Funções de distribuição de probabilidade para a deficiência hídrica mensal.

Abstract

Detailed determination of the probabilities of occurrence of certain levels of water deficiency (DH) is fundamental for the agricultural planning and the environmental administration in the public and private administration, what was not still determined for the central area of Rio Grande do Sul based on daily water balance of soil. The objective of this work was to determine the probability distribution functions (fdp) that best characterizes the distribution of the frequency of the values of water deficiency in the soil. DHs was determined by soil water balance for different capacities of available water of the soils of the region. To the values of total DH and maxima of each period were adjusted distribution functions. It was verified that the monthly values of DH of the soil are adjusted to the log-normal functions, gamma and exponential, being the best adjustment the fdp log-normal in the most cases and the function gamma in the months of smaller DH.