Práticas de manejo pecuário na microrregião de São Miguel do Araguaia, Goiás: uma análise a partir de dados de campo e de sensoriamento remoto
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2017-02-03
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Universidade Federal de Goiás
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Pasture degradation is a process in the tropical region and in Brazil, it is estimated that there are
approximately 100 million hectares under poor conservation and management conditions. This work aims to
understand, in an exploratory way, the quality of the Brachiaria Brizantha and Andropogon Gayanus species,
evaluating the seasonal and trend characteristics in relation to the conditioning factors of the degradation in
the microregion of São Miguel do Araguaia. The methodology consisted in the selection of pastures in three
levels of degradation for the species mentioned above; historical management for the last 15 years; and
estimated vegetative vigor analysis using satellite images from the MODIS sensor, i.e. product MOD13Q1 -
NDVI, for the period 2000 to 2015. The time series was analyzed using seasonal metrics and the algorithms
Breaks For Additive Season and Trend (BFAST) for trend analysis and identification of the degradation factors
for the three levels of degradation of both species. The results demonstrated the differentiation between the
three categories of pasture management (optimal, reasonable and poor) for the two grass species using data
collected in the field and orbital. According to the seasonal metrics, statistically, the species presented
differentiated vegetative vigor behaviors (t = 2,083, gl = 375, p <0.001), and the discrimination is higher using
the amplitude and maximum metrics of the NDVI index. The optimal pastures (t = 2.876, gl = 375, p <0.001)
and poor (t = 4,142, gl = 375, p <0.001) differed according to seasonal behavior, while reasonable pastures
did not (t = 0.745; = 375, p> 0.05). The optimal and reasonable pastures of B. Brizantha presented similar
behaviors over the analysis period, whereas the poor pasture presented differentiated behaviors for the
amplitude and average metrics. However, the optimal, reasonable and poor pastures of the A. Gayanus
species, despite having differentiated qualities and management in the field, the NDVI values throughout the
temporal series presented similar behaviors for both qualities. The Trends analysis showed that the high
temperatures of 2007 and 2010 generated negative breaks points for both species, while the years of 2009
and 2013 were points of positive breaks due to the increase in rainfall records. As a conclusion, moderate
resolution orbital data, particularly NDVI, allow the differentiation of pasture species and their respective
qualities through the analysis of time series and, on the other hand, trend analysis showed that both species
of grass showed high Sensitivity to the climatic factors, as El Niño and La Niña, in relation to the management
used.
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AGUADO, Oscar Ivan de Oro. Práticas de manejo pecuário na microrregião de São Miguel do Araguaia, Goiás: uma análise a partir de dados de campo e de sensoriamento remoto. 2017. 112 f. Dissertação (mestrado em Ciências Ambientais) - Universidade Federal de Goiás, Goiânia, 2017.