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1.
免耕对潮土不同粒级团聚体有机碳含量及微生物碳代谢活性的影响 总被引：13，自引：1，他引：13
利用中国科学院封丘农业生态国家实验站玉米-小麦轮作免耕定位试验平台,研究不同耕作方式对潮土不同粒级团聚体的分布、有机碳含量及微生物群落碳代谢活性的影响。结果表明,与传统翻耕处理相比,免耕潮土中大于250μm粒级团聚体显著增加(p0.05),50～2μm粒级团聚体显著减少(p0.05),250～50μm和小于2μm两个粒级团聚体没有明显变化;大于250μm和250～50μm两个粒级团聚体有机碳含量显著升高(p0.05),50～2μm和小于2μm两个粒级团聚体有机碳含量没有明显变化,250～50μm粒级取代50～2μm粒级成为对土壤有机碳总量贡献最大的团聚体。BIOLOG测试结果表明,免耕和翻耕两种措施下不同粒级团聚体微生物群落碳代谢特征存在明显差异,且免耕处理250～50μm和小于2μm两个粒级团聚体微生物群落碳代谢活性显著低于翻耕处理(p0.05)。结果显示,免耕有利于小粒级团聚体向大粒级团聚体方向聚合,大于50μm粒级团聚体固持的有机碳增多,其中持碳最多的250～50μm粒级团聚体的微生物碳代谢活性下降,故土壤有机碳稳定性升高。 相似文献
2.
土各粒级K+吸附特征有很大区别.在一定平衡液浓度下,颗粒越细,土壤固相吸附量越大,不同粒级固相吸附量大小顺序是(＜0.1m)＞(＜1m)＞(1～2m)＞(2～5m),不同粒级土壤有效阳离子交换量也具有相同的变化规律.混合样中不同粒级组分对吸附的贡献可用吸附贡献率表示,土各粒级饱和吸附贡献率大小顺序为(＜1m)＞(1～2m)＞(＞5m)＞(2～5m),其中粘粒部分的饱和吸附贡献率为85%左右.在供试混合土样中＜1m粒级吸附贡献率随平衡液浓度增大呈幂函数形式增大,相反,1～2m、2～5m粒级吸附贡献率随平衡液浓度增大则呈幂函数形式减小.实验证明混合样中不同粒级K+吸附存在交互作用,吸附交互作用大小可用吸附交互作用系数表征,＜1m和1～2m之间存在吸附负交互作用,且随平衡液浓度增大而增强.＜1m和2～5m之间存在吸附正交互作用,且随平衡液浓度增大而减弱.论述了建立土壤多粒级组分吸附方程的必要性,提出了多粒级组分吸附方程q＝ρ(c)rifi(c) 相似文献
3.
有机、无机肥料~(15)N在土壤不同粒级中的分布及其生物有效性 总被引：6，自引：2，他引：6
利用超声波分散—沉降法对利用15N标记的硫铵、稻草和猪粪培养处理一年后的土壤进行物理分级,研究了施入土壤的肥料N在土壤不同粒级中的分布,并利用黑麦草研究了土壤不同粒级中15N的有效性。结果表明,施用稻草和猪粪提高了0～2μm粒级和2～10μm粒级在土壤中的分配比例。硫铵15N、稻草15N和猪粪15N在土壤0～2μm粒级中的分布比例都在14%左右,在2～10μm和10～50μm粒级中的分布比例分别为22%和14%左右。但在>100μm(残渣)粒级中来自硫铵的15N比例为16%左右,而来自稻草和猪粪的15N比例则在30%以上。施用硫铵土壤的2～10μm粒级中,黑麦草对15N的利用率最高,50～100μm粒级中的15N利用率最低。而施用稻草和猪粪土壤的粒级中15N利用率以10～50μm粒级中最高。表明不同性质的肥料在土壤中的不同转化方向影响了肥料N在土壤不同粒级中的分布。由于不同粒级的土壤颗粒对有机物质的吸持力不同,从而决定了在不同粒级中N的生物有效性。 相似文献
4.
