Publications

@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}

}

@article{Walter2017,

title = {Copper in Citrus production: required but avoided},

author = {Franz Walter and Rieger Hippler and Rodrigo Marcelli Boaretto and José Antônio Quaggio and Dirceu Mattos-Jr},

url = {http://dx.doi.org/10.4322/crt.ICC067},

doi = {10.4322/crt.ICC067},

year  = {2017},

date = {2017-01-01},

pages = {99-106},

abstract = {Copper (Cu) deficiency affects young citrus trees mostly when fertilized with high nitrogen (N) rates and under reduced foliar applications of Cu-based fungicides. On the other hand, trees are prone to Cu toxicity resulting from excessive applications of fungicides to control foliar and fruit diseases in the orchards. Despite Cu present in pesticides is generally found in a water-insoluble form, which facilitates the formation of a pathogen protective layer on plant canopy surfaces, frequent use of these products causes an increases in Cu concentrations in soils and consequently root absorption of the metal. Copper deficiency reduces tree yield capacity by damaging many enzyme systems in plants, as well electron transport in the photosynthesis, whereas toxicity causes metabolic dysfunctions, mainly by increasing oxidative stress levels. This article summarizes the role of Cu nutritional disorders on nutrient status and production of citrus trees, as a basis for fine tuning health management of orchards required for superior plant productivity. O cobre na produção dos Citrus: necessário, porém prescindido RESUMO A deficiência de cobre (Cu) afeta plantas jovens de citros, principalmente quando adubadas com altas doses de nitrogênio (N) e sob reduzidas aplicações foliares de fungicidas cúpricos. Por outro lado, os citros estão sujeitos à toxicidade por Cu devido ao uso excessivo desses fungicidas para o controle de doenças foliares e de frutos nos pomares. Apesar do Cu nos fungicidas estar geralmente presente na forma insolúvel em água, o que facilita a formação de um filme de proteção contra o patógeno na superfície das folhas, o uso frequente desses produtos causa aumento na concentração de Cu no solo e consequentemente as raízes passam a absorver o metal. A deficiência de Cu reduz a produtividade das plantas por afetar a atividade de diversas enzimas, bem como o transporte de elétrons na fotossíntese, enquanto que a toxicidade causa disfunções metabólicas, principalmente pelo aumento dos níveis de estresse oxidativo. Este artigo apresenta os efeitos dos distúrbios nutricionais causados por Cu no estado nutricional e na produção de plantas cítricas, como base para o ajuste do manejo dos pomares de alta produtividade. Termos de indexação: Citrus, fungicidas cúpricos, nutrição de plantas, micronutriente. Hippler et al.},

keywords = {copper-based pesticides, Index terms: Citrus, micronutrient, plant nutrition},

pubstate = {published},

tppubtype = {article}

}