Combining the Stock Unearthing Method and Structure-from-Motion Photogrammetry for a Gapless Estimation of Soil Mobilisation in Vineyards

Abstract

In vineyards, especially on steep slopes like the Ruwer-Mosel Valley, Germany, soil erosion is a well-known environmental problem. Unfortunately, some enterprises and farmers are not aware of how much soil is being lost and the long-term negative impacts of soil erosion. The non-invasive technique of the stock unearthing method (SUM) can be used for a quick assessment of soil erosion in vineyards. SUM uses the graft union as a reference elevation for soil surface changes since the time of plantation commencement, which is modelled with the help of a geographic information system. A shortcoming of SUM is that the areas between the pair-vine cross sections are not surveyed, hence it is not accurate enough to identify erosion hot-spots. A structure-from-motion (SfM) photogrammetric technique is adopted to complement SUM to fill this data gap. Combining SUM (only measuring the graft unions) and SfM techniques could lead to an improved, easy and low-cost method with a higher accuracy for estimation of soil erosion based on interpolation by projection, and contact and gapless measuring. Thus, the main aim of this paper was to map the current soil surface level and to improve the accuracy of estimation of long-term soil mobilisation rates in vineyards. To achieve this goal, the TEPHOS (TErrestrial PHOtogrammetric Scanner), a static five camera array, was developed on a 20 m2 plot located in a steeply sloping vineyard of the Ruwer-Mosel Valley, Trier, Germany. A total soil mobilisation of 0.52 m3 (9.14 Mg ha yr−1) with soil surface level differences in excess of 30 cm in the 40 years since plantation commencement were recorded. Further research is, however, needed to reduce the number of photos used for the point cloud without loss of accuracy. This method can be useful for the observation of the impacts of other factors in vineyards, such as tillage erosion, runoff pathway detection or the trampling effect on soil erosion in vineyards.

Determining the best ISUM (Improved stock unearthing Method) sampling point number to model long-term soil transport and micro-topographical changes in vineyards

“…This vineyard was manually planted, and the graft unions were consistently placed at 2 cm height above the original ground level. This information was confirmed by the farmers in the field through non-formal interviews and it was also observed in new plantations near the study area (Remke et al, 2018). This optimal distance above ground reduces some complications caused by soil moisture, freezing, and fungi plagues on the plants.…”

Comparative Analysis of Splash Erosion Devices for Rainfall Simulation Experiments: A Laboratory Study

“…The device is also cheap and easy to install and manage. rich in organic carbon [11], with splash erosion being one of the key factors that are responsible for the redistribution of the minerals on the soil surface [12]; however, the microtopography should be also considered as the key factor for soil erosion on small scales [13,14].In arid and semi-arid areas, splash erosion also plays a major role in forming the landscape due to the control that exerts on shaping the landforms [15,16]. This is because the bare soils allow for the raindrop impact to develop a crust, and then to enhance surface runoff generation, which is a key process in the Mediterranean and temperate areas, such as Spain [17], Italy [18,19], Israel [20], or Iran [21].…”

“…The device is also cheap and easy to install and manage. rich in organic carbon [11], with splash erosion being one of the key factors that are responsible for the redistribution of the minerals on the soil surface [12]; however, the microtopography should be also considered as the key factor for soil erosion on small scales [13,14].…”

Automotive Radar in a UAV to Assess Earth Surface Processes and Land Responses

“…Furthermore, the impacts on land-use changes [ 44 , 45 , 46 ] due to the interaction between the microwave signal and different microwave absorbing materials in the soil can be evaluated. These devices would be suitable to be combined with in situ experiments or monitoring [ 47 ] and with optical data. The main use of the system is assessing the above-mentioned processes before or after specific events such as rain, wind, floods, etc., or analyzing the status of specific landforms.…”