%0 Journal Article
%T Impacts of Sewage Sludge in Tropical Soil: A Case Study in Brazil
%A Wagner Bettiol
%A Raquel Ghini
%J Applied and Environmental Soil Science
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/212807
%X A long-term assay was conducted to evaluate the environmental impacts of agriculture use of sewage sludge on a tropical soil. This paper describes and discusses the results obtained by applying a interdisciplinary approach and the valuable insights gained. Experimental site was located in Jaguari¨²na (SP, Brazil). Multiyear comparison was developed with the application of sewage sludge obtained from wastewater treatment plants at Barueri (domestic and industrial sewage) and Franca (domestic sewage), S£żo Paulo State. The treatments were control, mineral fertilization, and sewage sludge applied based on the N concentration that provides the same amount of N as in the mineral fertilization recommended for corn crop, two, four, and eight times the N recommended dosage. The results obtained indicated that the amount of sewage sludge used in agricultural areas must be calculated based on the N crop needs, and annual application must be avoided to prevent overapplications. 1. Introduction Sewage sludge contains organic matter and is rich in macro- and micronutrients, so the agricultural and forestry disposal is widely recommended [1¨C3]. However, sewage sludge also contains contaminants (heavy metals, organic compounds, and human pathogens) which should be considered when it is utilized in agricultural and forestry soils [1, 4]. Researches about sewage sludge disposal in soil are focused on its effects on soil fertility, plant development, and contamination by heavy metals and organic compounds. However, applications of this residue modify biological, chemical, and physical properties of the soils, consequently the dynamics of its microbiota, organic matter decomposition, nutrient cycling, physical structure of the soil, and pest and plant disease severity [4¨C10]. The studies on sewage sludge are conducted mainly under temperate conditions, with few studies in tropical climate. The few studies in tropical conditions are conducted mainly to assess the nutritional effects and problems with heavy metal from sewage sludge application. These studies are rarely performed by determining long-term environmental impacts of agricultural use of sewage sludge. Due to the fact that sewage sludge amount in Brazil is rapidly increasing, since its production was initiated twenty years ago, it is extremely important to gain knowledge and to learn about the long-term effects of sewage sludge applications on soil chemical, biological, and physical properties. Therefore, the objectives of this paper are to present and discuss the long-term effects of continued application of sewage
%U http://www.hindawi.com/journals/aess/2011/212807/