Nutrient Management Research Database

http://ucanr.edu/sites/Nutrient_Management_Solutions/files/212668.pdf

This multidisciplinary study examined the effects of nitrogen fertilization
on nectarine yield, fruit quality, brown rot and moth pests. Results indicate that excess nitrogen fertilization did not increase fruit yield or improve fruit quality; however, fruit on over-fertilized trees were more susceptible to attack from brown rot, peach twig borer and oriental fruit moth.

This article presents research that assessed the effect of nitrogen on nectarine yield and quality, postharvest fruit quality and pest management. A nitrogen rate experiment was initiated with 'Fantasia' nectarines at the Kearney Agricultural Center to investigate the effect of different nitrogen rates on the above parameters.  N treatments consisted of an unfertilized control and treatments with 100, 175, 250 and 325 lb N/ac/year applied.  All fertilizer application were followed immediately with furrow irrigation.  Yield, fruit quality, vegetative growth, fruit shading, and total leaf N, as well as soil nitrate were measured.

Companion studies also assessed metrics of fruit quality (fruit firmness, pH, titratable acidy, percent red surface color and soluble solids, as well as storage performance) and the incidence of brown rot and insect pest damage.  

Highlights of results include:

• Fertilization rates of 100- 325 lbs N/ac/year led to no significant differences in yield or fruit weight.
• Higher N rates significantly delayed fruit maturity and increased the total harvest period.  
• Vegetative growth and leaf N levels were correlated with N rate, and soil nitrates with applications of 175, 250 and 350 lb N/ac/year were higher than treatments with 100 lb N/ac/year applied.
• N treatments had no effect on most post-harvest quality metrics, although lower N rates produced more red color.
• Brown rot incidence in blossoms and mature fruit were generally higher in high N treatments. 
• Fruit damage by moth pests was significantly increased in high N treatments.