Growth, grain yield, and forage yield of maize hybrids fertilized with different nitrogen doses

The objective of this study is to evaluate the effect of fertilization with different doses of nitrogen on the growth and yield of six maize hybrids by determining initial growth, forage fresh matter yield (FFMY), forage dry matter yield (FDMY), grain dry matter content (GDMC), and total grain yield (TGY). The study was carried out in an experimental area of ESALQ/USP in the municipality of Piracicaba/SP, between November and March 2017, using a subsurface drip irrigation system. The experimental design was of completely randomized blocks in a 6 x 4 factorial scheme (hybrids x nitrogen doses) with four replicates. Hybrids Dow 2B587, DeKalb 175 Pro, Pioneer 30F53VYHR, Dow 2B587 PW, Dow 2B633PW C4M Cruiser, and Santa Helena SHS7930 PRO2 were used. The nitrogen concentrations used were 0 , 60, 120, and 180 kg ha-1. At the end of 40 days of evaluation of plant height, the best results were found for hybrids H2, H3, and H6. There was a significant interaction effect between hybrids and nitrogen doses on GDMC. The H1 hybrid presented the lowest GDMC (26.26%). All the studied variables increased linearly as nitrogen doses increased. The overall mean FFMY and FDMY were 81,953.87 and 23,993.10 kg ha-1, respectively.