Influence of Sewage Sludge Application on Physical and Biological Properties of Soils

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. C...