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The deficiency of calcium (Ca) reduces the quality and shelf life of fruits. In this scenario, although foliar spraying of Ca2+ has been used, altogether with soil fertilization, as an alternative to prevent deficiencies, little is known regarding its absorption dynamics by plant leaves. Herein, in vivo microprobe X-ray fluorescence was employed aiming to monitor the foliar absorption of CaCl2, Ca-citrate complex, and Ca3(PO4)2 nanoparticles with and without using adjuvant. We also investigated whether Sr2+ can be employed as Ca2+ proxy in foliar absorption studies. Moreover, the impact of treatments on the cuticle structure was evaluated by scanning electron microscopy. For this study, 45-day-old tomato (Solanum lycopersicum L., cv. Micro-Tom) plants were used as a model species. After 100 h, the leaves absorbed 90, 18, and 4% of aqueous CaCl2, Ca-citrate, and Ca3(PO4)2 nanoparticles, respectively. The addition of adjuvant increased the absorption of Ca-citrate to 28%, decreased that of CaCl2 to 77%, and did not affect Ca3(PO4)2. CaCl2 displayed an exponential decay absorption profile with half-lives of 15 h and 5 h without and with adjuvant, respectively. Ca-citrate and Ca3(PO4)2 exhibited absorption profiles that were closer to a linear behavior. Sr2+ was a suitable Ca2+ tracer because of its similar absorption profiles. Furthermore, the use of adjuvant affected the epicuticular crystal structure. Our findings reveal that CaCl2 was the most efficient Ca2+ source. The effects caused by adjuvant suggest that CaCl2 and Ca-citrate were absorbed mostly through hydrophilic and lipophilic pathways.

RESUMO

Potassium (K) is an essential element, which is often supplied to horticultural crops via foliar spraying. Some studies have investigated the effect of different foliar-applied K compounds; however, most studies have focussed on crop quality and yield parameters, or were performed with isolated leaf cuticles. The aim of this study was to evaluate the rates of the foliar ion penetration and leaf surface deposition of 130 mM K sprays of compounds with markedly different point of deliquescence (POD) and efflorescence (POE) values, the rates having been previously estimated in climate chamber trials. Shoots of field-grown, commercial olive trees were sprayed with K-nitrate (KNO3), K-sulphate (K2SO4), K-chloride (KCl), K-phosphate (K3PO4), K-carbonate (K2CO3) and K-bicarbonate (KHCO3), and leaf samples were collected after 3 and 24 h. Cation and anion concentrations were determined in the leaf tissues, and in a preliminary leaf water wash for estimating surface-deposited ion concentrations. No significant leaf tissue K increments were recorded between the K sprays. Olive tissue anion concentrations showed different patterns, and a chloride (Cl-) increase was detected 3 h after the foliar KCl supply. On the other hand, the foliar K applications led to leaf nitrate changes regardless of the K source supplied. High amounts of K and accompanying ions were recovered in the washing liquid of the foliar K-supplied leaves. Some foliar K treatments increased the leaf surface concentration of sulphate and chloride, suggesting a potential effect on leaf cell anion extrusion. Hence, despite no evidence of foliar K uptake, an effect of leaf anion concentrations was observed, indicating that foliar nutrient sprays may influence leaf and leaf surface anion balance.

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O objetivo geral desse trabalho foi desenvolver compostos de coordenação com os metais cobre, manganês, zinco, cobalto, níquel e magnésio com os aminoácidos L- ácido aspártico e glutâmico para aplicação como fertilizantes foliares e elucidação de seus prováveis mecanismos de absorção pela planta. Como plano de trabalho, pretendeu-se produzir alguns complexos metálicos com agentes complexantes que confiram características específicas: alta estabilidade termodinâmica e cinética quando comparado a quelatos usados comercialmente dos mesmos metais; alta solubilidade; compatibilidade com herbicidas e fungicidas e alta estabilidade frente a variações de pH. Os compostos foram caracterizados no estado sólido e/ou em solução aquosa, através de técnicas disponíveis em nosso laboratório, na Central Analítica do IQ-USP e/ou nos laboratórios da ICL América do Sul Ind. e Com. SA. Com o desenvolvimento dos compostos de coordenação, foram avaliados alguns parâmetros considerados imprescindíveis para garantia da qualidade do produto gerado, que foram então comparados aos de quelatos de EDTA (ácido etilenodiaminotetraacético) comercializados atualmente e que demonstraram vantagens. Para avaliar a eficiência dos produtos gerados foi realizada aplicação foliar em ao menos uma cultura e verificado o teor de cada nutriente após período de absorção e resposta produtiva, evidenciando e determinando o mecanismo de absorção realizado pela planta. Como resultado, desenvolveu-se uma série de produtos com alta tecnologia agregada que trouxeram benefícios nutricionais, sustentando uma nutrição de qualidade além de serem ecologicamente favoráveis (eco-friendly portfolio)

