PHYSICAL FRACTIONATION AND CARBON AND NITROGEN STOCKS IN SOIL AFTER POULTRY WASTE APPLICATIONS

FRACIONAMENTO FÍSICO E ESTOQUES DE CARBONO E NITROGÊNIO NO SOLO APÓS APLICAÇÕES S DE RESÍDUO AVIÁRIO

ABSTRACT

Residues from turkey production are often used as fertilizers in pastures near producing regions. These residues can contribute to the increase of carbon and nitrogen stocks in the soil. This study aimed to evaluate the cumulative effects of nine applications of turkey litter rates on C and N fractions and stocks in a Latossolo Vermelho distroférrico (Oxisol) cultivated under rotational grazing. The experimental area was divided into 16 pickets of 0.5 ha each and cultivated with Urochloa decumbens in a rotational grazing system. The treatments consisted of accumulated doses of turkey litter (38.3; 54.8 and 69.2 Mg ha⁻¹), with applications carried out between 2008 and 2017, in addition to a control treatment, without application of this material. After nine years of application, total organic carbon (TOC) and total nitrogen (TN) stocks in the soil increased as turkey litter rates increased, reaching increments in the 0-0.2 m layer of 11.2 Mg ha⁻¹ and 1.03 Mg ha⁻¹, respectively, when compared to the control treatment. In the same 0-0.2 m layer, the maximum increments in carbon stock in particulate organic matter (POC) and nitrogen stock in particulate organic matter (N-POM) were obtained with the estimated total doses of 62 and 66 Mg ha⁻¹, respectively. In addition to increasing the amount, the use of turkey litter improved the quality of the carbon present in the soil, since the carbon management index, in the 0-0.2 m layer, was increased by 124% when using the highest accumulated dose.

Keywords:
Turkey litter; Labile fraction; Oxisol