Articles
DISTRIBUTION AND RECYCLING OF CANOPY NITROGEN STORAGE RESERVES IN SWEET CHERRY (PRUNUS AVIUM L.) FRUITING BRANCHES FOLLOWING 15N-UREA FOLIAR APPLICATIONS AFTER HARVEST
Article number
1020_49
Pages
353 – 361
Language
English
Abstract
In sweet cherry, stored nitrogen (N) accumulated the previous fall after fruit harvest supports early spring growth.
To complement soil N supply, Chilean growers use foliar urea applications after harvest.
So far, the information regarding the effectiveness of foliar N applications in sweet cherry trees on dwarfing rootstocks is low.
To study the canopy distribution of N applied as urea foliar sprays, an experiment using a 6-yr-old Bing/Gisela®6 (GI6) sweet cherry orchard, located in Itahue, VII Region of Chile (35°0953S, 71°2043W), was carried out in 2007. The major goal was to investigate the N distribution and recycling in 3-yr-old fruiting branches (growth from 2004/2005, 2005/2006 and 2006/2007). A total of 60 branches were labeled using 15N-urea (2% conc.). The labeled urea was applied to the whole branch at four different dates or treatments (TR) after fruit harvest: TR1=Jan, TR2=Feb, TR3=Mar and TR4=Apr.
For each TR, a group of 15N-labeled branches were destructively harvested at 3 times/stages: 15 days after the foliar application (DAA), winter (dormancy, Jul) and spring (stage I of fruit development, Oct). Individual branches were divided into different tissues/organs, dried (70°C), ground and processed for GC-MS analysis.
In all TR, labeled urea was absorbed by leaves and translocated to different organs of the branch.
Most of the N translocation was basipetal.
The highest N content was observed in the fruiting section (2004/2005 growth). The Jan application (TR1) had the highest N use efficiency (NUE%). Buds and bark showed the highest N derived from fertilizer values (NDFF%). In all TR, stored N was recovered in new organs (flowers, immature fruits and young leaves) the following spring.
According to the results, urea sprays after fruit harvest constitute an effective alternative to complement soil N supply in sweet cherry trees with GI6 rootstock.
To complement soil N supply, Chilean growers use foliar urea applications after harvest.
So far, the information regarding the effectiveness of foliar N applications in sweet cherry trees on dwarfing rootstocks is low.
To study the canopy distribution of N applied as urea foliar sprays, an experiment using a 6-yr-old Bing/Gisela®6 (GI6) sweet cherry orchard, located in Itahue, VII Region of Chile (35°0953S, 71°2043W), was carried out in 2007. The major goal was to investigate the N distribution and recycling in 3-yr-old fruiting branches (growth from 2004/2005, 2005/2006 and 2006/2007). A total of 60 branches were labeled using 15N-urea (2% conc.). The labeled urea was applied to the whole branch at four different dates or treatments (TR) after fruit harvest: TR1=Jan, TR2=Feb, TR3=Mar and TR4=Apr.
For each TR, a group of 15N-labeled branches were destructively harvested at 3 times/stages: 15 days after the foliar application (DAA), winter (dormancy, Jul) and spring (stage I of fruit development, Oct). Individual branches were divided into different tissues/organs, dried (70°C), ground and processed for GC-MS analysis.
In all TR, labeled urea was absorbed by leaves and translocated to different organs of the branch.
Most of the N translocation was basipetal.
The highest N content was observed in the fruiting section (2004/2005 growth). The Jan application (TR1) had the highest N use efficiency (NUE%). Buds and bark showed the highest N derived from fertilizer values (NDFF%). In all TR, stored N was recovered in new organs (flowers, immature fruits and young leaves) the following spring.
According to the results, urea sprays after fruit harvest constitute an effective alternative to complement soil N supply in sweet cherry trees with GI6 rootstock.
Publication
Authors
M. Thielemann, R. Toro, M. Ayala
Keywords
leaves, fall, nitrogen use efficiency, NUE%, nitrogen derived from fertilizer, NDFF%
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