Lâminas de irrigação e doses de nitrogênio no cultivo de girassol.

Abstract

The experiment has the objective to study different aspects of the irrigation and nitrogen fertilization management of the sunflower under field conditions aiming to optimize its growth, development and production. The experiment was conducted at the Environmental and Agrarian Sciences Center, Campus II, Universidade Estadual da Paraiba, Lagoa Seca , PB, located in the Lagoa Seca County, Micro region of Campina Grande at a mean altitude of 634m, during the period of October 2008 to October 2009. The soil utilized was a low organic matter sandy clay loam and the sunflower used was hybrid Helio 360 submitted to five irrigation levels (40, 55, 70, 85 e 100 % of the Plant Evapotranspiration) and four doses of nitrogen (25, 50, 75 e 100 kg ha-1). The experimental design used was a 4 x 4 factorial on a randomized-complete block design, with 3 replicates. The data was analyses statistically using the SISVAR – ESAL - Lavras/MG soft, conducting the analyses of variance and regression analyses for the quantitative factors. The associated increase of irrigation and nitrogen fertilization increased significantly the growth, development, productivity and the oil content of the seeds, both in a qualitatively and in a quantitative manner.