共查询到19条相似文献，搜索用时 500 毫秒
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土壤侵蚀研究中核示踪技术的应用 总被引：4，自引：0，他引：4
核示踪技术是研究土壤侵蚀的一种新技术。本文简述了土壤侵蚀研究中核示踪技术的应用现状,并介绍了一种新方法———稳定性稀土元素（ＲＥＥ）示踪法。该方法可定量测定坡面不同地形部位的相对侵蚀量,揭示侵蚀过程中相对侵蚀量沿坡面的变化趋势,还可反映野外全坡长小区土壤侵蚀的分布模式。应用结果表明,稀土元素在土壤侵蚀时空分布、泥沙运移、沉积过程以及小流域泥沙来源等研究领域均有广阔的应用前景。 相似文献
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近30年来磁性示踪技术应用于土壤侵蚀领域的文献计量分析 总被引：1，自引：0，他引：1
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Pu同位素在土壤侵蚀示踪中的应用 总被引：2，自引：0，他引：2
137Cs示踪技术目前在土壤侵蚀研究中应用最为广泛,但是随着环境中137Cs的衰变,寻找可以替代的放射性核素具有十分重要的意义。人造放射性核素Pu同位素与137Cs来源相同,但半衰期更长,且更容易被土壤中的细颗粒物质吸附。特别是随着测量技术的发展,电感耦合等离子体质谱技术(ICP-MS)以及加速器质谱技术(AMS)等的应用,使得Pu同位素的测量较137Cs更高效、灵敏。因而Pu同位素成为可以替代137Cs进行土壤侵蚀示踪的理想元素。本文从Pu的来源及分布、Pu在土壤中的吸附和固定、Pu同位素的测量方法三个方面分析Pu同位素示踪土壤侵蚀的基础,并对Pu同位素示踪土壤侵蚀的基本原理和应用现状加以简述,探讨了今后Pu同位素在土壤侵蚀示踪应用中的主要研究方向。 相似文献
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利用放射性核素示踪研究土壤侵蚀已成为国际社会普遍关注的热点问题之一。7Be是一种在地球大气中由于宇宙射线轰击氧原子和氮原子靶核而产生的一种天然放射性核素,作为一种自然产生的、短寿命的放射性核素,它具有同137Cs2、10Pb、226Ra等放射性核素相似的示踪价值。介绍了7Be的应用背景、来源、示踪原理和7Be示踪技术现有的土壤侵蚀速率定量估算模型,提出了在我国应用7Be示踪技术开展土壤侵蚀的建议。 相似文献
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坡面侵蚀土壤磁化率及磁性示踪试验研究 总被引：4，自引：0，他引：4
通过在小流域坡面上进行的实地磁测、室内组分分离、组分磁测及坡面土壤侵蚀磁性示踪试验,对坡面不同空间部位土壤的磁化率特征和降雨后土壤磁化率变化的机理,以及利用磁性示踪法来研究坡面土壤侵蚀的可行性进行了探讨,结果表明,坡面土壤磁化率以上坡磁化率最低、中坡最高、下坡居中;土壤不同粒径组分磁化率与粒径大小存在密切联系,土壤不同粒径组分中以粒径在0.1～0.25mm的组分对土壤磁化率影响最大;在降雨后不同坡位土壤磁化率均发生变化,其机理是由于土壤遭到侵蚀后粒级组成发生变化,从而造成磁性矿物的含量发生变化,进而引起了土壤磁化率的改变;利用磁性示踪法来研究坡面土壤侵蚀是一个行之有效的方法。 相似文献
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红壤坡地土壤侵蚀定位土芯Eu示踪法研究 总被引：19，自引：5，他引：14
根据创立的土壤侵蚀定位土芯Eu示踪新方法,研究了红壤坡地不同土地利用方式下土壤侵蚀的垂直分布规律,介绍了新方法的产生背景和示踪原子选择,示踪用量估算,示踪实施,中子活化及侵蚀结果计算技术要点,以及在红壤坡地雷竹园的部分应用结果,结果表明,新方法对以片蚀和细泡侵蚀为主的红壤坡地是适用的,在复合坡面,随着面的陡,缓,土壤侵蚀表现强,强或沉积,反映了坡地土壤侵蚀的重直分布规律。 相似文献
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利用137Cs示踪技术研究滇池流域土壤侵蚀 总被引：2，自引：0，他引：2
核素示踪技术研究作为一种新的土壤侵蚀研究方法,已经在土壤侵蚀研究中获得了极大应用,并在土壤侵蚀的沉积、侵蚀、运移研究上取得许多成果。采用放射性核素作为土壤示踪剂,可以很好地进行流域尺度的范围研究,且可靠性比较高,省时省力。云贵高原在处于我国的西南地区,是我国南方水土流失严重的地区之一。本文应用137Cs示踪技术,研究了云南省滇池流域土壤侵蚀的强度分异规律:坡地不同地貌部位的土壤侵蚀速率是坡中部>坡下部>坡上部;不同土地利用类型和方式下的土壤平均侵蚀速率是耕地>非耕地。研究表明,整个流域平均土壤侵蚀速率为1 280 t km-2a-1,属于轻度侵蚀,地貌部位、坡度以及土地利用方式是影响土壤侵蚀的主要因素。 相似文献
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Gema Guzmán John N. Quinton Mark A. Nearing Lionel Mabit José A. Gómez 《Journal of Soils and Sediments》2013,13(4):816-833
Introduction
Interest in the use of sediment tracers as a tool to complement traditional water erosion or deposition measurements has increased due to the additional information they provide, such as sediment source identification, tracking of sediment movement across the landscape at various temporal and spatial scales, and estimation of soil erosion rates. For these reasons, the utility and robustness of sediment tracing approaches using a wide range of substances and soil properties have been evaluated in numerous studies.Conclusions
A review of established tracing approaches identified five distinct groups of tracing approaches: fallout radionuclides, rare earth elements, soil magnetism and magnetic substances, other tracers, and sediment fingerprinting techniques. This paper describes the basic theory of each tracing approach in assessing soil erosion and sediment redistribution, describing their methodology and main applications, and summarizing the commonalities and differences between the approaches. It also identifies research gaps and future trends. 相似文献12.
