SUSCETIBILIDADE DAS TERRAS SECAS DO ESTADO DO PIAUÍ: avaliação a partir de índices (susceptibility of the dry lands of piauí state to desertification: evaluation from indices)
Abstract
Desertificação é a degradação da terra nas zonas áridas, semi-áridas e sub-úmidas secas, que aqui denominamos terras secas, resultado das variações climáticas e das atividades humanas. As conseqüências de ordem ambiental, econômica, política, social e cultural da desertificação justificam a necessidade de identificar as terras secas do Estado do Piauí e sua suscetibilidade à desertificação. A suscetibilidade à desertificação das terras secas do Estado do Piauí foi avaliada a partir dos fatores erosividade, erodibilidade, declividade e cobertura vegetal que, combinados, conduziram à geração do índice de erosão natural do solo. A combinação, através do SIG IDRISI, do índice de erosão natural do solo com o índice climático permitiu a avaliação da suscetibilidade natural, bem como a simulação de uma suscetibilidade antrópica. Os resultados mostram que 45,3% do território piauiense enquadra-se em áreas suscetíveis a processos de desertificação, em diferentes níveis e que 94,6%, 5,2% e 0,2% da área de estudo apresentam, respectivamente, baixa, média e alta suscetibilidade natural à desertificação e 73,1%, 26,5% e 0,4% da área de estudo apresentam, respectivamente, baixa, média e alta suscetibilidade antrópica à desertificação.
Palavras-chave: Desertificação, equação universal de perdas de solo, Piauí.
ABSTRACT
Desertification is the degradation of the land in arid, semi-arid and sub-humid dry zones, that we call here dry lands, as a result of the variation of climatic and of the human activities. The consequences of environmental, economic, political, social and cultural orders of the desertification process justify the need of identification of the dry lands in the state of Piauí and it’s susceptibility to desertification. The susceptibility to desertification of the dry lands of the state of Piauí was evaluated from the erodibility, erosivity, slope and plant cover factors which were combined to generate a natural soil erosion index. The combination, through the use of GIS IDRISI, of the natural soil erosion index with the climatic index, allowed the evaluation of natural susceptibility as well as the simulation of antropic susceptibility. The results show that that 45.3% of the piauiense territory are areas susceptible to desertification processes, in different levels, that 94.6%, 5.2% and 0.2% of the studied area, present respectively, low, medium and high natural susceptibility to desertification and that 73.1%, 26.5% and 0.4% of the area of the study, present respectively, low, medium and high antropic susceptibility to desertification.
Key words: Desertification, universal soil loss equation, State of Piaui.
Authors who publish in this journal agree to the following terms:
- Authors retain the copyright and grant MERCATOR the right of first publication, with the work simultaneously licensed under the Creative Commons Attribution License, which allows the sharing of the work with recognition of the authorship of the work and initial publication in this journal.
- Authors are authorized to sign additional contracts separately, for non-exclusive distribution of the version of the work published in this journal (e.g., publish in an institutional repository or as a book chapter), with acknowledgment of authorship and initial publication in this journal.
- Authors are allowed and encouraged to publish and distribute their work online (e.g., in institutional repositories or on their personal page) at any point before or during the editorial process, as this can generate productive changes as well as increase the impact and citation of the published work (see The Effect of Free Access).
- Authors are responsible for the content of the manuscript published in the journal.
