Downward Movement of Soil Cations in Highly Weathered Soils Caused by Addition of Gypsum Paulo R. Ernani Department of Soil, Universidade do Estado de Santa Catarina (UDESC), CEP, Lages, SC, Brazil and National Council of Scientific and Technological Development (CNPq) David J. Miquelluti Department of Soil, Universidade do Estado de Santa Catarina (UDESC), CEP, Lages, SC, Brazil Sandra M. V. Fontoura Researcher of FAPA Joa ˜o Kaminski Department of Soil, Universidade Federal de Santa Maria, Santa Maria, RS Jaime A. Almeida Department of Soil, Universidade do Estado de Santa Catarina (UDESC), CEP, Lages, SC, Brazil Abstract: Besides supplying calcium (Ca) and sulfur (S) to plants, gypsum has recently been used in agriculture to ameliorate some soil physical and chemical properties, especially to alleviate aluminum phytotoxicity in subsoils. When applied in large quan- tities, however, gypsum may leach significant amounts of nutrients from the plow layer. This study was conducted to assess the effect of gypsum addition to the soil on the magnitude of cation leaching as well as the relationship of leaching with Received 7 December 2004, Accepted 30 August 2005 Address correspondence to Paulo R. Ernani, Department of Soil Science, Santa Catarina State University (UDESC), Caixa Postal 281, CEP 88520-000, Lages, SC, Brazil. E-mail: prernani@cav.udesc.br Communications in Soil Science and Plant Analysis, 37: 571–586, 2006 Copyright # Taylor & Francis Group, LLC ISSN 0010-3624 print/1532-2416 online DOI: 10.1080/00103620500449443 571