Can edaphic variables improve DTPA-based zinc diagnosis in corn?

BARBIERI, P.; SAINZ ROZAS, H.R.; WYNGAARD, N.; EYHERABIDE, M.; SALVAGIOTTI, F.; CORRENDO, A.A.; BARBAGELATA, P.A.; ESPÓSITO GOYA, G.P; COLAZO, J.C.; ECHEVERRÍA, H.E.

AGRONOMY JOURNAL

AMER SOC AGRONOMY

Año: 2017

0002-1962

Current zinc (Zn) diagnosticmethods for corn (Zea mays L) areoften based on soil DTPA (diethylenetriamine-pentaacetic acid) extractable Zn (DTPA-Zn).However, the calibration of the DTPA-Zn test may be influenced by other soilproperties such as pH, organic matter (SOM) and available Bray-P (PBray-1).Our objective was to assess the contribution of soil properties to a DTPA-Znmodel used to predict corn response to Zn fertilization under field conditions.We conducted 64 field trials  with two Zn-fertilizationtreatments: with and without Zn fertilization. In all sites, we measured SOM, PBray-1,pH, and DTPA-Zn at 0-20 cm depth before sowing. The yield difference betweenZn-fertilized and unfertilized treatments (Ydifference) wassignificant in 33% of the experimental site-years. In responsive site-years, theaverage Ydifference was 0.98 Mg ha-1 (11.4%). Soilorganic matter was the only property that was a significant addition to theDTPA-Zn model for predicting the corn relative yield (Model R2including SOM= 0.27). However, the improvement was nominal (Partial R2of SOM= 0.06). Use of DTPA-Zn alone was suitable to discriminate Znresponsiveness among site-years based on the Ydifference bycorrectly diagnosing 81% of the outcomes. . We determined three soil Zn-DTPA rangeswith different probability of resulting in a Ydifference greaterthan zero when fertilized with Zn: high (1.3 mg kg-1). These soil-testbased Zn recommendations improve the identification of Zn-deficient soils allowingprevention of yield loss from Zn deficiency and more rational use ofZn-fertilizers.