Agricultural Impacts on Soil Hydraulic Properties

Agricultural operations affect the soil¿s capability for water infiltration and storage. In this doctoral thesis, agricultural impacts in terms of soil compaction and different tillage techniques on the soil hydraulic properties and the water-conducting pores were analyzed. In the first part, infiltration measurements in differently compacted subsoil treatments of an arable field in Lincoln/New Zealand were used to characterize the effects on the soil¿s porosity and its associated water-conducting properties. In the second part, the impact of different tillage techniques ¿ conventional (CT), reduced (RT), and no-tillage (NT) ¿ on the hydraulic properties of an arable field in Raasdorf/Austria and its temporal dynamics were captured by repeated measurements. In the third part, data from the tillage study was used to parameterize a soil water simulation with constant and time-variable hydraulic parameters. The results of this thesis give evidence that soil hydraulic properties are strongly altered by soil compaction and different tillage operations. The thesis also shows the importance of temporal variations of soil hydraulic properties and its incorporation in hydrological models.