Effects of Co-Digestion Sludge Application on Soil Productivity

Abstract

Anaerobic digestion and agricultural use of sewage sludge are effective methods to treat and dispose of sewage sludge, respectively. Then, the anaerobic digested sewage sludge is applied in agricultural land and the improvement of soil properties can be expected. In this study, with the purpose of evaluating the potential of co-digestion sludge for agricultural use, plot experiments with two vegetable species (radish and Chinese cabbage) and three application dosages were carried out in a short term of six months. Focus was on soil physical properties, soil nutrient change and plant growth responses during the whole process. Results showed that application of co-digestion sludge had little effect on soil physical properties, including the bulk density, porosity, capillary porosity and non-capillary porosity. However, after the application of co-digestion sludge, the maximum increase in content of organic matter, total nitrogen, hydrolysable nitrogen, total phosphorus and available phosphorus in soil reached 51%, 125%, 212%, 15% and 87%, respectively, which supplied the available nutrients quickly and continuously. The application of co-digestion sludge promoted the growth of radish and Chinese cabbage, which was observed through increase of the leaf, root biomass and plants height. Consequently, co-digestion sludge has a good application prospect for improving soil productivity as fertilizer.