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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #138614

Title: SPRING GROWTH OF ALMOND NURSERY TREES DEPENDS UPON BOTH NITROGEN RESERVES AND SPRING NITROGEN APPLICATION

Author
item BI, GUIHONG
item Scagel, Carolyn
item CHEN, LAILIANG
item DONG, SHUFU
item FUCHIGAMI, LES

Submitted to: Proceedings American Society of Horticultural Sciences
Publication Type: Proceedings
Publication Acceptance Date: 9/5/2002
Publication Date: 10/1/2002
Citation: Bi, G., Scagel, C.F., Chen, L., Dong, S., Fuchigami, L. 2002. Spring growth of almond nursery trees depends upon both nitrogen reserves and spring nitrogen application. Proceedings American Society of Horticultural Sciences. 37(5).

Interpretive Summary: June-budded 'Nonpareil/Nemaguard' almond plants were fertigated with five nitrogen (N) concentrations from July to September. Plants were sprayed with water or 3% urea in October, harvested after natural leaf fall, and stored at 20C. Plants were transplanted into an N-free medium in the following spring and supplied with N-free liquid fertilizer or liquid fertilizer containing 15N-NH4NO3 for 70 days after bud break. Fertigation and foliar urea applications altered N reserves of almond nursery plants. Plants fertigated with higher N concentrations had higher N reserves in both stem and root. Foliar urea application increased stem and root N at each given N fertigation concentration. Both N reserves and N from spring application of fertilizer were used during early spring growth. Plants with higher levels of N reserves used more of these reserves for new shoot and leaf growth than plants with lower N reserves. The amount of spring applied N used for new shoot and leaf growth depended on the total reserve nitrogen available. Trees with low levels of nitrogen reserves primarily used nitrogen applied in the spring for new shoot and leaf growth. Therefore, this study confirms the importance of both reserve nitrogen and spring applications of N for regrowth performance of almond nursery plants during establishment in the spring. Application of N in the spring can improve almond nursery tree performance, especially for the trees with low reserve N level. Increasing N reserves in the fall and supplying plants with nitrogen in the spring can improve the above ground growth of almond nursery trees. For trees with low N reserves, however, spring N application is particularly important. .

Technical Abstract: June-budded 'Nonpareil/Nemaguard' almond (Prunus dulcis (Mill) D. A. Webb) plants were fertigated with five nitrogen (N) concentrations (0, 5, 10, 15, and 20 mM) from July to September. The plants were sprayed with water or 3% urea in October, harvested after natural leaf fall, and stored at 20C. One set of plants was destructively sampled for N reserves (total N content), and the remaining plants were transplanted into an N-free medium in the following spring after cold storage. They were supplied with N-free Hoagland solution or Hoagland solution containing 15N-NH4NO3 for 70 days after bud break. Fertigation and foliar urea applications altered N reserves of almond nursery plants. Plants fertigated with higher N concentrations had higher N reserves in both stem and root. Foliar urea application increased stem and root N at each given N fertigation concentration. Both N reserves and spring application of nitrogen were used during the growth of almond nursery plants in the spring. The amount of nitrogen reserves used for new shoot and leaf growth depended on the total amount of N reserves. Plants with higher levels of N reserves used more of these reserves for new shoot and leaf growth than plants with lower N reserves. The amount of spring applied N used for new shoot and leaf growth depended on the total reserve nitrogen available. Trees with low levels of nitrogen reserves primarily used nitrogen applied in the spring for new shoot and leaf growth. Therefore, this study confirms the importance of both reserve nitrogen and spring applications of N for regrowth performance of almond nursery plants during establishment in the spring. Application of N in the spring can improve almond nursery tree performance, especially for the trees with low reserve N level.