Predicting the effect of tilling practices on wind erosion activity: application of the Wind Erosion Prediction System in a sand drift area in The Netherlands

The inland drift sand area in The Netherlands forms a unique ecosystem in northern Europe, but is characterized by a rapid decline in both aeolian activity and area size. It is therefore necessary to investigate how the drift sand areas can be preserved, and how their immobilization by vegetation can be counteracted by introducing techniques that reactivate the aeolian processes. Four such techniques (rotary cultivator, beach sand cleaner, disc harrow and excavator) were evaluated during an 8-month experiment at Kootwijkerzand, The Netherlands. The effectiveness of the techniques to reactivate the aeolian processes was measured by investigating their effect on the horizontal sediment flux. Furthermore, the Wind Erosion Prediction System was used to simulate the effect of the different techniques, without the noise related to field measurements. Both field experiment and model simulation showed that the most effective method is the beach sand cleaner, followed by the rotary cultivator. Unlike measurement in the field, the model did not simulate any mass transport on the plot tilled with the excavator. Here incoming sediment could have initiated mass transport. In the case of the plot tilled with the disc harrow the model overestimated the transport. In reality, however, a surface layer with a high random roughness shows large variation in moisture content in space and time resulting in lower mass transport