This project aims the development of copper, manganese, zinc, cobalt, nickel and iron metal complexes with L-amino acids aspartic and glutamic acids for application as foliar fertilizers and elucidation of the probable incorporation/absorption mechanism by plants. As a work plan, it was intended to produce these metal complexes with complexing agents that provide specific characteristics: high thermodynamic and kinetic stabilities when compared to the corresponding EDTA chelates; high solubility; compatibility with herbicides and fungicides and high stability against pH variations. With the development of such coordination compounds, some parameters considered indispensable to quality assurance were then evaluated, in comparison to that of currently available commercial EDTA chelates. To evaluate the performance of the obtained compounds, two foliar applications in the same crop were carried out. Further, the content of each nutrient after the production period and the productive capacity were evaluated, aiming to elucidate the absorption mechanism of the plant. As a result, elaborated products with high added technology were obtained, capable of ameliorating the nutritional benefits, that can support an eco-friendly portfolio

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Herbicides and foliar fertilizers are commonly associated in soybean crops. However, these mixtures can cause different effects on the plants, therefore requiring further studies. Herein, we assess the selectivity of post-emergence herbicides associated with foliar fertilizer (FF) in soybean crops (Roundup Ready). The experiment was carried out in a randomized block design with four replications. The treatments applied were: chlorimuron (17.5 g a.i. ha-1), chlorimuron + FF (17.5 + 693 g a.i. ha-1), cloransulam (40 g a.i. ha-1), cloransulam + FF (40 + 693 g a.i. ha-1), fomesafen (225 g a.i. ha-1), fomesafen + FF (225 + 693 g a.i. ha-1), glyphosate (1,280 g a.i. ha-1), glyphosate + FF (1,280 + 693 g a.i. ha-1), and two controls, being one with manual weeding and the other without weed control. Visual assessments of phytotoxicity and chlorophyll index were carried out weekly from seven to thirty-five days after applying the treatments (DAA). In these periods, chlorophyll levels were also assessed. In addition, the yield, 1000-grain weight, and moisture data were assessed at the end of the crop cycle. Phytotoxicity was higher than 30% when cloransulam and chlorimuron were applied, while phytotoxicity was close to 5% for fomesafen and glyphosate, either in the absence or presence of foliar fertilizer. There was no significant difference in grain yield, 1000-grain weight, and moisture. The association of herbicides with zinc-based foliar fertilizer did not influence the selectivity of post-emergence herbicides applied to the RR soybean.(AU)

A associação de herbicidas com fertilizantes foliares é comumente adotada na cultura da soja. Entretanto, essas associações podem ocasionar diferentes efeitos quando aplicadas na soja, necessitando portanto de maiores estudos. Assim, objetivou-se avaliar a seletividade de herbicidas pós-emergentes associados com fertilizante foliar (FF) à base de zinco na cultura da soja RR (resistente ao glifosato). O experimento foi conduzido em delineamento experimental de blocos casualizados, com quatro repetições. Os tratamentos aplicados foram chlorimuron (17,5 g i.a. ha-1); chlorimuron + FF (17,5 + 693 g i.a. ha-1); cloransulam (40 g i.a. ha-1); cloransulam + FF (40 + 693 g i.a. ha-1); fomesafem (225 g i.a. ha-1); fomesafem + FF (225 + 693 g i.a. ha-1); glyphosate (1.280 g i.a. ha-1); glyphosate + FF (1.280 + 693 g i.a. ha-1) e duas testemunhas sendo uma capinada e outra infestada. Foram realizadas avaliações visuais de fitotoxicidade aos 7, 14, 21, 28 e 35 dias após a aplicação dos tratamentos (DAT), e também nessas épocas os teores de clorofila. Ao final do ciclo da cultura foram determinados os dados referentes a produtividade e o peso de 1000 grãos. A fitotoxicidade foi superior a 30% quando se aplicou o cloransulam e o chlorimuron, enquanto que para o fomesafem e o glyphosate a fitotoxicidade foram próximas a 5%, na ausência ou presença do fertilizante foliar. Não ocorreu diferença significativa para a produtividade de grãos, peso de 1000 grãos e umidade. A associação de herbicidas com fertilizante foliar a base de zinco não influenciou na seletividade dos herbicidas aplicados em pós-emergência na cultura da soja RR.(AU)

