深圳市不同城市密度区中环芳烃的发生、来源及生态风险评估   总被引：1，自引：0，他引：1  

ZHANG Di  WANG Jun-Jian  ZENG Hui 《土壤圈》2016,26(5):676-686

Urbanization may cause increased exposure levels to polycyclic aromatic hydrocarbons(PAHs) and associated health risks for over half of the world's population living in cities,but little evidence has shown a direct spatial relationship between urbanization and soil PAH pollution.Based on the monitored PAH concentrations in 188 topsoil(0-5 cm) samples in Shenzhen,the most rapidly developing city in China,in recent decades,we applied geographical demarcation to determine the occurrences,source apportionments,and spatial ecological risks of soil PAHs across five zones of varying urban densities.Mean concentrations of the 16 US Environmental Protection Agency(EPA) priority PAHs(Σ_(16)PAHs) and the 7 carcinogenic PAHs(Σ_7CarPAHs) both followed the order:Zone D(60%-80%constructive land density(CLD)) Zone E(80%-100%CLD) Zone C(40%-60%CLD) Zone B(20%-40%CLD) Zone A(0%-20%CLD),suggesting that the highest PAH levels occurred in the suburban-urban center transitional zone(Zone D) rather than the urban center zone(Zone E) in Shenzhen.There were significant correlations of Σ_(16)PAHs to TOC and sampling altitude across all samples but not within highly-urbanized regions(Zones D and E),implying a considerable disturbance of urbanization to the soil PAH pool.Source apportionments suggested that soil PAHs of all zones were mainly derived from fossil fuel combustion,with Zone E showing the highest contribution from oil sources among different zones.Spatial ecological risk analysis showed that the contaminated area(467 km~2;23.9%of total area;toxic equivalency quotients 33 ng g~(-1)) had a higher contribution from the highly-urbanized regions(Zones D and E) than the uncontaminated area(42.3%vs.18.1%).Overall,our study highlighted a strong spatial relationship between urbanization and soil PAH pollution.  相似文献   

Near-infrared spectroscopy for analysis of chemical and microbiological properties of forest soil organic horizons in a heavy-metal-polluted area     

Marcin Chodak  Maria Niklińska  Friedrich Beese 《Biology and Fertility of Soils》2007,44(1):171-180

In industrial areas, heavy metals may accumulate in forest soil organic horizons, affecting soil microorganisms and causing changes in the chemical composition of the accumulated organic matter. The objectives of this study were to test the ability of near-infrared spectroscopy (NIRS) to detect heavy metal effects on the chemical composition of forest soil O horizons and to test whether NIRS may be used to quantitatively determine total and exchangeable concentrations of Zn and Pb (Zn_t, Pb_t, Zn_ex, Pb_ex) and other chemical and microbial properties in forest soil O horizons polluted with heavy metals. The samples of O horizons (n = 79) were analyzed for organic C (C_org), total N and S (N_t, S_t), Zn_t, Pb_t, Zn_ex, Pb_ex, basal respiration (BR), microbial biomass (C_mic) and C_mic-to-C_org ratio. Spectra of the samples were recorded in the Vis-NIR range (400–2,500 nm). To detect heavy-metal-induced changes in the chemical composition of O horizons principal components (PC1–PC7) based on the spectral data were regressed against Zn_t + Pb_t values. A modified partial least squares method was used to develop calibration models for prediction of various chemical and microbial properties of the samples from their spectra. Regression analysis revealed a significant relationship between PC3 and PC5 (r = −0.27 and −0.34, respectively) and Zn_t + Pb_t values, indicating an effect of heavy metal pollution on the spectral properties of the O horizons and thus on their chemical composition. For quantitative estimations, the best calibration model was obtained for C_org-to-N_t ratio (r = 0.98). The models for C_org, N_t, and microbial properties were satisfactory but less accurate. NIRS failed to accurately predict S_t, C_org-to-S_t, Zn_t, Pb_t, Zn_ex, and Pb_ex.  相似文献   

有机固体废弃物堆肥的腐熟度评价指标   总被引：5，自引：2，他引：5  

刘卫星顾金刚  姜瑞波洪坚平 《中国土壤与肥料》2005,(3):3-7

有机固体废弃物堆肥的腐熟度指标是评价堆肥稳定及安全农用的重要参数,通过综述堆肥的物理、化学、生物学指标,提出评价堆肥的腐熟度时,物理指标一般作为辅助指标,化学指标中T值≤0 6、水溶性C/总有机N≤0 70可以稳定应用,核磁共振和红外光谱分析可以精细地评价腐熟后堆肥产品中各组分,发芽率指标可作为堆肥产品安全稳定的生物指标。在应用时要与BOD、CEC、腐殖化参数等多方面结合来评价堆肥的腐熟程度。  相似文献   

