CANDIDO, L. A.; http://lattes.cnpq.br/7705103746743754; CANDIDO, Luiz Antonio.
Resumen:
The use of irrigation in the Brazilian Northeast region has been
increasing, what requires, as an advise the acknowledge of crops water
requirements. So that, it was conducted a field experiment with a new peanut
cultivar, the BR1, during the 1996 growing season, in Rodelas-Ba. The research
had the objective of identifing the evapotranspiration estimation method most
appropriated to the peanut cropping conditions, as well as to determine the crop
water requirements for its whole growing cycle and to provide allowance to the its
irrigation efficiency. A micrometeorological tower was installed in the center of a
2ha peanut growing area with measurements of the instantaneous environmental
parameters been taken by a data logger system. The crop water consumption was
daily measured by two constant water table evapotranspirometers. The maximum
evapotranspiration daily value it was 11 mm/day in the seed maturity phenological
phase, reaching 632,2mm in the whole growing cycle. The soil available water
affected in about 30% the plants growth of the field, in comparison with the plants
of the evapotranspirometers. The daily change of the environmental parameters
showed a frequent occurrence of hot and dry air advection, always associated to
strong winds. The model for estimating the evapotranspiration showed a tendency
for overestimating ET in the initial crop growing phase and underestimating in the
final phase. According to the statistical analysis, the Penman-Monteith method
presented the best adjustment to the observed data (r^Q.74), getting better with
the use of crop variables more representatives of the daily period. Despite the
good adjustment of the Class "A" pan method (^=0.89), used for estimating the
reference evapotranspitation, the Penman-Monteith-FAO method showed more
consistenty values. Due to environmental conditions the obtained kc values were
higher than those of the literature and showed a subdivision in the flowering
phase. The irrigation of the peanut crop growng in the region of Rodelas-Ba shoud
be applied in the early morning with the water amount been established as a
function of the irrigation system efficiency and based on the crop coefficient
obtained by the Penman-Monteith-FAO method.