Methodological procedures, analysis of the aridity, desertification and semi-arid index for the municipality of Santa Filomena, Piauí, Brazil
Authors: Raimundo Mainar de Medeiros  , Luciano Marcelo Fallé Saboya  , Manoel Viera de França  , Romildo Morant de Holanda  , Victor Casimiro Piscoya  , Alex de Sousa Moraes  , Wagner Rodolfo de Araújo  , Moacyr Cunha Filho  
Published: October 2022

The municipality Santa Filomena that it was for is included in the Nucleus of Desertification of Gilbués, since all the other municipalities that are part of the same nucleus are. Data from the IBGE Demographic Census (2010) and the GDP of the municipalities published by IBGE (2009) were used. Social indicators of exclusion of education and income are sought. In addition to being reduced, GDP is far from ideal for a good quality of life. All the social indicators of the semiarid region are very bad. The evidence of the study allows us to conclude that, in fact, in this region, in relative terms, numbers are concentrated that allow the inclusion of these municipalities in the semi-arid area. In addition, the justifications for additional criteria because these municipalities belong to the Nucleus of Desertification of Gilbués, being the only one not yet contemplated with its inclusion in front of all the others already included, including those that belong to the other three nuclei existing in Brazil. The study of the aridity index and its tendency to desertification for the municipalities of Santa Filomena, Barreiras do Piauí, Gilbués and Monte Alegre do Piauí, Brazil was requested by a group of farmers, mayors and lawyers who intend to see the possibility of including these municipalities as a degraded area and its inclusions in the Brazilian semiarid region. The methodology used the calculations of aridity indexes by the water balance method developed by Thornthwaite and Mather (1948; 1955) with a field capacity (CAD) of 100 mm. The water balance graphs were used to demonstrate the variability of water surpluses and deficiencies, replacement and removal of water in the soil and visualization of interannual buoyancy. Electronic spreadsheets of evapotranspiration, evaporation, deficiency and annual water surplus were generated in order to understand their interannual fluctuations as an aid in erosive contributions and aridity indexes. The monthly rainfall for the period 1960-2017 was acquired from the climate bank of Superintendence for the development of the Northeast and from the Empresa de extensión Rural do Piauí where annual fluctuations, anomalies, moving averages, standard deviation, coefficient of variance, absolute maximums and minimums, in addition to studying the fluctuation of average temperatures and calculations of precipitation erosivity indices for the referred municipalities aiming at the objective of municipalities to be included in the semi-arid region and susceptible to desertification. The physiographic aspects, relief, fauna, flora and distance from the sea are evidenced and the edaphic contributions contribute to the incidence of aridity index and susceptibility to desertification in the studied area. The development of monoculture and improper planting techniques contributed to the increase in erosion rates and the tendency for changes in the semi-arid climate with very high risk of susceptibility. Areas identified as vulnerable to desertification, due to the lower aridity index, may not be located in the degraded area, and areas that present a higher aridity index and are not identified as vulnerability processes may be degraded to the point of being considered desertified areas. This variability may occur due to inappropriate use of the soil and environment. Temperature influences evapotranspiration, that is, the loss of water to the atmosphere, because the higher the temperature, the greater the evapotranspiration and, consequently, the lower the aridity index and, therefore, the greater the susceptibility to desertification. Possibly anthropic factors, the lack of afforestation in the beds of ponds, lakes, rivers, streams, streams, dams and water tables, the vertical construction and compaction of urban and rural soil plus transient meteorological systems and local factors may have contributed to periods ( months, years) with greater variability, however it is known that depending on the season, summer or winter, evapotranspiration and evaporation can really vary, as they are directly related to the seasons with higher and lower precipitation, variability in air temperature, air humidity between other variables such as solar radiation, cloud cover, wind speed and vapor saturation pressure, which can reduce the evaporative process.