基于混合高斯模型渗灌复合材料导水特性分析     

王晓健  毛一剑  张增志 《农业工程学报》2015,31(15):87-92

为了定量研究由蒙脱土和聚丙烯酰胺制备而成的渗灌复合材料导水特性与其组分之间及土壤湿度的关系,该文利用混合高斯模型模拟求解渗灌复合材料的平衡导水率、材料组分比例及土壤湿度之间的关系。设置9组组分比例不同(蒙脱土与聚丙烯酰胺质量比5~25)的渗灌复合材料在8个土壤湿度(土壤质量含水率3%~17%)下进行建模,另外2组((蒙脱土与聚丙烯酰胺质量比8和18)不同的组分制备而成复合材料在2组不同土壤湿度(土壤质量含水率4%和14%)下进行验证。结果表明:建立的渗灌复合材料平衡导水率与材料组分的关系函数,相应模拟值与实测值之间的均方根误差(root mean squared error,RMSE)≤25.87 g/h,误差平方和(sum of squares of error,SSE)≤160,决定系数(coefficient of multiple determination,R2)≥0.8933,利用混合高斯模型模拟平衡导水率、材料组分关系函数的相关参数与土壤湿度之间的关系,相应模拟值与实测值之间的RMSE≤195 g/h,SSE≤98350,决定系数R2≥0.6868,说明利用混合高斯模型拟合渗灌复合材料的平衡导水率、材料组分比例及土壤湿度之间的关系函数具有很好的稳定性、可行性及精确性;经验证,平衡导水率、材料组分比例及土壤湿度关系函数的模拟值与实测值之间的最大相对误差为14.14%,表明用该函数模拟渗灌复合材料H-C-M之间关系的可靠性。该研究对于后续的渗灌材料的研制及应用具有指导意义。  相似文献   

川中丘陵区城墙岩群和蓬莱镇组紫色岩上土壤性质研究   总被引：1，自引：0，他引：1  

胡玉福  邓良基  张世熔  凌静  黄成毅  方从刚 《土壤通报》2007,38(6):1076-1080

采用野外调查、取样和室内实验分析相结合的方法,研究了川中丘陵区白垩系城墙岩群(K1cg)和侏罗系蓬莱镇组(J3p)两种紫色母岩上土壤理化性质特征和差异,结果表明:两种紫色岩母质发育的土壤粘粒含量低,而砂粒含量高;土壤有机质和氮素含量低,而矿质养分含量丰富;在相同的地形部位上,J3p发育的土壤粘粒、全钾、速效钾和速效磷含量高于K1cg发育的土壤,而K1cg发育的土壤pH和土壤全磷均高于J3p发育的土壤,两种紫色岩母质形成的土壤有机质和氮素差异不明显。从丘顶到丘脚,土层逐渐增厚,土壤粘粒含量逐渐递增,砂粒含量逐渐递减;土壤有机质及各种矿质养分含量均呈递增趋势。  相似文献   

Composition and transformation of 1.4 nm minerals in cutan and matrix of alfisols in central China     

Li Huang  Wenfeng Tan  Fan Liu  Hongqing Hu  Qiaoyun Huang 《Journal of Soils and Sediments》2007,7(4):240-246

