Studies on The Availability of Azolla N and Urea N for Rice Growth Using 15N

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dc.contributor.author E.L. Sisworo
dc.contributor.author D.L. Eskew
dc.contributor.author W.H. Sisworo
dc.contributor.author H. Rasjid
dc.contributor.author H. Kadarusman
dc.date.accessioned 2010-06-15T02:55:58Z
dc.date.available 2010-06-15T02:55:58Z
dc.date.issued 1989
dc.identifier.uri http://repository.ipb.ac.id/handle/123456789/28426
dc.description.abstract Field experiments (20 m2 plots) were conducted to compare Azolla and urea as N sources for rice (Oryza sativa L.) in both the wet and dry seasons. Parallel microplot (1 m2) experiments were conducted using 15N. A total of approximately 60 kg N ha-1 was applied as urea, Azolla, or urea plus Azolla. Urea or Azolla applied with equal applications of 30 kg N ha-1 at transplanting (T) and at maximum tillering (MT) were equally effective for increasing rice grain yields in both seasons. Urea at 30 kg N ha-1 at T and Azolla 30 kg N ha-1 at MT was also equally effective. Urea applied by the locally recommended best split (40 kg at T and 20 kg at MT) gave a higher yield in the wet season, but an equal yield in the dry season. The average yield increase was 23% in the wet season, and 95% in the dry season. The proportion of the N taken up by the rice plants which was derived from urea (%NdfU) or Azolla (%NdfAz) was essentially identical for the treatments receiving the same N split. Recovery of 15N in the grain plus straw was also very similar. Positive yield responses to residual N were observed in the succeeding rice crop following both the wet and dry seasons, but the increases were not always statistically significant. Recovery of residual 15N ranged from 5.5 to 8.9% for both crops in succeeding seasons. Residual recovery from the urea applications was significantly higher than from Azolla in the crop succeeding the dry season crop. Azolla was equally effective as urea as an N source for rice production on a per kg N basis. id_ID
dc.publisher IPB (Bogor Agricultural University) id_ID
dc.title Studies on The Availability of Azolla N and Urea N for Rice Growth Using 15N id_ID


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