化肥对黑土不同粒级碳水化合物的影响 总被引：1，自引：1，他引：1
本文采集公主岭市长期定位监测基地不施肥和施用不同化肥的黑土,通过超声波分散-离心分离得到细黏粒(<0.2μm)、粗黏粒(0.2～2μm)、粉粒(2～53μm)、细砂粒(53～250μm)、粗砂粒(250～2000μm)5个颗粒级别,分析全土及不同粒级中土壤碳水化合物并进行含量与分布的比较。结果表明,黑土中不同粒级碳水化合物库的性质差异显著,碳水化合物多集中在粉+黏粒中;长期施用化肥后,黑土全土及各粒级碳水化合物库大小和浓度基本上没有变化;粗砂粒级(Gal+Man)(:Ara+Xyl)下降,表明该粒级中植物来源碳水化合物所占比重有所增加,暗示出粗砂粒级对施肥措施更为敏感。 相似文献
5.
Wang Yu Zhang Yi-ping 《土壤学报》2001,(2)
塿土各粒级Ｋ十吸附特征有很大区别。在一定平衡液浓度下，颗粒越细，土壤固相吸附量越大，不同粒级固相吸附量大小顺序是：（＜０．１μｍ）＞（＜１μｍ）＞（１－２μｍ）＞（２－５μｍ），不同粒级土壤有效阳离子交换量也具有相同的变化规律。混合样中不同粒级组分对吸附的贡献可用吸附贡献率表示，■土各粒级饱和吸附贡献率大小顺序为：（＜１μｍ）＞（１－２μｍ）＞（＞５μｍ）＞（２－５μｍ），其中粘粒部分的饱和吸附贡献率为８５％左右。在供试混合土样中＜１μｍ粒级吸附贡献率随平衡液浓度增大呈幂函数形式增大，相反，１～２μｍ、２－５μｍ粒级吸附贡献率随平衡液浓度增大则呈幂函数形式减小。实验证明混合样中不同粒级Ｋ＋吸附存在交互作用，吸附交互作用大小可用吸附交互作用系数表征，＜１μｍ和１－２μｍ之间存在吸附负交互作用，且随平衡液浓度增大而增强。＜１μｍ和２－５μｍ之间存在吸附正交互作用，且随平衡液浓度增大而减弱。论述了建立土壤多粒级组分吸附方程的必要性，提出了多粒级组分吸附方程： 相似文献
6.
宁镇地区黄棕壤土壤颗粒组成与~(137)Cs含量关系研究 总被引：1，自引：0，他引：1
土壤粒组组成对137Cs含量及其再分配过程具有决定作用,因此,137Cs吸附的粒度效应研究是运用其示踪土壤侵蚀的重要环节。宁镇地区代表性样点的土样测试与数据分析结果表明,黄棕壤耕作土不同粒级的土壤颗粒对137Cs有着不同的吸附效应:(1)2μm和2～5μm粒级土壤颗粒对137Cs有着较强的吸附能力;(2)5～10μm和10～50μm粒级的土壤颗粒含量与137Cs质量活度之间存在着明显的负相关;(3)50μm粒级的土壤颗粒含量与137Cs质量活度之间的关系较为复杂;(4)数据分析结果中出现的一些偏差可能与侵蚀作用所造成的颗粒分选以及沉积区物源复杂有关。 相似文献
7.
棕壤及其各粒级微团聚体对Cu~(2+)吸附解吸特性的研究 总被引：4，自引：0，他引：4
采用室内分析的方法,研究了棕壤及其各粒级微团聚体对Cu2+的吸附解吸作用。结果表明:棕壤与其各粒级微团聚体相比,对Cu2+的吸附能力较弱,而三级微团聚体对Cu2+的吸附能力的大小顺序为:<10μm粒级微团聚体>10~50μm粒级微团聚体>50~250μm粒级微团聚体。同时,通过NH4OAc,EDTA对Cu2+的解吸情况的研究得出,棕壤及其不同粒级微团聚体对Cu2+的吸附机制是不同的,在棕壤和各粒级微团聚体中,<10μm粒级的微团聚体对Cu2+的吸附机制以专性吸附为主,固定Cu2+的能力最强,从而能降低Cu2+的活性,不易为植物吸收,其次为10~50μm粒级微团聚体和棕壤,而50~250μm粒级微团聚体对Cu2+的吸附以静电吸附机制为主,其吸附的Cu2+可以被交换,因此固定Cu2+的能力较差。 相似文献
8.
