<b>Soil properties and cowpea yield after six years of consecutive amendment of composted tannery sludge

• Main Authors: Ademir Sérgio Ferreira de Araújo, Luciano Moura Lima, Wanderley José de Melo, Vilma Maria dos Santos, Fabio Fernando de Araujo
• Format: Article
• Language: English
• Published: Eduem (Editora da Universidade Estadual de Maringá) 2016-06-01
• Series: Acta Scientiarum: Agronomy
• Subjects: waste management; soil fertility; soil quality
• Online Access: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/28281
• ISSN: 1679-9275; 1807-8621

This study evaluated soil properties and cowpea yield after six years of consecutive amendment of composted tannery sludge. The compost was applied annually at 0, 2.5, 5, 10, and 20 Mg ha-1 and at the end of the sixth year, the chemical and physical properties of the soil were evaluated using a randomized block design. The Cr, P, K, Ca, Na and organic C contents and the pH and cation exchange capacity increased linearly after six years of compost amendment. The soil bulk density decreased linearly while the aggregate stability index increased after compost amendment. As a consequence of the changes in the chemical and physical properties of the soil, cowpea yield showed a quadratic response to the tannery rates, with an estimated maximum cowpea yield at 8.3 Mg ha-1. In conclusion, the soil chemical and physical properties improved after six years of composted tannery sludge amendment. However, the soil pH and the Cr and Na contents increased with composted tannery sludge amendment, which influenced the cowpea yield and resulted in a quadratic response to the compost.