原子荧光测定土壤样品中砷汞的若干问题探讨

试验采用水浴消解原子荧光法测定土壤样品中的汞和砷。研究了水介质、仪器记忆效应、酸度、硼氢化钾浓度对测定结果的影响。经国家一级标准物质验证,结果与标准值相符。

供给侧改革视角下基于土壤检测的苏锡常茶叶产业结构调整

供给侧改革在农业发展中就是调整产业结构,去产能要求减少低级粗放型生产,实行集约化精致化生产,精准农业,提高产品质量,实行农产品价值增值和溢价。通过对苏锡常土壤墒情评价,研究该区域土壤营养成分,发现该区域土壤富含硒,在江苏省居首位。茶叶在江苏是高附加值的农产品,结合硒富含量的特点,建议苏锡常以富硒茶叶为重点调整原本的产业结构。

质谱计在行星系统与小天体探测中的应用

质谱计多次应用于行星系统和小天体的大气层与土壤吸附气体或挥发组分及其同位素含量探索,是太阳系行星系统和小天体探测计划中的首选载荷之一。大气和土壤元素及其同位素组分探测对资源勘探、行星系统的宜居性、天体演化、起源及其重要事件的精准时间坐标研究等具有重要意义。质谱计已多次成功应用于火星、土星系、木星系、彗星等探测任务中开展大气环境探测。质谱计的探测对象主要包括太阳系行星、行星卫星如月球、木星伽利略卫星、土卫,以及地外小行星和彗星。四极杆质谱计在当前的深空空间环境探测活动中应用最为广泛。利用四极杆质谱计除可用于探测稀薄天体大气与土壤析出气体外,如增加抽真空能力的前端设计,则具备探测稠密大气成分的能力。中科院空间中心研发的星载质谱计已多次成功应用于地球行星大气成分和密度探测。

Effect of Reclamation Time and Land Use on Soil Properties in Changjiang River Estuary,China

The objective of this study is to analyze soil physical and chemical properties,soil comprehensive functions and impact factors after different years of reclamation.Based on the survey data taken from 216 soil sampling points in the Fengxian Reclamation Area of the Changjiang (Yangtze) River Estuary,China in April 2009 and remotely sensed TM data in 2006,while by virtue of multivariate analysis of variance (MANOVA),geo-statistical analysis (GA),prin-cipal component analysis (PCA) and canonical correspondence analysis (CCA),it was concluded that:1) With the in-crease in reclamation time,soil moisture,soil salinity,soil electric conductivity and soil particle size tended to decline,yet soil organic matter tended to increase.Soil available phosphorous tended to increase in the early reclamation period,yet it tended to decline after about 49 years of reclamation.Soil nitrate nitrogen,soil ammonia nitrogen and pH changed slightly in different reclamation years.Soil physical and chemical properties reached a steady state after about 30 years of reclamation.2) According to the results of PCA analysis,the weighted value (0.97 in total) that represents soil nutrient factors (soil nitrate nitrogen,soil organic matter,soil available phosphorous,soil ammonia nitrogen,pH and soil particle size) were higher than the weighted value (0.48 in total) of soil limiting factors (soil salinity,soil elec-tric conductivity and soil moisture).The higher the F value is,the better the soil quality is.3) Different land use types play different roles in the soil function maturity process,with farmlands providing the best contribution.4) Soil physi-cal and chemical properties in the reclamation area were mainly influenced by reclamation time,and then by land use types.The correlation (0.1905) of the composite index of soil function (F) with reclamation time was greater than that with land use types (-0.1161).

Characterization of Soil Quality Under Vegetable Production Along an Urban-Rural Gradient

Human activity and urbanization result in urban-rural environmental gradients. Understanding effect of the gradients on soil properties is necessary for management of the soils around urban areas. In this study, soil quality of some vegetable fields was characterized along an urban-rural gradient in Shaoxing County, Zhejiang Province. Fifteen soil physical and chemical properties were evaluated by using principal component analysis.Results showed that there was a great variation in the soil quality along the gradient. From rural to urban zones, soil organic matter, water-stable aggregates, cation exchangeable capacity (CEC), total N and P, and available K increased, whereas soil pH value decreased. In addition, Pb, Cu, Ni, Co, Zn and Cr in the soils tended to be accumulated toward the urban zone. Sequential chemical extraction showed that mobility of all the heavy metals in the soils tended to increase from the rural to the urban zones. The variation of soil properties accounted for by the first principal component was significantly explained by the difference in application rates of municipal wastes.

