The sowing density on oat productivity indicators

The sowing density adjustment in oat can maximize the productivity expression. The aim of this study is to define the behavior of productivity expression of biomass, grains, straw and harvest index through increasing sowing density in the main biotype cultivated in Southern Brazil. It proposes the possibility of indicating higher sowing density to the productivity maximization of biomass and grains. With the density adjusted to the grain productivity to simulate the reflexes on the biological and straw productivity and harvest index compared to recommended density, considering high and reduced tillering cultivars in different succession systems. The study was carried out in 2013, 2014 and  2015 in randomized block design with four replications in a 4 × 2 factorial scheme, for sowing density (100, 200, 300, 600 and 900 m-2) and oat cultivars (Brisasul and URS Taura), respectively, in the corn/oat and soybean/oat succession system. With the increase in sowing density, the biological and straw productivity evidence a linear behavior and the grain productivity and harvest index of quadratic behavior, regardless of the cultivar, agricultural year and succession system. It is possible to indicate a higher sowing density to the biomass and grain productivity maximization with sowing density close to 500 seeds m-2 in the main succession systems. In high and reduced tillering cultivars, the adjusted density compared to the recommended increased the biological and straw productivity, regardless of agricultural year and succession systems. Key words: Avena sativa, succession system, weather condition, regression.