AGROCLIMATIC POTENTIAL OF SUNFLOWER IN PA RAIBA STATE, BRAZIL .2. WATER REQUIREMENTS

Water requeriments of sunflower (Helianthus annuus L.) were compared w ith climatical conditions in order to determine better planting dates in different homogenous micro-regions (HMR) in Paraiba, Brazil. In the agroclimatic analysis of water requeriments for sunflower, the total water requirement TWR (product of monthly evapotranspiration and relat ive water use during the crop growing season) and the expected potenti al water deficit (PWD) were calculated. Regarding water availability, months with minimum PWD were considered as suitable planting dates. It was concluded, for dryland conditions, that the most suitable plantin g time of sunflower on Paraiba State would be through the period from March to April for HMR having long rainy season, and February to March for HMR having short rainy season, There are some HMR's where sunflow er production would be not appropriated.