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The agricultural production of maize (Zea mays L.) increases the risk of water erosion. Perennial crops like cup plant (Silphium perfoliatum L.) offer a sustainable alternative to produce biomass for biogas plants. The assessment of soil conservation measures requires calibrated soil erosion models that spatially identify soil erosion processes. These support decision-making by farmers and policymakers. Input parameters for the physically based soil erosion model EROSION 3D for cup plant cultivation were established in a field study. Rainfall simulation experiments were conducted to determine the model input parameter's skinfactor and surface roughness. The results showed a reduction of soil erosion and higher infiltration rates for cup plant resulting in higher skinfactors of 11.5 in June and 0.75 post-harvest (cup plant) compared to 1.2 in June and 0.21 post-harvest (maize). With the extended parameter catalogue of EROSION 3D for cup plant cultivation model simulations were conducted for a rainfall event in June (64 mm). The sediment budget would have been reduced by 92.6% through the growth of cup plant in comparison to conventionally grown maize. Perennial cup plant can, therefore, contribute to achieving the targets outlined in the European Green Deal by reducing soil erosion and enhancing soil health. [ABSTRACT FROM AUTHOR]

Due to changing climate and irregular weather patterns, event-based soil loss and sediment yield have become important issues in the agricultural areas. Several mathematical models and prediction methodologies have been used to estimate event-based soil loss and soil redistribution based on soil types, land management, hydrology and local topography. The use of short-lived beryllium-7 as a means of estimating event-based soil erosion/deposition rates has become an alternative to the traditional soil loss measurement methods. A new erosion model taking into account the movement of 7Be in soils has been presented recently. In order to direct the attention to the potential offered by this technique (measurements and mathematical model), a two-year study was performed at the erosion plots in Müncheberg, Germany, and twelve individual erosion rates were estimated. This paper presents a systematic comparison of the non-steady state 7Be model with the process-based erosion model EROSION-3D and measured data. The results demonstrate a close consistency between the erosion rates estimated by erosion models and the estimates provided by the 7Be model and can therefore be seen as a promising contribution to validating the use of this radionuclide to document short-term soil redistribution within the plot and deposited sediment at the bottom of the plot. [ABSTRACT FROM AUTHOR]

Agricultural management systems are in transition amongst others through the promotion of renewable energy by legislations such as the renewable energy law (EEG) in Germany or the EU Green Deal. Biomass production as renewable energy source has been increased continuously. So far, maize is mostly used as feedstock in e.g. biogas plants. However, the production of maize as an energy crop has led to criticism due to an increased risk of water erosion and associated water body eutrophication. This problem is further aggravated through the increase in precipitation extremes due to climate change. Alternative strategies for biogas crop production are strongly required with permanent crops being of particular interest. Well-calibrated models are essential to make proficient statements about the erosion reduction potential of alternative biogas crops on erosion prone sites in order to support planting and political decisions. To calibrate soil erosion models, it is necessary to parameterise the underlying model equations. Monitoring and quantifying water erosion of soil is labour and time consuming and therefore rarely conducted. A case study is presented that addresses the quantification of soil erosion under commercial conditions and thus gains experimental data to calibrate and validate soil erosion models for permanent bioenergy crops. The study starting in 2021 is conducted in the Elm low mountain region near Braunschweig and on the Pfullendorfer young moraine landscapes near Sigmaringen. It compares in a randomized block design with three replicates conventional maize cultivation, direct seeding management of maize, and the permanent plant Silphium perfoliatum L. Preliminary data obtained during the year of experimental establishment (2021) demonstrated that the experimental design of the runoff plots will allow the calibration of the physically based model Erosion 3D. First erosive natural rainfall events with EI30 intensities ranging from 8 N/h up to 73 N/h. Additionally, artificial precipitation extremes will be simulated if necessary in 2022 and 2023. It is expected that increasing positive effects of the permanent crop will be seen with each additional year. [ABSTRACT FROM AUTHOR]

Spatial assessment of soil properties needs conversion of point data to an area-oriented model. Methods are required that create a reproducible map. The development of a map is shown by the example of cation exchange capacity. Twenty sorption types are formed and derived from the vertical sequence of values for substrate types and are aggregated to six main types. A qualitative assessment of the main CEC sorption types is carried out with comparative ranking. The association of different substrate types on an areal soil pattern requires the identification of sorption association types. These are shown by the areal share of the main sorption types for the substrate types involved in each case. For interpreting the site parameters from the MMK (Mittelmaßstäbige Landwirtschaftliche Standortkartierung), the procedure is presented in detail. An example of the results is shown with CEC maps. Tables complement the visualization for different areas, defined by administrative or natural landscape boundaries. The application of this method for relative evaluation of CEC is demonstrated using KA5-rules. The CEC characterization of agricultural areas can be reproduced on the basis of the mapping units of soil maps with different scales (BÜK 200). The areal-specific labeling of CEC constitutes soil-related decision guideline. [ABSTRACT FROM AUTHOR]

