Observations measured in field and greenhouse experiments always contain errors. These errors can arise from measurement error, local or positional conditions of the experimental units, or from the randomization of experimental units. In statistical analysis errors can be modelled as independent effects or as spatially correlated effects with an appropriate variance–covariance structure. Using a suitable experimental design, a part of the variance can be captured through blocking of the experimental units. If experimental units (e.g. pots within a greenhouse) are mobile, they can be re-arranged during the experiment. This re-arrangement enables a separation of variation due to time-invariant position effects and variation due to the experimental units. If re-arrangement is successful, the time-invariant positional effect can average out for experimental units moved between different positions during the experiment. While re-arrangement is commonly done in greenhouse experiments, data to quantify its usefulness is limited. A uniformity greenhouse experiment with barley (Hordeum vulgare L.) to compare re-arrangement of pots with a range of designs under fixed-position arrangement showed that both methods can reduce the residual variance and the average standard error of a difference. All designs with fixed-position arrangement, which accounted for the known north–south gradient in the greenhouse, outperformed re-arrangement. An α-design with block size four performed best across seven plant growth traits. Blocking with a fixed-position arrangement was more efficient in improving precision of greenhouse experiments than re-arrangement of pots and hence can be recommended for comparable greenhouse experiments.

中文翻译：

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温室实验中花盆的封闭和重新布置：哪种方法更有效？

在野外和温室实验中测量的观察结果总是包含错误。这些误差可能来自测量误差、实验单元的局部或位置条件，或者来自实验单元的随机化。在统计分析中，误差可以建模为独立效应或具有适当方差-协方差结构的空间相关效应。使用合适的实验设计，除了方差之外，还可以通过封闭实验单元来捕获。如果实验单元（例如温室内的花盆）是可移动的，则可以在实验期间重新布置它们。这种重新安排能够分离由于时间不变的位置效应引起的变化和由于实验单元引起的变化。如果重组成功，对于在实验期间在不同位置之间移动的实验单元，时不变的位置效应可以平均化。虽然重新安排通常在温室实验中进行，但量化其有用性的数据是有限的。用大麦 (Hordeum vulgare L.) 进行的均匀温室实验比较了盆栽的重新排列与固定位置排列下的一系列设计，结果表明这两种方法都可以减少残差方差和平均标准误差。所有具有固定位置布置的设计，占温室中已知的南北梯度，都优于重新布置。块大小为 4 的 α 设计在七种植物生长性状中表现最佳。