Purpose

Traditional laboratory measurements of soil water diffusivity (D) and soil water retention curve (SWRC) are always time-consuming and labor-intensive. Therefore, this paper aims to present a simple and robust test method for determining D and SWRC without reducing accuracy.

Design/methodology/approach

In this study, a D model of unsaturated soil was established based on Gardner–Russo model and then a combination of Gardner–Russo model with one-dimensional horizontal absorption method to obtain n and a parameters of Gardner–Russo model. One-dimensional horizontal absorption experiments on loam, silt loam and sandy clay loam were conducted to obtain the relationships between measured infiltration rate and cumulative infiltration with wetting front distance. Based on the obtained relationships, the measured infiltration data from the one-dimensional horizontal absorption tests were used to calculate n and a parameters and further constructing D and SWRC.

Findings

Both the calculated D and SWRC inversed from the infiltration data were in good agreement with the measured ones that obtained from the traditional horizontal absorption method and the centrifuge method, respectively. Error analysis indicated that only the infiltration data are enough to reliably synchronously determine D and SWRC.

Originality/value

A simple and robust method is proposed for synchronous determination of soil water diffusivity and water retention curve.

中文翻译：

---

从入渗数据确定土壤水分水力参数

目的

传统的土壤水分扩散率 ( D ) 和土壤保水曲线 (SWRC) 的实验室测量总是费时费力。因此，本文旨在提出一种简单而稳健的测试方法，用于在不降低精度的情况下确定D和 SWRC。

设计/方法/方法

本研究基于Gardner-Russo模型建立非饱和土的D模型，然后将Gardner-Russo模型与一维水平吸收法相结合，得到n和Gardner-Russo模型的参数。对壤土、粉砂壤土和砂质粘壤土进行一维水平吸水试验，得到实测入渗率与累积入渗量与湿锋距离的关系。基于得到的关系，从一维水平吸收试验中测得的入渗数据用于计算n和a参数，并进一步构建D和SWRC。

发现

从入渗数据反演得到的D和SWRC与传统水平吸收法和离心法分别得到的实测值吻合良好。误差分析表明，只有入渗数据足以可靠地同步确定D和 SWRC。

原创性/价值

提出了一种简单而稳健的土壤水分扩散率和保水曲线同步测定方法。