Influence of foliar applications of humic acids on yield and fruit quality of table grape cv. Italia

Abstract

<p style="text-align: justify;"><strong>Aims</strong>: The responses in growth, yield and quality components of a Vitis vinifera cultivar (Italia) to the foliar applications of two humic acids extracted from a soil and a compost have been studied.</p><p style="text-align: justify;"><strong>Methods and results</strong>: The foliar applications of the two humic acids were performed in two years and six different dates of the season. Both humic acids were tested at two different concentrations, 5 and 20 mg/L. Throughout the trial, different analyses were performed (SPAD, chlorophyll content, titrable acidity, soluble sugars, pH, yield). Grapevines treated with the two humic acids exhibited both significant increases in total chlorophyll content and reductions of the chlorophyll a/b ratio. Application of humic acids significantly decreased titrable acidity and increased °Brix/acidity ratio. Generally, the treatments with humic acids significantly increased berry size, and as a consequence the yield.</p><p style="text-align: justify;"><strong>Conclusions</strong>: Humic acids exerted some positive effects (chlorophyll content, acidity, berry size) in Italia table grape. Better results were obtained when the compost humic acid was sprayed.</p><p style="text-align: justify;"><strong>Significance and impact of study</strong>: This study gives new information about the positive effects of foliar application of humic acids, active components of soil and compost organic matter, on yield and fruit quality of table grape. In organic viticulture humic acids may find a valid and appropriate application for a technical and economical use.</p>

Desempenho do abacaxizeiro 'Vitória' em resposta à aplicação de ácidos húmicos durante a aclimatação

“…Tal mecanismo pode explicar os resultados obtidos, isto é, promoção do desenvolvimento radicular e acúmulo de nutrientes das plantas de abacazixeiro submetidas à aplicação de AH (Quadro 2 e 3). É possível que a ativação das H + -ATPases pelos AH promova a despolarização da membrana plasmática e, com isso, a ativação de transportadores secundários responsáveis pelo incremento da absorção de macro e micronutrientes (Sondergaard et al, 2004 Ferrara & Brunetti (2008), que, no entanto, verificaram diminuição da razão entre clorofila a e clorofila b. Por outro lado, Liu et al (1998) verificaram que a aplicação de ácidos húmicos (0, 100, 200, 400 mg L -1 ) na gramínea Agrostis stolonifera não alterou o teor de clorofila, apesar de ter afetado o processo fotossintético. As diferenças encontradas na literatura (Liu et al, 1998;Ferrara & Brunetti, 2008) indicam a presença de interações entre os fatores: fonte e dose de AH, genótipo e ambiente de cultivo.…”

“…Os ácidos húmicos (AH), formados por agregados moleculares heterogêneos e estabilizados por pontes de hidrogênio e interações hidrofóbicas (Piccolo, 2001), favorecem o desenvolvimento do sistema radicular Rodda et al, 2006;Zandonadi et al, 2007), o acúmulo de nutrientes (Vaughan & Malcolm, 1985;Chen & Avaid, 1990;Chen et al, 2004) e a biossíntese de clorofilas (Ferrara & Brunetti, 2008). Para culturas como arroz (Tejada & Gonzalez, 2004), trigo (Delfine et al, 2005) e videira (Ferrara & Brunetti, 2008), tem sido relatada a promoção de crescimento pela aplicação foliar de AH. Em abacaxizeiro, o uso de AH poderia ser uma estratégia viável na aclimatação de plantas propagadas in vitro, pois poderia promover maior crescimento, resultando em redução no longo tempo necessário para a transferência das plantas para o cultivo em campo.…”

<b>Impact of humic substances and nitrogen fertilising on the fruit quality and yield of custard apple

“…Humic substances, when applied directly onto the soil or substrate, have been used for plant production because these substances improve soil fertility and nutrient availability, according to Eyheraguibel et al (2008). Studies on the use of humic substances on fruit species are rarely reported in the literature; however, some investigations have been conducted with papaya (CAVALCANTE et al, 2011b), grape (FERRARA;BRUNETTI, 2008) and watermelon (SALMAN et al, 2005), with promising results. In addition, studies on fertilising yellow passion fruit with products containing humic substances developed under field conditions can be found in the scientific literature, including studies by Cavalcante et al (2008) and Cavalcante et al (2012b).…”

Fertigation of ‘BRS Princesa’ banana with humic substance and saponin-based plant extracts

“…There are reports about the mechanisms of action of HS on plants (Nardi et al, 2002;Façanha et al, 2002;Canellas et al, 2009;Canellas and Olivares, 2014;Nardi et al, 2016). Recent publication of research results involving commercial plantations is available in the literature (Ferrara andBrunetti, 2008, Hartz andBottoms, 2010;Lima et al, 2011;Selim and Mosa, 2012;Lodhi et al, 2013). However, information is still scarce for tropical fruit crops.…”