With the aim of analyzing the effects caused by temporal variability of rains over sunflower (Helianthus annuus L.) tillage income and development in function of nitrogen fertilization and cultivars, experiments with sunflower tillage were performed in Alagoinha-PB in the years of 1995,1996,1998 in the municipal district of Esperança-PB in 1998. In this occasion four levels of nitrogen were verified (0, 30, 60 and 90kg.ha-1), two cultivars (one precocious and another late) in blocks at random with four repetitions. Beyond these experiments, some data about pluvial precipitation were analyzed. During the performance of the experiments we analyzed the tillage phenological stages, biomass accumulation and income and its components. In relation to the results, was verified in Alagoinha-PB an annual average rains of this period (1981 - 1999) around 1.018,6mm. The sunflower vegetative and reproductive stages have changed according to the distribution of rains during the tillage cycle. The adopted treatment answers for tillage over the analyzed variations were depending on the distribution of rains during the tillage development stages. There was also a big variation in the tillage answers in relation to the nitrogen levels and in the cultivars in function of weather.
production; fertilization; crop management
