Contribution of nitrogen from urea applied at different rates and times on grapevine nutrition

Abstract

In Brazilian vineyards planted in sandy soils, nitrogen (N) should be applied at optimal rates and timing that correspond to greatest demand, thus minimizing N losses. The aim of this study was to evaluate the grapevine N distribution and recovery of urea-15 N applied at budding and bloom. In 2009, in a vineyard (Vitis vinifera cv. Cabernet Sauvignon) planted in Santana do Livramento, south Brazil, grapevines were treated with 10 kg N ha −1 at budding +10 kg N ha −1 at full bloom (10B + 10F); 20 kg N ha −1 at budding +20 kg N ha −1 at full bloom (20B + 20F); 20 kg N ha −1 at budding (20B); and 40 kg N ha −1 at full bloom (40F). Budding of grapevines in 2009 and 2010 was at the end of August and full bloom in November. In February 2010 and 2011, grapevine organs (leaves, berries, stem and roots) were collected, and in February 2011 soil samples were also collected in the profile. The wine-producing grapevines grown in the sandy soil took up more N derived from 20B treatment, compared with other N treatments, especially in the first crop season. The N derived from fertilizer applied at different rates and time was preferentially distributed in annual plant organs, but most N contained in the plant organs was derived from other sources than the fertilizer N. In the following season, 15 N applied in the previous year was recovered preferentially in leaves and fruits, again in low amounts. Nitrogen derived from fertilizer applied at different rates and time in a sandy soil apparently contributes little to grapevine nutrition.

Yield and must composition of 'Cabernet Sauvignon' grapevines subjected to nitrogen application in soil with high organic matter content

“…On the other hand, N added to the soil may be related to the high root emission capacity of grapevines during budding and especially at flowering (Radville et al, 2016). This potentiates the uptake of water and nutrients, such as N present in soil, or of N forms resulting from the application of urea at budding (Brunetto et al, 2016).…”

“…The leaves collected at veraison were also sensitive in detecting the increase of N in the plants subjected to applications of increasing N doses in soil (Table 1), most likely derived from the fertilizer and other soil sources (Brunetto et al, 2014;Brunetto et al, 2016). The increase of N content in the tissue at veraison increased even at doses of 76 and 59 kg of N ha -1 in crop seasons 2012/13 and 2013/14, respectively.…”

“…Together with mild temperatures (25ºC), it stimulates the action of extracellular enzymes such as urease, which degrade the urea molecule, increasing the infiltration of N forms in soil, both of the fertilizer and of the mineralization of organic matter or decomposing residues. This process reduces N losses by volatilization in the form of ammonia (Lorensini et al, 2012), enhancing the uptake of N forms by the grapevines (Brunetto et al, 2016). There was high rainfall (1400 mm) in crop season 2012/13, but it was 25% lower than in 2013/14.…”

“…Part of the soil organic matter and plant residues deposited on the soil may be mineralized by the microbial population, increasing the concentration of N forms in soil solution, which can be absorbed by the grapevines (Barlow et al, 2009;Burns et al, 2016), reducing the use of N derived from the fertilizer (Agnelli et al, 2014;Brunetto et al, 2016). However, part of the N derived from higher N doses may be lost in vineyards by surface runoff (Sorrenti & Toselli, 2016) leaching (Lorensini et al, 2012) and volatilization as ammonia and nitrous oxide (Lorensini et al, 2012;Hannam et al, 2016), reducing the amount of N derived from the fertilizer used by the plants (Brunetto et al, 2016).…”

“…The bicarbonate may possibly decompose into carbon dioxide and hydroxyl. If ammonium reacts with hydroxyl, ammonia may be prompted by the atmosphere (Brunetto et al, 2016). However, part of this ammonium can be transformed into nitrate, which is the most stable mineral form of N in the soil.…”