O efeito da aplicação da água residuária nos teores de carbono e nitrogênio em planossolo nátrico no Semiárido Paraibano.

Abstract

The application of wastewater has great potential in agriculture as it is an alternative source of water and provides nutrients. However, research related to its effects on C and N forms in soil is still incipient. In this context, the objective of this research was to evaluate the effect of the application of reuse water on C and N forms in a Planossolo Nátrico. The experiment was carried out in a subdivided plots scheme with repeated measures in time and space, two sampling times (before and after application of wastewater) and two sampling layers (0-15 and 15-30 cm), totalizing four treatments, with four blocks. The wastewater was applied by dripping once a week, at a flow rate of 14 L plant-1. For principal component analysis (PCA), two groups were formed, distinguishing the times of application of waste water and the layers of 0-15 cm 15-30 cm. The following soil chemical attributes were analyzed: total organic carbon (COT), water soluble carbon (CSA), carbon associated with fulvic acid (C-AF), carbon associated with humic acid (C-AH), carbon associated with humina (C-HU), total nitrogen (NT), nitrate (NO3-), ammonium (NH4 +) and alkaline extract (EA) C-AF / COT, C-AH / COT, C-HU / CT and EA / COT. The use of wastewater increased the content of the organic matter in the soil as well as the N-nitric levels in the soil, but the contents of all variables analyzed did not differ in relation to the layers 0-15 cm and 15-30 cm, being an indication of the improvement of the chemical properties of the soil.