Nutrient Management Effects on Wine Grape Tissue Nutrient Content

Abstract

With limited research supporting local nutrient management decisions in North Carolina grape (Vitis vinifera) production, field studies (2015–17) were conducted to evaluate late season foliar nitrogen (N) application on leaf and petiole N concentration and yeast assimilable N (YAN) in the fruit. Foliar urea (1% v/v) was applied at different rates and application times beginning pre-and post-veraison. Compared to soil applied N, late season foliar N substantially enhanced petiole N and grape YAN. Smaller split N applications were generally more effective in increasing YAN than single larger N rates. These data demonstrate the value of assessing plant N content at full bloom with petiole N analysis or remote sensing to guide foliar N management decisions. Additional field studies (2008–11) were conducted to evaluate pre-bud soil applied phosphorus (P) and potassium (K) effects on petiole P and K nutrient status. Fertilizer P and K were initially broadcast applied (0–896 kg P2O5 ha−1; 0–672 kg K2O ha−1) prior to bud-break in 2008–09 and petiole P and K at full bloom soil test P and K were monitored for three to four years after application. Soil test and petiole P and K were significantly increased with increasing P and K rates, which subsequently declined to near unfertilized levels over the sampling time depending on site and P and K rate applied. These data demonstrate the value of annually monitoring petiole P and K levels to accurately assess plant P and K status to better inform nutrient management decisions.

Evaluation of foliar applications of urea at three concentrations on grape amino acids composition

“…In other cases, YAN concentration did not increase when initial YAN concentration in control sample was higher than 140 mg N L −1 . 3,15,18 However, in other previous studies, YAN concentration increased when initial YAN concentration was lower 8,14,19 or higher [9][10][11][15][16][17]28 than 140 mg N L −1 .…”

“…Ancín‐Azpilicueta et al 11 . found that foliar application increased pH and total acidity in Tempranillo must and Havlin et al 17 . found that malic acid concentration increased after applying urea.…”

“…applied urea from veraison to harvest (2 and 4 kg N ha −1 ), Garde‐Cerdán et al 9 . sprayed 0.9 kg N ha −1 at veraison and Havlin et al 17 . sprayed different urea doses (between 11.2 and 44.8 kg N ha −1 ) from pre‐veraison to post‐veraison.…”

“…and Jiménez‐Moreno et al 10 . However, there are other studies that started spraying treatments before veraison and finish at post‐veraison such as Hannam et al ., 16 Havlin et al 17 . and Lasa et al 3 .…”

“…6 Regarding application timing, previous studies assessed the effect of providing sprays at different times during the growing season at different frequencies of application. Most studies have evaluated the impact of foliar applications sprayed at one moment, and veraison was the most common moment for urea treatments, such as Tozzini et al, 15 Garde-Cerdán et al, 9 Pérez-Álvarez et al 13 and Jiménez-Moreno et al 10 However, there are other studies that started spraying treatments before veraison and finish at post-veraison such as Hannam et al, 16 Havlin et al 17 and Lasa et al 3 which sprayed at three different plant developmental stages (pre-veraison, veraison and post-veraison). Moreover, previous urea foliar application investigations were developed with various urea doses.…”