Preserving and/or improving the organic matter content of soils are essential for soil fertility. Therefore, organic matter input into the soil is necessary and sewage sludge compost application seems to be a possible method. We studied the effect of sewage sludge compost on acidic sandy soil in the Nyírség region, Hungary.

After 10 years of regular sewage sludge compost application we found an increase in parameters connected with organic matter content in the treatments of 9, 18 and 27 t ha-1 sewage sludge compost. The loss-on-ignition, the total carbon and nitrogen content, the humus and organic carbon content were higher in the treated plots compared to the control but significant treatment effect was found only in the highest dose treatment. In line with the organic matter input the intensity of decomposition processes increased, too. It was indicated by the elevated level of CO2 emission of soil.

Regular application of good quality sewage sludge compost resulted in favourable changes of soil chemical parameter connected with organic matter content. Quantitative and qualitative improving of organic matter content of soils are the basic requirement for safety plant production.

Keywords: sewage sludge compost, organic matter content, long-term experiment