Abstract

Soils at a Long Term Ecological Research site near Lake Hoare in Taylor Valley, Antarctica, were investigated during November/December 1999. The soils alongside 6 experimental plots at the research site were described, repeatedly sampled over a 17-day period, and the gravimetric water content, particle size, and conductivity determined daily. At one nearby location, the soil water content was repeatedly measured after a plot irrigation, while at another, the water content of soil adjacent to a snow patch was repeatedly measured to determine the rate of water loss during thawing of snow. Soils at 2 sites at higher elevations outside the research area were also examined for comparison.

The soils at the experimental plots were generally similar but differed in stoniness, the presence of occasional silty layers, and the depth to ice-cemented ground. Water contents (gravimetric) of surface horizons were <0.5% and increased with depth through the active layer to 12% or greater in the ice-cemented permafrost. There were small variations in the water content of surface horizons over the 17-day sampling period with larger variations at depth. A few siltier horizons had higher water contents. The water content profiles and <2 mm% particle size trends were broadly similar for all the sites. Conductivities were low, except in silty horizons where values were markedly higher. At the irrigated site, water was progressively lost over the first 9 days, after which values were close to those at unirrigated sites. There was a less marked loss of water from the soil alongside the thawing snow patch but an increased loss after all snow had thawed. The higher elevation soils outside the experimental area were more weathered and had higher salinities indicating a significantly greater soil age.

Small changes in water content in the surface horizons appeared to be related to changing weather conditions, whereas at greater soil depth, changes in the water content corresponded with the increasing thawing depth. The results illustrate the dynamic nature of soil moisture over short periods of time in Antarctic Cold Desert soils.