坡面侵蚀土壤磁化率变化机理的研究 总被引：1，自引：1，他引：1
研究了土壤磁化率与土壤物理性质的关系,结果表明:应用干筛法在不同粒级土团中获得的0.1～0.25mm粒级的土团主导土壤的磁化率,各组分土团中大于0.1mm的组分磁化率与粒径呈反相关,小于0.1mm的组分磁化率与粒径呈正相关。土壤比重、土壤总孔隙度、崩解速率等均与土壤磁化率呈负相关,且土壤崩解速率与土壤磁化率呈极显著负相关;土壤磁化率与容重、粒径小于0.25mm的水稳性团粒组分和大于0.05mm的机械组分含量呈显著正相关。坡面土壤侵蚀导致坡面物质发生再分布,使得土壤颗粒组成、容重、比重、孔隙度等土壤物理性质发生变化,进而使得坡面不同空间部位土壤磁化率出现差异。 相似文献
9.
不同区域稻田土壤复合体有机碳分配及δ~(13)C特征 总被引：1，自引：0，他引：1
选取位于5个不同区域(吉林龙井、河南封丘、浙江慈溪、江西进贤和海南海口)的代表性稻田,对其土壤复合体有机碳分配及δ13C特征进行了研究。结果表明,不同区域稻田土壤中各粒级复合体含量(质量百分比)变化主要体现在<2μm和>50μm粒级部分。南方稻田0-20 cm土层中<2μm复合体含量较20-40 cm土层低,而北方稻田0-20 cm土层则较20-40 cm土层高。稻田0-20 cm和20-40 cm土层中,<50μm各粒级土壤复合体有机碳含量的变化趋势基本一致;>50μm复合体有机碳含量则在稻田20-40 cm土层中出现急剧下降,显著低于表层。农田土壤有机碳主要集中在<10μm复合体中。气候条件、耕作制度和起源土壤对农田土壤复合体有机碳分配有显著影响,其中稻田耕作环境更有利于表层粗有机体的累积。不同区域稻田0-20 cm土层中,土壤复合体粒级越小,其有机碳δ13C值越高,碳库活性越低;而20-40 cm稻田土层中复合体有机碳库活性则并非严格遵循粗粒活性高于细粒的规律,在>50μm粗粒复合体中表现尤为明显。 相似文献
10.
旅游干扰对太原万柏林生态园土壤团聚体稳定性及有机碳分布的影响 总被引：1，自引：0，他引：1
以太原万柏林生态园为试验对象,研究了旅游干扰对土壤团聚体组成及有机碳分布的影响。结果表明,随着旅游干扰强度增强,景区土壤< 1 mm粒级团聚体数量逐渐升高,而> 1 mm粒级团聚体数量、水稳性团聚体平均质量直径（MWD）和平均几何直径（GMD）则均逐渐降低;土壤总有机碳含量和各粒级团聚体有机碳含量均随旅游干扰强度增强而逐渐降低,且0 ~ 20 cm土层、> 1.0 mm粒级团聚体降低幅度高于20 ~ 40 cm土层、< 0.5 mm粒级团聚体;随着旅游干扰强度的增加,>2 mm粒级团聚体对土壤有机碳的贡献率逐渐降低,而< 1 mm粒级团聚体贡献率逐渐升高。综上所述,旅游干扰会显著降低景区土壤团聚体稳定性和有机碳含量,破坏土壤质量,建议相关部门合理制定旅游环境容量、提高游客环保意识,减轻负面影响。 相似文献
11.
《CATENA》1998,32(2):131-142
The mineral magnetic properties of sediment are increasingly being used to determine the sources of sediment, and associated nutrients and contaminants in drainage basins. This study was undertaken to measure the relative contributions of the magnetic mineral components in sediment (i.e., components associated with surface bound Fe, the heavy mineral fraction, and as inclusions in particles) to determine the extent to which they represent the bulk of the sediment. Deposited channel sediment samples from the tributaries and downstream reach at the first major confluence in the headwaters of Killimicat Creek, New South Wales, were sieved to separate 6 particle size fractions, and the mineral magnetic properties measured to determine the relative contribution of sediment from the smaller tributary basin. The finest sand component (63–125 μm) was then separated into light and heavy mineral fractions, and magnetic measurements made on each fraction. Magnetic parameter data from the 63–125 μm fraction, measured before density separation, show a dominance of sediment (70±12%) derived from the smaller tributary basin. Measurements of the light sediment fraction give a similar result (73±13%). The proportion of the heavy mineral fraction delivered from the smaller tributary is 78±38%. The light mineral fraction of all of the samples were treated with HCl to remove surface bound Fe, and subsequent magnetic measurements show that 41–94% of the mass specific magnetic susceptibility is attributable to magnetic minerals associated with surface bound Fe. The heavy mineral component, while <4% by weight of the 63–125 μm fraction, contributes 5–40% of the total magnetic susceptibility. The results show that most of the magnetic mineral component (>60%) is associated with sediment particles, rather than the discrete heavy mineral component. 相似文献
12.
