【作者】 李树辉；

【导师】 王道龙；

【作者基本信息】 中国农业科学院 ， 作物生态学， 2011， 博士

【摘要】 本文以北方典型区域（山东寿光、河南商丘、吉林四平、甘肃武威）的设施菜地为研究对象,通过田间调查、室内分析和定位试验,系统研究了重金属在设施菜地中的累积特征、剖面分布与迁移规律,进行了设施菜地系统中重金属的平衡估算,并针对设施菜地重金属累积问题,提出了重金属累积及污染防控的对策,通过研究得到的主要结果如下:1.山东寿光设施菜地中As、Cd、Cu、Zn、Cr、Ni、Pb的平均含量分别为9.63、0.52、33.91、124.20、53.04、29.04、17.96 mg·kg^-1;河南商丘分别为11.08、0.30、25.03、73.53、51.06、26.68、14.53 mg·kg^-1,吉林四平分别为12.47、0.467、37.20、87.68、67.50、25.17、17.98 mg·kg^-1,甘肃武威分别为13.33、0.42、33.85、85.31、53.12、28.59、20.76 mg·kg^-1,各区域设施菜地重金属均出现了不同程度的累积。2.将设施菜地重金属含量与国家土壤环境质量II级标准比较,除Cd、Zn、Ni存在少量样本超标外,上述4个区域设施菜地其它重金属含量均在国家允许范围内,土壤质量整体状况尚可,在所有重金属中,四个区域以Cd超标问题最为突出,Cd在各区域的样本超标比例顺序为:吉林四平（39.8%）>山东寿光（27.4%）>河南商丘（6.1%）>甘肃武威（1.0%）。3.根据各区域重金属含量随着设施年限的变化规律看,4个区域设施土壤重金属含量随着年限的延长呈现不同程度的累积趋势,据初步估计,As、Cd、Cu、Zn、Cr、Ni、Pb在山东寿光设施菜地累积速率分别为0.105、0.033、0.923、2.010、0.370、0.281、0.324 mg·kg^-1·a^-1,在河南商丘则分别为0.116、0.001、0.517、1.628、0.225、0.122、0.203 mg·kg^-1·a^-1,在吉林四平分别为0.164、0.035、1.223、2.629、1.076、0.248、0.143 mg·kg^-1·a^-1,在甘肃武威分别为0.194、0.025、1.022、2.691、0.156、0.481 mg·kg^-1·a^-1,整体来说,Cu和Zn的累积速率最快。高毒元素Cd尽管累积速率最低,但其达到国家土壤II级标准值的时间最短,风险相对较高。4.山东寿光和甘肃武威的设施菜地土壤剖面重金属存在一定程度的累积趋势,表层土壤重金属含量普遍较高,随着土层深度的增加,重金属含量多呈现出不断降低的趋势。山东寿光表层土壤重金属Cd、Cu、Zn的含量随种植年限的增加呈现显著升高的趋势（P<0.05）,甘肃武威的设施菜地重金属含量随着设施年限的增加而不断累积的趋势明显;与小麦地及新建大棚相比较,相同土层设施菜地土壤中重金属含量明显较高。5.通过在甘肃武威两年的田间定位试验,结果表明设施菜地进行蔬菜种植过程中重金属的输入途径主要来自于化肥和有机肥,其中,有机肥对设施菜地重金属的输入通量远远超过化肥。在不同的施肥处理下,重金属输入速率均以有机和无机配施（MNPK）处理最高,其最大输入通量分别为0.043 kg·ha^-1·a^-1、Cu16.910 kg·ha^-1·a^-1、Zn45.617 kg·ha^-1·a^-1、Cr1.668 kg·ha^-1·a^-1、Ni1.297 kg·ha^-1·a^-1、Pb1.431kg·ha^-1·a^-1。同时发现蔬菜植物秸秆和果实收获物是设施菜地重金属输出的主要渠道,通过作物果实收获带走的重金属量远远超过植物秸秆的重金属输出量。6.根据对设施菜地重金属输入输出平衡估算的结果,除个别元素外,不同施肥处理下重金属均有不同程度的盈余,其中MNPK、1/2MNPK、M处理的重金属盈余量相对较高,NPK处理较低;从平衡通量看,重金属累积速率最高的为MNPK处理,Cd、Cu、Zn、Cr、Ni、Pb的累积速率分别为0.042 kg·ha^-1·a^-1、16.750kg·ha^-1·a^-1、44.849 kg·ha^-1·a^-1、1.653 kg·ha^-1·a^-1、1.271 kg·ha^-1·a^-1、1.419 kg·ha^-1·a^-1。7.通过对北方4个典型区域设施菜地重金属累积的成因分析表明,设施菜地重金属的累积与肥料用量、质量密切相关。山东寿光土壤重金属Cd、Cr、Cu、Pb、Zn的含量与有机肥施用量间呈显著对数正相关关系（P<0.05）,化肥施用量与土壤Cd、Zn含量间呈显著对数正相关;河南商丘有机肥施用量与土壤Cd含量间极显著对数正相关（P<0.01）;甘肃武威菜地有机肥施用水平与砷含量间显著正相关（P<0.05）,多年化肥累积施用量与土壤Zn含量间呈显著对数正相关。含重金属有机肥和化肥的施用是导致设施菜地重金属累积的主要原因。8.对重金属含量超标的设施菜地,可从设施菜地生产基地选址、投入品源头监控、低吸收作物种植、农艺措施调整等角度进行调控,减少重金属进入农田,降低土壤中重金属的生物有效性及作物对重金属的吸收;对重金属污染土壤,则应采取物理、化学、生物以及生物-化学的方法进行修复。在采取源头监控、过程阻断和污染修复等措施的同时,应加大对重金属超标农田安全利用与调控、重金属污染农田修复技术等的科技投入,加强环境立法并严格执法。更多还原

【Abstract】 Through the investigation of typical soils of protected vegetable cultivation in Shouguang of Shandong Province, Shangqiu of Henan Province, Siping of Jilin Province, Wuwei of Gansu Province in the North China, the characteristics of heavy metal accumulation and their distributions in the soil profiles and the mobility of heavy metals were studied systematically via laboratory analysis and field experiments. The balance of heavy metals between inputs and outputs in the soils of the protected vegetable cultivation was calculated. The strategies for regulation of the accumulation and contamination of heavy metals in the soils of the protected vegetable cultivation were also highlighted. The obtained results