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Soybean is one of the most demanding annual crops in boron (B), however, there is a divergence regarding the best phenological stage to carry out this application via foliar. Therefore, the objective of the present work was to evaluate the influence of different times of foliar application of B, with and without splitting, on flowering, productivity, and components of soybean production. For this, an experiment was carried out in the field, the experimental design used was in randomized blocks, with seven times of foliar applications of B (control, 100% 15 V4, 100% R1, 100% R3, 50% V4 + 50% R1, 50% V4 + 50% R3 and 50% R1 + 50% R3) and four replications, totaling 28 experimental plots. The number of flowers, number of beginning pod, B content in plants, weight of 1000 grains (g) and productivity were analyzed. The highest B content was observed with applications in the V4 (50%) + R1 (50%) and V4 (50%) + R3 (50%) stages, that is, part in the vegetative stage and part in the reproductive stage. The application of B did not result in a significant difference in relation to the number of inflorescences per plant. There was no significant effect of the times of foliar application of B for the variable of number of pods per plant, number of inflorescences and productivity. For weight of 1000 grains (g) higher values were found in V4, R1 and R3 and in the control. Therefore, the foliar application of boron in the stages V4 (50%) + R1(50%) and V4(50%) + R3 (50%) increased the levels of B in the plant, while in R1+R3 it provided the highest number of beginning pods. However, there was no effect of boron application for grain yield regardless of the time of application.(AU)

A soja é uma das culturas anuais mais exigentes em boro (B), no entanto, existe uma divergência em relação sobre qual melhor estádio fenológico para efetuar essa aplicação via foliar. Logo, o objetivo do presente trabalho foi avaliar a influência de diferentes épocas de aplicação foliar de B, com e sem parcelamento no florescimento, produtividade e componentes da produção da soja. Para tal, foi realizado um experimento em campo, o delineamento experimental utilizado foi em blocos ao acaso, com sete épocas de aplicações foliares de B (testemunha, 100% 15 V4, 100% R1, 100% R3, 50% V4 + 50% R1, 50% V4 + 50% R3 e 50% R1 + 50% R3) e quatro repetições, totalizando 28 parcelas experimentais. Foram analisados o número de flores, número de canivete, teor de B nas plantas, peso de 1000 grãos (g) e a produtividade. O maior teor B foi observado com aplicações nos estádios V4 (50%) + R1 (50%) e V4 (50%) + R3 (50%) isto é, parte no estádio vegetativo e parte no estádio reprodutivo. A aplicação de B não resultou em diferença significativa em relação ao número de inflorescências por planta. Não houve efeito significativo das épocas de aplicação foliar de B para a variável de número de vagens por planta, número de inflorescências e produtividade. Para peso de 1000 grãos(g)foram encontrados maiores valores em V4, R1 e R3 e na testemunha. Portanto, a aplicação foliar de boro nos estádios V4 (50%) + R1 (50%) e V4 (50%) + R3 (50%) aumentou os níveis de B na planta, enquanto em R1+R3 proporcionou o maior número de canivetes. No entanto, não houve efeito da aplicação de boro para a produtividade de grãos independente da época de aplicação.(AU)

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Foliar fertilization with calcium (Ca) and boron (B) at flowering can promote flower retention and pod fixation, thereby increasing the number of pods per plant and, in turn, crop productivity. The objective of this work was to investigate the effects of Ca + B fertilization during flowering on the nutritional, metabolic and yield performance of soybean (Glycine max L.) The treatments consisted of the presence and the absence of Ca + B fertilization in two growing seasons. Crop nutritional status, gas exchange parameters, photosynthetic enzyme activity (Rubisco), total soluble sugar content, total leaf protein concentration, agronomic parameters, and grain yield were evaluated. Foliar Ca + B fertilization increased water use efficiency and carboxylation efficiency, and the improvement in photosynthesis led to higher leaf sugar and protein concentrations. The improvement in metabolic activity promoted a greater number of pods and grains plant-1, culminating in higher yields. These results indicate that foliar fertilization with Ca + B can efficiently improve carbon metabolism, resulting in better yields in soybean.

