INFLUÊNCIA DA LÂMINA DE IRRIGAÇÃO NO CULTIVO DE GIRASSOL

Abstract

The sunflower is a rustic culture that has low efficiency of water use being necessary to define appropriate management of irrigation to increase the viability of its cultivation. The water is essential for the proper functioning of the metabolic activities of plants reflecting mainly in morphology. Irrigation is an important technique to meet the water needs of plants in a rational and sustainable manner, increasing crop productivity. The aim of this study was to evaluate the effects of different irrigation levels in sunflower cultivation. The experiment was conducted in pots allocated bench and greenhouse environment on campus II at the Universidade do Oeste Paulista, Presidente Prudente -SP. The experimental design was a randomized block, with 5 dephts of irrigation (50 %, 75 %, 100 %, 125 % and 150 % of crop evapotranspiration - ETc) and 4 repetitions, totaling 20 plots . To determine the irrigation levels we used the Penman -Monteith method recommended by FAO. The parameters were determined: plant height, the diameter of the flower, the number of leaves, dry mass of shoot, dry mass of the inflorescence, root length, root dry weight and root/shoot. The water depth of 125 % ETc showed the highest values for dry matter and root, and root length. The production of the depth of irrigaton 100% ETc water met the sunflower need, favoring the formation of floral chapter. Thus, it is recommended the depth of irrigation of 100% ETc for the production of potted sunflower to the climatic conditions of Presidente Prudente.

Keywords

• Helianthus annuus
• water use efficiency
• water requirement