Evaluation of Dynamic Biotic and Abiotic Processes at the Soil Surface Affected by Different Agricultural Management Systems.
Marcus Zeiger and Nicola Fohrer. Dep. Hydrology & Water Resources Management, Ecology Centre CAU Kiel, Olshausenstr. 40, Kiel, D-24098, Germany
The development of soil surface seals due to the impact of raindrops has considerable negative effects for agriculture (e.g. erosion) and the environment (e.g. increased flood risk due to higher surface runoff). The mechanism of the breakdown of aggregates and development of surface crusts is well studied. However, little attention has been given to the dynamic processes at the soil surface in the field. In this presentation we give an insight to the field experimental approach to identify dynamics of biotic and abiotic processes at the soil surface during crust formation and degradation. Three sites in Schleswig-Holstein (northern Germany) were selected for the investigation. The sites are characterised by different intensity of agricultural land use, i.e. conventional farming and organic farming. Soil surface conditions are monitored by digital image analysis. The activity of the soil enzymes acid phosphatase and beta-glucosidase as well as biomass carbon (Cmic) are investigated as indicators of the biological state of the top 3 cm of the soil. Information on weather conditions and soil water content contributes to the knowledge about the system and helps for interpreting the results. We present an overview on the experimental setup and show results of the dynamic biotic and abiotic processes at the soil surface. A clear impact of the agricultural management system on the activity of both enzymes as well as a significant impact on infiltration could be observed. The biologically most active sites showed also the lowest decrease of infiltration rate due to surface sealing processes.