In hummocky landscapes, soil erosion is forming truncated profiles at steep slope positions and colluvial soils in topographic depressions thereby affecting soil organic carbon (SOC) storage and distribution. However, knowledge on (i) the spatial distribution and composition of differently stable organic matter (OM) fractions in arable landscapes and (ii) the dynamics in composition of OM in run-off and eroded particles during single erosion events is still limited. Our objectives are (i) to compare amount and composition of OM fractions from top-soils at eroded, colluvic, and non-eroded slope positions, and (ii) to analyze the dynamics in OM composition of material transferred during erosion. Soil samples were from a Luvisol at plateau, an eroded Luvisol at mid slope (6% slope gradient), a calcaric Regosol at steep slope (13%), and a colluvic Regosol hollow position. From these soil samples pyrophosphate soluble (OM-PY) OM fraction was extracted sequentially. Material transferred during erosion events were sampled at foot-slopes of neighbored (a) no-till and (b) a conventionally tilled experimental fields, and then separated into dissolved (run-off) and particulate fractions (sediment). Soil, OM-PY fractions, run-off and sediment samples were analyzed using transmission Fourier transform infrared (FTIR) spectroscopy. FTIR spectra of OM-PY from top-soils at the steep slope position (caRG) show the highest intensities of C-H (alkyl groups) and C=O (carboxyl groups) absorption bands. The C-H/C=O ratio in OM-PY decreased with increasing contents of oxalate soluble Fe and Al oxides from steep slope (0.25 for caRG-Ap) towards plateau, and hollow position (0.09 for coRG-Ap) reflecting that the downslope-deposited Ap material, which is higher in poorly crystalline Fe and Al oxides, consists of relatively stable OM. The CH/C=O ratios in FTIR spectra of run-off and sediments sampled during erosion events at the foot slope of the no tilled site were found to decrease with time but also reflect differences in rainfall intensity. Temporal changes in CH/C=O ratios of run-off samples are different to the ones of the sediments samples, indicating different dynamics in OM that could be transferred over longer (run-off) or shorter distances (sediments). During erosion OM enriched in C=O may preferably interact with soil components like iron oxides since the C=O groups are known for their interaction with soil minerals. Knowledge on OM-mineral interactions may help to improve our understanding of organic matter processing at the interface between terrestrial and aquatic ecosystems. [ABSTRACT FROM AUTHOR]

The monitoring of extreme weather events is crucial to adapt measures for farmers, support decision making and refining soil policies especially in the context of climate change. A precondition for an effective monitoring is the availability of indices representing the spatiotemporal dynamic of influencing factors like precipitation and soil coverage.Against this background, we introduce a core algorithms of the „Extreme weather Monitoring and Risk Assessment" tool (EMRA), which enables a dynamic geodata integration as well as the spatial and temporal identification of extreme weather events in Germany.On the example of the county Uckermark, which is situated in north-eastern Germany, and the crop type winter wheat, we present a process chain for the derivation of a dynamic precipitation and soil cover index for specific phenological phases and parcels. The algorithm couples Germany-wide phenological information, MODIS satellite imagery as well as daily data sets of precipitation (Gerstmann et al. 2016, Möller et al. 2017). The resulting database allows the localization of historical and current hot spot parcels, which show a potentially high risk of soil erosion during sensitive crops' growing periods. I doing so, more complex soil erosion models can be parameterized in an efficient and focused manner (Volk et al. 2010) or more detailed assessments can be made by using high resolution data. This includes the detection of soil surface's changes by remote sensed imagery or the comparison of terrain surfaces before and after rainfall events using digital elevation data.ReferencesGerstmann, H., Doktor, D., Glässer, C., Möller, M., 2016. PHASE: A geostatistical model for the kriging-based spatial prediction of crop phenology using public phenological and climatological observations. Computers and Elelctronics in Agriculture 127, 726-738.Möller, M., Gerstmann, H., Gao, F., Dahms, T. C., Förster, M., 2017. Coupling of phenological information and simulated vegetation index time series: Limitations and potentials for the assessment and monitoring of soil erosion risk. CATENA 150, 192-205.Volk, M., Möller, M., Wurbs, D., 2010. A pragmatic approach for soil erosion risk assessment within policy hierarchies. Land Use Policy 27 (4), 997-1009. [ABSTRACT FROM AUTHOR]