Salinity, sodicity and microbiological properties of an Ultisol cultivated with saltbush and irrigated with saline effluents

Abstract

The objective of this work was to evaluate the effects of irrigation with saline effl uents, from red tilapia production ponds, on chemical and microbiological properties of soils cultivated with saltbush (Atriplex
nummularia Lindl). Four areas were used, from which two were irrigated with saline waste and cultivated with A. nummularia, during one and fi ve years. The other two areas were not irrigated, and one was cultivated with natural vegetation and the other with the halophyte. The parameters related to soil salinity and sodicity were evaluated, as well as the following characteristics: microbial biomass carbon (Cmic); Cmic/organic carbon; the activity of acid and alcaline phosphatase enzymes, beta-glucosidase, protease, L-asparaginase and
L-glutaminase. The addition of salts affected the physical and chemical properties of the soils irrigated with saline effl uents, with a tendency to salinization and sodifi cation. The salinity affected the microbiological
properties of irrigated soil, but the cultivation with the halophyte improved the production of the studied enzymes. A. nummularia cultivation in areas that received saline effl uents from irrigation improves soil fertility and microbiological properties, but does not prevent salinity.