Effects of the times of application of a soil humic acid on berry quality of table grape (Vitis vinifera L.) cv Italia

Abstract

Humic acids are the most active components of soil organic matter and have been shown to have an hormone-like activity thus stimulating plant growth. The objective of this work was to verify the quantitative and qualitative yield responses of the table grape cv. Italia after the application of a humic acid at various phenological stages. The humic acid used in this study has been extracted from a clay soil of the Apulia region and was applied at a concentration of 100 mg L -1 in four different times: pre-bloom (I), full-bloom (II), fruit set (III) and veraison (IV) and in two years, 2007 and 2008. The following parameters were measured at harvesting: berry size, °Brix, pH and titratable acidity. Finally, the °Brix/titratable acidity ratio has been calculated. Soil Plant Analysis Development (SPAD) readings were performed every 30 days up to harvesting time on the leaves of the middle shoots. No statistical differences were observed between the two years for all the parameters examined. The humic acid applied at full-bloom (II) induced a significant increase of berry size (width and weight) and a significant improvement of the other quality parameters (titratable acidity and °Brix/titratable acidity) with respect to the control. This study confirmed that humic acids, if applied at full-bloom, can induce significant increase of qualitative and quantitative parameters in table grape and can find a positive application in an organic and sustainable viticulture.Additional key words: foliar sprays, hormone-like activity, overhead system («tendone»), phenological stages, SPAD. ResumenEfectos de los tiempos de aplicación de un ácido húmico del suelo sobre la calidad de las bayas de uva de mesa (Vitis vinifera L.) cv Italia Los ácidos húmicos son los componentes más activos de la materia orgánica del suelo y se ha demostrado que tienen una actividad similar a las hormonas, estimulando así el crecimiento de las plantas. El objetivo de este trabajo fue verificar los incrementos en el rendimiento cuantitativo y cualitativo de la uva de mesa cv. Italia después de la aplicación de un ácido húmico en diferentes etapas fenológicas. El ácido húmico se extrajo de un suelo arcilloso de la región de Apulia y se aplicó a una concentración de 100 mg L -1 en cuatro momentos diferentes: pre-flor (I), plena floración (II), fruto (III) y envero (IV), y en dos años, 2007 y 2008. Se midieron los siguientes parámetros en la época de la cosecha: tamaño de la baya, °Brix, pH, acidez titulable y ratio °Brix/acidez titulable. Cada 30 días hasta la épo-ca de cosecha se realizaron lecturas SPAD sobre las hojas de los brotes medios. Para todos los parámetros examinados no se observaron diferencias estadísticas entre los dos años. El ácido húmico aplicado en plena floración (II) indujo un aumento significativo del tamaño de las bayas (anchura y peso) y una mejora significativa de los demás parámetros de calidad (acidez titulable y °Brix/acidez) con respecto al control. Este estudio confirmó que los ácidos húmicos, si se aplican en plena flo...

Effect of some Organic and Bio-Fertilizers on" Thompson Seedless" Grapevines Under New Reclaimed Sandy Soil

“…Supplying the vines with N as 25 to 75% inorganic N plus organic manures enriched with algae was preferable in improving quality of the berries in terms of increasing berry weight and dimensions, TSS, Tss/acid ratio and reducing sugars and decreasing total acidity% and both nitrate and nitrite in the juice rather than application of N via inorganic N fertilization alone (Mohamed et al, 2014). Humic acid is the active constituents of organic humus, which can play a very important role in soil conditioning and plant growth and they have different effects on plants (Ferrara and Brunetti, 2010). Humic acid play an important role directly and indirectly in nutrition of the plants (Lobartini et al, 1997).…”

EFFECT OF POTASSIUM HUMATE APPLICATIONS ON FRUIT YIELD AND THEIR QUALITY OF Carica papaya PLANT GROWN UNDER ORGANIC CULTURE CONDITIONS

“…Humic substances are recognized as a key component of soil fertility properties, since they control chemical and biological properties of the rhizosphere (Nardi et al, (2005) that are divided into three main fractions: humic acids, fulvic acids and humin. Accordingly, humic acids are the main fractions of humic substances and the most active components of soil and compost organic matter (Ferrara and Brunetti, 2010). Humic substances have been used on plant production directly on soil or substrate due to the two relations of these substances with soil fertility and availability of nutrients (Eyheraguibel et al, 2008).…”

Characterization of terrestrial dissolved organic matter fractionated by pH and polarity and their biological effects on plant growth

“…Peaks at even nominal masses are those that contain either an odd number of nitrogen atoms or are 13 C isotopes of the 12 C peaks at the previous nominal mass [39]. The presence of the 13 C isotopes 1.0034 m/z units away from their corresponding 12 C peaks indicate that the ions are singly charged [39,40]. Numerous peaks (up to 25) were detected at each nominal mass, indicating the complexity of each sample.…”

“…All samples were analyzed at a range of DOC values (approximately 0.5-8 mg/L C), and acquired spectra were corrected for their inner filter effects and Rayleigh masking using the Aqualog V3.6 software, which was also utilized for area integrations. Humic-like peaks A and C were integrated at [Ex 240-300 nm; Em 400-500 nm] and [Ex 300-360 nm; Em 400-500 nm], respectively, while peptide-like peak T was integrated at [Ex 240-300 nm; Em 250-350 nm] [12]. Specific UV absorption at 254 nm (SUVA254) was calculated based on the absorbance at 254 nm and the DOC concentration [31], and the fluorescence index (FI) was calculated from the ratio of emission intensity at 470:520 nm at excitation 370 nm [24,32].…”

“…Humic substances have long been regarded as beneficial to soil fertility and plant growth, and there are multiple excellent reviews on the subject that encompass decades of studies [4][5][6]. The positive outcomes are likely a combination of both direct and indirect effects, and humic substances have been shown to suppress the effect of pathogens and fungi, enhance lateral root development and root length/density, increase the cation exchange capacity and pH buffering capacity of soils, increase the availability and uptake of micronutrients, and promote growth and development via a hormone-like mechanism [7][8][9][10][11][12][13]. While there are many studies that have demonstrated improved plant health by treatment with humic substances, several questions remain, such as the best way to treat plants (seed vs. soil vs. foliar application), the rate/amount for treatment, and when to perform application(s), among numerous others.…”