Background, Aims, and Scope  Hydroxy interlayered vermiculite (HIV) and vermiculite are commonly referred to as 1.4 nm minerals. In the subtropical soils of central China, the concentration of vermiculites decreased while that of HIVs increased gradually from north to south as the intensity of soil formation or eluviation increases in the same direction. The cutans in these soils closely interact with air, roots, microbes, water and dissolved ions in soils. Cutans may therefore be expected to exert an important influence on the formation of 1.4 nm minerals relative to the matrix soils. However, little is known about the transformation of 1.4 nm minerals in Alfisols in central China. Here, we investigate the compositional differences of 1.4 nm minerals in cutans and matrix soils, and the probable transformation of vermiculite to HIV or vice versa when sodium citrate and sodium acetate are added to matrix Alfisols. Methods  Cutans and matrix soils were separated from three soils in the northern subtropical zone in China. The samples were analyzed for Fe, Mn, exchangeable cations, organic matter(O.M.), pH, and clay minerals. To 10 mL of matrix soil, suspensions containing about 250 mg (oven-dry weight) of clay was added with 5 mL of 0.4 mol/dm³ or 2 mol/dm³ of sodium citrate or sodium acetate solution and 5 mL of 0.2 mol/dm³ mixed solutions of CaCl₂, Mg(NO₃)₂ and KCl. After its pH was adjusted to 6.0, the mixture was ‘incubated’ for 120 or 210 days (more than one season or half a year) during which period it was shaken for 1 hour every day. The clay mineral composition of the samples was determined after incubation. Results  Both vermiculites and HIVs were present in matrix soils, but only vermiculties were detected in cutans. The addition of organic ligands (citrate and acetate) promoted the transformation of HIV to vermiculite. This transformation was obvious for the matrix soils that had been incubated with 0.5 mol/dm³ sodium citrate for 210 days while sodium acetate was less effective in this regard. The promoting effect of organic ligands is dependent on type and concentration as well as incubation time. This would suggest the reverse transformation occurred in the formation of cutans compared with a vermiculite-to-HIV transformation in the subtropical soils of central China from north to south. Discussion  The position and environment of cutans in the B horizon together with the pH, organic matter and exchangeable base status in cutans seem conducive to the co-existence of vermiculite and HIV in the soils, but only vermiculite is found in cutans. The transformation of HIV to vermiculite in incubation experiments could be divided into two steps: 1) Cheluviation of organic matter to the interlayer hydroxy-aluminums from HIVs. 2) Rebasification of hydrated cations into the interlayers of vermiculites. Conclusions  The clay minerals in cutans can interact with organic ligands and nutrient elements excreted by roots. Under conditions of frequent wetting and drying and high pH, and when the concentrations of exchangeable bases, iron-manganese oxides, clays, and organic matter are high, the exchangeable cations can be incorporated into the interlayers of HIV, thereby promoting the partial transformation of HIV to vermiculite in rhizosphere soils. Recommendations and Perspectives  Cutan is at the interface of material and energy exchange involved in physical, chemical and biochemical reactions in the rhizosphere. These factors strongly affect the compositions of cutans. HIVs in (upper or adjacent) matrix soils may transform to vermiculites during cutan formation in these special soil environments. ESS-Submission Editor: Jizheng (Jim) He (jzhe@rcees.ac.cn)  相似文献   

深松和秸秆还田对旋耕农田土壤有机碳活性组分的影响   总被引：4，自引：4，他引：4  

田慎重  张玉凤  边文范  董亮  Jiafa Luo  郭洪海 《农业工程学报》2020,36(2):185-192

土壤有机碳(soil organic carbon,SOC)及其活性组分能够敏感响应耕作方式变化及有机物输入。为对比长期旋耕农田进行深松后土壤有机碳各活性组分及比例变化,该研究基于连续7a的旋耕转变为深松和秸秆管理长期定位试验,对比了旋耕无秸秆还田处理(rotary tillage with straw removal,RT)、旋耕秸秆还田处理(rotary tillage with straw return,RTS)、旋耕转变为深松无秸秆还田处理(rotary tillage conversion to subsoiling with straw removal,RT-DT)、旋耕转变为深松秸秆还田处理(rotary tillage conversion to subsoiling with straw return,RTS-DTS)下土壤有机碳(soil organic carbon,SOC)、颗粒有机碳(particulate organic carbon,POC)、易氧化有机碳(readily oxidizable organic carbon,ROC)、微生物生物量碳(microbial biomass carbon,MBC)、溶解性有机碳(dissolved organic carbon,DOC)、活性有机碳(labile organic carbon,LOC)在土壤有机碳中比例的变化及各组分间的相互关系。研究结果表明,耕作方式从旋耕转变为深松和秸秆还田对SOC及其各活性组分均产生显著影响,耕作方式转变、秸秆还田及两者的交互效应是影响SOC及其活性组分的主要因素。秸秆还田显著提高了RTS处理和RTS-DTS处理的SOC含量,分别比RT和RT-DT处理高6.1%~15.6%和19.1%~32.3%。并且转变耕作方式后RTS-DTS处理比于RTS处理SOC含量提高16.9%~20.0%。同时,RTS-DTS处理的POC含量比RTS处理高13.6%~53.8%;但RT-DT和RTS-DTS处理的土壤ROC含量较RT和RTS处理都呈下降趋势,RTS-DTS处理的ROC含量比RTS处理下降4.6%~10%;MBC含量降低23.8%~30.6%。虽然秸秆还田显著提高了各处理的DOC含量,但RTS转变为RTS-DTS处理后,其3个土层的DOC含量下降了8%~41%。相比于RT和RTS处理,RT-DT和RTS-DTS处理0~30 cm各土层中LOC在SOC中的比例显著下降。相关性分析结果表明,除POC与ROC之间无显著性相关关系外,SOC及各组分间均呈显著(P<0.05)或极显著(P<0.01)的相关关系。耕作方式转变为深松和秸秆还田提高了SOC含量的同时,显著降低了SOC中的活性有机碳组分,这更有利于SOC的有效积累,促进土壤碳库的稳定固存。  相似文献   

