Reduction of nitrogen fertilization in the function of complementary inoculation times with Azospirillum brasilense on second corn crop in the Cerrado

• Grant number: 18/10221-8
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): July 01, 2018
• Effective date (End): June 30, 2019
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal researcher: Marcelo Carvalho Minhoto Teixeira Filho
• Grantee: Ingrid Torres Pereira
• Home Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil

Abstract

Recently, several studies have confirmed the technical and economical viability of inoculation with Azospirillum brasilense in maize crop, including with increasing nitrogen fertilization efficiency. However, there is practically no research on the complementary inoculation with this bacterium in maize, as has been done with some success in soybean cultivation with Bradyrhizobium japonicum. The hypothesis of this unpublished research is that complementary inoculation with A. brasilense may at certain stages of development of maize increase even more the efficiency of nitrogen fertilization. The objective of this research will be evaluate the technical viability of the complementary inoculation with Azospirillum brasiliense via foliar at different times and combinations, associated to the reduction of nitrogen fertilization in the topdressing, nutrient concentration, nutrient uptake and removal, production components and grain yield of second crop maize in Cerrado region. The experiment will be conducted in an Oxisol with clayey soil and no-tillage system. The experimental design will be in randomized blocks with 8 treatments and four replicates, being: 1) Control (without inoculation and without nitrogen fertilization of cover); 2) Without inoculation and with application of the recommended dose of N (150 kg ha-1) in topdressing; 3) No inoculation + 75% of the recommended dose of N (112.5 kg ha-1) in topdressing; 4) Inoculation of seed with A. brasilense + 75% of the recommended dose of N; 5) Inoculation of seed and in stage V3 with A. brasilense + 75% of the recommended dose of N; 6) Inoculation of seed and in stages V3 and V6 with A. brasilense + 75% of the recommended dose of N; 7) Seed inoculation and in stages V3 and R1 with A. brasilense + 75% of the recommended dose of N; 8) Inoculation of seed and in stages V6 and R1 with A. brasilense + 75% of the recommended dose of N. Will be evaluated: the leaf chlorophyll index (LCI); concentrations of N, P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn in the diagnostic leaf; plant heights and spike insertion; diameter of the stem; numbers of rows per ear, of grain per row and grain per ear; mass of 100 grains; grain yield; accumulation of nutrients in the dry matter of the shoot and in the grains at the end of the cycle. In addition, the agronomic efficiency of the treatments will be calculated. (AU)