砷对蔬菜生长的影响和临界值的研究

本文研究了紫色土添加砷对蔬菜生长的影响与临界值,并采用灰色系统的关联度分析方法,使它们与土壤性度联系起来,结果表明:三种紫色土砷的临界值一般为:红紫泥> 灰棕紫泥>红棕紫泥.     

草甸棕壤中镉、铅、油含量对微生物类群和生化活性的影响

本研究以重金属化合物(CdCl_2、PbCl_2)和矿物油作为土壤的污染物,分析土壤中镉、铅、油的含量对土壤微生物类群与生化活性的影响。结果表明,镉、铅、油对水旱田中的细菌抑制作用比较明显,对放线菌、真菌抑制作用较差。小剂量的镉、铅、油对固氮菌有刺激作用,大剂量则有抑制作用。对尿酶和硝化细菌的代谢有明显抑制作用,对其它酶类不明显。 从含重金属的平板培养基上反映出土壤对重金属的掩蔽作用。污染物对微生物的生化活性的临界毒害浓度分别为:镉 5—60ppm;铅 300—500ppm;油 500—5000ppm。     

全国土壤侵蚀量估算及其在吸附态氮磷流失量匡算中的应用

应用土壤流失方程(USLE),根据我国土壤水力侵蚀分类分级标准,建立了大尺度区域土壤侵蚀量的估算模型;基于GIS技术平台,利用土壤普查数据,构建了全国表层土壤氮磷含量数据库,完成了2000年全国境内水土流失影响下吸附态氮磷的流失量估算.经数据合理性分析验证后得出以下结论:(1)全国因水土流失引发的吸附态氮素和磷素的流失总量分别达到104.22×104t和34.65×104t;(2)长江、珠江和黄河三大流域的吸附态氮、磷流失量之和分别占全国总量的83%和89%,单位面积(1km2)吸附态氮、磷的流失量分别介于6.0×10-4～0.53t和2.1×10-4～0.13t之间;(3)吸附态氮的重点流失区主要分布在长江中上游水土易蚀区、黄河中游沟壑区、西辽河上游区、珠江流域红水河、西江等上游区以及怒江、澜沧江下游区.     

北京市公园土壤铜、铅含量及化学形态分布特征

对北京市的12个公园进行表层、深层土壤样品的重金属Cu、Pb含量分析,并对其中10个公园的表层、深层土壤样品进行Cu、Pb的化学形态分析。研究结果表明:北京市部分公园的深层土壤已在某种程度上受到人为扰动,大多数公园表层土壤中存在着一定的Cu、Pb含量积累现象,总体上市区公园比郊区公园明显。公园表层、深层土壤中Cu形态分布的总体规律均为残渣晶格态>有机结合态>铁锰氧化物结合态>碳酸盐结合态>可交换态,表层、深层土壤中Pb形态分布的总体规律均为残渣晶格态>铁锰氧化物结合态>有机结合态>碳酸盐结合态>可交换态,但表层土壤中活性态Cu、Pb的平均比例较深层土壤均有所上升,部分市区公园表层土壤中Cu、Pb的含量较高且活性态比例较大,具有一定的释放潜力和生物有效性。     

Adsorption and correlation with their thermodynamic properties of triazine herbicides on soils

IntroductionAdsorptionofherbicidesonsoilfromwaterisanimportantfactoraffectingtheirfate,biologicalactivity,andpersistenceinsoil watersystem .Itisoftenaffectedbyseveralpropertiesofsoil.Betterunderstandingofadsorptionanditsaffectingfactorswillmakeitpossibletoadjusttheherbicidedosageaccordingtosoilproperties,thusreducingtheenvironmentalpollutionofherbicidesintheenvironment.Fig .1　StructuresofthreetriazineherbicidesAmongthepost emergentherbicides,triazineherbicidesaremostcommonlyusedworldwideonco…     

