赤泥增加了11.36%和8.30%;稻草产量与稻谷产量不同,随赤泥施用量的增加而下降。水稻生长各时期土壤pH值和土壤阳离子交换量随赤泥施用量的增加均有不同程度的提高,施用赤泥不仅能在短时间内提高土壤pH值,还具有持续性。赤泥因其呈碱性可提高土壤pH值,而土壤pH值升高将使大量易溶性Cd向难溶态转化,pH值升高是导致土壤Cd活性降低最直接的原因。施用赤泥后土壤有效态Cd质量分数减少是土壤pH值升高与土壤吸附能力增强共同作用的结果。水稻糙米中Cd的质量分数随赤泥施用量的增加而降低。与不施赤泥对照处理相比,早稻施赤泥RM-1、RM-2、RM-3、RM-4和RM-5处理糙米中Cd的质量分数分别降低了10.34%、31.03%、34.48%、41.38%和64.5%,晚稻糙米Cd质量分数分别降低了14.29%、32.14%、35.71%、39.29%和46.43%。其主要原因是施用赤泥后土壤有效态Cd质量分数减少。更多还原

【Abstract】 The present paper aims to introduce our research findings of the effect of the red-mud application amount on the remedial function for CD and rice growth in CD-contaminated soil.The results of our experimental study have shown that the rice grain yield tends to increase with the increase of the red mud use first and then begins to decrease.For the early rice,the yield of the fields after being treated with 4 500 kg/hm2 red mud proves to be highest.But for the late rice,the yield of the fields after treatment with 3 000 kg/hm2 of red mud also proves to be highest.Comparing the yields of the early rice and late rice,we found that the yields have increased by 11.36% and 8.30% respectively in contrast to the fields without use of red mud;but the yield of rice straw tends to increase with the increase of red mud use.In addition,the soil pH value and soil cation exchange capacity gained increase to some extent with the increasing use of red mud during the rice growing stage.Further studies help us to find that the application of red mud can not only promote the soil pH improvement in a short period,but also displays persistent positive effect,with particular positive effect on the soil contaminated by the heavy metals.The reason is that red mud contains alkaline and the red mud addition helps to increase the pH value of the soil,large amount of soluble Cd helps to transform insoluble Cd with greater pH value in the soil.AS the Cd activity decreases,pH value would increase in the soil.With the decrease of soil’s Cd content,there would be the combined results of the increased pH value and the soil’s adsorptive power.The content of Cd in the brown rice fields tends to decrease with the increasingly use of red mud.As compared with the control group,the content variations of Cd in the brown rice are RM-1,RM-2,RM-3,RM-4 and RM-5.The content of Cd after red mud treated tends to decrease by 10.34%,31.03%,34.48%,41.38% and 64.5% in the early rice,respectively,whereas those in RM-1,RM-2,RM-3,RM-4 and RM-5 treatments tend to decrease by 14.29%,32.14%,35.71%,39.29% and 46.43% in late rice,respectively.The basic reason,we believe,is that the soil’s available Cd content has decreased after the red mud treatment.更多还原