1. Department of Soil, Federal University of Santa Maria, Santa Maria, Brazil
2. Department of Plant Physiology, Santa Maria, Brazil
3. Department of Environmental Engineering, Santa Maria, Brazil
4. Instituto Phytus, Itaara, Brazil
5. Department of Soil and Plant Nutrition, Piracicaba, Brazil
6. Department of Forest Sciences, Curitiba, Brazil
7. Department of Agricultural Engineering, Federal University of Santa Maria, Cachoeira do Sul, Brazil