生物质炭对铅镉复合污染稻田土壤修复效应研究

发布时间：2018-08-16 12:20

【摘要】：高效发展的现代农业在产生了巨大的经济效益的同时,也给稻田土壤带来了日益突出的环境问题,尤其以稻田土壤重金属和有机污染日益加重为典型代表。许多相关领域专家学者已着手对重金属污染、有机污染以及重金属、有机复合污染土壤的修复和综合治理等工作开展调研,提出可供参考的修复治理方案。生物质炭是一种固态物质,这类物质的形成条件为部分或完全缺氧状态下,在较低温度中热解炭化所得,具有高度芳香化、巨大比表面积和多孔性特征,使其在吸附方面效果显著,可有效降低在土壤和污水中土壤重金属和有机污染物的活性。本论文着手于稻田土壤受重金属污染严重这一现状,通过室内盆栽及野外大田试验,探究生物质炭的输入对受铅镉复合污染的稻田土壤是否存在相关性并测出相应数据为受重金属污染稻田土壤的修复提供数据和试验参考。具体研究结果如下：通过水稻盆栽试验,探究了在仅施肥、施肥与堆肥、施肥与堆肥再加入晚季稻秸秆三种处理方式下,选用两个采样点的青紫泥和黄泥田进行土壤盆栽试验,研究生物质炭输入下的稻田土壤修复环境效应。结果表明,施加含炭堆肥后比对照组平均增产14.3%,施加含炭堆肥比施加普通堆肥增产8.65%,说明堆肥污泥中添加了生物质炭能够更有效地提高土壤中养分含量以及增加土壤中的离子交换量。同时,也在一定程度上降低了土壤盐度的增加量,有助于土壤性质的改善,促使水稻增产。添加生物炭后,稻田土壤pH值逐步提高,并影响到Cd、Pb的水解平衡。稻田土壤交换态Cd、Pb含量与水稻糙米吸收量表现极显著相关,这说明生物质炭可显著降低土壤中交换态Cd、Pb,从而降低水稻糙米中的Cd、Pb含量。施入生物质炭后,土壤交换态Cd含量平均降低平均44.4%,糙米中的Cd含量平均降低了49.5%；土壤交换态Pb含量平均降低91.0%,糙米中的Pb含量平均降低了61.3%,表明生物质炭输入对于降低稻田土壤重金属含量具有显著性效果。利用大田水稻试验,进一步研究了在四个不同处理方式下,生物质炭对受污染稻田土壤和稻田作物的修复成效及作用原理。结果表明,在降低重金属向水稻植株内迁移速率方面,喷施生物质炭与过磷酸钙的处理要优于对照组,稻米中重金属Pb、Zn和Cd含量分别降低52.0%、19.4%和43.1%。在水稻植株内,Pb和Zn的含量顺序为：根茎叶壳稻米。各类重金属高低迁移能力顺序为：CdZnPb,其中Cd的迁移能力最强。磷溶液的喷施对水稻产量的增收有一定作用,由数据得出该实验中水稻产量从0.59kg·m-2增加到0.72kg·m2；同时,稻米内Pb、Zn和Cd等重金属含量呈显著性降低趋势。
[Abstract]:Modern agriculture with high efficiency not only brings great economic benefits, but also brings more and more serious environmental problems to paddy soil. Especially, heavy metals and organic pollution in paddy soil are becoming more and more serious. Many experts and scholars in related fields have carried out research on heavy metal pollution, organic pollution, heavy metal and organic compound pollution soil remediation and comprehensive treatment, and put forward some remediation schemes for reference. Biomass carbon is a kind of solid material, which is formed under partial or complete anoxic conditions and pyrolytic carbonization at lower temperature, with high aromatization, large specific surface area and porous characteristics. It can effectively reduce the activity of heavy metals and organic pollutants in soil and sewage. In this paper, the present situation of heavy metal pollution in paddy soil was studied, and pot and field experiments were carried out in the field. To explore the correlation between biomass carbon input and Paddy soil contaminated by lead and cadmium and to find out the corresponding data to provide data and experimental reference for the remediation of paddy soil contaminated by heavy metals. The results are as follows: through the pot experiment of rice, the pot experiment of soil was carried out by using two sampling sites, green purple mud and yellow mud, under the three treatments of fertilization only, fertilization and composting, and adding the straw of late cropping rice. Environmental effects of soil remediation in paddy fields under carbon input from graduate students. The results show that Compared with the control group, the average increase of carbon compost was 14.3 and 8.65 respectively, which indicated that the addition of biomass carbon to the compost sludge could increase the nutrient content and the ion exchange in the soil more effectively. At the same time, the increase of soil salinity is reduced to some extent, which is helpful to the improvement of soil properties and the increase of rice yield. With the addition of biochar, the pH value of paddy soil increased gradually, and the hydrolytic balance of CD ~ (2 +) Pb was affected. The CD ~ (2 +) ~ (2 +) Pb content in paddy soil was significantly correlated with the absorption of brown rice, which indicated that biomass charcoal could significantly reduce the content of CD ~ (2 +) Pbin in the soil and thus the content of CD ~ (2 +) ~ (2 +) Pb in brown rice. After application of biomass carbon, the average content of exchangeable CD in soil decreased by 44.4%, and the content of CD in brown rice decreased by 49.5% on average. The average content of Pb in soil was reduced by 91.0% and that in brown rice was decreased by 61.3%, which indicated that the input of biomass carbon had significant effect on reducing the content of heavy metals in paddy soil. In this paper, the effects of biomass carbon on the remediation of contaminated paddy soils and paddy crops under four different treatments were further studied by using field rice experiments. The results showed that the treatment of spraying biomass carbon and calcium superphosphate was superior to the control group in reducing the migration rate of heavy metals into rice plants, and the contents of Pb, Zn and CD in rice decreased by 52.0% and 43.1%, respectively. The order of Pb and Zn contents in rice plants was as follows: rhizome, leaf and shell rice. The order of high and low migration ability of heavy metals was: 1. CdZnPb, among which CD was the strongest. The results showed that the rice yield increased from 0.59kg m-2 to 0.72kg m2, and the contents of heavy metals such as Pb, Zn and CD in rice decreased significantly.
【学位授予单位】：浙江农林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53

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