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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #162779

Title: TIMING OF APPLICATION AFFECTS LEAF AND ROOT N UPTAKE IN YOUNG FUJI/M.9 APPLE TREES

Author
item DONG, SHUFU
item CHENG, LAILIANG
item Scagel, Carolyn
item FUCHIGAMI, LESLIE

Submitted to: Journal of Horticultural Science and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2004
Publication Date: 1/1/2005
Citation: Dong, S., Cheng, L., Scagel, C.F., Fuchigami, L.H. 2005. Timing of application affects leaf and root n uptake in young fuji/m.9 apple trees. Journal of Horticultural Science and Biotechnology. 80(1)116-120.

Interpretive Summary: Matching fertilizer application to crop demand requires knowledge of when and how plants can best take up nutrients from fertilizer. The ability of leaves and roots to take up nitrogen (N) was compared at different growth stages in young apple trees. Leaves were found to take up more N in May and September than roots, while roots took up more N than leaves in July. Plants were least efficient in taking up N from soil in May and most efficient at taking up N from foliar fertilizer application in September. Our results suggested that foliar application of N early in the season, following by soil N application in the mid season, and then foliar application again late in the season is an efficient N management strategy in orchards.

Technical Abstract: Leaf and root nitrogen (N) uptake was compared at different growth stages in young apple trees. One-year-old potted Fuji/M.9 trees were supplied with 1% 15N-labelled urea either by foliar or soil applications in May, July and September. Trees receiving only water served as controls. The trees were harvested 10 days after 15N application, separated into shoots (leaves and current-year stems), stem (previous-year wood) and roots. Biomass and total N and 15N content of all tissues were determined. New shoot biomass and total tree biomass increased as the season advanced while root biomass peaked in July. Leaf N uptake was higher than root uptake in May and September, while root N uptake was higher than leaf uptake in July. Leaf N uptake increased as the season advanced, while root N uptake was highest in July. The lowest 15N recovery (10.79%) was obtained in May with soil N application, and the highest 15N recovery (48.28%) was obtained in September with foliar N application. Our results suggested that foliar application of N early in the season, following by soil N application in the mid season, and then foliar application again late in the season is an efficient N management strategy in orchards.