Efficiency of foliar application of sparingly soluble sources of boron and zinc in citrus

Autor: Luiza Oliveira Macedo, Dirceu Mattos Júnior, Rodrigo Jacobassi, Franz Walter Rieger Hippler, José Antônio Quaggio, Rodrigo Marcelli Boaretto
Jazyk: English<br />Spanish; Castilian<br />Portuguese
Rok vydání: 2020
Předmět:
Zdroj: Scientia Agricola, Vol 78, Iss 1 (2020)
Druh dokumentu: article
ISSN: 1678-992X
1678-992x
DOI: 10.1590/1678-992x-2018-0387
Popis: ABSTRACT This study evaluated leaf supply of zinc (Zn) and boron (B) using either soluble or sparingly soluble fertilizers in young sweet orange trees. Three experiments were set up in a greenhouse to compare two sources and four doses (control, low, adequate and high) of fertilizers as follows: (i) Experiment I (B): boric acid and calcium borate; (ii) Experiment II (Zn): Zn sulfate and Zn oxide; and (iii) Experiment III (B + Zn): boric acid + Zn Sulfate and Zn Borate. The sparingly soluble sources were effective in increasing the Zn and B leaf concentration. Dry matter of the aerial part increased 18 % with B applications in adequate concentration independent of the B fertilizer sources. In contrast, trees did not grow well with applications of adequate concentration of Zn as Zn Sulfate or high Zn concentration as Zn borate. Superoxide dismutase activity in leaves increased with applications of low concentration of Zn as Zn oxide and decreased with high concentration of Zn from either source. Polyphenol oxidase activity increased with application of adequate concentration of B as boric acid and high concentration of B as calcium borate. Furthermore, the upper concentrations of Zn were toxic in orange trees when the source was Zn sulfate. Increases in plant growth without damage to leaf tissue and positive responses of key enzymes of orange trees in a range of nutrient concentration applications demonstrated the practical use of sparingly soluble fertilizers to supplying B and Zn foliarily to plants.
Databáze: Directory of Open Access Journals
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