Relationships Between Radionuclide Content and Textural Properties in Irish Sea Intertidal Sediments
Intertidal sediments from a range of depositional environments in the eastern Irish Sea have been analysed with regard to their radionuclide content, particle size distribution and magnetic properties. Concentrations of241Am and137Cs are highly influenced by the abundance of sediment finer than 32μm in fine-grained sedimentary environments, whilst radionuclide activity in coarser sediments is less dependent on particle size. Investigation of the magnetic properties of these sediments highlights a similar association between this size fraction and magnetic remanence, the latter being shown to offer strong potential as a grain size proxy in monitoring137Cs concentrations in fine-grained sediments. Analysis of particle size fractions indicates the extent to which137Cs may be enriched in the clay size fractions of both tine and coarse sediments. 相似文献
13.
Purpose
Identifying the spatial distribution and degree of heavy metal contamination in the soils is required for urban environmental management. Magnetic measurement provides a rapid means of determining spatial distribution and degree of soil pollution and identifying various anthropogenic sources of heavy metals. The purpose of this study was to characterize the magnetic signature of heavy metal contamination and identify the sources of heavy metals in urban soils from steel industrial city.Materials and methods
A total of 115 urban topsoils from Anshan city, Northeast China, were collected and determined for magnetic properties and heavy metal concentration. Magnetic susceptibility (χlf) and saturation isothermal remanent magnetization (SIRM) were determined as proxy for ferrimagnetic mineral concentration. Magnetic minerals were identified by using Curie temperature, X-ray diffraction (XRD), and scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectrometer (EDS). The Pearson’ correlation and matrix cluster analyses were used to establish the relationship between magnetic parameters and heavy metal concentrations.Results and discussion
Urban topsoils exhibit characteristic magnetic enhancement. The magnetic measurement in particle size fractions indicates that 50–2 μm fraction has the highest low-field magnetic susceptibility (χlf), while <2 μm has the highest frequency-dependent magnetic susceptibility (χfd) value. The soil χlf and SIRM values are significantly correlated with the contents of metals (Fe, Pb, Zn, Cu, and Cr) and Tomlinson pollution load index (PLI), which indicates that χlf and SIRM could be served as better indicators for the pollution of heavy metals in the urban topsoil. Spatial distribution maps of χlf, SIRM, and PLI indicate that the pollution hotspots tend to associate with the regions within and close to steel industrial zones. XRD and Curie temperature analyses indicate that the main magnetic minerals of urban topsoils are magnetite (Fe3O4), hematite (α-Fe2O3), and metallic iron. Magnetic minerals mostly occur in the pseudo-single-domain/multidomain (PSD/MD) grain size range, which is the dominant contributor to the magnetic enhancement of topsoils. SEM observation reveals that magnetic particles in soils exist in irregular-shaped particles and spherule. Results reveal that heavy metals from industrially derived and traffic emissions coexist with coarse-grained magnetic phases.Conclusions
It is concluded that the magnetic measurement could be regarded as a proxy tool to detect the level of heavy metal pollution and identify the source of heavy metals in urban soils. Magnetic properties provide a fast and inexpensive method to map the spatial distribution of long-term pollution from steel industrial origin on region scale.14.
