Importance of short-term temporal variability in soil physical properties for soil water modelling under different tillage practices
Importance of short-term temporal variability in soil physical properties for soil water modelling under different tillage practices
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DOI：
10.1016/j.still.2021.105132
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发表时间：
2021-07-08
影响因子：
6.5
通讯作者：
Hallett, Paul D.
中科院分区：
文献类型：
--
作者：
Geris, Josie;Verrot, Lucile;Hallett, Paul D.
在水文学研究中，特别是在水文模型中，土壤特性通常被假定为随时间变化是静态的。虽然人们很好地认识到，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，很少有研究侧重于量化这种变化对土壤水文的影响，特别是在短期内（即季节性）。本研究探讨了水文模型中纳入这种短期时变土壤特性的价值。它是基于土壤水力学性质的时间字段数据下免耕直播和常规耕作下做犁到0.2米和耙。它在苏格兰进行了一项控制耕作实验，土壤结构稳定性非常好，在温带海洋性气候中经历了温和的降雨（Ko center dot ppen Cfb）。从2013年4月至8月期间在0.025，0.095和0.275 m深度三次采样的完整土壤芯中收集保水性数据;（i）耕作后立即，（ii）大麦作物建立1个月后和（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，翻耕土壤失去孔隙度。我们假设免耕土壤的季节性时间变异性较小，但发现它与翻耕土壤相当，尽管孔隙结构变化遵循不同的趋势。这些变化反映在货车Van Schlichten拟合参数，如果占1-D HYDRUS建模，有一个显着的影响，随着时间的推移，模拟土壤含水量的预测，假设一个静态的孔隙结构相比。使用多个采样事件的数据，而不是一个采样事件，导致高达44%的差异，土壤含水量的预测，并增加了1.5倍的时间变异性。因此，我们的研究结果表明，这是很重要的土壤水分模拟研究中的土壤物理性质的短期时间变异，不应被忽视的默认值，特别是在耕地农业土壤。
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 timevariable, 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 (Ko center dot ppen 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.