CAN EDAPHIC VARIABLES IMPROVE DTPA-BASED ZINC DIAGNOSIS IN CORN?

BARBIERI PABLO ANDRÉS; SAINZ ROZAS HERNAN RENE; WINGAARD NICOLAS; REUSSI CALVO NAHUEL; EYHERABIDE MERCEDES; FERNANDO SALVAGIOTTI; ADRIAN CORRENDO; BARBAGELATA PEDRO; ESPOSITO GOYA GABRIEL; COLAZO JUAN CRUZ; ECHEVERRIA HERNAN

SOIL SCIENCE SOCIETY OF AMERICA JOURNAL

SOIL SCI SOC AMER

Lugar: Wisconsin; Año: 2017

0361-5995

Current zinc (Zn) diagnostic methods for corn (Zea mays L) are often based on soil DTPA (diethylenetriamine-pentaacetic acid) extractable Zn (DTPA-Zn). However, the calibration of the DTPA-Zn test may be influenced by other soil properties 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-Zn model used to predict corn response to Zn fertilization under field conditions. We conducted 64 field trials with two Zn-fertilization treatments: 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 between Zn-fertilized and unfertilized treatments (Ydifference) was significant in 33% of the experimental site-years. In responsive site-years, the average Ydifference was 0.98 Mg ha-1 (11.4%). Soil organic matter was the only property that was a significant addition to the DTPA-Zn model for predicting the corn relative yield (Model R2 including SOM= 0.27). However, the improvement was nominal (Partial R2 of SOM= 0.06). Use of DTPA-Zn alone was suitable to discriminate Zn responsiveness among site-years based on the Ydifference by correctly diagnosing 81% of the outcomes. . We determined three soil Zn-DTPA ranges with different probability of resulting in a Ydifference greater than zero when fertilized with Zn: high (1.3 mg kg-1). These soil-test based Zn recommendations improve the identification of Zn-deficient soils allowing prevention of yield loss from Zn deficiency and more rational use of Zn-fertilizers.KEY WORDS: phosphorus; pH; organic matter