Response of sunflower plants to two sowing periods and to two fertilization levels. II. Plant characteristics associated with the sunflower harvest

Abstract

With the objective of identifying possible interactions among plant density, planting date and soil fertility as well to assess their effects on agronomic traits associated with the sun-flower harvest, an experiment was conducted at Eldorado do Sul, RS, Brazil, during the 1988/89 growing season. Four plant densities (30,000; 45,000; 60,000 and 75,000 pl/ha) and two planting dates (July, 27^th and September, 19^th) were tested with and without fertilizer application. The seed moisture at 29 and 36 days (first planting date) and at 22 and 29 days (second planting date) after the anthesis was higher in lower density. Plant height, at the stages R₁ and R₆, increased as plant density increased. Stem and head diameters decreased as plant density increased. In all treatments, plant lodging or plant breaking broken was not significant, regardless of sowing date.