Instituto de Ciências Agrárias - CAF

URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11784

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Impacts of deforestation on water balance components of a watershed on the Brazilian East Coast
(Revista Brasileira de Ciência do Solo, 2014-05-14) Pereira, Donizete dos Reis; Almeida, André Quintão de; Martinez, Mauro Aparecido; Rosa, David Rafael Quintão
The Brazilian East coast was intensely affected by deforestation, which drastically cut back the original biome. The possible impacts of this process on water resources are still unknown. The purpose of this study was an evaluation of the impacts of deforestation on the main water balance components of the Galo creek watershed, in the State of Espírito Santo, on the East coast of Brazil. Considering the real conditions of the watershed, the SWAT model was calibrated with data from 1997 to 2000 and validated for the period between 2001 and 2003. The calibration and validation processes were evaluated by the Nash-Sutcliffe efficiency coefficient and by the statistical parameters (determination coefficient, slope coefficient and F test) of the regression model adjusted for estimated and measured flow data. After calibration and validation of the model, new simulations were carried out for three different land use scenarios: a scenario in compliance with the law (C1), assuming the preservation of PPAs (permanent preservation areas); an optimistic scenario (C2), which considers the watershed to be almost entirely covered by native vegetation; and a pessimistic scenario (C3), in which the watershed would be almost entirely covered by pasture. The scenarios C1, C2 and C3 represent a soil cover of native forest of 76, 97 and 0 %, respectively. The results were compared with the simulation, considering the real scenario (C0) with 54 % forest cover. The Nash-Sutcliffe coefficients were 0.65 and 0.70 for calibration and validation, respectively, indicating satisfactory results in the flow simulation. A mean reduction of 10 % of the native forest cover would cause a mean annual increase of approximately 11.5 mm in total runoff at the watershed outlet. Reforestation would ensure minimum flows in the dry period and regulate the maximum flow of the main watercourse of the watershed.
Spatialization of soil quality index in the Sub-Basin of Posses, Extrema, Minas Gerais
(Revista Brasileira de Engenharia Agrícola e Ambiental, 2016-01) Lima, Gabriela C.; Silva, Marx L. N.; Freitas, Diego A. F. de; Cândido, Bernardo M.; Curi, Nilton; Oliveira, Marcelo S. de
This study aimed to determine and spatialize the soil quality index (SQI), in relation to chemical and physical attributes, and evaluate its use in the payment for environmental services in the Sub-Basin of Posses, Extrema-MG, Brazil, which represents the Atlantic Forest Biome. SQI values were influenced by both the replacement of native forests by stands of eucalyptus and by pastures and annual crops, reflecting in the reduction of soil quality in the sampled layer in the evaluated systems. The spatialization of SQI showed values ranging from 0.40 to 0.80, with some specific areas with high values and others with values above 1.00 (native forest). The reforestation with eucalyptus conditioned most of the soils with low chemical and physical deterioration, due to accumulation of litter. The lowest SQI values are associated with pastures. SQI adjusted to the exponential model, which allowed the use of ordinary Kriging. The SQI has a great potential of use in the payment to farmers who provide services of soil and water conservation.