利用~(137)Cs技术研究土壤可蚀性的时空变异(英文) 总被引：3，自引：0，他引：3
土壤可蚀性的研究变异性是当代土壤侵蚀预测预报研究的核心。本综述了土壤可蚀性变异性研究的进展及存在的问题,提出了利用＾１３７Ｃｓ法定量测定土壤可蚀性时空变异的新技术。 相似文献
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T. E. Schumacher M. J. Lindstrom J. A. Schumacher G. D. Lemme 《Soil & Tillage Research》1999,51(3-4):331-339
The advent of precision farming practices has heightened interest in managing field variability to optimize profitability. The large variation in yields across many producer fields demonstrated by yield–monitor–equipped combines has generated concern about management-induced causes of spatial variation in soil productivity. Soil translocation from erosion processes may result in variation in soil properties across field landscape positions that produce long-term changes in soil productivity. The objective of this study was to examine the relationships between soil redistribution caused by tillage and water erosion and the resulting spatial variability of soil productivity in a soil catena in eastern South Dakota. An empirical model developed to estimate tillage erosion was used to evaluate changes expected in the soil profile over a 50-year period on a typical toposequence found in eastern South Dakota and western Minnesota. Changes in the soil profile due to water erosion over a 50-year period were evaluated using the WEPP hillslope model. The tillage erosion model and the WEPP hillslope model were run concurrently for a 50-year period to evaluate the combined effect of the two processes. The resulting changes in soil properties of the root zone were evaluated for changes in productivity using a productivity index model. Tillage erosion resulted in soil loss in the shoulder position, while soil loss from water erosion occurred primarily in the mid to lower backslope position. The decline in soil productivity was greater when both processes were combined compared to either process acting alone. Water erosion contributed to nearly all the decline in soil productivity in the backslope position when both tillage and water erosion processes were combined. The net effect of soil translocation from the combined effects of tillage and water erosion is an increase in spatial variability of crop yields and a likely decline in overall soil productivity. 相似文献
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Developing a magnetic tracer to study soil erosion 总被引：6，自引：0，他引：6
Soil erosion is commonly measured as the quantity of sediment leaving a plot or watershed. The techniques for measuring soil erosion patterns and sediment redistribution within plots or watersheds by direct monitoring are very limited. The objective of this study was to develop a direct and non-intrusive tracer method to study the sources, patterns and rates of erosion and deposition of sediments in erosion plots. The magnetic tracer developed in this study consisted of polystyrene plastic beads embedded with a magnetic powder (magnetite). The “magnetized” beads, with a mean weight diameter of 3.2 mm and particle density of about 1.2 g cm−3, were uniformly mixed with soil and tested in the laboratory using simulated rainfall and inflow studies to simulate the