Irrigation Levels and Potassium Doses in the Growth of Sunflower Cultivated in Soil of the Brazilian Cerrado

Abstract

The chief limiting factor in sunflower (Helianthus annuus L.) development is water deficit. Besides the dearth of water, large amounts of mainly potassium (K) are essential for the favourable development and bountiful harvest of the culture. This study aimed to evaluate the growth of sunflower plants cv. SYN 042 cultivated in red Cerrado Oxisol with controlled irrigation levels and K doses. Randomized block design was selected in a 5x4 factorial scheme, administering 5 K doses (0, 40, 80, 160 and 240 mg dm -3 of K 2 O) and 4 different water replacement levels in the soil (75, 100, 125 and 150% of field capacity (FC)), with 4 replications. The following characteristics were evaluated: Plant height, stem diameter, Chlorophyll index, inner and outer diameters of the chapter,