Natural heterogeneity of soil properties complicates the analysis of water and solute transport under field conditions. To overcome this limitation, a field experiment adopting a scale-dependent treatment distribution was conducted and frequency-domain analysis was used to characterize the spatial distribution of temporal water status change and Br- concentration determined in soil solution samples at various times. The objective of this study was to evaluate the impact of soil surface roughness and rain characteristics on Br- leaching and water infiltration during simulated rain and the following redistribution. On a 48- by 3-m transect, rain intensity and the time delay between Br- application and subsequent rain were arranged in a cyclic layout at distinct scales. Nests of tensiometers and suction probes were installed at 1-m intervals along the experimental transect to monitor temporal matric potential changes and Br- concentrations at different depths, respectively. The results showed that Br- concentrations measured 1 h after simulated rain were generally greater than those measured 1 d later at all depths. The "dominant factors" influencing the horizontal distribution of Br- measured at these two times differed for each depth except 100 cm. The spatial variation scale of temporal matric potential change varied with time and depth, corresponding with different boundary conditions. Matric potential change in some cases, reflected information other than the boundary conditions investigated, such as hydraulic conductivity, contributing to the scale-variant behavior of Br- leaching. These findings have important implications not only for agricultural management but also for hydrological modeling at the field scale.
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机译：土壤性质的天然异质性使田间条件下水和溶质运移的分析变得复杂。为了克服这一局限性，进行了采用比例依赖处理分布的野外试验，并使用频域分析来表征土壤溶液样品在不同时间的瞬时水状态变化和Br-浓度的空间分布。这项研究的目的是评估模拟降雨和随后的再分配过程中土壤表面粗糙度和降雨特征对Br淋失和水分入渗的影响。在一个48 x 3 m的样带上，降雨强度和Br施用与随后降雨之间的时间延迟以不同的比例以周期性的方式排列。沿实验样条以1-m的间隔安装张力计和吸力探针的巢穴，以分别监测不同深度处的时间矩阵电势变化和Br-浓度。结果表明，模拟降雨后1 h测得的Br-浓度通常大于所有深度1 d后测得的浓度。除了100 cm以外，每种深度下影响这两次测量的Br-水平分布的“主要因素”都不同。时间矩阵势变化的空间变化尺度随时间和深度而变化，对应于不同的边界条件。在某些情况下，基质电势的变化反映了除所研究的边界条件以外的其他信息，例如水力传导率，这有助于Br浸出的尺度变化行为。这些发现不仅对农业管理有重要意义，而且对田间规模的水文模拟也有重要意义。
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