The long-term storage of soil organic matter (SOM) in forest soils is still poorly understood. In this study, particle size fractionation in combination with accelerator mass spectroscopy (AMS) and solid state 13C nuclear magnetic resonance (NMR) spectroscopy was applied to investigate organic carbon (OC) stabilisation in Cambisol and Luvisol profiles under spruce (Picea abies) and beech (Fagus sylvatica L.) forests. In most samples, OC was preferentially associated with <2 μm fractions. Throughout soil profiles the contribution of OC in the clay fraction to the total OC increased from 27%-53% in A horizons to 44-86% in E, B and EB horizons. The 200-2000 μm fractions from all sites and all depths showed a percentage of modern C (pmC)>100. They were enriched in 14C owing to high inputs of recent material from leaves and roots. Clearly less active material was associated with <2 and 2-20 μm fractions. This demonstrated that the particle size fractionation procedure applied to our study was capable to isolate a young OC fraction in all samples. The pmC values were strongly decreasing with depth but the decrease was much more pronounced in the fine fractions. The <2 and 2-20 μm fractions of B, E and EB horizons revealed radiocarbon ages between 512 and 4745 years before present which indicated that the SOM in those horizons was little affected by the recent vegetation. The major components of labile and stable SOM pools in topsoils and subsoils were always O/N-alkyl C (28-53%) and alkyl C (14-48%) compounds. NMR spectra of bulk soils and particle size fractions indicated that high alkyl C and O/N-alkyl C proportions throughout the soil profile are typical of Cambisols and Luvisols which were not subjected to regular burning. A relation between radiocarbon age and chemical composition throughout soil profiles was not observed. This suggests that the long-term stabilisation of SOM is mainly controlled by the existence of various mechanisms of protection offered by the soil matrix and soil minerals but not by the chemical structure of SOM itself. 相似文献
15.
David M. Oliver Christopher D. Clegg A. Louise Heathwaite Philip M. Haygarth 《Water, air, and soil pollution》2007,185(1-4):369-375
This study reports on the attachment preference of a faecally derived bacterium, Escherichia coli, to soil particles of defined size fractions. In a batch sorption experiment using a clay loam soil it was found that 35% of introduced E. coli cells were associated with soil particulates >2 μm diameter. Of this 35%, most of the E. coli (14%) were found to be associated with the size fraction 15–4 μm. This was attributed to the larger number of particles within this size range and its consequently greater surface area available for attachment. When results were normalised with respect to estimates of the surface area available for bacterial cell attachment to each size fraction, it was found that E. coli preferentially attached to those soil particles within the size range 30–16 μm. For soil particles >2 μm, E. coli showed at least 3.9 times more preference to associate with the 30–16 μm than any other fraction. We report that E. coli can associate with different soil particle size fractions in varying proportions and that this is likely to impact on the hydrological transfer of cells through soil and have clear implications for our wider understanding of the attachment dynamics of faecally derived bacteria in soils of different compositions. 相似文献
16.
有机肥对棕壤不同粒级有机碳和氮的影响 总被引：3，自引：1，他引：3
采集棕壤长期肥料定位试验站不施肥和施用不同用量有机肥的土壤,通过超声波分散—离心分离得到细黏粒(<0.2μm)、粗黏粒(0.2～2μm)、粉粒(2～53μm)、细砂粒(53～250μm)和粗砂粒(250～2000μm)5个颗粒级别后,分析全土及不同粒级中土壤有机碳和氮并进行含量与分布的比较。结果表明,有机质主要分布于黏粒级中,其含量占全土有机碳的42.8%、全氮的58.3%,碳氮比随着粒级的增加而逐渐增大,表明氮易于在小粒级中富集。长期施用有机肥后,全土及各粒级有机碳和氮含量均有显著增加;砂粒级中有机碳和氮的富集系数升高,黏粒级中富集系数降低,粉粒级和砂粒级中的碳氮比降低。增加有机肥的用量加强了全土和各粒级对有机碳和氮的积累,同时加强了粉粒级和砂粒级碳氮比降低的程度。 相似文献
17.
