Adubação NPK e irrigação na cultura do girassol em dois tipos de solo.

Abstract

Lateíy the demand for renewable sources have been increasing sharply, so research on oilseed plants stand out in the scientific fíeld. In several places on the planet there is no information on the production system of the sunflower. However, under conditions of semi-arid, are incipient data on fertilizer management and irrigation. In this sense, two experiments were conducted, the first under Regosol between November/2009 February/2010 and the second with Cromic Luvisol during July and November 2010 to assess the responses of sunflower {Helianthus annuus L.) related to growth and production in function of the NPK fertilization and irrigation. Eleven treatments NPK fertilization were analyzed 0, 60, 80 and 100 kg N ha"1; 0, 80, 100 and 120 kg P205 ha"1 and 0, 60, 80 and 100 kg K20 ha"1, distributed in the Baconian matrix and four available soil water content (55, 70, 85% and 100 AD). The experimental design was completely randomized in triplicate, a total of 132 experimental units, consisting of pot with a capacity of 35 L. Was evaluated in two soils, growth, production and yield components of sunflower cv. Embrapa 122-V2000, based on analysis of variance and regression. It was found that, in the experiment with Regosol, fertilization and available soil water content in the soil alone affected the sunflower, and ali variables had a linear behavior as a function of available water. Even for this soil, the nutrients studied, the order of importance to the culture was: nitrogen>potassium> phosphorus. In the second experiment (Cromic Luvisol), only the number of leaves of sunflower was affected by the interaction leveis of P2Os x irrigation and drought stress was more damaging to the behavior of sunflower that nutritional stress. A general evaluation, the recommended doses and for the Regosol and Cromic Luvisol is 100:120:120 and 60:120:120 kg ha"1 NPK, respectively.