The soil P application can affect Zn availability to plants, depending on the application. The objective of this study was to evaluate corn (Zea mays L.) response to zinc (Zn) addition to the soil and to determine its critical level in the soil and in the plant, in relation to added phosphorus (P) placement, using two soil samples from Minas Gerais, Brazil, in a greenhouse experiment. The experiment was conducted in a factorial arrangement (2 x 3 x 6), with two soils [Red Yellow Latosol of the Una Variation (Oxisol) and Red-Yellow Podzolic (Ultisol), named LU and PVA, respectively]; three forms of added P placement (5, 10 and 30% of the total volume of soil in a dosage of 200 mg dm-3), and six Zn dosages (0, 1, 2, 4, 6 and 8 mg dm-3). The dry matter production and the contents of Zn in the aerial part of the corn plants were determined. The addition of Zn linearly increased (p < 0.01) its content in the soil and plant uptake. The critical levels for the LU soil ranged from 0.91 to 2.13 mg dm-3 of Zn as determined by the Mehlich-1 extractor and plant levels ranged from 18.0 to 24.6 mg kg-1. These levels were higher when P was placed in smaller soil volumes. P placement affected the Zn content in the plant. In LU soil, when P was placed at the smallest soil volume and Zn privation, the corn plants presented elevated P levels.
Critical level of zinc; phosphorus placement; interaction Zn/P