有机地表覆盖材料对树穴土壤理化性质的影响   总被引：1，自引：0，他引：1  

李啸冲  孙向阳  李素艳  王心语  熊凯毅  郑燚  周文志 《水土保持学报》2020,34(1):322-326

通过大田试验,研究有机地表覆盖材料对土壤理化性质的影响。以圆明园公园内的桑葚林(Morus alba L.)树穴土壤为研究对象设置6种处理,即水性聚氨酯胶黏剂有机覆盖垫(A)、水性聚氨酯与淀粉胶黏剂混合比9∶1有机覆盖垫(B)、水性聚氨酯与淀粉胶黏剂混合比8∶2有机覆盖垫(C)、水性聚氨酯与淀粉胶黏剂混合比7∶3有机覆盖垫(D)、木片覆盖(M)和无覆盖处理(CK),对不同地表覆盖材料的覆盖效果进行评价。结果表明:(1)总体来看,1年后不同有机地表覆盖材料覆盖下树穴土壤的容重、孔隙度、持水量等物理指标以及不同土层土壤pH变化不大。(2)与CK相比,不同有机地表覆盖材料可增加土壤中有机质、碱解氮、有效磷、速效钾的含量,覆盖后0-10 cm土层比10-20 cm土层的效果更为明显。综合考虑,不同有机地表覆盖材料能够改善土壤养分含量,水性聚氨酯与淀粉胶黏剂混合比8∶2有机覆盖垫(C)为5种有机地表覆盖材料中最适合裸露树穴的覆盖材料。  相似文献   

Production of Pearl Millet Irrigated with Different Levels of Brackish Water and Organic Matter     

Jaciele Beserra de Lira  Alberício Pereira de Andrade  André Luiz Rodrigues Magalhães  Fleming Sena Campos  Gherman Garcia Leal de Araújo  Diana Signor Deon 《Communications in Soil Science and Plant Analysis》2020,51(5):701-709

ABSTRACT

The objective is to determine the growth, yield and chemical characteristics of pearl millet irrigated with different levels of brackish water and organic matter in two cultivation cycles. The experimental design was randomized blocks in a 4 × 4 factorial arrangement, composed of 4 levels of brackish irrigation (25, 50, 75 and 100% evapotranspiration), 4 levels of organic matter (0, 15, 30 and 45 t ha^?1) with 3 repetitions. Along two cultivation cycles, pearl millet crop was analyzed for: plant growth variables, fresh and dry mass production, water-use efficiency, and chemical composition. There was significant interaction between applied water levels and organic matter for lignin in the 2nd cut (P < .05). The number of leaves, number of dead leaves and fresh mass production were influenced by the isolated effect of brackish water levels in cut 1 (P < .05). In turn, fresh mass production, dry mass production, plant height, leaves length, panicle length, fresh mass production, crude protein and ether extract were influenced by the isolated effect of saline water levels in the 2nd cut (P < .05). Growth, biomass production and chemical composition variables in second cut are positively influenced by different brackish irrigation levels under low rainfall conditions.  相似文献   

Soil organic matter beyond molecular structure Part I: Macromolecular and supramolecular characteristics     

Gabriele E. Schaumann 《植物养料与土壤学杂志》2006,169(2):145-156

This contribution reviews and discusses structural aspects of soil organic matter (SOM) and humic substances (HS) with special respect to the macromolecular and the supramolecular view. It can be concluded that (1) dissolved humic acids behave as supramolecular associations of relatively small molecules with an enormous flexibility of reaction of environmental conditions, (2) multivalent cations may increase the apparent molecular weight by the formation of coordinative crosslinks in dissolved and undissolved natural organic matter (NOM), (3) sorption nonlinearity in solid humic acids and SOM may be due to polymer properties of NOM, (4) sorbates affect sorbent characteristics of SOM, and (5) hysteresis and conditioning effects in SOM can up to now best be explained with the polymer analogy. A distinct polydispersivity of SOM over a wide range of molecular masses is to be assumed. The supramolecular and the macromolecular models were derived from humic acids with different composition and on the basis of different sample states. Although the supramolecular model has not explicitely been shown for unfractionated DOM, the combination of all discussed studies suggests supramolecular as well as macromolecular characteristics of NOM. Neither macromolecules nor small molecules can be fully excluded in solid and dissolved SOM. Microregions with different properties provide different types of sorption sites. SOM is suggested to be regarded as amorphous material. This point of view is not restricted to high molecular masses and may supplement our understanding of SOM by the model of physical aging.  相似文献