Sulphate adsorption and pedological attributes to determination of gypsum rates for amelioration of subsoil acidity

• Grant number: 08/01389-0
• Support Opportunities: Regular Research Grants
• Start date: October 01, 2008
• End date: January 31, 2011
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Marcio Koiti Chiba
• Grantee: Marcio Koiti Chiba
• Host Institution: Instituto Agronômico (IAC). Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Campinas , SP, Brazil

Abstract

With about 70% of whole territorial area occupied by acid soils, Brazilian crop yield was reduced in 40% due to hazardous effects of soil acidity on plants development. In this scenario aluminum and manganese occurs in phytotoxic amounts reducing plant efficiency in obtain water and nutrients. To correct this situation liming, although efficient, has its beneficial effects restrict to superficial soil layer. In the other hand, application of gypsum control Al hazardous effects in soil profile and increase calcium and sulphate availability. The gypsum reaction efficiency is related with chemical, physical and mineralogical soil attributes and, in this way, differs from a soil to another. For this reason and based on the improving no-till soil management adoption is important to find technological solutions that comprises local recommendations for soil fertility amelioration, including the subsoil, in a economic and environmental manner. This work aim to study the soil attributes in sulphate sorption mechanisms in order to establish gypsum application rates in different environments. It will be studied soils with different restriction levels for root development commonly named "chemical barrier". The maximum sulphate adsorption will be studied using Langmuir isotherms fitted to each soil and the more important soil attributes will be studied by multivariate statistical approach and principal components analyses. (AU)