RESUMO

This study was developed to examine the growth, yield, chemical composition and in situ degradability of elephant grass cv. Napier (Pennisetum purpureum). Five spraying protocols with biostimulants were tested, namely, Control - no application; 1BR - bioregulator at seven days; 2BR - bioregulator at seven days + bioregulator and foliar fertilization at 20 days; 2BR2 - bioregulator at seven days + bioregulator and foliar fertilization at 20 days + ethylene inhibitor at 30 days; and 3BR - bioregulator at seven days + bioregulator and foliar fertilization at 20 days + ethylene inhibitor and bioregulator at 30 days. The grass was cut evenly at a height of 15 cm and harvested at 70 days of regrowth. The experimental area was divided into two blocks according to the slope. Ninety plots were used, totaling an area of 4,608 m2. Each plot was composed of four 4-m rows spaced 80 cm apart. Chemical composition, morphological traits and forage digestibility data were evaluated. The 3BR protocol, with more bioregulator-based applications, resulted in higher canopy (9.78%) and stem (9.58%) compared with control group. The 2BR and 2BR2 treatments provided a 6.5% higher stem than control treatment. The improvement in the nutritional value of Pennisetum purpureum cv. Napier was due to the 17.55% increase in crude protein (CP) content provided by protocol 3BR relative to control group. Treatments 2BR2 and 3BR improved the effective degradability of dry matter (DM). The application of biostimulant protocols increased the potential degradability of neutral detergent fiber (NDF) (+4.1%), with the greatest response seen in treatment 2BR2 in comparison with control treatment. Biostimulant protocols increase the canopy and stem heights and CP content. The application of a bioregulator associated with foliar fertilization and ethylene inhibitor improves the effective degradability of DM and NDF and the potential degradability of NDF in Pennisetum purpureum cv. Napier harvested at 70 days of regrowth.(AU)

Objetivou-se avaliar o crescimento, a produtividade, a composição bromatológica e a degradabilidade in situ do capim-elefante cv. Napier (Pennisetum purpureum). Foram efetuados cinco diferentes protocolos de pulverização com bioestimulantes: Controle - nenhuma aplicação, 1BR - biorregulador aos 7 dias; 2BR - biorregulador aos 7 dias, biorregulador e adubação foliar aos 20 dias; 2BR2 - biorregulador aos 7 dias, biorregulador e adubação foliar aos 20 dias, inibidor de etileno aos 30 dias; 3BR - biorregulador aos 7 dias, biorregulador e adubação foliar aos 20 dias, inibidor de etileno e biorregulador aos 30 dias. Foi realizado o corte de uniformização do capim a 15 centímetros de altura, sendo a colheita efetuada aos 70 dias de rebrota. A área experimental foi dividida em dois blocos de acordo com a declividade. Foram utilizadas 90 parcelas, totalizando 4.608 m2 de área. Cada parcela foi composta por quatro linhas de quatro metros cada, com espaço entrelinhas de 80 centímetros. Os dados foram avaliados quanto à composição química, características morfológicas e digestibilidade da forragem. O protocolo 3BR, com mais aplicações à base de biorreguladores, resultou em dossel maior (9,78%) e maior altura de caule (9,58%) em relação ao grupo controle, bem como os tratamentos 2BR e 2BR2 promoveram aumento da altura de caule em 6,5% se comparado com tratamento controle. A melhoria no valor nutricional do Pennisetum purpureum cv. Napier se deu em função da elevação no teor de proteína bruta (PB) de 17,55% em relação ao grupo controle com o protocolo 3BR. Houve aumento da degradabilidade efetiva da matéria seca (MS) para os tratamentos 2BR2 e 3BR. A aplicação dos protocolos de bioestimulantes aumentou a degradabilidade potencial da fibra em detergente neutro (FDN) (+4,1%), com maior resposta para o tratamento 2BR2 em relação ao tratamento controle. Os protocolos de bioestimulantes elevam a altura do dossel e do caule e incrementam o teor de PB. A aplicação de biorregulador, associado à adubação foliar e inibidor de etileno melhora a degradabilidade efetiva da MS e FDN e a degradabilidade potencial da FDN do Pennisetum purpureum cv. Napier cortado aos 70 dias de rebrota.(AU)

