Doroteu Honório Guedes Filho - Department of Agricultural Engineering, Federal University of Campina Grande,Av. Aprigio Veloso, ۸۸۲, Campina Grande, Paraiba, Brazil
Lucia Helena Garófalo Chaves - Department of Agricultural Engineering, Federal University of Campina Grande,Av. Aprigio Veloso, ۸۸۲, Campina Grande, Paraiba, Brazil Corresponding Author
Vinícius Batista Campos - Federal Institute of Amapa, Av. Tancredo Neves, ۲.۹۶۵,Campus Laranjal Do Jari, Macapá, Amapá, Brazil
José Amilton Santos Júnior - Department of Agricultural Engineering, Federal University of Campina Grande,Av. Aprigio Veloso, ۸۸۲, Campina Grande, Paraiba, Brazil

In order to study the effects of nitrogen and available soil water levels on growth and yield components of sunflower (cv. Embrapa 122 / V-2000), an experiment was carried out from November 2009 toOctober 2010 in the Agricultural Engineering Department of the Federal University of Campina Grande, CampinaGrande, Paraiba, Brazil. The treatments were arranged as a completely randomized design, in a 4×4 factorial experiment (four nitrogen levels and four available soil water levels), with three replications, totaling 48experimental units. The nitrogen (N) levels in kg haG1 were: 0; 60; 80 and 100 added as urea; the available soil water (AW) levels were 55; 70; 85 and 100%. In conclusion, this study showed that the application of nitrogen fertilizer levels and available soil water levels led to significant increase in growth and production traits except for the dry weight of 1000 seeds.

Irrigation % Nitrogen fertilizer % Helliantus annuus L