Effect of mycorrhizae on phosphate fertilization efficiency and maize growth under field conditions

Phosphorus (P) is a plant macronutrient that is indispensable for maize (Zea mays L.) production. However, P is difficult to manage in weathered soils, and its fertilization practice has low efficiency because it becomes unavailable for absorption by plant roots. Symbiosis of plants with arbuscular mycorrhizal fungi increases plant growth and enhances P uptake from the soil that is not directly available to the roots. Thus, the objective of this study was to determine how inoculation with Rhizophagus intraradices and phosphate fertilization interacts and influences the development and productivity of second-crop maize. The experiment was conducted in Selvíria, Mato Grosso do Sul, Brazil, in 2019 and 2020, both in a Typic Haplorthox. A randomized block design in subdivided plots was used for the phosphate application during crop sowing (0, 25, 50, 75, and 100% concentrations of the recommended level), and the secondary treatments were the doses of mycorrhizal inoculant (0, 60, 120 and 180 g ha^-1) applied to the seed using a dry powder inoculant containing 20,800 infectious propagules per gram of the arbuscular mycorrhizal fungus R. intraradices. Only in the first year of the experiment, inoculation and phosphate fertilization promoted benefits to the maize crop, indicating potential to increase yield.