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Vineyards are one of the eco-geomorphological systems most conditioned by human activity in Germany. The vineyards of the Ruwer Valley (Germany) are characterized by high soil erosion rates and rill problems on steep slopes (between 23 and 26°) caused by the increasingly frequent heavy rainfall events as well as deterioration due to incorrect land use managements. The objective of this paper is to determine and to quantify the hydrological and erosive phenomena in one vineyard in Germany during different seasons and under different management conditions (before, during and after vintage). For this purpose, a combined methodology was applied. Climatic (rainfall depth distributions and return periods), pedological (soil analysis and classification), geomorphological (sediment movements and rills evolution) and biological (botanic marks on the vines) variables were used on the two experimental plots in the village of Waldrach (Trier, region of Rhineland-Palatinate). The results showed high infiltration rates (near 100 %) and subsurface flow which were detected by rainfall simulations performed at different times of the year (between September and December). The highest variations of the monitored rills (lateral and frontal movements) were noted before and during vintage, when footsteps occurred concentrated during a short period of time (between September and October). Finally, two maps of soil loss were generated, indicated by botanic marks on the graft union of the vines. 62.5 t ha-1 yr-1 soil loss was registered in the experimental plots of the new vineyards (2 years), while 3.4 t ha-1 yr-1 was recorded in the old one (35 years). [ABSTRACT FROM AUTHOR]

The averaging behavior of two capacitance water content sensors in nonuniform wetted sand samples was assessed and compared with the averaging behavior of a time domain reflectometry (TDR) water content sensor in identical samples. Four different nonuniform wetting situations were assessed. In one of the four experiments, the orientation of the capacitance sensor was altered, while in another the sensitivity along the length of the sensor was tested. For one of the tested sensor types, the overestimation of the volumetric water content (VWC) was 0.034 compared with the value determined by drying, while the corresponding TDR value deviated 0.009. The conclusion is that in a nonuniform wetted soil profile, the capacitance sensors tested weigh the wet parts more heavily than the dry parts, resulting in an overestimation of the average VWC. Therefore we conclude that the capacitance sensors tested are less suitable for applications in situations where both nonuniform wetted profiles are encountered and accurate VWC measurements are required. [ABSTRACT FROM AUTHOR]

The partial discharge (PD) and electric breakdown mechanisms in SF6 at a plug contact in the pressure range 25–150 kPa were investigated at ambient temperature in a plug–plate arrangement. This parameter range has similar particle number densities as in the previous investigation of the dielectric recovery in a high-voltage circuit breaker (Seeger et al 2012 J. Phys. D: Appl. Phys.45 395204), where optical access was limited and the relevant parameters of pressure and temperature could only be determined indirectly by computational fluid dynamic simulations. The present investigation did not have these limitations, since the pressure and temperature were well defined. Optical observation by an image intensified high speed camera in combination with a photo multiplier tube allowed an understanding of the various mechanisms for the PDs and breakdown to be gained. The breakdown fields and PD parameters could be well described by a simple leader model in the pressure range 75–150 kPa for negative polarity and above 25 kPa for positive polarity. Discrepancies with the model are observed below 75 kPa for negative polarity and at 25 kPa for positive polarity. This could be explained by a slow, repetitive heating mechanism which has not been reported so far. [ABSTRACT FROM AUTHOR]

It is well known that rainfall causes soil erosion in sloping German vineyards, but little is known about the effect of age of plantation on soil erosion, which is relevant to understand and design sustainable management systems. In the Ruwer-Mosel valley, young (1- to 4-years) and old (35- to 38-years after the plantation) vineyards were selected to assess soil and water losses by using two-paired Gerlach troughs over three years (2013-2015). In the young vineyard, the overland flow was 107 L m-1 and soil loss 1000 g m-1 in the year of the plantation, and decreased drastically over the two subsequent years (19 L m-1; 428 g m-1). In the old vineyard, soil (from 1081 g m-1 to 1308 g m-1) and water (from 67 L m-1 to 102 L m-1) losses were 1.2 and 1.63 times higher, respectively, than in the young vineyard.