Gheorghe Damian Christof Lanzerstorfer Floarea Damian Gheorghe Iepure 《Water, air, and soil pollution》2018,229(6):202
The Cop?a Mic? area is one of the most polluted anthropic sites in Romania. Because higher heavy metal concentrations occur in finer fractions, this research focuses on the size fraction <?500 μm. Two kilograms soil sample was sieved on the 500-μm sieve and was air classified into size fractions down to the low micrometer range. The size fraction’s composition was investigated by ICP-OES IC, XRD, and FTIR spectrometry. Approximately 80 and 62% of the material was smaller than 2 mm and <?500 μm, respectively. The predominant size fraction had a mass median diameter (MMD) of approximately 75 μm. The smallest size fraction with a MMD of 2.2 μm had a share of 3.6% and contained the highest amount of heavy metals. The concentrations of Pb, Zn, Cd, Cu, Sb, and As exceeded the legally regulated values for soils according to Romanian legislation. The respective concentrations were 26,900, 27,600, 415, 2130, 466, and 915 mg·kg?1. In the coarser size fractions 5, 4, and 3, the predominant minerals were quartz and alkaline feldspar, while in the finer size fractions 1 and 2, the clay minerals and total carbon (TC) were predominant. Illites and montmorillonites in the fine fraction composition retain heavy metals due to the high levels of cation exchange capacity. Black carbon accumulated in soil acts as a heavy metal adsorbent due to its porosity and high specific surface area. The good correlation between heavy metals and TC in the top soil can be an indicator of the level of heavy metal pollution. 相似文献
18.
Hamada M. Abdelrahman Dan C. Olk Dana Dinnes Domenico Ventrella Teodoro Miano Claudio Cocozza 《Journal of Soils and Sediments》2016,16(10):2375-2384
Purpose
The study aimed to describe the carbohydrates and amino compounds content in soil, the light fraction (LF), the >53 μm particulate organic matter (POM), and the mobile humic acid (MHA) fraction and to find out whether the carbohydrates and amino compounds can be used to explain the origin of SOM fractions.Materials and methods
Soil samples were collected from two agricultural fields managed under organic farming in southern Italy. The LF, the POM, and the MHA were sequentially extracted from each soil sample then characterized. Seven neutral sugars and 19 amino compounds (amino acids and amino sugars) were determined in each soil sample and its correspondent fractions.Results and discussion
The MHA contained less carbohydrate than the LF or the POM but its carbohydrates, although dominated by arabinose, were relatively with larger microbial contribution as revealed by the mannose/xylose ratio. The amino compounds were generally less in the LF or the POM than in the MHA, while the fungal (aspartic and serine) and bacterial (alanine and glycine) amino acids were larger in the MHA than in the LF or the POM, underlining the microbial contribution to the MHA. Results from both sites indicated that total carbohydrates content decreased moving from the LF (younger fraction) to the MHA (older fraction), which seems to follow a decomposition continuum of organic matter in the soil-plant system.Conclusions
The study showed that the MHA is a labile humified fraction of soil C due to its content of carbohydrates and concluded that the content of carbohydrates and amino compounds in the LF, the POM and the MHA can depict the nature of these fractions and their cycling pattern and response to land management.19.
The highest emissions of CO2 from soils and most pronounced priming effect (PE) from soils generally occur immediately after slurry application. However, the influence of different particle size slurry fractions on net soil C respiration dynamics and PE has not been studied. Therefore, a slurry separation technique based on particle sizes was used in the present study. Six distinct fractions (>2000, 425-2000, 250-425, 150-250, 45-150, <45 μm) were generated from two dairy slurries (one from cows fed a predominantly maize silage diet and the other from cows fed a grass silage diet) were applied to soil. During the first days of the 332 days experiment, all slurry fraction amendments significantly increased soil CO2 effluxes (by 2-8 times) compared to the non-amended control. The increased CO2 emission rates had a negative relationship with slurry particle size, but its duration was positively correlated with slurry particle size. The percentage of the cumulative CO2 emitted was only higher in the first 8 days in the finest slurry particle sizes (<150 μm). The proportion of slurry-derived C emitted as CO2 2 h after addition to soil varied between 29% and 100% of total emitted CO2-C. Generally, the proportion of slurry-derived C emitted initially decreased rapidly in the <250 μm fractions, but decreased more slowly or even increased in the >250 μm fractions. The overall contribution of slurry C to total CO2 emissions was higher in smaller slurry particle size treatments in the first days after application. The addition of the various slurry fractions to soil caused both significant positive and negative PEs on the soil organic matter mineralization. The timing and type (positive or negative) of PE depended on the slurry particle size. Clearly, farm based separation pre-treatment leading to two or more fractions with different particle sizes has also the potential to reduce or modify short-term CO2 emissions immediately after slurry application to soil. 相似文献