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Nitrogen Utilization by Rice Using 15N‐Depleted Ammonium Sulfate 1
Author(s) -
Patrick W. H.,
Delaune R. D.,
Peterson F. J.
Publication year - 1974
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1974.00021962006600060032x
Subject(s) - nitrogen , agronomy , ammonium sulfate , fertilizer , growing season , chemistry , field experiment , ammonium , nitrogen fertilizer , nitrogen deficiency , yield (engineering) , zoology , biology , materials science , organic chemistry , chromatography , metallurgy
A field experiment utilizing 15 N‐depleted ammonium sulfate was carried out to determine the efficiency with which lowland rice utilized fertilizer nitrogen in large (2.1 ✕15.2 m) plots. Relative uptake of labelled and nonlabelled nitrogen was followed throughout the growing season. At the soft dough stage, small (0.84 m 2 ) subplots were cut and the total aboveground uptake of labelled and non‐labelled nitrogen determined. Labelled and non‐labelled nitrogen contents of the harvested grain was determined. The results showed that nitrogen utilization by lowland rice ( Oryza saliva L.) was poor, with 17 and 23% recovery of applied nitrogen in the aboveground portion of the crop at the soft dough stage for 56 and 112 kg/ha rates, respectively. Approximately 12% of the applied nitrogen was recovered in the unmilled grain. The fraction of plant nitrogen coming from fertilizer was relatively high (about three‐fourths) early in the season but decreased to as little as one‐fifth as the season progresssed. Yield response, total nitrogen uptake, and uptake of fertilizer nitrogen were higher for the 112 kg/ha rate than for the 56 kg/ha rate. Even though nitrogen utilization was low, fertilizer nitrogen markedly increased the yield of grain.