LAUSR

Maize ( Zea mays L.) is a plant of the Poaceae family, originating in Central America and cultivated in practically every region of the world. In Brazil, it is the most important cereal for the economy, but the productivity is lower when compared to other countries. This may be due to inadequate plant density per unit area, low soil fertility and spatial arrangement of plants. Thus, the development of better performance hybrids and changes in sowing density and spacing appear as techniques for increasing productivity without increasing production costs. Therefore, the objective of this work is to evaluate the agronomic performance of two maize hybrids as a function of plant population and row spacing in semiarid microclimate to identify those agronomic and microclimatic factors that influence it. Two simultaneous fieldwork were conducted in an experimental area, at the microregion of Paraiba swamp. A randomized complete block design was used with six treatments distributed in a 2 x 3 factorial scheme, resulting from the combination of two maize hybrids (H1 and H2) and three population densities (40,000, 60,000 and 80,000 plants.ha -1 ) for Experiment 1; and two maize hybrids (H1 and H2) and three spacings (0.40, 0.60 and 0.80 m) for Experiment 2. In general, the results of this study suggest that larger populations of maize provide significant increases in grain yield for microclimatic conditions Paraiba semiarid, and when environmental factors are not limiting.