Determining Mehlich‐3 and DTPA extractable soil zinc optimum economic threshold for maize

Abstract

Zinc (Zn) deficiency is the most widespread micronutrient deficiency in crops, and it affects more than 160 million ha of arable land worldwide (Alloway, 2009). Maize (Zea mays L.) is one of the most susceptible crops to this nutrient deficiency (Brown et al., 1993). Zinc deficiency can be avoided by the application of Zn fertilizers. However, to achieve rational Zn fertilizer management, the development, correlation, calibration and interpretation of soil test methods to diagnose plant-available soil Zn are necessary (Dahnke & Olson, 1990). The use of an adequate diagnostic method would avert under-or over-application of Zn, thereby reducing economic losses.

DTPA‐extractable zinc threshold for wheat grain yield response to zinc fertilization in Mollisols

“…In soils from the Pampas region, Barbieri et al (2017) andMartínez Cuesta et al (2020) reported DTPA-Zn critical thresholds for corn (0.99 and 1.02 mg kg −1 , respectively) similar to the one determined for wheat in the present study. Although corn has a greater potential yield than wheat, and thus a greater absolute demand for Zn per unit area, both crops have similar aboveground Zn requirement for grain production (∼42-55 g Zn Mg −1 ) (Nayyar et al, 2001;Bender et al, 2013;Ciampitti & Vyn et al, 2013;Liu et al, 2019).…”

“…Also, wheat GY response to Zn fertilization and RY were not correlated with the maximum yield at each site (p = .54 and p = .62, respectively). This behavior has already been reported for Zn in corn (Barbieri et al, 2017;Martínez Cuesta et al, 2020) and other nutrients with low soil mobility (Dodd & Mallarino, 2005) that reach the root surface by diffusion and root interception (Bray, 1954). These observations suggest that the GY response to Zn fertilization is more related to the capacity of soils to provide available Zn to the roots than to the absolute crop demand for Zn.…”

“…Using a sufficiency level approach, the soil DTPA-Zn critical threshold necessary to achieve a fixed 95% RY goal was 1.03 mg kg −1 , with a 95% confidence interval from 0.87 to 1.23 mg kg −1 (Figure 2). The fitted curve can also be used to determine a variable economic threshold, following the procedure described by Martínez Cuesta et al (2020).…”

“…However, a critical threshold of soil nutrient availability to predict GY response must be determined by field trials (Dahnke & Olson, 1990). The DTPA-Zn has adequately discriminated Zn-responsive sites when corn (Zea mays L.) is grown in Mollisols (Barbieri et al, 2017;Martínez Cuesta et al, 2020). Nevertheless, a DTPA-Zn critical threshold must be defined for each specific soil and crop, as the thresholds vary depending on the soil nutrient supplying capacity and the crop use efficiency (Tagore et al, 2017).…”

Evaluation of the Phytoremediation Potential of the Sinapis alba Plant Using Extractable Metal Concentrations

“…EDTA and DTPA are two chelating agents commonly used in sorption-desorption studies due to their ability to form stable complexes with a wide variety of metals. The nonselective nature of EDTA in metal extraction is a disadvantage, as this agent extracts a wide variety of metals, including alkaline earth cations such as Ca and Mg. Another disadvantage would be that EDTA is hardly biodegradable and can remain adsorbed on soil particles [34,35]. With calcium being the primary cation of the adsorption complex of soils, the M2-CaCl 2 solution is more capable of extracting other cations adsorbed on the surface of soil particles than other solutions without Ca.…”