Effects of Land Use Patterns on Soil Heavy Metal Contents

Through sampling in farmland and analysis in laboratory,the contents and the pollution level of Cr,Cu,As,Pb,Zn in different soils were studied. The comparative result showed that the As in all soil samples are lower than the mean value of Shaanxi and whole nation,the Cr in lower half soil samples are higher than the mean value of Shaanxi and whole nation,the Cu and Zn in majority soil samples are higher than the mean value of Shaanxi and whole nation,and the Pb in all soil samples is higher than the mean value of Shaanxi and whole nation. The single factor pollution index and multi-factor pollution index method were used to evaluate the soil pollution. According to Soil Environmental Quality Standard,the studied soils were at unpolluted degrees,the soils were clear,the quality of soil adapt to the crop growth,and not affect the quality of agricultural product.

Characteristics and Risk Assessment of Soil Heavy Metal Contents in Facility Agriculture of Guangxi

[Objectives]To study the characteristics of soil heavy metal contents in facility agriculture of Guangxi and analyze its risks.[Methods]The heavy metal content of 30 surface soil samples taken from facility agriculture in Guangxi was analyzed.The status of soil heavy metal pollution in facility agriculture of Guangxi was evaluated by the single factor index method,geo-accumulation index method and Hakanson potential ecological risk index method with reference to the soil background value in Guangxi.[Results]Compared with the soil background value in Guangxi,the over-limit rates of heavy metals cadmium,lead,arsenic,chromium,mercury,copper and zinc in soil samples were 56.67%,56.67%,16.67%,30.00%,50.00%,60.00%and 80.00%,respectively.Compared with the screening values of the Soil Environmental Quality-Risk Control Standard for Soil Contamination of Agricultural Land(for trial implementation)(GB15618-2018),the overlimit rates of the heavy metals cadmium,arsenic,copper and zinc in the surface soil of agricultural facilities in Guangxi were 56.67%,10.00%,16.67%and 23.33%,respectively.Except for the average content of soil cadmium exceeding the screening value,the evaluation content of the other six soil heavy metals did not exceed the screening value.According to the evaluation results of the single factor pollution index method,the surface soil arsenic and chromium of the agricultural facilities in Guangxi belonged to the clean level,lead,mercury,and copper belonged to mild pollution,and cadmium and zinc belonged to moderate pollution.According to the evaluation results of the geo-accumulation index,the lead,arsenic,chromium and mercury in the surface soil of the agricultural facilities in Guangxi belonged to the pollution-free level,while the cadmium,copper and zinc belonged to the mild-moderate pollution.According to the evaluation results of the potential ecological risk index method,the potential ecological risks of the heavy metals of lead,arsenic,chromium,copper and zinc in the soil of agricultural facilities in Guangxi belonged to low potential ecological risk level,and the potential ecological risks of cadmium and mercury belonged to moderate risk level.The potential ecological risk index(RI)of the seven heavy metals in the soil was 132.46,which belonged to moderate potential ecological risk.The largest contribution of soil heavy metals to the potential ecological risk index was cadmium and mercury.[Conclusions]Taking the soil of facility agriculture in Guangxi as the object,this paper studied the characteristics of heavy metal content in facility agricultural soil and its risk assessment,in order to provide a scientific basis for facility soil heavy metal risk prevention and control and provide safe technology for facility agriculture.

Investigation and Evaluation on Soil Heavy Metal Contents in Fruit Producing Area in Baise City,Guangxi Zhuang Autonomous Region

[Objective] This study was conducted to investigate heavy metal conditions in fruit producing area in Baise City, Guangxi Province. [Method] Heavy metal contents in 106 soil samples collected from fruit producing area in Youjiang District, Baise City, Guangxi Province were analyzed, and soil heavy metal pollution condition in this area was estimated applying single factor index method and Hakanson＇ potential ecological risk index method with reference to the second grade of National Soil Environmental Quality Standard and soil background values of this area. [Result] According to the second grade of National Soil Environmental Quality Standard, soil heavy metals in this fruit producing area is at the level of no pollution; and the total potential ecological risk pollution risk （RI） of soil heavy metals was 97.7, indicating no risk. [Conclusion] The fruit producing area in Baise City, Guangxi Province is free of heavy metal pollution.

