Water balance and ecophysiology of Eucalyptus saligna, Eucalyptus dunnii, and Eucalyptus benthamii in the Pampa biome
Visualizar/ Abrir
Data
2022-06-13Primeiro coorientador
Tabaldi, Luciane Almeri
Primeiro membro da banca
Baumhardt, Edner
Segundo membro da banca
Garcia, Lara Gabrielle
Terceiro membro da banca
Deus Junior, José Carlos de
Quarto membro da banca
Hakamada, Rodrigo Eiji
Metadata
Mostrar registro completoResumo
Cultivated areas with eucalyptus crops have increased in Southern Brazil, mainly in regions of
native grasslands in the Pampa biome. The effects of this alteration on hydrological processes
are little known, especially those related to water consumption by plants, transpiration and
evapotranspiration at the plant scale, and the propagation of their impacts to the watershed scale.
Monitoring sap flow is an alternative for quantifying transpiration and increasing the accuracy
of evapotranspiration estimates based on climatic variables. This study aims to describe how
eucalyptus stands influence hydrological processes in the Pampa biome, which is of great
interest for environmental conservation and the economy of the state of Rio Grande do Sul.
Emphasis is put on the physiological dynamics associated with the movement of water in the
soil-plant-atmosphere system, and the transfer of this information to different scales of analysis.
The study was conducted in a forest watershed cultivated with Eucalyptus benthamii in the
Pampa Biome (0.80 km2
), where three plots were allocated containing Eucalyptus saligna,
Eucalyptus dunnii, and Eucalyptus benthamii. Rainfall was monitored using pluviographs
distributed in the watershed area, and streamflow was measured using linigraphs in a
monitoring section installed at the watershed outlet. Sap flow monitoring was performed on
eight eucalyptus plants distributed in each plot, using a thermal dissipation xylem flow
measurement system at 30-minute intervals. Interception and runoff were monitored for each
rainfall event in plots distributed in the stand. Soil water moisture was monitored using
frequency domain reflectometry sensors installed in a depth of 2.0 m. Climatic variables were
obtained from the Brazilian National Institute of Meteorology. The data obtained were used to
quantify water balance in different scenarios, using the transpiration measured for each species.
The transpiration rates were variable among species (Eucalyptus saligna > Eucalyptus
benthamii > Eucalyptus dunnii). Eucalyptus saligna accounted for the highest productivity
rates, but accounting the highest transpiration resulted into the smallest water use efficiency
compared with the other species. The ecophysiological dynamics of the studied species were
strongly related to climatic variables such as radiation and vapor pressure deficit. Moreover,
the variation in transpiration rates resulted in different crop coefficients, being 0.52, 0.79, and
1.14 annually, for the 7-year-old plantation of Eucalyptus dunnii, Eucalyptus benthamii, and
Eucalyptus saligna, respectively. These species influenced the evaluated hydrological
processes with variable intensities. Through water balance evaluation, the highest water deficit
occurred for the simulation with Eucalyptus saligna, which presented the highest transpiration
rate and Kc. Understanding of water use efficiency variation between species is a crucial factor
in reducing water demand by commercial forests at the watershed scale, where species with
higher productivity should be avoided for areas with critical water availability.
Coleções
Os arquivos de licença a seguir estão associados a este item: