Estudo agrometeorológico baseado em alguns modelos de umidade do solo.

Abstract

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.