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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #151620
Title: N UPTAKE SOIL RETENTION AND LOSS OF SOIL APPLIED 15NH415NO3 IN YOUNG FUJI/M.26 APPLE TREES WITH DIFFERENT N STATUS

Author
item DONG, SHUFU - PACIFIC AGRI-FOOD RESEARC
item CHENG, LAILIANG - CORNELL UNIVERSITY
item Scagel, Carolyn
item FUCHIGAMI, LESLIE - OREGON STATE UNIVERSITY

Submitted to: Journal of Horticultural Science and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2003
Publication Date: 4/1/2004
Citation: Dong, S., Cheng, L., Scagel, C.F., Fuchigami, L.H. N uptake soil retention and loss of soil applied 15nh415no3 in young fuji/m.26 apple trees with different N status. Journal of Horticultural Science and Biotechnology. 2004. 79(3) p. 395-400.

Interpretive Summary: Nitrogen (N) uptake, and soil retention and loss of soil applied N were studied in young Fuji/M.26 apple (Malus domestica Borkh) trees with different N backgrounds. Trees were fertigated with three rates of N during the first growing season. In the second growing season trees were replanted in N-free medium and were fertigated with Hoagland's nutrient solution without N. Half of the trees received 15NH415NO3 in June and the others received no N as control. Trees from each treatment were harvested at one, two and four weeks after 15N application, and the amount of 15N and total N in soil and plant tissues was determined. N content in trees at the end of the first growing season increased with increasing rates of N fertigation and new shoot and leaf growth in the following season was positively related to reserve N. Four weeks after application of 15N, tree uptake of N accounted for about 60% of applied 15N, while about 20% of the N still remained in the soil, and another 20% of the N was lost. N uptake by young apple trees was related to their background N status and trees with lower N contents are more efficient in taking up N than those with high N content on a root biomass basis. However, there wass no much difference in total N uptake on a whole tree basis as low N trees had a smaller root system than high N trees. A significant proportion (~20%) of applied N was lost into environment within four weeks after N application even when measures are taken to minimize loss and high root uptake efficiency is observed. Our results suggested that trees with lower N status are more efficient in N uptake from soil when abundant N available, and it is more important to supply N to trees with low N reserves than trees with high N reserves in orchard management.

Technical Abstract: Nitrogen (N) uptake, and soil retention and loss of soil applied N were studied in young Fuji/M.26 apple (Malus domestica Borkh)trees with different N backgrounds. Trees were fertigated with 5, 10 or 20 mM N twice during the first growing season then harvested and bare-root stored in a 2'C cold room. A subsample from each treatment were destructively sampled for determining tree growth and N status. In April, the trees were replanted in N-free medium. Each tree received Hoagland's nutrient solution without N weekly through the experiment. Half of the trees from each group received 15NH415NO3 June and the others received no N as control. Trees from each treatment were harvested at one, two and four weeks after 15N application, and separated into new shoots and leaves, old stem and shank, and roots. The amount of 15N and total N in soil and plant tissues was determined. N content in trees at the end of the first growing season increased with increasing rates of N fertigation. New shoot and leaf growth in the following season was positively related to reserve N. 15N uptake occurred during the four weeks after 15N application while soil 15N retention decreased. There was no significant difference in the total 15N uptake per tree. However, trees with the lowest N contents at the end of the first growing season had the highest rate of 15N uptake per unit root dry weight. Four weeks after application of 15N, tree uptake of N accounted for about 60% of applied 15N, while about 20% of the N still remained in the soil, and another 20% of the N was lost. Efficiency of N use during the experiment was not related to initial N content of trees. Our results suggested that trees with lower N status are more efficient in N uptake from soil.