Desenvolvimento do capim-sudão, por meio de análise numérica, semeado em diferentes épocas

Abstract

The objectives of this study were to estimate the duration of the subperiods, total cycle and number of cuts of BRS Estribo Sudan grass and to determine the Fdp (probability distribution functions) that best characterize the data distribution for the conditions of Pelotas-RS, Brazil, through simulated development in different. Sowing dates, and its relationship with the ENSO (El Niño South Oscillation). The study was conducted based on results published in the literature and meteorological data from 1971 to 2020, obtained at the Agroclimatological Station of Pelotas. The development simulation was carried out for six sowing dates, from September to February, using the thermal time method using the data of average daily air temperature and base temperature. Adjustment of the data to Fdp exponential, gamma, lognormal, normal and Weibull was performed. After the simulation of crop development, agricultural years were classified according to the occurrence of the ENOS phenomenon. The duration of the total cycle can vary from 234 days to 81 days, resulting in approximately 7 and 2 cuts, respectively, for the sowing dates corresponding to the beginning (September) and end (February) of the sowing season studied. It can be concluded that the duration of the cycle and the subperiods are longer on September dates and decreases until February sowing dates. The lognormal distribution better estimated the duration of the developmental periods of Sudan grass. ENSO does not cause a statistically difference in the duration of the sub-periods (except for the emergence to the first cut subperiod), number of cuts and the cycle length of the BRS Estribo Sudan grass.