Nitrogen Volatilization from Rice Leaves. II. Effects of Source of Applied Nitrogen in Nutrient Culture Solution1
- P. R. F. da Silva and
- C. A. Stutte2
The objective of this study was to determine the effects of source of N applied in nutrient media on the rate of volatile N lost from leaves of two rice (Oryza saliva L) cultivars in conjunction with the transpirational water vapors. The water-soluble, non-elemental N in the condensate was analyzed by pyro-chemiluminescence.
The N source in the nutrient culture solution did not significantly affect the rate of volatile N loss from the ‘Y’ and third leaves at tillering and panicle initiation. However, at heading the Y leaf of ‘Labelle’ and the third leaf of ‘Lebonnet’ grown in nitrate medium lost N at a lower rate than the corresponding leaves of plants supplied with ammonia. The percentage of N lost in oxidized form(s) was not affected by source of N applied in the nutrient solution at any of the three stages examined. The relative amounts of reduced and oxidized forms of volatile N loss varied with the growth stage; at heading the percentage of N lost in oxidized form(s) was lower than that at tillering and panicle initiation regardless of cultivar, leaf position, and N source applied. The percentage of N lost in oxidized form(s) varied from 8 to 28% of the total loss. For both cultivars the transpiration rates were not statistically affected by N source, but transpiration rate of the Y leaf was higher than that of the third leaf from the top at panicle initiator! and heading.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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