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In rainy locations, sweet cherry is cultivated under plastic covers, which are useful to prevent fruit cracking but decrease cherry quality such as firmness and acidity. Here we evaluate the impact of pre-harvest K foliar applications on harvest and post-harvest fruit quality and condition of sweet cherry cultivated under plastic covers in southern Chile orchards. The study was performed on two commercial orchards (cv. Regina), located in different regions, during two consecutive seasons. In all cases, a conventional K regime (four sprays) was compared to an intensive K regimen (seven sprays). Results showed that cherries from the most southern region revealed lower acidity but higher soluble solids content weight and size. The intensive K regime improved the firmness and acidity of fruits of covered trees at harvest and post-harvest. Moreover, we found that condition defects were higher in fruits from un-covered trees and that trees grown under intensive K regime showed lower levels of cracking at harvest and pitting at post-harvest compared to trees treated with the conventional K regime. Otherwise, pedicel browning was inconsistently affected by K sprays. Our results revealed that an intensive K regime could improve the quality and condition of fruits at harvest and post-harvest in covered orchards of sweet cherry cv. Regina; however, the impacts can significantly vary depending on season and locality.

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RESUMEN Aunque el zinc (Zn) es un microelemento esencial para la nutrición del café por su efecto directo sobre el crecimiento y porque sus deficiencias en las etapas vegetativas son cada vez más comunes, son pocas las investigaciones relacionadas con este nutriente en Colombia. Por ello, con el objetivo de evaluar la respuesta del café variedad Colombia renovado por zoca a la fertilización con zinc (Zn), se realizó una investigación en tres localidades: Venecia, Gigante y Timbío. Los tratamientos consistieron en tres dosis de Zn (5, 10 y 20 kg.ha-1), aplicadas al suelo en forma de óxido (ZnO), y tres dosis de Zn (0,045, 0,09 y 0,18 kg.ha-1), aplicadas vía foliar como quelato, además de un testigo sin aplicación de Zn. Durante el primer año, la aplicación edáfica se realizó a los dos y ocho meses después del zoqueo, y a partir del segundo año, cada seis meses con la recomendación NPK según el análisis de suelo. La aplicación foliar se realizó a los 60 y 90 días después del pico de floración tanto para la cosecha principal como para la mitaca de cada sitio. Se midió la producción anual de café cereza y acumulada durante cuatro años. Para las condiciones del estudio la fertilización edáfica o foliar de Zn no tuvo efectos significativos en la producción de café cereza pero si se registraron aumentos en los niveles de Zn en el suelo y en las hojas.

ABSTRACT Even though Zn is an essential micronutrient for coffee nutrition due to its direct effect on plant growth and because Zn deficiencies are more and more frequent, research related to this nutrient in coffee in Colombia is still little. For these reasons, aiming to determine the Colombian variety coffee crop response to zinc fertilization (Zn) in three sites of the Colombian coffee region, the supply of three Zn rates applied to soil in the form of ZnO (5, 10 and 20 kg.ha-1), and three doses of Zn quelate applied via foliar (0.5, 1.0 and 2.0 kg.ha-1), plus a control without Zn were evaluated. The research was carried out in three sites: Venecia, Gigante and Timbio. During the first year soil treatments were applied two and eight months after trimming, and from the second year the edaphic application was carried out every six months simultaneously with the NPK recommendation according to soil analysis. Foliar application was carried out at 60 and 90 days after the blooming peak for both main harvest and the "mitaca" of each site. Coffee berries yield annually and accumulated over four years were analyzed. For the study conditions the Zn application both edaphic and foliar did not affect significantly coffee yield but did increase the Zn contents at soil and leaves.

