有机肥对土壤—小麦、高粱系统中重金属污染的环境效应研究

【作者】 刘文拔；

【导师】 张崇玉；

【作者基本信息】 贵州大学 ， 环境科学， 2008， 硕士

【摘要】 本研究以冬小麦、高粱为实验对象,其中小麦采用盆栽和大田实验相结合,高梁采用盆栽实验。在小麦实验中研究了不同有机肥施用量在不同Pb、Hg、Ni、Cd污染程度下对冬小麦根际土壤中Pb、Hg、Ni、Cd的形态转化、迁移及植物有效性的影响。在高粱实验中究了不同有机肥施用量在不同Pb、Hg、Cd污染程度下对高粱根际土壤中Pb、Hg、Cd的形态转化、迁移及植物有效性的影响。最后对贵州北部小麦、高粱种植区土壤—作物系统重金属污染做了环境质量评价。通过分析和研究,得出了主要结论如下:(1)施用有机肥可明显增加土壤中有机质、全氮、全磷和全钾的含量。同时使得试验土壤的pH值呈弱碱性。(2)小麦实验中随着外源汞、铅、镉、镍施入量的增加,土壤全量汞、铅、镉、镍和有效态汞、铅、镉、镍含量也随之增加,导致小麦吸收汞、铅、镉、镍增加;在苗期土壤中有效态汞、铅、镉、镍含量与小麦根部、茎叶汞、铅、镉、镍含量均达到显著正相关关系;在收获期,土壤有效态汞、铅、镉、镍含量与小麦根部、茎叶和籽粒汞、铅、镉、镍含量仍然都呈现显著正相关关系。(3)小麦实验中土壤有效态汞、铅、镉、镍含量的高低明显地受有机肥施用量的影响。从小麦苗期到收获期,施用有机肥均对土样中有效态汞、铅、镉、镍有一定的吸附抑制作用,在同一汞、铅、镉、镍水平,随着有机肥施用量的增加,土壤中有效态含量逐渐减少。经相关分析,四个汞、铅、镉、镍水平下有机肥施用量与土壤有效态汞、铅、镉、镍含量之间的相关系数在苗期收获期均呈显著负相关。土壤有机肥对土壤有效汞、铅、镉、镍的抑制效果以低汞、铅、镉、镍高有机肥处理效果最为显著;而高汞、铅、镉、镍低有机肥处理效果最差。(4)小麦实验中有机肥的施用直接影响土壤重金属有效态的含量,继而影响小麦对土壤汞、铅、镉、镍的吸收。相关分析结果表明,在苗期汞、铅、镉、镍的低水平下,有机肥施用量与茎叶、根部汞、铅、镉、镍含量之间达到显著负相关水平,在汞、铅、镉、镍的高水平下,有机肥施用量与茎叶、根部汞、铅、镉、镍含量之间呈负相关关系;在收获期有机肥施用量与茎叶汞、铅、镉、镍含量均呈显著负相关,与根部汞、铅、镉、镍含量呈显著负相关,而对籽粒吸收汞、铅、镉、镍的影响随外源汞、铅、镉、镍施入量的不同变化较大。(5)高粱实验中随着外源汞、铅、镉施入量的增加,土壤全量汞、铅、镉和有效态汞、铅、镉含量也增加,导致高粱吸收汞、铅、镉的量也增加;在苗期土壤中有效态汞、铅、镉的含量与高粱根部、茎叶汞、铅、镉的含量均达到显著正相关关系:在收获期,土壤有效态汞、铅、镉的含量与高粱根部、茎叶和籽粒汞、铅、镉的含量仍然都呈现显著正相关关系。(6)高粱实验中土壤有效态汞、铅、镉含量的高低明显地受有机肥施用量的影响。从高粱苗期到收获期,施用有机肥均对土样中有效态汞、铅、镉有一定的吸附抑制作用,在同一汞、铅、镉水平,随着有机肥施用量的增加,土壤中有效态含量逐渐减少。经相关分析,三个汞、铅、镉水平下有机肥施用量与土壤有效态汞、铅、镉含量之间的相关系数在苗期收获期均呈显著负相关。土壤有机肥对土壤有效汞、铅、镉的抑制效果以低汞、铅、镉高有机肥处理效果最为显著;而以高汞、铅、镉低有机肥处理效果最差。(7)高粱实验中有机肥的施用直接影响土壤重金属有效态的含量,继而影响高粱对土壤汞、铅、镉的吸收。相关分析结果表明,在苗期汞、铅、镉的低水平下,有机肥施用量与茎叶、根部汞、铅、镉含量之间达到显著负相关水平,在汞、铅、镉的高水平下,有机肥施用量与茎叶、根部汞、铅、镉、镍含量之间呈负相关;在收获期有机肥施用量与茎叶汞、铅、镉含量均呈显著负相关,与根部汞、铅、镉含量呈显著负相关,而对籽粒吸收汞、铅、镉的影响随外源汞、铅、镉施入量的不同有较大的变化。(8)在小麦苗期各部分吸收汞、铅、镉、镍量的规律为根部＞茎叶,在收获期小麦各部分吸收汞、铅、镉、镍量的规律为根部＞茎叶＞籽粒;在高粱苗期各部分吸收汞、铅、镉量的规律为根部＞茎叶,在收获期小麦各部分吸收汞、铅、镉的量规律为根部＞茎叶＞籽粒。(9)在小麦盆栽实验中最好的抑小麦吸收汞、铅、镉、镍的有机肥水平是:F2(0.3kg/盆)、F3(0.5kg/盆),换算成每千克土壤施多少克有机肥为:F2(40g/kg)、F2(67g/kg);在小麦大田实验中最好的抑小麦吸收汞、铅、镉、镍的有机肥水平是:D(300kg/亩),E(350kg/亩),换算成每平方米施多少千克有机肥为:D(0.45kg/m~2),E(0.53kg/m~2)。在高粱盆栽实验中最好的抑高粱吸收汞、铅、镉的有机肥水平是:F2(0.1kg/盆),换算成每千克土壤施多少克有机肥为:F2(13g/kg)。(10)对于黔北小麦、高粱种植区土壤—作物系统重金属污染的评价结果明,黔北小麦、高粱种植区土壤均未受到污染,但是土壤中Pb已经达到警戒水平;农作物小麦、高粱中的Cd、Hg、Pb、和Ni等元素含量处于食品安全水平以下。更多还原

