Derivation of soil parameters based on laser scanning point clouds

Due to agricultural use, soils are vulnerable to erosion by wind and water. Erosion permanently degrades soils and thus minimises the ability of soils to provide ecosystem services. Serious consequences of soil erosion can be observed both on cultivated land (e.g. reduced soil fertility, crop failures) and apart from it (e.g. nutrient inputs to water bodies, pollution of infrastructure).

An important tool in soil protection enforcement is the monitoring of soil erosion events. In this context, terrestrial laser scanning as a non-contact and quasi-continuous measuring technique has established as a measuring technique. The research work of the Chair of Geodetic Sensor Systems focuses on the modelling of the resulting point clouds and the subsequent derivation of descriptive parameters.

Derivation of soil parameters based on laser scanning point clouds


Fig. 1: Point clouds of a cultivated field. Left: Original point cloud. Right: Point cloud after vegetation filtering (Harmening et al. 2023).

Quantification of erosion-induced soil loss

Of particular interest in erosion monitoring is the quantification of erosion-related soil loss. At the Chair of Geodetic Sensor Systems, methods are being developed that allow the quantification of heavy rainfall-induced soil erosion on the basis of approximating B-spline curves and surfaces.

Fig. 2: Determination of profile-wise soil erosion using two B-spline curves (Harmening et al. 2022).

Determination of soil roughness

The vulnerability of soil with respect to erosion is determined to a large extent by its roughness, as it has a direct influence on the soil’s infiltration capacity as well as on the hydraulics of surface runoff. The quantification of soil roughness thus allows a risk assessment of the soil with regard to its vulnerability with respect to erosion, while the monitoring of roughness over time simultaneously provides information on erosion that has occurred.

At the Chair of Geodetic Sensor Systems, methods are being developed with which the roughness of soils can be determined on the basis of laser scanning point clouds. For this purpose, the soil roughness is interpreted as the realisation of a stochastic process, which can be described with the help of variograms. The range and the sill variance of these variograms can be interpreted as parameters of the soil roughness.


Abb. 3: Directional variograms for quantifying soil roughness