Relationship of Soil Qualities to Maize Growth Under Increasing Phosphorus Supply in Acid Soils of Southern Cameroon

A large array of soil properties influences plant growth response to phosphorus(P) fertilizer input in acid soils. We carried out a pot experiment using three contrasted acid soils from southern Cameroon with the following main objectives:i) to assess the main soil causal factors of different maize(Zea mays L.) growth response to applied P and ii) to statistically model soil quality variation across soil types as well as their relationships to dry matter production. The soils used are classified as Typic Kandiudox(TKO) ,Rhodic Kandiudult(RKU) ,and Typic Kandiudult(TKU) . Analysis of variance,regression,and principal component analyses were used for data analysis and interpretation. Shoot dry matter yield(DMY) was significantly affected by soil type and P rate with no significant interaction. Predicted maximum attainable DMY was lowest in the TKO(26.2 g pot-1) as compared to 35.6 and 36.7 g pot-1 for the RKU and TKU,respectively. Properties that positively influenced DMY were the levels of inorganic NaHCO3-extractable P,individual basic cations(Ca,Mg,and K) ,and pH. Their effects contrasted with those of exchangeable Al and C/N ratio,which significantly depressed DMY. Principal component analysis yielded similar results,identifying 4 orthogonal components,which accounted for 84.7% of the total system variance(TSV) . Principal component 1 was identified as soil nutrient deficiency explaining 35.9% of TSV. This soil quality varied significantly among the studied soils,emerging as the only soil quality which significantly(P < 0.05) correlated with maize growth. The 2nd,3rd,and 4th components were identified as soil organic matter contents,texture,and HCl-extractable P,respectively.

Historical Development in Soil Micromorphological Imaging

The book ＂micropedolog＂ by Kubieana and a large number of publications has induced many people to practice soil micromorphology. Quantification of the soil fabric and its components was a major challenge. The use of the image analyses in soil science was a breakthrough. Attempts to make soil thin sections go back to the beginning of the 2oth century. Microscopic techniques and recently high resolution electron microscope and use of computer assisted imaging techniques enabled the in vitro study of soils in three dimensional levels. It is now possible to store and process massive amounts of data. Micro- morphological concepts and techniques are applied in paleopedological, ecological, and archaeological studies. The aim of this work was to examine soil micromorphological imaging in historical perspective.

Polychlorinated biphenyis in Beijing soil of China

The concentrations of polychlorinated biphenyls （PCBs） have been determined in soils collected in Beijing of China. According to Principle Component Analysis （PCA） of PCBs, the possible sources were studied. Relationship between PCBs and soil organic materials revealed that higher chlorinated PCBs are more inclined to be adsorbed by particles rich of organic materials. But the low chlorinated homologues are dominant in Beijing soils, which is very different from the foreign studies. It was concluded that the application of relatively low chlorinated commercial PCBs in China was the main reason leading to this homologue composition character. Besides, the relatively short pollution history is also one of the main reasons. PCA of PCBs data in Beijing soil and atmospheric deposition samples revealed that some other emission sources such as atmospheric deposition, automobile exhaust; chemical and petrochemical industry and steel industry may be the important reasons of elevated PCBs concentrations in Beijing soil

Minimum Data Set for Assessing Soil Quality in Farmland of Northeast China

Soil quality assessment provides a tool for agriculture managers and policy makers to gain a better understanding of how various agricultural systems affect soil resources. Soil quality of Hailun County, a typical soybean （Glycine max L. Merill） growing area located in Northeast China, was evaluated using soil quality index （SQI） methods. Each SQI was computed using a minimum data set （MDS） selected using principal components analysis （PCA） as a data reduction technique. Eight MDS indicators were selected from 20 physical and chemical soil measurements. The MDS accounted for 74.9% of the total variance in the total data set （TDS）. The SQI values for 88 soil samples were evaluated with linear scoring techniques and various weight methods. The results showed that SQI values correlated well with soybean yield （r = 0.658＊＊） when indicators in MDS were weighted by the regression coefficient computed for each yield and index. Stepwise regression between yield and principal components （PCs） indicated that available boron （AvB）, available phosphorus （AvP）, available potassium （AvK）, available iron （AvFe） and texture were the main factors limiting soybean yield. The method used to select an MDS could not only appropriately assess soil quality but also be used as a powerful tool for soil nutrient diagnosis at the regional level.