02170naa a2200313 a 450000100080000000500110000800800410001902200140006002400440007410000220011824500960014026000090023652012920024565000180153765000130155565000160156865000190158465000090160365000190161265000160163165000170164765000250166470000210168970000170171070000200172770000210174770000220176877300660179021349782023-09-27       2021    bl uuuu     u00u1 u    #d  a1435-06457 ahttps://doi.org/10.1002/agj2.208922DOI1 aSANTOS, M. P. dos  aNitrogen determination in irrigated rice using spectral reflectance.h[electronic resource]  c2021  aPrecision N management using optical radiation sensors is a promising management strategy. Using a combination of three spectral reflectance bands, 22 vegetation indices (VI) were calculated and evaluated for their efficiency in estimating N status in irrigated rice during growth stages. The results obtained here have showed a promising strategy to include crop stages as covariate in generalist models to predict the N status parameters for irrigated rice. This approach is interesting because it reduces the need for specific models, with different structures, for each crop stage. In addition, including crop stages as a covariate in the prediction models allows knowing the rice N status according to the crop stage, which is essential for efficient nitrogen management in commercial crops. The results obtained here show the beginning of vegetative stage (V1 to V9) significantly affects the prediction of all N status parameters. The dry leaf biomass (DLB), leaf area index (LAI), leaf N uptake (LNU) and N nutrition index (NNI) can be adequately predicted with combinations of just two vegetative indices (VI). These results show the importance of using active sensors with more than two fixed bands, preferably including a red-edge band, for effective crop N status estimation.  aEcophysiology  aNitrogen  aReflectance  aRemote sensing  aRice  aArroz Irrigado  aNitrogênio  aOryza Sativa  aSensoriamento Remoto1 aHEINEMANN, A. B.1 aSTONE, L. F.1 aMATTA, D. H. da1 aCASTRO, J. R. de1 aSANTOS, A. B. dos  tAgronomy Journalgv. 113, n. 6, p. 5087-5101, Nov./Dec. 2021.