Derivation of soil Pb/Cd/As thresholds for safety of vegetable planting: A case study for pakchoi in Guangdong Province,China

Regional guidelines for soil heavy metals,in conjunction with specific crops,are proposed to better assess soil environmental quality.In this study,large amounts of soils with different levels of Pb/Cd/As pollution were collected in Guangdong Province,China,to carry out a pot experiment,which was closer to the actual situation and properties of the heavy metal contaminated soils.Taking the widely planted vegetable pakchoi as the research object,we analyzed the correlations between the Pb/Cd/As concentrations in pakchoi and the total or available soil Pb/Cd/As concentrations and established their optimal regression equations.And then,the total and available soil Pb/Cd/As thresholds for pakchoi were calculated according to the allowable Pb/Cd/As limits in pakchoi and were compared with the current soil assessment standards.Furthermore,a lot of paired vegetable-soil samples in field were collected and their pollution situations were assessed by both the current limit thresholds and the calculated thresholds.Obviously,it was more consistent to assess the Cd and As pollution situation of the vegetable and soil samples with the calculated soil thresholds than the current soil assessment thresholds.It further proved that it was necessary to explore the soil heavy metal thresholds for safety of vegetable in specific regions,which would be more scientific and practical to guide safety production of local agricultural products and effective utilization of soil resources.

Study on the proposed environmental guidelines for Cd, Hg, Pb and As in soil of China

This paper deals with the soil-environmental standard. According to the current situation of researching on the soil-environmental quality guideline at home and abroad, and on the basis of the foundations and principles of enacting the soil-environmental standard, the soil environment quality guideline values of Hg, Cd, Pb and As were suggested.

Soil Pollution along Kalwa Bridge at Thane Creek of Maharashtra, India

The present investigation deals with the assessment of pollution status along the wetland of Thane Creek, which has been subjected to a lot of pollution from the Asia’s biggest Thane—Belapur Industrial Complex located at the south of Mumbai harbor along the west coast of India. This paper advocates habitat conservation and ecological studies with special reference to the physico-chemical characteristics and heavy metal pollution in the soil along the creek area. In the present investigation, the pH, electrical conductivity, bulk density, alkalinity and chlorinity values recorded were observed to be high during dry seasons and low during rainy season. The soil samples were also analyzed for their heavy metal contents like nickel, zinc, cadmium, copper, iron, arsenic and mercury. It was observed that, the concentration of these heavy metals increases gradually in dry seasons, followed by sharp decrease during rainy season. These heavy metals have a marked effect on the aquatic flora and fauna which through bio magnification enter the food chain and ultimately affect the human beings as well. The present experimental data on heavy metal pollution in soil samples collected along Kalwa bridge of Thane Creek points out to the need of regular monitoring of water resources and further improvement in the industrial waste water treatment methods. If the present conditions continue for a long period, the creek may soon become ecologically inactive.

川西铜矿周边土壤铬含量高光谱反演研究

矿产资源的开采,给其周边土壤带来许多环境问题,如何快速筛查出矿区周边土壤污染情况尤为重要。本文以川西某铜矿周边土壤作为研究对象,采用LASSO算法对SG平滑后的高光谱数据R SG和经过多元散射校正(MSC)、一阶微分(FD)、倒数变换(RT)的光谱数据进行特征波段的筛选。使用偏最小二乘回归(PLSR)、随机森林(RF)、支持向量机回归(SVR)、极端梯度提升(XGBoost)、反向传播神经网络(BPNN)5种模型进行反演。结果表明,R SG、MSC、FD筛选出的特征波段集中在近红外区域,RT筛选出的特征波段集中在可见光区域;MSC-SVR模型的R 2,RMSE和RPD分别为0.763、6.745、2.06,在所有模型中精度最高,该模型可用于研究区土壤中铬的快速监测。

林芝市巴宜区—工布江达路段土壤重金属分布特征分析

以林拉高级公路为调查对象,对公路路旁表层土壤进行调查和分布特征分析。选取林芝市巴宜区至工布江达路段更具有代表性。研究方法使用多种酸混合消解土壤样品,用原子吸收分光光度法确定公路沿线的土壤样品中重金属Pb、Cr、Zn、Cd、Mn、Cu的含量。结论表明林芝市巴宜区至工布江达路段公路土壤均受到不同程度的重金属污染,其中镉金属污染水平较为严重,铬金属污染水平最轻,较为清洁,其余重金属污染均处于不同程度的轻度污染,其污染程度由低至高Zn<Cu<Pb<Mn,公路不同位置受到重金属含量差异较明显。根据金属含量分析相关性结果表明:Cu、Pd、Cr三种重金属污染可能为同源污染,Zn、Cd金属污染为同源污染。

