AirSUM - Structure from Motion supported Stock Unearthing Method: Erosion modeling in Viennese vineyards

Abstract

Soil mobilization is particularly high in viticulture. In Austria and especially in Vienna, soil protection measures are frequently implemented, without the vintners knowing about the extent of erosion rates and where they can take additional measures in particular. However, new methods for erosion estimation with high accuracy and cost efficiency are expected to improve this situation. Of which one application will be presented in this study.A relatively fast and low-cost possibility is the stock unearthing method (SUM), which provides a rough estimation of erosion, based on biomarkers but neglects the inter-row area. The improved ISUM is using additional measurement points in this area and therefore delivering more accurate erosion volumes. Additionally, the use of structure from motion (SfM) DEMs provided respectable results on small plots in vineyards. The combination of SUM and SfM allows the new airSUM approach to provide a significantly more precise estimation of annual erosion rates, making rendering interpolation techniques unnecessary. The resulting model represents the present relief and is able to reproduce visible runoff patterns. The use of airSUM enabled the detection of 32.7 m3 (avg. of ~83.9 t ha-1 yr-1) soil erosion on an area of 700 m2 in a period of 8 years. Erosion hotspots could be modeled mainly in the wheel tracks with depths of up to 20.5 cm parallel to the slope and correspond excellently with field observations. This is partly due to the compaction of the surface, but mainly due to the preferential runoff and erosion. The identification of the erosion hot spots, runoff breaches and consequently runoff concentration allows the precise allocation of mitigation funds to reduce overland flow and erosion.