interrill and rill components of soil erosion, respectively. In the interrill and rill experiments, the tracer was transported in the same proportion it was initially mixed with the soil. Given this fact, a magnetometer, which measures the soil's magnetic susceptibility, could be used to identify areas of deposition or detachment. The magnetic susceptibility would be increased or reduced depending on whether deposition or detachment occurs. To simulate detachment and deposition, a magnetometer was tested for different tracer concentrations and different thickness of soil containing the tracer. The magnetometer promises to be a sensitive, accurate, and useful tool to study the spatial variation of soil erosion when magnetic tracers are used. 相似文献
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On US military installations, training activities such as vehicle use disturb ground and vegetation cover of landscapes, and increase potential rainfall runoff and soil erosion. In order to sustain training lands, soil erosion is of major concern. Thus there is a need for sampling designs to monitor degradation and recovery of land conditions. Traditionally, permanent plots are used to obtain the change of land conditions. However, the permanent plots often provide less information over time in characterizing the land conditions because of the fixed number and locations of plots. In this paper, we analyzed the sufficiency of a permanent plot sample and developed a method to improve the re-measurements of the permanent plots over time for a monitoring system of soil erosion based on spatial and temporal variability of a random function. We first applied a local variability based sampling method to generate reference samples that have sampling distances varying spatially and temporally to monitor a soil erosion relevant cover factor for an installation, Fort Riley, USA. Then, we compared a permanent sample with the reference samples annually over 13 years to determine additional sampling in the areas with high variability and temporarily suspending measurements of the permanent plots in the areas with low variability. The local variability based sampling provides estimates of local variability of the cover factor and thus is more cost-efficient than random sampling. By comparison with a reference samples, the re-measurements obtained should more accurately characterize the dynamics of the land conditions. 相似文献
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等高植物篱模式下土壤物理性质变化与水土保持效果研究进展 总被引：7，自引：0，他引：7
等高植物篱模式就是在坡耕地上每隔4~8m的距离沿等高线将植物篱与作物种植带相间分布的一种农林复合经营模式,用于坡耕地的水土保持。已有的研究结果表明,等高植物篱技术用于坡耕地可有效地改善土壤物理性质和土壤水分状况,防治坡耕地水土流失效果显著,土壤水分的季节性再分配也有利于农作物的生长。但是该系统内植物篱和农作物相互之间的水分和养分关系有待深入研究。 相似文献
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南方红壤区不同侵蚀程度下耕地土壤有效磷空间 分布特征及其驱动因素 总被引：2，自引：0，他引：2
以江西省兴国县耕地土壤有效磷为研究对象,结合高程、坡度、成土母质、土壤质地、耕层厚度和地貌类型等因素,运用Spearman相关性分析、回归分析和普通克里格法,对不同侵蚀程度下土壤有效磷空间变异及其驱动因素进行研究。结果表明:随着侵蚀程度的加深,土壤有效磷均值呈下降趋势,当侵蚀程度不断加重时,土壤有效磷均值又呈上升趋势。不同侵蚀程度下土壤有效磷含量差异显著(P0.001)。变异系数由大到小依次为极强度侵蚀(35.20%)剧烈侵蚀(28.09%)轻微侵蚀(28.02%)重度侵蚀(27.90%)无明显侵蚀(25.96%)中度侵蚀(25.78%)。在无明显侵蚀时,成土母质能独立解释1.7%的土壤有效磷空间变异。在轻微侵蚀、中度侵蚀和重度侵蚀时,高程的独立解释能力分别为5.7%、2.3%和2.9%。在极强度侵蚀时,成土母质的独立解释能力为5.0%。在剧烈侵蚀时高程的独立解释能力为1.9%。因此,高程和成土母质是不同侵蚀程度下土壤有效磷空间变异的驱动因素。研究成果为不同侵蚀程度下合理开展耕地利用和水土保持工作提供了参考。 相似文献