HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Becker, M. Articles by Ottow, J. C. G. Search for Related Content PubMed Articles by Becker, M. Articles by Ottow, J. C. G. Agricola Articles by Becker, M. Articles by Ottow, J. C. G.

Nitrogen Losses and Lowland Rice Yield as Affected by Residue Nitrogen Release

West Africa Rice Development Association (WARDA), 01 B.P. 2551, 01 Bouaké, Côte d'Ivoire

J. K. Ladha^*

Soil and Water Sciences Division, The International Rice Research Institute (IRRI), P.O. Box 933, 1099 Manila, Philippines

J. C. G. Ottow

Institut für Mikrobiologie und Landeskultur, Justus-Liebig-Universität, 6300 Giessen, Germany

* Corresponding author ( j.k.ladha{at}cgnet.com).

ABSTRACT

Synchronizing N supply from incorporated plant residues with N demand of rice (Oryza sativa L.) may increase the plant's N use efficiency and reduce soil N losses. This hypothesis was tested under flooded lowland conditions in a three-season field experiment. Leguminous green manures and rice straw with various lignin to N ratios (L/N) and urea were compared using N release, rice N uptake, N use efficiency, grain yield, and total ¹⁵N balance as criteria. Basally applied urea resulted in high initial soil NH⁺₄. Where residues were applied, exchangeable NH⁺₄-N varied as a function of L/N. Daily N uptake by rice peaked at 4 wk. Matching of soil NH⁺₄-N with daily rice N uptake was less apparent in urea and Sesbania rostrata Brem. S. Oberm. treatments than in the S. rostrata-rice straw mixture treatment. Nitrogen-15 balances indicated that the mismatch between supply and demand may have caused the measured N losses of 35% from urea and 6 to 10% from S. rostrata applied at 60 kg N ha^–1. Synchronized N supply and rice N uptake resulted in negligible N loss and increased the portion of applied N remaining in the soil, but it did not cause a yield increase. Sesbania rostrata-rice straw mixture depressed yield and N use efficiency in the dry season when yield potential was high. A residual effect was observed in the S. rostrata-rice straw treatment in the third unfertilized crop, resulting in a 10% increase in grain yield. Apparently, synchronizing soil N supply with N demand by incorporating residues with suitable chemical composition may not immediately increase rice grain yields, but it improves long-term soil fertility.

Received for publication August 23, 1993.

This article has been cited by other articles:

				A. J. Eagle, J. A. Bird, J. E. Hill, W. R. Horwath, and C. van Kessel Nitrogen Dynamics and Fertilizer Use Efficiency in Rice following Straw Incorporation and Winter Flooding Agron. J., November 1, 2001; 93(6): 1346 - 1354. [Abstract] [Full Text] [PDF]

				M. S. Aulakh, T.S. Khera, J. W. Doran, and K. F. Bronson Managing Crop Residue with Green Manure, Urea, and Tillage in a Rice-Wheat Rotation Soil Sci. Soc. Am. J., May 1, 2001; 65(3): 820 - 827. [Abstract] [Full Text] [PDF]

				A. J. Eagle, J. A. Bird, W. R. Horwath, B. A. Linquist, S. M. Brouder, J. E. Hill, and C. van Kessel Rice Yield and Nitrogen Utilization Efficiency under Alternative Straw Management Practices Agron. J., November 1, 2000; 92(6): 1096 - 1103. [Abstract] [Full Text]