Foliar application of low-biuret urea and humic acid influences on the growth and leaf mineral composition of Nonpareil almond seedlings under South Sinai conditions

Abstract

A field experiment was conducted on almond seedlings (Prunus amygdalus B.) cv. Nonpareil to study the effect of low-biuret urea (LBU) and humic acid foliar spray on growth and leaf nutrient status at two seasons (2014 and 2015) in El Tor, South Sinai governorate, Egypt. There were nine treatments namely, T1- Control, T2- 2 g/L LBU, T3- 3 g/L LBU, T4- 2 g/L humic acid, T5- 3 g/L humic acid, T6- 2 g/L LBU +2 g/L humic acid, T7- 2 g/L LBU +3 g/L humic acid, T8- 3 g/L LBU +2 g/L humic acid and T9- 3 g/L LBU + 3 g/L humic acid  with three replications under randomized complete block design, five seedlings were considered a replicate. The results indicated that the maximum stem length (127.90 and 128.28 cm), stem diameter (27.21 and 28.33 mm), leaf area (3.35 and 3.43 cm²), shoot fresh weight (58.52 and 72.19 g) and shoot dry weight (59.06 and 61.93 g) during 2014 and 2015 season, respectively were recorded in T8 treatment. Maximum number of branches (24.21 and 29.20 / seedlings), number of leaves (335.20 and 386.20 / seedlings), leaf fresh weight (53.98 and 57.16 g) and leaf dry weight (44.98 and 47.46 g) in the first and second seasons, respectively were recorded in T9. It was found that, spraying with humic acid and urea at all concentrations significantly increased leaf macro and micro-elements. Maximum leaf nitrogen content was also recorded in T9 treatment (1.70 and 1.74 %) during two seasons, whereas the highest leaf P content (1.30 and 1.43 %), leaf K content (2.23 and 2.60 %), leaf Mg content (0.24 and 0.25 %), leaf Ca content (2.10 and 2.28 %), leaf Fe content (253.01 and 255.70 ppm), leaf Zn content (27.64 and 28.89 ppm) and leaf Mn content (64.14 and 65.91 ppm) were recorded in T8 in almond seedlings variety Nonpareil.