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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #155758

Title: THE METHOD OF N APPLICATION IN SUMMER AFFECTS PLANT GROWTH AND N UPTAKE IN AUTUMN IN YOUNG FUJI/M26 APPLE TREES

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

Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/7/2004
Publication Date: 8/1/2005
Citation: Dong, S., Cheng, L., Scagel, C.F., Fuchigami, L.H. 2005. The method of n application in summer affects plant growth and n uptake in autumn in young fuji/m26 apple trees. Communications in Soil Science and Plant Analysis. 36:1465-1477.

Interpretive Summary: The influence of nitrogen (N) fertilizer application methods during the summer and the autumn on growth of young Fuji/M26 apple trees was studied using one-year-old bench-grafted trees. Trees were treated weekly from late June to early September with 0.5% urea either by foliar or soil application. At the end of September, a subsample of trees from each treatment were harvested, and shoot and root growth and leaf N content were determined. In mid-October, trees from each treatment were randomly divided into three subgroups. One group received soil application of water (control), the other groups received either a foliar or soil application of 3% 15N-urea. After natural leaf defoliation, trees were harvested and total N and 15N content of stems (all above ground tissue) and roots was determined. Regardless of application method, N application during the summer promoted plant growth and increased leaf N content. Soil N application during the summer stimulated more shoot and extension root growth than foliar N application. In contrast the foliar N application in the summer promoted more feeder root growth than soil N application. Regardless of application method, autumn N application after terminal bud set increased total plant N content. In the autumn, trees that received soil N applications in the summer had more 15N uptake by leaves, while trees receiving foliar N applications in the summer had more 15N uptake by roots. Our results suggest that the differential influence of N application methods during the summer on growth and partitioning of trees influences tree responsiveness to autumn N applications. The best method of N application in the autumn to increase N storage and efficiency of N use depends on the method of N application in the summer.

Technical Abstract: Effects of foliar vs soil nitrogen (N) application during the summer and the autumn were studied in young Fuji/M26 apple trees (Malus domestica Borkh). One-year-old bench-grafted trees were treated weekly from late June to early September with 0.5% urea either by foliar or soil application. At the end of September, a subsample of trees from each treatment were harvested, and shoot and root growth and leaf N content were determined. In mid-October, trees from each treatment were randomly divided into three subgroups. One group received soil application of water (control), the other groups received either a foliar or soil application of 3% 15N-urea. After natural leaf defoliation, trees were harvested and total N and 15N content of stems and roots was determined. Regardless of application method, N application during the summer promoted plant growth and increased leaf N content. Soil N application during the summer stimulated more shoot and extension root growth than foliar N application. In contrast the foliar N application in the summer promoted more feeder root growth than soil N application. Regardless of application method, autumn N application after terminal bud set had little effect on current-year growth, but increased total plant N content. In the autumn, trees that received soil N applications in the summer had more 15N uptake by leaves, while trees receiving foliar N applications in the summer had more 15N uptake by roots. Our results suggest that the differential influence of N application methods during the summer on growth and partitioning of trees influences tree responsiveness to autumn N applications. The best method of N application in the autumn to increase N storage and efficiency of N use depends on the method of N application in the summer.