【Abstract】 This research has been did under the environment of GuiZhou karst special landform, the object of experiment is the winter wheat and sorghum,The winter wheat and sorghum were studied by the pot and field experiment.We have researched the influence of winter wheat and Sorghum rhizosphere soil Pb,Hg,Ni and Cd shape transformation and plant validity.Main conclusions are as follows:(1) Applying increase the content of Organic matter,total nitrogen,total pH and total potassium organic fertilizer,and the pH value of soil to assume the weak basicity.(2) In the wheat field/pot experiments,The analytic result indicated that the contents of total Hg,Cd,Ni,Pb and available Hg,Cd,Ni,Pb in soils were increased with increasing amount of Hg,Cd,Ni,Pb added,so that the content of Hg,Cd,Ni,Pb in winter wheat was increased.Relationships between contents of available Hg,Cd,Ni,Pb in soils and contents of Hg,Cd,Ni,Pb in roots,stems/leaves and seeds of wheat were significant positivly correlated respectively.(3) In the wheat field/pot experiments,The available Hg,Cd,Ni,Pb in soils were obvious Influenced by the organic fertilizer.The restraining effect of applied organic fertilizer for contents of available Hg,Cd,Ni,Pb in soils is that treatment of higher organic fertilizer with lower Hg,Cd,Ni,Pb is best.(4) In the wheat field/pot experiments,Relationships between amount of applied organic fertilizer and contents of Hg,Cd,Ni,Pb in wheat root and stem/leaf under lower Hg,Cd,Ni, Pb level in seeding period are negative correlated significantly,but Relationships between amount of applied organic fertilizer and contents of Hg,Cd,Ni,Pb in wheat root,stem/leaf and seed under all Hg,Cd,Ni,Pb levels in harvesting period are significant negative correlated respectively..(5) in the sorghum pot experiments,The analytic result indicated that the contents of total Hg,Cd,Pb and available Hg,Cd,Pb in soils were increased with increasing amount of Hg,Cd,Pb added,so that the content of Hg,Cd,Pb in sorghum was increased. Relationships between contents of available Hg,Cd,Pb in soils and contents of Hg,Cd,Pb in roots,stems/leaves and seeds of sorghum were significant positivly correlated respectively.(6) In the sorghum pot experiments,The available Hg,Cd,Pb in soils were obvious Influenced by the organic fertilizer.The restraining effect of applied organic fertilizer for contents of available Hg,Cd,Pb in soils is that treatment of higher organic fertilizer with lower Hg,Cd,Pb is best too.(7) In the sorghum pot experiments,Relationships between amount of applied organic fertilizer and contents of Hg,Cd,Pb in sorghum root and stem/leaf under lower Hg,Cd,Pb level in seeding period are significant negative correlated respectively,but Relationships between amount of applied organic fertilizer and contents of Hg,Cd,Pb in sorghum root, stern/leaf and seed under all Hg,Cd,Pb levels in harvesting period are significant negative correlated respectively.(8) The distribution regular of contents of Hg,Cd,Ni,Pb in wheat organs is that root＞stem/leaf＞seed.;The distribution regular of contents of Hg,Cd,Pb in sorghum a organs is root＞stem/leaf＞seed.(9) In pot’s experiment of wheat:the best level of organic fertilizer for reduce the Hg,Cd, Ni,Pb of wheat is F2(40g/kg)、F3(67g/kg);In field’s experiment of wheat:the best level of organic fertilizer for reduce the Hg,Cd,Ni,Pb of wheat is D(0.45kg/m~2) and E (0.53kg/m~2);In pot’s experiment of sorghum:the best level of organic fertilizer for reduce the Hg,Cd,Ni,Pb of sorghum is F2(13g/kg).(10) The result of Environmental evaluation indicated that the soil of wheat、sorghum planter area of Guizhou has not been polluted,but the Pb already reached the Warning level; The Cd,Hg,Pb,and Ni are all below the food safety level.Therefore we knows the heavy metal content in soil of wheat、sorghum planting area is low,the environmental quality of soil is good in wheat and sorghum planter area of Guizhou.更多还原