DANTAS, P. R. C.; DANTAS, Paulo Roberto Colaço.
Resumen:
Results of agrometeorological studies based on four soil moisture models are
presentend in this thesis. The study is confined to selected locations in Paraiba state. The
daily water balance model of Thornthwaite was used to evaluate crop growing periods and
irrigation needs at the stations. The versatile soil moisture budget was used to determine
the optimum growing periods and irrigation requirements of corn crop at six stations in the
state. The MUCMUL model was used to study the water loss from a field of soybean.
Finally the model of Serafini was used to evaluate the incidence of agricultural droughts in
different parts of the state.
Crop growing periods at given locality will be longer for deep-rooted crops than for
crops with shallow root depth. Growing periods based on climatological mean monthly
values of precipitation and potential evapotranspiration will lead to erroneous conclusions
in this region. Even during the optimum growing for corn crop at the six stations studied
significant amounts of supplementary irrigation is necessary. The use of different Z tables
in the versatile soil moisture budget model produces significant changes in the estimated
available moisture content. Increase in row spacing in Soybean crop results in a sharp
decrease in transpiration loss from the field. It is shown that daily monitoring of crop water
stress can be of much value in irrigation scheduling.