固废拆解场重金属污染土壤的生物质炭生态修复研究

固废拆解场承载大量的固体废弃物,导致周边土壤重金属污染程度严重,故提出固废拆解场重金属污染土壤的生物质炭生态修复研究。选定实验区域,制备生物质炭,制定实验方案,设置五个实验组,添加不同剂量的生物质炭,测定修复效果。实验结果表明:随着生物质炭施用剂量的增加,土壤中重金属含量与总氮含量呈现先降低后升高的趋势,土壤pH值、微生物数量与酶活性呈现先升高后降低的趋势,有机质含量呈现先升高后稳定的趋势。当生物质炭添加剂量为20%时,土壤重金属污染治理、生态修复性能达到最佳状态。

上海市奉贤区农田土壤-农产品中的重金属含量特征和污染评价

为分析奉贤区农田土壤和农产品的重金属污染状况,采集粮田、菜田和果园3种作物的农田土壤及其对应农产品,分别测定土壤8种重金属元素(Hg、As、Cd、Cr、Pb、Cu、Zn和Ni)和农产品5种重金属元素(Pb、Cd、Cr、As和Hg)的含量特征,采用单项污染指数法、综合污染指数法、积累指数法和富集因子等方法对土壤-农产品中重金属元素进行污染风险评价,并将地统计学与因子分析相结合分析农田土壤重金属的空间分布特征。结果表明:与上海市土壤背景值相比,奉贤区农田土壤Hg、Cd、Cr、Zn和Ni的平均含量较高,分别是背景值的1.40、1.36、1.06、1.15倍和1.44倍。单项及综合污染指数值显示土壤重金属处于无污染水平;但Cd、Ni、Hg元素的积累指数值显示无-中度污染水平,其中有4.92%农田土壤处于Hg元素的中度污染。在空间分布上,Hg呈连片分布;As、Cd整体含量低,南北区域分布;Cr、Zn呈条带状分布,自南往北递增状态;Pb呈散点状分布;Cu元素整体含量高,呈东西梯度分布;Ni元素呈岛状分布。因子分析中,因子1包括Cu和Zn,因子2是Pb,因子3包括Cd、Cr,因子4是Ni,因子5是As和因子6是Hg。奉贤地区土壤重金属含量主要受到工业源、农业源、交通源和自然源影响较大,应加强污染源控制,降低风险水平。农产品样中的5种重金属均未超出标准限量值,单项及综合污染指数值显示农产品重金属属于清洁水平。经土样和农产品样中的重金属含量相关性分析,两者无相关,农产品对土壤重金属的富集因子较小。不同土地利用方式对土壤和农产品中重金属含量影响较大,菜地土壤和农产品对Cd较为敏感,吸收能力较强,而果园土壤和农产品对各重金属吸收总体较弱。在农业生产中可以根据作物吸收重金属特性来调整种植结构,以减轻重金属污染。综合来看,奉贤区土壤-农产品系统中重金属累积程度低,但局部农田土壤中重金属含量存在轻微污染,需引起重视。

有机肥与化肥配施对夏播玉米产量和土壤肥力的影响

为探索有机肥与化肥配施对全株玉米产量和土壤肥力的影响,以乐玉1号玉米为试材,通过田间试验,设置不施肥(CK)、全部化肥(HF)、牛粪单施(N1)、牛粪替代20%化肥(N2)、牛粪替代30%化肥(N3)、羊粪单施(Y1)、羊粪替代20%化肥(Y2)、羊粪替代30%化肥(Y3)共8个处理,测定全株玉米干草产量、氮磷钾素积累量和重金属含量以及土壤理化性质等相关指标。结果表明,Y2和Y3处理的全株玉米干草产量和氮磷钾积累量优于其他处理;N2处理的Cu积累量和Y1处理的Zn积累量最高;0~20cm土层以N3处理的有机质、速效磷、铵态氮、硝态氮和阳离子交换含量最高。可见,低总氮水平下,羊粪替代20%和30%化肥处理对全株玉米生长及养分积累有积极作用,牛粪替代30%化肥改良土壤肥力效果较好。

