Assessment of nickel's sufficiency critical levels in cultivated soils, employing commonly used calibration techniques

Abstract

Although Ni has been officially recognized as an essential micronutrient for all higher plants since 2004, research on assessing its sufficiency critical levels with different soil tests is missing in the literature. The objective of the study was to determine Ni critical levels in unpolluted cultivated soils utilizing four methods, employing three commonly used calibration techniques. Ten soils with different physical–chemical properties and low Ni content were treated with Ni at rates of 1, 2, 4, and 8 mg kg−1. After equilibration for one month, the soils were analyzed for extractable Ni by four methods, namely DTPA, AB‐DTPA, AAAc‐EDTA, and Mehlich‐3. Response to soil‐applied Ni was assessed by a greenhouse pot experiment, with the untreated and Ni‐treated soils in three replications, using ryegrass (Lolium perenne L.). The aboveground biomass of ryegrass was harvested two months after sowing, dry weight of biomass was measured and relative biomass yield was calculated. Nickel's critical levels were determined employing the: (a) graphical technique of Brown and co‐workers, (b) Mitscherlich–Bray equation, and (c) Cate and Nelson graphical technique. According to the first technique, Ni critical levels were ≈ 2 mg kg−1 for the DTPA and AB‐DTPA methods, and 6.0 and 5.3 mg kg−1 for the AAAc‐EDTA and Mehlich‐3 methods, respectively. Similar levels were obtained by the Mitscherlich–Bray equation. However, the critical levels assessed by the Cate and Nelson technique were lower and ranged from 0.5 to 1.3 mg kg−1 for all four methods. Conclusively, Ni sufficiency critical levels for all four methods are expected to range at levels of a few mg Ni kg−1 of soil. As far as the three calibration techniques are concerned, a distinct boundary between Ni response and non‐response was accomplished by none. However, the fact that 60–74% of the soils were correctly separated into responsive and non‐responsive to added Ni by the graphical technique of Brown and co‐workers suggests that this is the most suitable technique.

Transfert en cadmium et zinc vers l’orge de printemps en sols contaminés et non contaminés de Belgique : évaluation et prédiction

“…Une analyse Cate-Nelson a été effectuée sur la population générale afin de calibrer une réponse Cd Grain ou Zn Grain selon les teneurs pseudo-totales en Cd ou en Zn mesurées dans les sols. Une analyse Cate-Nelson est une technique traditionnellement utilisée en agronomie, en particulier pour calibrer la réponse prévue d'une culture en fonction de données d'essai sur les sols (Mangiafico, 2013), par exemple un rendement ou une concentration dans une plante (Dang et al, 1993 ;Collins et Allinson, 2004 ;Mallarino et Atia, 2005 ;Zare et al, 2009 ;Nikoli et al, 2016).…”

Determination of Critical Value of Available Soil Phosphorus for Wheat (Triticum Aestivum L.) in Calcareous Soils From Greece

“…The Cate-Nelson graphical technique (Cate and Nelson, 1965) has been used by several researchers for the determination of nutrients' critical levels, mainly macronutrients (Bilias and Barbayiannis, 2016; Sobulo, 2008) and micronutrients (Nikoli et al, 2016). In this technique, data regarding the available soil nutrients (x-axis) are plotted against a biological parameter (y-axis), such as the plant tissue concentration of the nutrient, the absolute or relative yield, or the uptake, in order to separate the soils into two groups.…”