Ariovaldo Antonio Tadeu Lucas

Causas e consequências do processo de salinização dos solos

The process of soil salinization is typical of arid and semi-arid regions, often resulting from the combination of geological formation predominant in the landscape, poor distribution of rainfall, poor drainage and inadequate farm. The exploitation of natural resources with the use of inadequate techniques has favored the increase of the degree of degradation, because they affect agricultural production and the environment, causing a number of problems of social and political order. One area can remain saline during years with low or moderate salinity, unless the problem is detected. A further increase in the salt content can cause cessation of agricultural land in a few years since higher amounts of salts in the soil cause changes in the physical characteristics of the soils and slows or prevents the growth of plants, mainly due to increased osmotic potential and indirect toxicity of certain elements. Strategies such as the use of extracting plants, the use of gypsum and lime as the use of techniques to improve drainage of the soil, are adopted for reclamation by excess salts, and that when applied together can minimize the deleterious effects of excess salts in soil.

Calibration of hydrodynamic model MIKE 11 for the sub-basin of the Piauitinga river, Sergipe, Brazil

In Piauitinga river sub-basin the environment has been suffering from negative actions by humans such as deforestation around springs, inadequate use of the uptaken water, inappropriate use in domestic activities, siltation and sand exploitation, and contamination by domestic, industrial and agricultural residuals. The present study presents the onedimensional hydrodynamic MIKE 11 model calibration that simulates the water flow in estuary, rivers, irrigation systems, channels and other water bodies. The aim of this work was to fit the MIKE 11 model to available discharge data for this sub-basin. Data from the period of 1994 to 1995 were used for calibration and data from 1996 to 2006 for validation, except the 1997 year, from which data were not available. Manning’s roughness coefficient was the main parameter used for the Piauitinga river sub-basin discharge calibration and other parameters were heat balance, water stratification and groundwater leakage. Results showed LUCAS, A. A. T.; NETTO, A. O. A.; FOLEGATTI, M. V.; FERREIRA, R. A. Calibração do modelo hidrodinâmico MIKE 11 para a sub-bacia hidrográfica do rio Piauitinga, Sergipe, Brasil. Ambi-Agua, Taubaté, v. 5, n. 3, p. 195-207, 2010. (doi:10.4136/ambi-agua.162) 196 that the model had an excellent performance for the Piauitinga basin and had an efficiency coefficient of 0.9 for both periods. This demonstrates that this model can be used to estimate the water quantity in Piauitinga river sub-basin.