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Conventional and Controlled‐Release Nitrogen Sources for Rice
Author(s) -
Wells B. R.,
Shockley P. A.
Publication year - 1975
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1975.03615995003900030045x
Subject(s) - loam , coated urea , agronomy , urea , nitrogen , soil water , ammonium sulfate , growing season , silt , chemistry , oryza sativa , ammonium , seedling , zoology , environmental science , biology , soil science , organic chemistry , paleontology , biochemistry , chromatography , gene
Tests were conducted for the years 1967–1972 with rice ( Oryza sativa L., cv. ‘Starbonnet’) to compare various formulations of sulfur‐coated urea (SCU) and iso‐butylidene diurea, (I.B.D.U.) with urea and ammonium sulfate as nitrogen sources on both silt loam and clay soils. The N sources were applied either preplant or topdress at rates up to 235 kg/ha to drill‐seeded rice which was flooded at approximately 2 weeks following seedling emergence. Grain yields, dry weight, and N uptake indicated that the controlled‐release N sources could be used to regulate rate of N supply to the plant throughout the growing season. Growth of direct seeded rice was slowed considerably during the early part of the growing season due to the slow rate of N release but grain yields were not drastically altered. Grain yields on the silt loam soils following use of the controlled‐release N fertilizers were consistently equal to those following use of urea or ammonium sulfate. On the clay soils under intermittent flooding, use of SCU resulted in increased yields as compared to urea applied preplant, and in one year resulted in increased yields as compared to urea applied in split top‐dress doses. Both SCU and I.B.D.U. were suitable N sources for rice growing under the water management systems employed in these studies.