Soil properties are often assumed to be static over time in hydrological studies, especially in hydrological modelling. Although it is well appreciated that soil structure and its impact on hydraulic properties are time-variable, particularly on cultivated land, very few studies have focused on quantifying the influence of such changes on soil hydrology, especially at the short term (i.e. seasonal). This study explored the value of incorporating such short-term time-variable soil properties in hydrological models. It is based on soil hydraulic properties from temporal field data under no-till done by direct seeding and under conventional cultivation done by ploughing to 0.2 m and harrowing. It uses a controlled tillage experiment in Scotland, on a soil with very good structural stability that experiences gentle rainfall in a temperate oceanic climate (Köppen Cfb). Water retention data were collected from intact soil cores sampled at 0.025, 0.095 and 0.275 m depth at three times between April and August 2013; (i) immediately following tillage, (ii) at barley crop establishment 1 month later and (iii) after harvest. Soil structure varied over time, with no-till soils gaining porosity and ploughed soils losing porosity. We hypothesised that no-till soils would have less seasonal temporal variability, but found it to be comparable to ploughed soils, albeit with pore structure changes following different trends. These changes were reflected in Van Genuchten fitting parameters, which if accounted for in 1-D HYDRUS modelling, had a marked impact on modelled soil water content over time if contrasted to predictions assuming a static pore structure. Using data from multiple sampling events, as opposed to one sampling event, resulted in up to a 44 % difference in soil water content predictions and increased the temporal variability by a factor of 1.5. Hence, our results have demonstrated that it is important to account for short-term temporal variability in soil physical properties in soil water modelling studies, and should not be ignored as a default, particularly on cultivated agricultural soils.

在水文研究中，尤其是在水文建模中，土壤特性通常被假定为随着时间的推移是静态的。尽管土壤结构及其对水力特性的影响是随时间变化的，特别是在耕地上，但很少有研究关注量化这种变化对土壤水文的影响，尤其是在短期（即季节性）。本研究探讨了将这种短期随时间变化的土壤特性纳入水文模型的价值。它基于土壤水力特性，根据时间现场数据，在免耕直接播种和常规耕作下耕作 0.2 m 并进行耙耕。它使用了苏格兰的受控耕作试验，在具有非常好的结构稳定性的土壤上，在温带海洋气候中经历温和的降雨（Köppen Cfb）。2013 年 4 月至 8 月 3 次从 0.025、0.095 和 0.275 m 深度采样的完整土芯中收集保水数据；(i) 耕种后立即，​​(ii) 1 个月后大麦作物种植时和 (iii) 收获后。土壤结构随着时间的推移而变化，免耕土壤获得孔隙度，耕作土壤失去孔隙度。我们假设免耕土壤的季节性时间变化较小，但发现它与犁过的土壤相当，尽管孔隙结构随不同趋势而变化。这些变化反映在 Van Genuchten 拟合参数中，如果在 1-D HYDRUS 建模中考虑这些参数，如果与假设静态孔隙结构的预测相比，随着时间的推移，对模拟的土壤含水量有显着影响。使用来自多个采样事件的数据，而不是一个采样事件，导致土壤含水量预测的差异高达 44%，并将时间变异性增加了 1.5 倍。因此，我们的结果表明，在土壤水模型研究中考虑土壤物理特性的短期时间变化是很重要的，并且不应作为默认设置而被忽略，尤其是在耕作的农业土壤上。