Field determination of unsaturated hydraulic conductivity of forest soils
This study introduces a field method to determine unsaturated hydraulic conductivity which is applicable to sloping terrain with a limited water supply. A single steel ring infiltrometer and an artificial rainfall simulator are used in this method to reduce the amount of water required to attain a steady-state flux condition. Six tensiometers and a time domain reflectometry (TDR) are employed as the soil capillary pressure head and the volumetric soil water content measurement devices, respectively. Water contents measured by the TDR are corrected using a simple calibration method suggested by Hook and Livingston (1996). Unsaturated hydraulic conductivities are computed based on the instantaneous profile method using capillary pressure head and water content changes measured during a drainage process. The proposed method was applied to a forest soil profile in Rokko Mountain range. Results showed that the relationships between the unsaturated hydraulic conductivity and capillary pressure head developed by the proposed method coincide well with those measured by the conventional steady-state laboratory experiment. The proposedin-situ method is the effective simple means to determine unsaturated hydraulic conductivities of forest soils, since this method is enough accurate and consuming less amount of water and time.
Unsaturated Hydraulic Conductivity Estimation of a Forest Soil Assuming a Stochastic-Convective Process
Measurement of soil hydraulic conductivity requires considerable time and effort, which makes it difficult to characterize this important parameter across larger areas, especially remote forest regions. Forest soils are frequently texturally coarser than those in agricultural areas, making them more probable candidates for applications building on the stochastic-convective hypothesis. We developed a method for measuring unsaturated soil hydraulic conductivity based on the analysis of a dye tracer resident concentration profile. In the experiment, partially saturated, steady-state water flow was established in a forest allophanic soil by a sprinkler operating at 50 mm h^(–1), after which the water application was switched to a 10 mg L^(–1) Brilliant Blue FCF solution. The tracer was applied continuously until its cumulative infiltration reached 125 mm, after which the stained soil profile was exposed and photographed. The picture was subjected to an image analysis procedure designed to obtain the resident concentration profile of the tracer. The concentration was fitted to the solution of the convective lognormal transfer function, whose parameters were used in further calculations using functional relationships derived from the stochastic-convective framework. The resulting hydraulic conductivity as a function of soil water content agreed within an order of magnitude with the relationship obtained by the instantaneous profile method. While the Mualem–van Genuchten model better reproduced the shape of that relationship, it strongly underestimated the hydraulic conductivity across the soil water content interval of interest (0.1–0.4). Finally, ways to improve the predictive capacity of the stochastic-convective approach in terms of the general trends of the functional relationship were proposed.
The German centenary of the First World War
In the run up to the 2014 centenary of the First World War, the German public was gripped by a heated debate on the origins of the war. This article explores the nature of this controversy and its role in shaping national commemoration of the Great War. It also draws parallels between the commemorations of the fiftieth anniversary of the outbreak of the war in 1964 and those of 2014. Through a comparison of Germany’s national memories of the war with those in Britain and France, the article also reveals how different and sometimes conflicting national interpretations of the history of the First World War have affected centenary commemoration. Memories of the First World War are nation-specific, constructed and developed over time to suit a particular view of a country’s past. Moreover, they can be instrumental in influencing that country’s future development and relations with its neighbours.