Cellulosic industrial waste to enhance Pinus taeda nutrition and growth: a study in subtropical Brazil

The objectives of this work were to evaluate the influence of a compost (cellulosic sludge - 70%, boiler ash - 30%) on the development of Pinus taeda trees on low-growth sites in subtropical Brazil that displayed symptoms of deficiency in previous cycles, and to evaluate how the compost influences soil chemical characteristics. Six months after seedling transplant, five rates (control, 14, 25, 49 and 60 Mg ha(-1)) of compost were manually broadcast. For the following three years, soil and needle samples were collected for nutrient analysis along with plant growth measurements. Soil analysis indicated small increase in K availability and decrease in exchangeable Al. Large growth enhancements were observed in terms of plant height and diameter at breast height, and needle chlorosis disappeared when compost was applied. After three years of compost application, trunk volume increased from 13 m(3) ha(-1) in the control to 37 m(3) ha(-1) in the 49 Mg ha(-1) treatment. P. taeda growth was inversely related to Mn and directly related to K and B foliar concentration. Findings suggest that compost application should be encouraged since it enhances initial growth of P. taeda, being an important way to recycle residue from the paper industry and contribute to more sustainable management of low fertility soils.