02208naa a2200313 a 450000100080000000500110000800800410001902200140006002400390007410000190011324500990013226000090023152013630024065000200160365000160162365000090163965000160164865000120166465000210167665000100169765000160170765000170172365000070174065000250174765000090177265000090178170000180179077300860180820932122018-07-12       2018    bl uuuu     u00u1 u    #d  a1532-24167 a10.1080/00103624.2018.14248922DOI1 aFAGERIA, N. K.  aComparative efficiency of nitrogen sources for lowland rice production.h[electronic resource]  c2018  aRice (Oryza sativa L.) is the staple food for more than 50% world population and nitrogen (N) is one of the most yield-limiting nutrients for rice production worldwide. A greenhouse experiment was conducted to evaluate the efficiency of three N sources for lowland rice production. The N sources used were ammonium sulfate, common urea, and polymer-coated urea. There were three N rates, i.e. 100, 200, and 400 mg N kg-1 applied with three sources plus one control treatment (0 mg N kg-1). Growth, yield, and yield components were significantly increased either in a linear or quadratic fashion with the addition of N fertilizers in the range of 0?400 mg kg-1 soil. Maximum grain yield was obtained with the addition of ammonium sulfate at 100, 200, and 400 mg kg-1 of soil. Common urea and polymer-coated urea were more or less similar in grain production at 100 and 200 mg N kg-1. However, at 400 mg N kg-1 treatments, polymer-coated urea produced the lowest grain yield. Most of the growth and yield components were positively related to grain yield, except spikelet sterility which was negatively related to grain yield. Nitrogen use efficiency decreased with increasing N rate in all the three N sources. Maximum N use efficiency was obtained with the addition of ammonium sulfate at lower as well as at higher N rates compared with other two N sources.  aBase saturation  aGrain yield  aRice  aRoot growth  aSoil pH  aYield components  aArroz  aNitrogênio  aOryza Sativa  aPh  aPonto de Saturação  aRaiz  aSolo1 aSANTOS, A. B.  tCommunications in Soil Science and Plant Analysisgv. 49, n. 5, p. 515-525, 2018.