Mechanical Properties of Greenlandic Soils.

Description

For the Greenlandic farmers, the effects of climate change are not only of negative nature. Due to the rising temperatures and the accompanying extension of the vegetation period, the farmers are able to produce more and more diverse agricultural products. However, conversion of ancient pastures to arable land should be treated with care, as the properties of Greenlandic soils are not well known. There is a basic need of knowledge about the physical properties of these soils to prevent an eventual deterioration of their agronomic potential. In the present study, we explored mechanical properties of agricultural soils from the south of Greenland with reference to Danish agricultural soils with similar and contrasted particle size analysis. Undisturbed soil cores were collected in the topsoil in three locations in South Greenland and three locations in Denmark. The soil cores were saturated with water, and drained to reach a matric potential of -100 hPa. Uniaxial confined compression tests were performed on each core using a strain controlled method at a constant speed of 1 mm min-1. The soil cores were loaded twice, first to 800 and then to 1000 kPa, with an unloading period of 60 sec. The precompression stress, the compression index, the swelling index, and the rebound were determined from the stress-strain curves for each core. Finally, the cores were oven dried for 24 hours to determine the dry bulk density and the water content. Measured mechanical properties of the Greenlandic soils indicated a higher short-term resilience than for the Danish soils at equivalent particle size distribution and dry bulk density. The determination of the precompression stress as a measure of soil strength resulted in comparable values for both, Greenlandic and Danish soils. This is noteworthy because the Greenlandic soils have significantly lower initial bulk densities than most of the Danish reference soils. In addition, resilience to compression was linearly related to the initial structure of the cores for all six locations, which might lead to a common framework to predict mechanical behavior of these soils.

Period	9 Jan 2019
Held at	Soil Science Society of America, United States
Degree of Recognition	International