Summary: The potential for using soil P reserves has been evaluated since 2014, in experiments with maize in monoculture and intercropped with brachiaria and in rotation with soybean. In order to evaluate the residual effect of these P reserves in the soil when compared to recent P applications, treatments with rates of P (0, 22 and 44 kg of P ha-1) were included as maintenance. Also, the effect of inoculation with arbuscular-mycorrhiza was evaluated. Results showed that, in this specific case and after four years of P ?draw down? by the corn grain, legacy P in soil alone (without addition P fertilization) led to a significantly lower cumulative grain yield than with P fertilization, when other nutrients in the soil were at adequate levels. In this research there is no evidence that the use of brachiaria intercropping with corn associated with mycorrhiza can optimize the use of residual phosphorus. In general, the brachiaria intercropped with corn reduced grain yield, due mainly brachiaria management. The potential and the time for utilization of P reserves in the soil is closely related to the bioavailability of P evaluated by extractor (Mehlich1), whose values must be above the critical levels preestablished that provide economic productivity for farmers.

Publication year: 2021

Types of publication: Paper in annals and proceedings

Unit: Embrapa Maize & Sorghum

Keywords: Fósforo, Legacy-P, Maintenance-P, Micorriza, Mycorrhizae, Solo