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Controlled Release Urea Improved Nitrogen Use Efficiency, Activities of Leaf Enzymes, and Rice Yield
Author(s) -
Yang Yuechao,
Zhang Min,
Li Y.C,
Fan Xiaohui,
Geng Yuqing
Publication year - 2012
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/sssaj2012.0173
Subject(s) - cru , nitrate reductase , loam , agronomy , glutamine synthetase , urea , chemistry , oryza sativa , nitrogen , biology , glutamine , soil water , biochemistry , ecology , organic chemistry , amino acid , climate change , gene
The effects of a controlled release urea (CRU) on concentration of N in root zones, activities of N metabolism enzymes in leaves, and N use efficiency of rice ( Oryza sativa L.) grown on a silt loam soil in lysimeters were investigated. The entire amount (100–300 kg N ha −1 ) of the CRU was incorporated into a plug for growing the rice seedlings while the regular urea was split into three applications (the standard practice). Results indicated that the N release of CRU closely matched the N requirements of the rice, and the commingling of the CRU with the rice seeds increased N concentration within the root zone and enhanced the activities of glutamine synthetase (GS), glutamine 2‐oxoglutarate amidotransferase (GOGAT) and nitrate reductase (NR) in leaves. At the same N rate, the apparent N use efficiency of the CRU applied at 300 kg N ha −1 was 27.6 and 22.9% higher than that of conventional urea treatment in 2007 and 2008, respectively. Although the CRU at 200 kg N ha −1 supplied one‐third less N than the urea at 300 kg N ha −1 , the CRU produced 3 to 5.9% more grain than the urea. Placing the CRU with rice seeds without additional fertilizer application during the entire growing season significantly increased N availability in soils and improved rice growth and led to use of less N fertilizers for greater rice grain yield.