Proceedings of the EEC Seminar Organized jointly by the CEC and the Institute for Soil Fertility, Haren (Gr) and held in Groningen, The Netherlands, June 12-13, 1980

The agricultural value of sewage sludges is well known and a lot of published data has demonstrated the positive effects of sludge appli- cations on plant growth and yield. These effects are probably due mainly to the nitrogen and phosphorus content of sewage sludges. But, as sludges are more organic than mineral, we can expect an effect of the organic matter added to the soil on soil fertility. Certainly, in the future, landspreading of sludges will be regulated, taking into account pollution hazards for waters (excess of nitrogen and phosphorus supply compared to plant needs and soil...