Publications

@article{Macedo2021,

title = {Characterization and use efficiency of sparingly soluble fertilizer of boron and zinc for foliar application in coffee plants},

author = {Luiza Oliveira Macedo and Dirceu Mattos-Jr and Rodrigo Candido Jacobassi and Guilherme Petená and José Antonio Quaggio and Rodrigo Marcelli Boaretto},

url = {http://www.scielo.br/j/brag/a/YrgpKfn8wmcnGTpmXZJwHjJ/?lang=en},

doi = {10.1590/1678-4499.20200329},

issn = {0006-8705},

year  = {2021},

date = {2021-01-01},

journal = {Bragantia},

volume = {80},

publisher = {Instituto Agronômico de Campinas},

abstract = {ABSTRACT Deficiencies of boron and zinc occur in coffee plantations despite the many fertilizer sources offered by the industry for the agriculture. Sparingly soluble fertilizers (SSF) have been used in several countries for many years. However, their effectiveness when applied to leaves is highly contested, and information about their use efficiency is still lacking. Experiments were set up to characterize the SSF of B and Zn according to particle size of fertilizers, and the spreading and retention of the particles in the leaf, comparing SSF (calcium borate, Zn oxide, and Zn borate) with soluble sources (boric acid and Zn sulfate) in four doses (mg.L-1): Experiment I (B 0, 130, 260, and 520), Experiment II (Zn 0, 200, 600, and 1,800), and experiment III (B 0, 43, 129, and 387, and Zn 0, 200, 600, and 1,800), to supply B and Zn for coffee plants. Microparticles of the SSF were found adhered to coffee leaves, and the Zn oxide was the one with the smallest particle size. SSFs were effective at increasing the Zn and B leaf concentrations in coffee. Dry matter of coffee increased 15% with applications of 270 mg.L-1 of B as calcium borate and 384 mg.L-1 of B as boric acid. Foliar application of Zn oxide at the dose of 1,800 mg.L-1 of Zn increased the leaf areas of the plants. High doses of Zn sulfate caused toxicity to coffee plants due to high saline concentrations. The microparticles found retained on the surface of the coffee leaves increased leaf concentration of B and Zn, which explained variations in the dry matter measurements and show the potential of the SSF for the development of fertilizers to improve the availability of micronutrients to coffee.},

keywords = {leaf spraying, micronutrients, microparticles, nutrient sources},

pubstate = {published},

tppubtype = {article}

}

@article{Macedo2020,

title = {Efficiency of foliar application of sparingly soluble sources of boron and zinc in citrus},

author = {Luiza Oliveira Macedo and Dirceu Mattos Júnior and Rodrigo Jacobassi and Franz Walter Rieger Hippler and José Antônio Quaggio and Rodrigo Marcelli Boaretto},

url = {http://www.scielo.br/j/sa/a/Qbqq5YFDvQkYRHHm3gVSTbK/?lang=en},

doi = {10.1590/1678-992X-2018-0387},

issn = {1678-992X},

year  = {2020},

date = {2020-01-01},

journal = {Scientia Agricola},

volume = {78},

issue = {1},

pages = {2021},

publisher = {Escola Superior de Agricultura "Luiz de Queiroz"},

abstract = {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.},

keywords = {fertilizer use, leaf spraying, micronutrients, microparticles},

pubstate = {published},

tppubtype = {article}

}

@article{Macedo2017,

title = {Use of sparingly soluble micronutrients sources for citrus production},

author = {Luisa Oliveira Macedo and Rodrigo Marcelli Boaretto and Rodrigo Candido Jacobassi and Natália Fernandes Carr and José Antonio Quaggio Dirceu Mattos-Jr. and Luisa Oliveira Macedo and Rodrigo Marcelli Boaretto and Rodrigo Candido Jacobassi and Natália Fernandes Carr and José Antonio Quaggio Dirceu Mattos-Jr.},

url = {http://citrusrt.ccsm.br/journal/citrusrt/article/doi/10.4322/crt.ICC099},

doi = {10.4322/CRT.ICC099},

year  = {2017},

date = {2017-01-01},

journal = {Citrus Research & Technology},

volume = {38},

issue = {2},

pages = {1-10},

publisher = {Centro de Citricultura Sylvio Moreira/Instituto Agronômico},

abstract = {Despite a diverse array of micronutrient fertilizers is manufactured in the world, plant nutritional disorders remain a challenge for many growers. In Brazil, boron (B), zinc (Zn) and manganese (Mn) are the most limiting micronutrients to citrus production. In the soil, B is prone to leaching losses and the metallic nutrients are less available to the plants due to the lower mobility and high fixation to the colloids of the clay fraction. Therefore, foliar applications have represented a major strategy for micronutrient supply to citrus trees, even though; efficiency of such practice is still debated. Differential agronomic responses of sources are attributed to the companion ion of the chemical species, the solubility in water and the particle size of the fertilizer granules. The purpose of this review is to discuss the role of sparingly soluble fertilizer in the nutrition of citrus plants. The development of suspension concentrates, based on sparingly soluble inorganic micronutrient sources, is the single most significant advance in technology recently that has resulted in a wide range of commercial products for growers. The sparingly soluble sources when applied to the soil reduce adsorption of the metal. In foliar sprays, the particles adhered to the leaf surface can serve as a solid phase to restore the micronutrient supply during a prolonged growth phase of the leaf. In both situations, the gradual release of the nutrients may reduce absorption rate and the risk of phytotoxicity. Satisfactory results for the use of sparingly soluble sources were demonstrated, but further studies are necessary to validate the efficacy of foliar application of sparingly soluble sources, which will enable the registration of these products with the official regulatory agencies and allow the recommendation to the citrus growers.},

keywords = {foliar spray, Index terms: fertilizer efficacy, microparticles, plant nutrition},

pubstate = {published},

tppubtype = {article}

}