Comportamento do girassol submetido a doses de nitrogénio e níveis de água de irrigação.

Abstract

The search for sustainable alternatives to mitigate negative environmental impacts and the provision of supplementary food and clean energy has emphasized the potential of sunflower, in evidence in recent years. The expansion of this crop in Brazil, especially in the northeast of the country, suggests the need for management information which can increase their productivity. Thus, the aim of the present work was to study the behavior of sunflower (variety EMBRAPA 122/V-2000) on growth and production when submitted to nitrogen treatments (0, 60, 80 and 100 kg ha"1) and available water (55, 70, 85 and 100%) in a Eutrophic Entisol. The experimental design was a 4 x 4 completely randomized factorial scheme with three replications, totalizing 48 experimental units. The growth and production variables the biomass production and achenes, water consumption and crop cycle, using regression analyses. It was observed that in general, ali growth variables showed a linear increase with the available water in soil and nitrogen treatments. In general, the production variables showed a linear increase with available soil water and a non linear for the nitrogen treatments. The interaction between water and nitrogen did not affect the growth of phytomass production of sunflower, with exception to the percentage of viable achenes. The duration of the crop cycle was not affected by soil water availability being around 98 days for the 100 kg N ha"1; it was found that for 10% each increment in available water the consumption plant increases 18.26%.