Phosphorus rates associated with inoculation of different bacteria that promote plant growth in corn crop

Abstract

Phosphate fertilizers are applied in large amounts in corn, despite its low demand by plants when compared to nitrogen and potassium. Phosphorus is one of the most limiting nutrients in the development of this cereal, especially in tropical soils that generally have a low P content and a predominance of acidity. For this reason, for a more sustainable agriculture, the use of bacteria with the capacity to solubilize the unavailable phosphorus and to promote the growth of plants, especially of roots, can increase the efficiency of the phosphate fertilization, seems to be an interesting alternative to the current agriculture, lacking research. Thus, the objective of this research will be to evaluate the agronomic efficiency of phosphorus doses associated with inoculation with Azospirillum brasilense, Pseudomonas fluorescens or Bacillus subtilis, as well as leaf nutrients concentration, and productions components and grain yield of corn, in Cerrado region. The experiment will be carried out in an experimental area belonging to the Faculty of Engineering of Ilha Solteira - UNESP, in Selvíria - MS, in an Oxisol with a clay texture. The experimental design will be in randomized blocks with four replications, arranged in a 4 x 5 factorial scheme, being: 4 types of inoculation (with A. brasilense, with P. fluorescens, with B. subtilis and without inoculation) and 5 doses of P2O5 (0; 17.5 kg ha-1 being 25% of the recommended dose, 35 kg ha-1 being 50% of the recommended dose, 70 kg ha-1 being the recommended dose and 105 kg ha-1 being 150% of the dose recommended), applied in the sowing line. 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 and spike insertion heights; production components; grain yield; agronomic efficiency; accumulation of P in the dry matter of the shoot at the end of the cycle and of P in the grains; and the P content in the soil in the 0 to 0.20 m, after harvesting the crop in corn sowing line. (AU)