Maize sowing dates in the hinterland region of Northeast Brazil

Abstract

Maize in Alagoas State, Northeast of Brazil, is mostly cultivated under rainfed conditions, however there are few studies evaluating the best sowing dates. The aim of this work was to assess sowing dates for the maize crop in the municipality of Arapiraca, located in a typical hinterland (Agreste) region of Alagoas State, based on the Water Requirement Satisfaction Index (WRSI). The WRSI was computed by means of a simple soil water balance model and the reference evapotranspiration was determined by the standard Penman-Monteith-FAO56 method. Daily values of air temperature, relative humidity, wind speed, sunshine duration and precipitation were measured in a conventional weather station, in the period from 1973 to 2008. The sowing dates for maize in Arapiraca with the lowest risks of water deficit lies between June 3 and June 23. Sowing maize in the beginning of April appears to be a very strategic alternative since it offers very low water deficit risk at the flowering crop stage. However, this might require water supplement at first stages of the crop due to the high-water deficit risks.