氯唑磷在土壤中的降解性能与移动性研究

在实验室与野外田间状态下，研究了氯唑磷农药在砂土，砂壤土及粘壤土中的降解特性，降解速率依次为：砂壤土〉粘壤土〉矿土；其降解半衰期分别为４７．２、５９．８和６７．３ｄ。     

应用δ~(13)C值探讨土壤中有机碳的迁移规律

C3 植物与C4 植物具明显的δ13C值差异 ,利用这种特性 ,选取荔波茂兰喀斯特森林边缘处这个C3植物—C4 植物转换生长的地点 ,分别采集森林与农田各三个剖面的土壤样品 ,根据测定其土壤总有机碳、不同粒径及不同比重组分的δ13C值间的相互关系来推导土壤有机碳的若干迁移规律     

煤矿区表层土壤中芳香烃组成、分布特征及标志化合物研究

采用GC-MS技术分析了平顶山市石龙区土壤样品中多环芳烃(PAHs)污染物的化学组成及分布特征,共鉴定出78种代表性化合物,包括11种US EPA优控PAHs.结果表明,总体上土壤样品中单体烃菲、荧蒽、芴、芘含量比较高.在不同功能区域芳烃含量差别较大,采矿区及焦化厂区土壤中芳烃含量明显高于污灌区和农业区,而煤矸石山附近土壤中芳烃含量最高.采矿区、焦化厂区和污灌区土壤中低环数PAHs的比例远大于高环数PAHs,农业区反之.通过对(ρ)MP/(ρ)P、MPI1、(ρ)P/(ρ)A、(ρ)FL/(ρ)PY等参数值的分析认为,煤尘、烟灰沉降是石龙区土壤中PAHs积累的主要影响因素.由单体烃与PAHs的相关性分析得知,苊和蒽可作为煤矿区域表层土壤中PAHs的标志性污染物.     

稻米和土壤中农美利残留量气相色谱分析方法的研究

建立了测定稻田土壤、稻米中农美利残留量的气相色谱分析方法。用配有NPD的气相色谱仪、DB-1301毛细管柱测定稻田土壤及稻米中农美利的残留量，最低检测浓度为0．01mg／kg、平均回收率为80．4％-99．8％，变异系数为6．3％-11．7％，均达到残留分析的要求。     

Implications of Land Use Changes on Carbon Dynamics and Sequestration—Evaluation from Forestry Datasets, India

Forests and soils are a major sink of carbon, and land use changes can affect the magnitude of above ground and below ground carbon stores and the net flux of carbon between the land and the atmosphere. Studies on methods for examining the future consequences of changes in patterns of land use change and carbon flux gains importance, as they provide different options for CO₂ mitigation strategies. In this study, a simulation approach combining Markov chain processes and carbon pools for forests and soils has been implemented to study the carbon flows over a period of time. Markov chains have been computed by converting the land use change and forestry data of India from 1997 to 1999 into a matrix of conditional probabilities reflecting the changes from one class at time t to another class time t+1. Results from Markov modeling suggested Indian forests as a potential sink for 0.94 Gt carbon, with an increase in dense forest area of about 75.93 Mha and decrease of about 3.4 Mha and 5.0 Mha in open and scrub forests, if similar land use changes that occurred during 1997–1999 would continue. The limiting probabilities suggested 34.27 percent as dense forest, 6.90 as open forest, 0.4 percent mangrove forest, 0.1 percent scrub and 58 percent as non-forest area. Although Indian forests are found to be a potential carbon sink, analysis of results from transition probabilities for different years till 2050 suggests that, the forests will continue to be a source of about 20.59 MtC to the atmosphere. The implications of these results in the context of increasing anthropogenic pressure on open and scrub forests and their contribution to carbon source from land use change and forestry sector are discussed. Some of the mitigation aspects to reduce greenhouse gas emissions from land use change and forestry sector in India are also reviewed in the study.