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首页> 外文期刊>European Journal of Soil Science >Estimating the regional mean status and change of soil properties: two distinct objectives for soil survey
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Estimating the regional mean status and change of soil properties: two distinct objectives for soil survey

机译：估算区域平均状况和土壤性质的变化：土壤调查的两个不同目标

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摘要

There is a general requirement for inventories to establish the status of soils with respect to key indicator properties, and for monitoring to detect changes in these indicators. The design of sampling protocols for soil survey must meet these dual requirements. This paper emphasizes that the status and change of an indicator are different variables and so their variability may differ. We therefore may not assume that a sampling scheme that is suitable for inventory is also suitable for monitoring; this poses a practical problem since information on the variability of the change in soil is not in general available at present. In this paper some plausible statistical models of change in the soil are examined, and their implications for sampling to estimate mean change in large regions are considered. Paired sampling, with baseline and resampling at common sites, is generally preferable to sampling at independent sites on the two dates, unless the error from relocation of the sample sites is large by comparison to other sources of variation. A simple process model of soil organic carbon in soils of lowland tropical forest is used to examine the problem of resampling to estimate change. This shows the expected advantages of paired sampling for change, and the very different sampling requirements that may pertain for inventory and monitoring. One implication of these results is that, while sampling schemes for inventory may be designed on the basis of available information (from samples taken at a single time), the precise requirements for monitoring might not be apparent until a reconnaissance resampling is undertaken subsequently.
机译：通常需要清单来确定关键指标属性方面的土壤状况，并进行监测以检测这些指标的变化。用于土壤调查的采样协议的设计必须满足这些双重要求。本文强调指出，指标的状态和变化是不同的变量，因此其可变性可能不同。因此，我们可能不会认为适合库存的抽样方案也适合监测。这造成了一个实际的问题，因为目前通常无法获得有关土壤变化变化性的信息。在本文中，研究了一些合理的土壤变化统计模型，并考虑了它们对抽样估计大区域平均变化的影响。通常，在两个日期进行配对采样并在公共站点进行基线采样和重采样比在两个日期在独立站点进行采样更为可取，除非与其他变异来源相比，采样站点重新定位带来的误差较大。利用低地热带森林土壤中有机碳的简单过程模型，研究了重采样问题以估算变化。这显示了成对抽样以进行变更的预期优势，以及可能与清单和监视有关的非常不同的抽样要求。这些结果的一个暗示是，尽管可以根据（从一次采样中获取的）可用信息来设计库存采样方案，但是直到随后进行侦察重新采样后，监视的精确要求可能才变得明显。

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