Sandy soils and brown forest soils in the Nyírség Region with their shallow fertile soil layer have unfavourable water management properties. The results of new experiments show that sewage sludge compost application can improve this colloids poor acidic soils. The aim of the measurements was to determine the effect of compost treatment on soil structure, thereby on the process of water infiltration into the soil. To measure the hydraulic conductivity of the soil and to characterize its the erodibility, a soil rainfall simulator was used.

The experiment was established in 2003 at the Research Institute of Nyíregyháza, University of Debrecen on brown forest soil. The applied compost was prepared from sewage sludge (40%), straw (25%), bentonite (5%) and rhyolite (30%). The applied compost doses are: 0, 9, 18 and 27 t ha-1 of dry matter.

The direct effects of sewage sludge compost application were the improved soil structure and water management. Our results show that the organic and mineral materials of compost had a positive effect on soil structure. The soil structure resisted the destructive effects of the simulated, high intensity (185 mm h-1) rainfall and the rate of water infiltration into the soil increased. The effects of higher compost doses (18–27 t ha-1) the water infiltration did not decrease with time, the infiltration rate remained high and virtually unchanged during the measurement. However, in the control plot there was significantly higher water erosion.

The beneficial effect of compost application on soil structure can be more expressed in the future in case of high-intensity precipitation events, which could cause major erosion damage on sand hills.

Keywords: brown forest soil, sewage sludge compost, infiltration, erosion