Effects of the successive application of stabilized secondary sludge from the cellulose wastewater treatment plant to degraded Chilean volcanic soils

摘要

The aim of this work was to evaluate the effects of the successive application of stabilized secondary sludge from cellulose on the physico-chemical properties of soils of southern Chile. The soils used in this study were two Andisol belonging to Gorbea and Freire series and an Ultisol (Collipulli series) characterized by different contents of organic matter and pH. The sludge used as amendment was stabilized pulp mill sludge (pH 7.0; OM 75%; N 586 mg/kg; P 313 mg/kg) obtained from an aerated pond that treated bleached kraft mill wastewater collected from a landfill after one year disposal. The sludge application in the soils was realized at rates of 0, 10, 20 and 30 t/ha divided in four applications during one year. The effect of the addition of sludge on the soil was evaluated through macro and micro nutrients soil levels. The application of different doses of pulp mill sludge in the soil improved the physico-chemical properties of soils, especially after the third application. In general, pulp mill sludge application increased the contents of O.M, N, P, macro and microelement content. Specifically, the Ultisol soil belong Collipulli series showed the largest increase in O.M content (27%). This would indicate that soils with lower organic matter content are more likely to be rewarded by the application of a highly organic amendment such as pulp mill sludge.