Optimizing nitrogen fertilization with Azospirillum brasilense and biostimulants for green corn

In tropical and subtropical regions, nitrogen (N) is often limited and significantly impacts corn production costs. In this context, bio-inputs have been used to reduce N and water supplied to plants. This study assesses the impact of varying N levels, Azospirillum brasilense seed inoculation, and biostimulant use on the agronomic performance of summer-grown green corn ( Zea mays L.) across three growing seasons (2017/2018, 2018/2019, and 2019/2020). Five N-fertilizer levels (0, 30, 60, 90, and 120 kg N ha(-1) ), two A. brasilense seed inoculation levels (0 and 100 mL ha(-1) ), and two biostimulant doses (0.0 and 1.0 L ha(-1) ) were evaluated in a completely randomized block design, arranged in a 5 x 2 x 2 factorial scheme, with four replications. Results showed that A. brasilense seed treatment did not increase ear yield or kernel protein content (PROT) and reduced PROT when combined with the two highest N levels. The application of biostimulant increased ear weight by 5.08% in the 2018/2019 growing season, leading to an increase in PROT. However, the use of inoculant and biostimulant did not reduce the amount of N-fertilizer applied to green corn plants.