were as follows:1. The contents of As, Cd, Cu, Zn, Cr, Ni, and Pb in the soils of the protected vegetable cultivation in Shouguang of Shandong Province was with 9.63, 0.52, 33.91, 124.20, 53.04, 29.04, and 17.96 mg·kg^-1, respectively, while it was with 11.08, 0.30, 25.03, 73.53, 51.06, 26.68, and 14.53 mg·kg^-1 respectively in Shangqiu of Henan Province. It was with 12.47, 0.47, 37.20, 87.68, 67.50, 25.17, and 17.98 mg·kg^-1 respectively in Siping of Jilin Province, and with 13.33, 0.42, 33.85, 85.31, 53.12, 28.59, and 20.76 mg·kg^-1 respectively in Wuwei of Gansu Province. Heavy metal accumulation occurred in soils of the protected vegetable cultivation for these areas in the North China.2. Compared to the second grade standard values of National Soil Quality, heavy metal contents in most samples did not exceed the recommended value with the exception of Cd, Zn and Ni in some soil samples. Generally speaking, the accumulation of heavy metals had relatively small environmental risk. Among all investigated heavy metals, the most serious accumulation was observed for cadmium. The percentage of soil samples exceeding the national standard from high to low was in order of Siping （39.8%）, Shouguang （27.4%）, Shangqiu （6.1%）, and Wuwei （1.0%）.3. The heavy metal accumulation in the soils of the protected vegetable cultivation generally increased with the cultivation time prolonging in all studied regions. It was estimated that the accumulating rate of As, Cd, Cu, Zn, Cr, Ni, and Pb in the soils of the protected vegetable cultivation in Shouguang was with 0.105, 0.033, 0.923, 2.010, 0.370, 0.281, and 0.324 mg·kg^-1·a^-1, respectively, while it was with 0.116, 0.001, 0.517, 1.628, 0.225, 0.122, and 0.203 mg·kg^-1·a^-1 respectively in Shangqiu, and with 0.164, 0.035, 1.223, 2.629, 1.076, 0.248, and 0.143 mg·kg^-1·a^-1 respectively in Siping. It was with 0.194, 0.025, 1.022, 2.691, 0.156, and 0.481 mg·kg^-1·a^-1 respectively in Wuwei. Generally speaking, the highest accumulation rate occurred for Cu and Zn, and the lowest rate for highly toxic element of Cd.4. The distribution of heavy metal contents in the soil profiles showed that the heavy metal accumulated in the different soil layers and the highest concentration of heavy metals appeared in the surface soil layer. With the increase of the soil depth, most heavy metal content continuously decreased in Shouguang and Wuwei. In contrast with that of wheat field and vegetable field （0 year）, heavy metal contents increased in the same soil layer in protected cultivation, which indicated some environmental risk to local groundwater. 