Information about water retention in stony soils lags behind due to methodological difficulties. We applied a new strategy to measure the water retention in soils with coarse fragments (CFs) and to get insights into the effect of CFs porosity on water retention. Water retention at zero, 10, and 150 m suction, bulk density, and the mass fraction of six particle size classes were measured in undisturbed blocks from soils with variable CFs contents, originating from three parent materials. The results showed that some soils contain porous CFs (2–250 mm) with a water holding capacity as high as the fine fraction (<2 mm). The water held in the suction range of 1–150 m in a soil with porous CFs was twice as high as in soils with non-porous CFs. Multilinear regressions revealed that both the water retention capacity at 1 m suction and in the range 1–150 m were more dependent on bulk density than on the fraction of CFs and fine particles. In the soil with porous CFs, there was no correlation between their fraction and soil water retention. These results show that the bulk water retention capacity of soils with CFs is underestimated when not considering the internal porosity of the CFs. A better understanding of the effect of the porosity of CFs on bulk soil porosity and water retention is important to propose suitable pedotransfer functions and refine physically-based hydraulic functions for stony soils.

中文翻译：

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粗碎块的颗粒排列和内部孔隙率影响石质土壤的保水性

由于方法上的困难，有关石质土壤保水性的信息滞后。我们采用了一种新策略来测量粗碎片 (CF) 土壤中的保水性，并深入了解 CFs 孔隙率对保水性的影响。在来自三种母质、具有不同 CF 含量的土壤中的未扰动块中测量了零、10 和 150 m 吸力下的保水性、堆积密度和六种粒径等级的质量分数。结果表明，一些土壤含有多孔CF（2-250毫米），其持水能力与细粒部分（<2毫米）一样高。具有多孔 CF 的土壤在 1-150 m 吸力范围内的持水量是具有无孔 CF 的土壤的两倍。多线性回归表明，1 m 吸力和 1-150 m 范围内的保水能力更依赖于堆积密度，而不是 CF 和细颗粒的分数。在含有多孔CF的土壤中，它们的分数与土壤持水量之间不存在相关性。这些结果表明，当不考虑 CF 的内部孔隙率时，含有 CF 的土壤的总体保水能力被低估。更好地了解 CF 的孔隙度对土体孔隙度和保水性的影响对于提出合适的土壤传递函数和细化石质土壤的基于物理的水力函数非常重要。它们的分数与土壤持水量之间没有相关性。这些结果表明，当不考虑 CF 的内部孔隙率时，含有 CF 的土壤的总体保水能力被低估。更好地了解 CF 的孔隙度对土体孔隙度和保水性的影响对于提出合适的土壤传递函数和细化石质土壤的基于物理的水力函数非常重要。它们的分数与土壤持水量之间没有相关性。这些结果表明，当不考虑 CF 的内部孔隙率时，含有 CF 的土壤的总体保水能力被低估。更好地了解 CF 的孔隙度对土体孔隙度和保水性的影响对于提出合适的土壤传递函数和细化石质土壤的基于物理的水力函数非常重要。