02147naa a2200277 a 450000100080000000500110000800800410001902200140006002400380007410000190011224501050013126000090023652013520024565000280159765000090162565000100163465000180164465000160166265000140167865000170169265000090170970000160171870000210173470000180175577300960177319813122025-04-03       2014    bl uuuu     u00u1 u    #d  a0010-36247 a10.1080/00103624.2013.8619072DOI1 aFAGERIA, N. K.  aNitrogen uptake and use efficiency in upland rice under two nitrogen sources.h[electronic resource]  c2014  aUpland rice is an important crop in South America, including Brazil. Nitrogen (N) is one of the most yield-limiting nutrients in upland rice production in Brazil. A greenhouse experiment was conducted to evaluate N uptake and use efficiency as influenced by N sources. The soil used in the experiment was an Oxisol. The N sources were ammonium sulfate and urea, and N rates were 0, 50, 100, 150, 300, and 400 mg kg−1 of soil. Nitrogen concentrations in the root, shoot, and grain were significantly influenced by N sources. The N rate and N source significantly influenced the N uptake in root, shoot, and grain. Similarly, nitrogen rate by N source interaction was also significant for N uptake in the root, shoot, and grain, indicating N source has a significant influence on uptake of N. Overall, concentration (content per unit dry weight) of N was greater in the grain, followed by root and shoot. Agronomical efficiency, apparent recovery efficiency, and utilization efficiency of N were significantly influenced by N rate and varied with N sources. However, physiological and agrophysiological efficiencies were only influenced significantly by N sources. Overall, N recovery efficiency was 33% for ammonium sulfate and 37% for urea. Hence, the large amount of N lost from soil?plant system may be by denitrification or voltilization.  aNutrient use efficiency  aRice  aArroz  aMicroelemento  aNitrogênio  aNutriente  aOryza sativa  aSolo1 aMOREIRA, A.1 aMORAES, L. A. C.1 aMORAES, M. F.  tCommunications in Soil Science and Plant Analysis, New Yorkgv. 45, n. 4, p. 461-469, 2014.