Caracterização de águas de reservatórios superficiais para uso em microirrigação

Abstract

Water is the most important and restrictive factor for the agricultural cultures so, the knowledge of its qualitative composition is important to the verticalization of productivity. For the microirrigation systems (located irrigation), its requirement in physical and chemical quality is bigger, because of the reduced diameter of its components, particularly the transmitters. The objective of this work was to characterize the superficial waters of UFSM campus in order to use them in microirrigation, trying to identify the levels of chemical and physical parameters that influence the irrigation system, ground and plant. Four principal dams of the UFSM were characterized (Área Nova,, Solos ,Madame ,and Várzea). Three samples were collected in each dam ,casually, one meter of depth, in two dates in January 2007, one before and other after precipitation completing 24 samples. The following parameters were analyzed: suspended solids ,dissolved solids, pH, electrical conductivity, calcium, magnesium, sodium ,phosphorus, nitrogen, boron, total iron and it was calculated the value of absorption of sodium. Determinations of laboratory and in situ were done. The study showed that relating to parameters, except total iron, the Nova Àrea dam revealed the greatest values, followed by the Solos dam, Madame and Várzea. Values significantly superior were observed due to the particular characteristic of the source contribution area. It was also verified that differences occurred in the levels of some parameters relating to the two dates of the collection, explained by the administration given to she spill basin of contribution area, because the grounds of dams are similar and are from the same map unit São Pedro. Relating to the use of these waters in microirrigation, it was verified that Nova Área and Solos dams have restrictions to that total iron level, suspended solids and pH. The calculated RAS, when compared with the electrical conductivity, was classified as a severe risk to the infiltration rate in all dams. It was concluded that differences in the studied parameters varied according to the given conduct to the spill and that Madame and Várzea dams would be used in microirrigation since their levels of calcium and magnesium in the ground are elevated