Grain Cadmium and Zinc Concentrations in Maize Influenced by Genotypic Variations and Zinc Fertilization

Abstract

Zinc (Zn) fertilization could be a viable approach for minimizing cadmium (Cd) accumulation in the food chain. The present study was carried out to investigate the role of various Zn fertilization treatments (control, foliar application at tasseling stage, foliar application at milky stage, rubber ash application, soil application of ZnSO4) and cultivars (Pop 2004B, Pop 2006, Azam, Sarhad (W), Pahari) on grain yield, grain Zn, and grain Cd concentrations in maize. All Zn fertilization treatments resulted in a significantly higher grain yield, higher grain Zn concentration, and reduced grain Cd concentration. The application of rubber ash remained the best among all Zn fertilization treatments as it resulted in a higher grain yield of 62% and a reduced grain Cd concentration by 57% compared to control. Contradictions were apparent between cultivars, and the cultivars which recorded a higher grain yield had a lower Zn concentration in their grains and vice versa. Regarding Cd accumulation, all cultivars except Azam, retained less Cd with increased grain Zn concentration. Future studies should focus on breeding/selection of high yielding and high quality cultivars. Furthermore, the feasibility of rubber ash maybe tested under different climatic and edaphic conditions against other heavy metals and other crops as well.

Absorption and distribution of cadmium of three maize hybrids in three environments

“…As expected, the Cd rate used was directly proportional to soil concentration (Figure 3b), which coincides with findings reported in the literature (Arduini et al, 2014;Fahad et al, 2015); both applied CdCl 2 rates were higher than the critical threshold of this element in soils (1 mg kg -1 ). Regarding the maize cultivars under study, no effect was recorded on soil total Cd concentration ( Figure 3c).…”

“…Therefore, the low grain Cd accumulation could be due to several factors: 1) uptake and translocation limitations generated in the root (Adeniji et al, 2010;Yang et al, 2014), which suggests that maize plants appear to have more efficient defence mechanisms than other crops to deal with Cd toxicity, including its accumulation in the root (Adeniji et al, 2010); 2) soil available Zn concentration since Zn is an antagonist to plant Cd uptake (Tanwir et al, 2015); and 3) low Cd concentration could be attributable to the high agronomic efficiency of nutrient use (kg DM produced per kg of applied nutrient) obtained in this experiment (data not shown) compared with other studies cited in the literature, which implied an overall nutrient dilution effect (Fahad et al, 2015). However, applying increasing Cd rates produced an increase of more than 100% in maize grain Cd accumulation when compared with the control with no applied Cd (Arduini et al, 2014;Yang et al, 2014).…”

“…When comparing environments, higher total Cd concentration was found in La Serena (Figure 3a), which could be associated with its initial Cd content (Table 2) and available Zn concentration (Degryse et al, 2009;Fahad et al, 2015). Even though initial soil total Cd concentration in La Serena was higher than in Los Tilos and Chillán (Table 2), this order was not maintained when concentrations were analyzed at the end of crop growth (Figure 3a).…”

“…Among the agricultural crops that are important for Cd in the human diet are, durum wheat (Triticum turgidum L. var. durum), maize (Zea mays L.), wheat (Triticum aestivum L.), oat (Avena sativa L.), barley (Hordeum vulgare L.), rice (Oryza sativa L.), and pea (Pisum sativum L.); these have exhibited Cd concentrations over the limits permitted for human health (Fahad et al, 2015;Quezada-Hinojosa et al, 2015).…”

Effects of tire rubber ash and zinc sulfate on crop productivity and cadmium accumulation in five rice cultivars under field conditions

“…Zn deficiency is widespread worldwide in many temperate and tropical climates (Fageria et al 2003;Slaton et al 2005;Fahad et al 2015b). Brar and Sekhon (1976) stated that formation of insoluble franklinite (ZnFe 2 O 4 ) compound (submerged soil), insoluble ZnS (intense reduced condition), insoluble ZnCO 3 (partial pressure of CO 2 coupled with decomposition of OM), and insoluble Zn(OH) 2 (alkaline pH) decreased the Zn availability in submerged soils.…”