AMF和PGPR联合芦苇修复重金属污染河道底泥的效应

研究旨在探究河道底泥重金属污染下丛枝菌根真菌(Arbuscular Mycorrhizal Fungi,AMF)与植物根际促生菌(Plant Growth-Promoting Rhizobacteria,PGPR)对芦苇生长、磷吸收以及重金属去除的效应。以沈阳市浑河河道底泥为研究对象,对芦苇接种AMF双网无梗囊霉(Acaulospora bireticulata,AM1)、摩西斗管囊霉(Funneliformis mosseae,AM2)、PGPR黏质沙雷氏菌(Serratia marcescens,PG)、双网无梗囊霉+黏质沙雷氏菌(APG1)、摩西斗管囊霉+黏质沙雷氏菌(APG2)和不接种对照(CK)共6个处理。结果显示,AMF能够促进PGPR在芦苇根区土壤以及根内的定殖数量,而PGPR能够促进AMF侵染发育,增加其侵染率、泡囊数以及孢子数。AMF、PGPR或AMF+PGPR处理均显著增加了芦苇生物量以及地上部和根系磷质量比,促进了植物对底泥中重金属(Cd、Zn、Pb、Cu)的吸收,降低了土壤中重金属含量。在各处理下,APG2处理对底泥中重金属的去除率最高,达33.24%~55.51%,土壤中过氧化氢酶、蔗糖酶、脲酶和碱性磷酸酶活性也显著高于AM1、AM2、PG和CK处理。此外,底泥重金属在芦苇内的分布均为根系大于地上部,可见芦苇根系对重金属的吸收和富集能力较强,且以APG2处理下对Cd、Zn、Pb的吸收效果最好,分别是CK处理的2.4倍、2.0倍以及1.7倍。因此,AMF和PGPR双接种可提高芦苇P吸收量以及土壤酶活性,促进芦苇生长,而AMF和PGPR能够相互促进,增加对底泥重金属的去除效率,其中APG2是最佳组合。

干旱区绿洲农田土壤重金属含量高光谱反演

对新疆渭库绿洲土壤样本的As、Hg、Pb、Cr、Zn和Cu共6种重金属含量与高光谱关系进行分析,基于逐步回归方法筛选出特征波段,采用地理加权回归(GWR)和普通最小二乘法回归(OLS)构建土壤重金属的高光谱反演模型.结果显示:1)研究区的6种重金属元素含量存在一定的差异,土壤中的平均重金属含量依次为Zn>Pb>Cr>Cu>As>Hg,均未超过国家土壤背景值.研究区的Pb平均含量高于当地(新疆)土壤背景值,即研究区表土层中的Pb元素明显富集;2)不同的光谱变换使土壤重金属的光谱特征均得到了增强,但强度有所差异,经过二阶微分变换(SD)和一阶立方根微分变换(CRFD)的土壤光谱相对于原始光谱增强最显著;3)从模型验证来看,在反演6个土壤重金属元素含量时,GWR的R^(2)高于OLS,其中Zn的R^(2)接近0.8,Cu的R^(2)接近0.6,表明模型有一定预测能力,而As、Hg、Pb和Cr的R^(2)均依然低于0.5,模型预测能力并不理想;4)两种模型预测的6种土壤重金属含量的空间分布表现出一定的空间差异性.其中,As元素空间分布差异在这两种预测模型中最大,而其余5种重金属元素Hg、Pb、Cr、Zn和Cu的分布则较为均匀.通过高光谱反射率估算土壤重金属元素含量,实现了干旱区绿洲农田土壤重金属元素含量的高效快速反演,为干旱区绿洲农田土壤重金属元素含量动态监测提供了可靠的技术支撑.

基于SPA-BPNN的成都市天府新区东部土壤As含量高光谱估测建模

为明确成都平原城市边缘带土壤中重金属As含量,以四川省成都市天府新区东部为研究区,对土壤原始高光谱数据进行一阶微分(FD)、二阶微分(SD)、去包络线(CR)和标准正态变换(SNV)处理,利用皮尔逊相关系数(PCC)和连续投影算法(SPA)筛选出最佳变换光谱的特征波段,分别建立偏最小二乘(PLSR)、极限学习机(ELM)、随机森林(RF)和BP神经网络(BPNN)4种回归模型,利用高光谱数据进行土壤重金属As含量估测并进行精度验证。结果表明,经去包络线一阶微分(CR-FD)变换的光谱与土壤重金属As含量相关性显著提升,由0.473提高到0.848;无论是基于PCC还是SPA算法筛选出的特征波段,非线性模型的拟合度以及预测精度均高于线性模型;相对于PCC算法,利用SPA算法筛选的特征波段建立的模型预测精度明显提升,PLSR、ELM、RF、BPNN模型验证集的决定系数(R2)分别为0.786、0.847、0.856、0.942。因此,以SPA算法筛选出的光谱波段作为自变量构建的BPNN模型(SPA-BPNN)是研究区内As含量的最优估测模型。