5. According to the field experiments for two years in Wuwei, Gansu Province, the main input sources were from chemical fertilizer and organic fertilizer, and the input amount from organic fertilizer was much more than that from chemical fertilizer. For different fertilization treatments, the highest input rate into the soils of the protected vegetable cultivation was with 0.043 kg·ha^-1·a^-1for Cd, 16.910 kg·ha^-1·a^-1 for Cu, 45.617 kg·ha^-1·a^-1 for Zn, 1.668 kg·ha^-1·a^-1 for Cr, 1.297 kg·ha^-1·a^-1 for Ni, and 1.431 kg·ha^-1·a^-1 for Pb, respectively, and all of them appeared in MNPK （manure plus chemical fertilizers） treatment. Meanwhile, the most important output channel for heavy metals from soils of the protected vegetable cultivation was through vegetable plant straws and fruits. The heavy metal amount removed by fruits was much more than that by straws.6. Balancing the inputs and outputs of heavy metals in soils of the protected vegetable cultivation, it was indicated that heavy metals under different treatments had different levels of surplus except few elements. The rather high surplus occurred in MNPK, 1/2MNPK, and M （manure） treatments, while much less surplus was for NPK （Chemical fertilizers） treatment. The highest accumulating rate occurred for MNPK treatment, which was with 0.042, 16.750, 44.849, 1.653, 1.271and 1.419 kg·ha^-1·a^-1 for Cd, Cu, Zn, Cr, Ni, and Pb respectively.7. By analyzing the sources of heavy metal accumulation in the soils of the protected vegetable cultivation in the four typical regions, it showed that the heavy metal accumulation was closely related to the amount and quality of fertilizer applied to the soil. In Shouguang, Shandong Province, logarithmic significant positive correlations were found between the content of Cd, Cr, Cu, Pb, and Zn in soils and the organic fertilizer application amount （P<0.05）, as well as those between the chemical fertilizer application amount and the contents of Cd and Zn in soils. In Shangqiu of Henan Province, Logarithmic positive correlation was also found between the application amount of organic fertilizer and soil Cd content at 0.01 significant levels. The arsenic content was significantly correlated with the organic fertilizer application level （P<0.05）, while logarithmic positive correlation was found between soil Zn and the chemical fertilizer application amount. Application of chemical and organic fertilizer was one of the main reasons for heavy metal accumulation in the surveyed soils of the protected vegetable cultivation.8. In order to reduce the amount of the heavy metals entering into soils of the protected vegetable cultivation, the availability of heavy metals in soils and uptake amount of heavy metals by vegetables, several methods were recommended including the base selection for vegetable production under protected cultivation, detection and control of heavy metals of input source, plantation of crops with low adsorption for heavy metals. For seriously contaminated soils with heavy metals, such techniques as physical, chemical and biological approaches can be adopted. Therefore, measures like source control, process block and soil remediation should be taken on one hand, investment addition for research on science and technology of safe utilization and regulation technique for farmland polluted by heavy metals, environmental legislation and strict law enforcement were also necessary on the other hand.更多还原