Short-term effects of a secondary paper mill sludge application on soil properties in a Psammentic Haplumbrept under cultivation

Paper mill sludges (paper pulps) are proposed for use in agriculture to improve soil fertility. The organic matter composition of paper pulp, slurry and treated soils was investigated by means of wet chemistry and cross polarization magic angle spinning (CPMAS) carbon-13 nuclear magnetic resonance (NMR) spectroscopy. The pulp consists of about 70% O-alkyl carbon, whereas dry matter of the slurry only contains 40% O-alkyl carbon, but 37% alkyl carbon. All soil organic matter (SOM) data indicate no significant modification of the SOM quality due to the unique application of pulp and slurry, despite the fact that organic matter of both materials differs considerably from SOM. In addition, an increase of total organic carbon (TOC) due to the paper mill pulp application disappears within 1 year. From the ecological point of view, the data suggests that the application of paper mill pulp combined with cattle slurry within the crop rotation will not affect the soil ecosystem in a negative way. The effect of an annual application has to be proved by further studies. (C) 1997 Elsevier Science B.V.