土壤灭菌和杀真菌剂对大豆生长和重金属累积的影响

【目的】研究土壤灭菌和杀真菌剂(苯菌灵)对大豆生长和重金属累积的影响。【方法】以污染农田土壤为基质开展室内盆栽试验,在土壤灭菌和施用苯菌灵的条件下,测定大豆的生长指标、叶绿素含量、抗氧化生理指标、重金属(铅、锌、镉和铜)含量与累积量以及土壤重金属有效态含量。【结果】与原状土壤相比,土壤灭菌处理导致大豆株高、茎叶和果实生物量分别降低21.00%、43.92%和44.47%,但可以使根系生物量增加56.57%。土壤灭菌和施用苯菌灵处理均可显著增加土壤有效态铅含量,增幅分别为160.62%和179.00%;均可显著降低土壤有效态锌含量,降幅分别为33.82%和17.37%。土壤灭菌还可显著增加大豆根系中的锌、镉含量以及铅、锌、镉、铜累积量,显著降低大豆茎叶和果实中的铅、铜累积量,增加铅、锌和镉的富集系数。施用苯菌灵可显著增加类胡萝卜素以及茎叶和根系中的铅含量,增幅分别为77.00%、36.87%和12.43%;显著增加大豆茎叶中的铅累积量;显著增加铅的富集系数和转运系数;但对大豆生长、抗氧化生理及其他重金属累积无显著影响。【结论】完全消除土壤微生物抑制了大豆的生长,并显著降低了大豆对重金属的耐性与累积能力,说明土壤微生物在大豆生长和重金属耐性方面有重要作用。

猪场沼液还田对土壤和植物重金属含量的影响

还田消纳是猪场沼液资源化利用的主要方式。由于沼液中含有多种金属元素,过量浇灌会引发土壤重金属污染。目前,关于猪场沼液对耕地土壤和植物重金属污染特征的影响及其影响因子的研究还不够深入。在广西生猪养殖区,选取了4种不同耕地利用类型(叶菜类、果树类、饲草类、药草类)和14个样地,就不同沼液浇灌强度对土壤与植物重金属的影响规律及其影响因子进行研究。结果表明:在14个样地0~40 cm表层土壤中,重金属Cu、Zn、Cd的输入强度最大,且其含量和土壤pH变化和与沼液浇灌总量呈显著(p<0.05)正相关;在4种耕地类型中,杂交象草和空心菜的可食用部分Cu、Zn、Cd、Pb、Cr含量与沼液浇灌总量呈显著正相关;在沼液还田中,由于Cu、Zn的输入强度大,而植物对其的富集系数又较低,因此土壤中Cu、Zn积累较快;浇灌沼液对叶菜类和果树类的主要污染风险是Pb和Cd,而对杂交象草的污染风险较小。

连作对土壤质量及硝态氮含量、菜心产量和品质的级联影响

为探索露地连作菜心(Brassica chinensis var.parachinensis)产量和土壤状况变化,开展了以土壤重金属累积、土壤肥力和土壤结构的3因素3水平正交试验。结果表明:影响菜心产量的主次因素顺序为土壤结构、土壤重金属累积和土壤肥力;土壤重金属累积和土壤肥力交互作用、土壤结构和土壤肥力交互作用均对菜心产量的影响显著(P<0.05),其他因素交互影响不显著。影响土壤硝态氮含量的主次因素顺序为土壤重金属累积、土壤结构、土壤肥力,其中,土壤重金属累积和土壤结构交互作用对硝态氮的影响显著(P<0.05)。经响应曲面法得出:当土壤重金属累积综合指数(SHI)<1.0、土壤肥力综合指数(SFI)≥6.5、土壤结构综合指数(SSI)≥1.95时,菜心产量和土壤硝态氮含量维持在较高水平。为了验证模型准确性,进行了Logitic回归分析,将3个连作年限与SHI、SFI、SSI、产量、硝态氮含量进行了拟合。基于这一分析,进一步预测了连续种植5年、9年和13年后这些指标的预测数值。测定品质指标发现,连作5年、9年和13年的各项指标预测值和实测值的RMSE值均小于0.83,具有较高的一致性。连作年限≥5年时,菜心产量、品质和土壤硝态氮含量显著下降(P<0.05),且较Box-Behnken模型优化值降低。因此,当菜心连作年限不超过4年时,土壤才有较高的生产力来保证菜心稳产和较优的品质。

