บทคัดย่องานวิจัย

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Nitrogen uptake and allocation by field-grown 'Arapaho' thornless blackberry.

Naraguma, J.; Clark, J. R.; Norman, R. J.; McNew, R. W.;

Journal of Plant Nutrition Year: 1999 Vol: 22 Issue: 4/5 Pages: 753-768 Ref: 28 ref.

1999

บทคัดย่อ

Nitrogen uptake and allocation by field-grown 'Arapaho' thornless blackberry.

 

Spring surface applications of 15N-labelled urea were made in March 1995 and 1996 to one- and 2-year-old, field-grown blackberry cv. Arapaho plants in Arkansas, USA. Individual whole-plant samples were collected preharvest (late May), postharvest (mid-July) and in early dormancy (late October). Plant parts separated for analysis were roots, primocanes, floricanes, primocane leaves, floricane leaves and fruits. Soil samples were also taken from within the plant drip line at each sample date. Plants collected in October had the most total dry matter, with roots, primocanes and primocane leaves contributing most to this total. Total N content decreased in all vegetative tissues (leaves and canes) from May to October. Compared to other plant tissues, floricane leaves and primocanes recovered significantly more fertilizer N in May while roots and primocane leaves contained more in October of each year. Floricanes and fruits did not increase in fertilizer N levels during the sampling period. Overall,

the lowest percentage fertilizer N recovery for whole plants was 12.8% for May 1995 and the highest was 32.4% for October 1996. Recovery of fertilizer N in the topsoil ranged from a low of 12.9% in October 1995 to a high of 38.6% in May 1996. There were no statistical differences in percentage recovery of fertilizer N from topsoil among sample dates. Recovery of fertilizer N from subsoil in the October sample was much lower than that in May, probably due mostly to plant uptake, but also possibly to a downward movement out of the sample area by leaching or from other loss mechanisms. Averaging all sample dates, recovery was 59.5% in 1995 and 75.8% in 1996 for the plant and soil combined, with the remainder probably lost via volatilization, leaching and/or denitrification.