RESUMO Embora o zinco (Zn) seja um microelemento essencial para a nutrição do café devido a seu efeito direto no crescimento e porque suas deficiências nas etapas vegetativas são cada vez mais comuns, há pouca pesquisa relacionada a este nutriente na Colômbia. Por esta razão, com o objetivo de avaliar a resposta do café da variedade Colômbia, renovado pelo zoca, à fertilização com zinco (Zn), foi realizada uma investigação em três locais: Venecia, Gigante e Timbío. Os tratamentos consistiram em três doses de Zn (5, 10 e 20 kg.ha-1), aplicadas ao solo na forma de óxido (ZnO), e três doses de Zn (0,045, 0,09 e 0,18 kg.ha-1), aplicadas por aplicação foliar como quelato, além de um controle sem aplicação de Zn. Durante o primeiro ano, a aplicação do solo foi realizada dois e oito meses após a enxada, e a partir do segundo ano, a cada seis meses com a recomendação da NPK de acordo com a análise do solo. A aplicação foliar foi feita aos 60 e 90 dias após o pico de floração, tanto para a cultura principal como para a mitaca em cada local. A produção anual e cumulativa de café cereja foi medida ao longo de quatro anos. Para as condições do estudo, a fertilização do solo ou foliar Zn não teve efeito significativo na produção de café cereja, mas foram registrados aumentos nos níveis de solo e de Zn foliar.

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O milho representa um dos principais cereais cultivados e consumidos no mundo, apresentando, no entanto, baixa produtividade quando comparado ao potencial produtivo da cultura. A fim de direcionar esforços para maximizar a eficiência produtiva da cultura do milho, este trabalho teve por objetivo avaliar o desenvolvimento e produtividade de quatro genótipos de milho (variedade IPR114, o híbrido simples SYN7B28, o híbrido duplo FEROZ e o híbrido triplo DEFENDER) submetidos a diferentes modos de aplicação de zinco (1- testemunha; 2- sulfato de zinco via semente; 3- produto Always® via foliar em uma aplicação e 4- produto Always® via foliar em duas aplicações). O experimento foi conduzido na Fazenda Escola Capão da Onça, Universidade Estadual de Ponta Grossa, Ponta Grossa/PR, em delineamento experimental blocos casualizados, constituindo um fatorial 4x4, com 4 repetições. As variáveis analisadas foram: diâmetro de colmo, altura de planta, número de folhas por planta; altura da inserção da primeira espiga, número de fileira por espiga, número de grãos por fileira, produtividade e massa de 1000 grãos. Os modos de aplicação de Zn pouco influenciaram o desenvolvimento vegetativo dos genótipos de milho. A variedade IPR114 apresentou menor produtividade e não respondeu a aplicação de Zn. Os modos de aplicação de Zn testados foram eficientes, aumentando significativamente a produtividade dos híbridos de milho SYN7B28, FEROZ e DEFENDER, sendo o híbrido triplo (DEFENDER) mais responsivo.

Corn represents one of the main cereals cultivated and consumed around the world, however, presenting low productivity when compared to the crop productive potential. In order to direct efforts to maximize the productive efficiency of the corn crop, this work aimed to evaluate the development and productivity of four maize genotypes (variety IPR114, the simple hybrid SYN7B28, the double hybrid FEROZ and the triple hybrid DEFENDER) submitted to different modes of zinc application (1- control; 2- zinc sulfate through seeds treatment; 3- Always® product through a foliar application and 4- Always® product through two foliar applications). The experiment was carried out at School Farm Capão da Onça, State University of Ponta Grossa, Ponta Grossa/PR, in a randomized block design, constituting a 4x4 factorial, with 4 replications. The variables analyzed were stalk diameter, shoot height, number of leaves per plant; height of insertion of the first cob, number of rows per cob, number of grains per row, mass of 1000 grains and productivity. The methods of application of Zn had little influence on the vegetative development of maize genotypes. The IPR114 variety showed lower productivity and did not respond to the application of Zn. The tested Zn application methods were efficient, significantly increasing the productivity of the SYN7B28, FIERCE and DEFENDER corn hybrids, being the triple hybrid (DEFENDER) more responsive.

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