生物质燃料灰渣替代化肥在甘薯上的应用

为探究生物质燃料灰渣施用于土壤对甘薯生长的影响,本研究通过盆栽试验和大田试验相结合的方式,确定生物质灰渣的适宜用量范围,分析施用生物质灰渣对甘薯重金属含量、产量和品质以及土壤理化性质的影响.盆栽试验表明,当生物质灰渣添加的质量分数为1%~5%时,甘薯幼苗可正常生长,且不会造成薯苗体内重金属含量超标,其中:添加5%的甘薯幼苗生物量和株高较对照增幅最大,分别为111.13%和27.60%(P<0.05);与对照相比,添加3%和5%的生物质灰渣显著增加了土壤有机碳(TOC)、水解性氮(AN)和速效钾(AK)的质量分数,增幅分别为4.58%~8.40%、6.31%~11.28%、4.21%~13.16%,而对土壤pH和有效磷(AP)无显著影响(P>0.05).当生物质灰渣以3000 kg/667 m 2施于大田时,土壤TOC、AN和AK质量分数分别平均显著增加19.52%、30.95%和36.88%,土壤AP含量无显著变化.施用生物质灰渣的甘薯产量与品质(淀粉、还原糖、可溶性糖和蛋白质含量)与常规施肥土壤相当,且未造成土壤pH增加和重金属含量超标.结果表明,施用生物质灰渣可达到替代化学肥料的效果,保证甘薯的健壮生长,既实现了生物质灰渣“变废为宝”,又节约了施肥成本.因此,合理有效地将生物质灰渣应用于农业,不仅可以促进农业生产的良性循环,而且避免造成环境污染.

不同改良剂组合对茄子产量和重金属含量及土壤农化性状的影响

为酸化土壤治理和安全利用提供依据,通过设置7个不同处理,分别为配方肥T1(CK)、配方肥+土壤改良剂(石灰粉T2、农用氢氧化镁T3、特贝钙土壤调理剂T4)、有机肥+土壤改良剂(石灰粉T5、农用氢氧化镁T6、特贝钙土壤调理剂T7),比较不同改良剂组合对茄子产量和重金属含量、土壤农化性状的影响。结果表明:与单施配方肥(CK)相比,在酸性土壤上施用有机肥+土壤改良剂、配方肥+土壤改良剂组合可显著增加作物产量,降低茄子重金属含量,改善土壤农化性状。在增加茄子产量、降低茄子Cr含量效果方面,有机肥+土壤改良剂组合优于配方肥+土壤改良剂组合,在降低茄子Cd含量效果方面,配方肥+土壤改良剂组合效果更好。在改良土壤农化性状效果方面,两者规律不明显。

荒漠草原不同重金属污染对牛枝子叶片—土壤生态化学计量特征的影响

探究荒漠草原牛枝子(Lespedeza potaninii)在不同重金属污染梯度下的生长状况,通过其不同重金属污染梯度下牛枝子叶片及土壤中碳(C)、氮(N)、磷(P)含量的变化以及对其他土壤理化性质的变化,明确在不同重金属污染梯度下牛枝子对养分的利用状况、生态适应策略。结果表明:在不同污染梯度下牛枝子叶片总C含量变化差异不明显,牛枝子叶片全N、全P含量呈先上升后下降的趋势。土壤总C、全N、全P含量在对照组CK下最高,随着重金属污染梯度的升高整体呈下降的趋势,随着重金属污染梯度的升高,土壤速效P、速效K、电导率整体上呈先上升后下降的趋势,土壤碱解氮整体呈下降趋势,土壤pH变化不显著。牛枝子叶片全N与全P与土壤总C呈极显著正相关(P<0.01),土壤总C与土壤全N、土壤C/N、C/P、N/P表现出极显著正相关(P<0.01)。在低浓度重金属下促进植物吸收营养元素,但过了其承载的重金属浓度时就会阻碍植物对营养元素的吸收。