Influência do uso de efluente de esgoto doméstico tratado para irrigação nas propriedades físico-hídricas de um solo em região semiárida

Abstract

The use of treated wastewater in irrigation is an alternative solution to the hydric scarcity, which occur in several countries. The semiarid region in Brazilian northeast has long periods of drought and the major income source is family agriculture and livestock. The reuse shows as a solution to cattle food production even in dry periods, avoiding rural exodus. But those wastewater presents high levels of salt and organic matter, able to modify the soil structure and its hydraulic properties. This works aims to evaluate the changes in physic and hydric soil properties occasioned by the application of treated wastewater to the cultivation of forage palm, through 6 years, in sandy soil. The infiltration three-dimensional tests of soil were applied in the field following the Beerkan methodology and collected deformed and undeformed soil samples to the physic characterization of soil and to determine the water repellency in soil due to hydrophobic compost in domestic effluent. The soil irrigated with wastewater showed a 700% increase in sodium levels in soil, and clay dispersion in the surface layer, resulting reduction in soil infiltration rate and water soil retention capacity. Although showing physic properties changes and in water behavior, the sandy soil proved resistant to changes occasioned by treated wastewater irrigation, thus classified as non-repellent to soil water.