Growth, nutrient accumulation and yield of onion as a function of micronutrient fertilization

Nubia M F Bertino,Rodolfo R De A Lacerda,João P N Da Costa,Romualdo M C Costa,Victor E De V Gomes,Leilson C Grangeiro

doi:10.1590/1807-1929/agriambi.v26n2p126-134

Nubia M F Bertino, Rodolfo R De A Lacerda + Show 4 more

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https://doi.org/10.1590/1807-1929/agriambi.v26n2p126-134

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Abstract

ABSTRACT Micronutrients structurally constitute several enzymes and act as a cofactor of essential proteins to maintain cell function, thereby contributing to crop growth and yield. The objective of this study was to evaluate the leaf content, growth, accumulation of micronutrients, classification and yield of onion as a function of fertilization with boron, cooper and zinc in two years of cultivation. The experiments were carried out from June to November in 2018 and 2019, in a soil classified as Ultisol, both at the Rafael Fernandes Experimental Farm, belonging to the Universidade Federal Rural do Semiárido, in the municipality of Mossoró, Rio Grande do Norte, Brazil. The experimental design was in randomized blocks with 15 treatments and four replicates. The treatments consisted of application of doses of B, Cu and Zn, in two experiments. Contents of B, Cu and Zn in the diagnostic leaf, growth, accumulation of B, Cu and Zn in the leaf, bulb and total, classification and commercial, non-commercial and total yields were evaluated. Application of B, Cu and Zn did not influence the number of leaves, relation of bulb shape, leaf, bulb, and total dry mass and yield of onion. Application of B, Cu and Zn, respectively at doses of 1-2-1 kg ha-1 favored a greater accumulation of B, Zn and Cu in the bulb. Higher number of leaves, leaf dry mass, bulb dry mass, total dry mass, class 1 bulbs and non-commercial yield were produced in Experiment 1.

Highlights

The response of onion crop to the addition of micronutrients depends on the availability of micronutrients in the soil, pH, organic matter content, and interaction with other chemical elements
The contents of B in the diagnostic leaf of onion in Experiment 1 varied from 30.5 to 115.5 mg kg-1, the highest values being associated with the application of 1 and 2 kg ha-1 of B
The amount of CaCO3 supplied via irrigation water until the period of collection of the onion diagnostic leaf, in Experiment 2, was 480 kg ha-1; with this, it can be explained why the B content was higher in the treatment that did not have boron (T4), because the amount of CaCO3 supplied via irrigation water may have influenced the response to the isolated application of B (T2 and T3) in the experiment 2 (Table 2)

Summary

Introduction

The response of onion crop to the addition of micronutrients depends on the availability of micronutrients in the soil, pH, organic matter content, and interaction with other chemical elements. The application of Zn, Mn, B, Cu and Fe in onion crop increases the concentration of nutrients in the leaves, triggering enzymatic activation, increased carbohydrate metabolism, bulb diameter, bulb weight and commercial and total bulb yields (El-Tohamy et al, 2009; Acharya et al, 2015). In an alkaline soil deficient in Zn and B, Acharya et al (2015) studied application via soil and leaf of these nutrients in onion, observing an increase in the diameter of bulbs with the application of 10 kg ha-1 of borax and 60% increase in yield with foliar spraying of 0.5% zinc sulfate in comparison to the control. The authors observed no increase in yield with the application of B and Mn

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