Effect of foliar and soil application of urea on leaf nutrients concentrations, yield and fruit quality of pomegranate

Abstract

The influence of foliar application of 1% urea and four rates of urea (100, 200, 300 and 400 g tree -1 ) as soil application (deep fertilizer placement) were studied on leaf nutrients concentrations, yield and fruit quality of 'Malas e Torsh e Saveh' pomegranate (Punica granatum L.) during 2010 and 2011 growing seasons. Trees that received 300 and 400 g urea as soil application showed positive significant response on fruit yield, average fruit weight, aril weight percent of fruit, 100 arils weight, fruit diameter and TSS. Foliar application of urea had also significant effects on average fruit weight, aril weight percent of fruit and 100 arils weight.Nitrogen concentration increased linearly in leaves with the increase in rate of urea-applied.According to results, deep soil application of urea under the conditions of this study was more effective on pomegranate fruit yield and quality characters than foliar application of urea.

Effects of Foliar Nano-nitrogen and Urea Fertilizers on the Physical and Chemical Properties of Pomegranate (Punica granatum cv. Ardestani) Fruits

“…Although no information on N sufficiency ranges in pomegranate are available to the best of our knowledge, leaf N concentrations lower that 2% are generally considered low in many fruit tree crops, including almond, apple, apricot, cherry, fig, lemon, and peach (Benton-Jones et al, 1991). Similar leaf N concentrations (in the range 1.73% to 1.94%) to those found here have been reported in Iranian pomegranate trees grown in the field without any fertilization (Hasani et al, 2012(Hasani et al, , 2016 or with a standard fertilizer management (Davarpanah et al, 2016a). In one of the main pomegranate crop areas in Turkey the N leaf concentrations in August were 2.2%, values higher than those found here (Korkmaz and Askin, 2015).…”

“…Foliar N treatments led to increases in the leaf N concentration up to values higher than 2%, with the exception of the more diluted nanofertilizer (nN1). Increases found in the concentration of N in pomegranate leaves after N fertilization are similar to those observed in grape (Delgado et al, 2006), apple (Amiri et al, 2008), and pomegranate trees (Hasani et al, 2016), and a positive linear correlation between the N concentrations applied and leaf N concentration has also been reported in pomegranate (Hasani et al, 2016). In most previous studies foliar N sprays led to increases in the concentration of N in the leaves, but it is known that the internal distribution of N absorbed after foliar fertilization depends on the timing of application.…”

“…Foliar N treatments improved fruit yield mainly due to increases in the number of fruits per tree, with the best results being obtained with the treatments supplying 2.7 and 24.4 g N/tree (nN1 and U1, respectively). Increases in yield and number of fruits per tree with N fertilization have been previously reported on citrus (El-Otmani et al, 2002;Lovatt, 1999), apple (Amiri et al, 2008), sweet cherry (Mitre et al, 2012), and mango (Sarker and Rahim, 2013), whereas in pomegranate trees it has been reported that soil urea application increased fruit yield and number of fruits per tree, with urea sprays being ineffective in increasing fruit yield (Hasani et al, 2016). Processing of N uptake by plant roots can be limited by soil low temperature and low activity of roots, whereas foliar N application is insensitive to those factors (Etehadnejad and Aboutalebi, 2014).…”

“…Therefore, the five treatments used were control, nN1, nN2, U1, and U2. Similar foliar urea doses (0.5% to 2%) have been recently used in foliar fertilization experiments in pomegranate trees (Hasani et al, 2016;Ramezanian et al, 2009). The fertilizer solution was prepared by diluting the nN commercial liquid product or commercial urea with underground water available in wells in the orchard.…”

“…Urea is the most commonly used N source for foliar fertilization (Etehadnejad and Aboutalebi, 2014;Fern andez et al, 2013;Swietlik and Faust, 1984) due to several characteristics, including its high solubility in water, nonpolarity, rapid leaf absorption, and low phytotoxicity (Bondada et al, 2001;Etehadnejad and Aboutalebi, 2014;Yamada et al, 1965). Although foliar fertilization is not aimed to fully replace soil fertilization, it has been found that the effects of foliar applications of urea in spring are similar or even better than those of soil applications regarding improvements in fruit yield and quality (Blasberg, 1953;Fisher and Cook, 1950;Hasani et al, 2016).…”