02692naa a2200289 a 450000100080000000500110000800800410001902200140006002400360007410000170011024501310012726000090025850001120026752017210037965000200210065300200212065300160214065300290215665300200218565300100220570000240221570000190223970000170225870000150227570000180229077300940230810625102021-11-01       2021    bl uuuu     u00u1 u    #d  a1385-22567 a10.1007/s11119-021-09837-42DOI1 aDE SOUZA, R.  aUse of fluorescence indices as predictors of crop N status and yield for greenhouse sweet pepper crops.h[electronic resource]  c2021  aArticle history: Accepted 18 August 2021; Published 09 September 2021. Contiene información suplementaria.  aABSTRACT. - To increase nitrogen (N) use efficiency and reduce water pollution from vegetable production, it is necessary to optimize N management. Fluorescence-based optical sensors are devices that can improve N fertilization through non-destructive field monitoring of crop variables. The aim of this work was to compare the performance of five fluorescence indices (SFR-R, SFR-G, FLAV, NBI-R, and NBI-G) to predict crop variables, as dry matter production, crop N content, crop N uptake, Nitrogen Nutrition Index (NNI), absolute and relative yield, in sweet pepper (Capsicum annuum) crops grown in greenhouse. Fluorescence measurements were periodically made with the Multiplex® 3.6 sensor throughout three cropping cycles subjected to five N application treatments. The performance of fluorescence indices to predict crop variables considered calibration and validation analyses. In general, the five fluorescence indices were strongly related with NNI, crop N content and relative yield. The best performing indices to predict crop N content and NNI at the early stages of the crops (i.e., vegetative and flowering phenological stages) were the SFR indices, both under red (SFR-R) and green (SFR-G) excitation. However, in the final stage of the crop (i.e., harvest stage), the best performing indices were NBI, both under red (NBI-R) and green (NBI-G) excitation, and FLAV. The two SFR indices best predicted relative yield of sweet pepper at early growth stages. Overall, the fluorescence sensor and the fluorescence indices evaluated were able to predict crop variables related to N status in sweet pepper. They have the capacity to be incorporated into best N management practices. © 2021, The Author(s).  aCAPSICUM ANNUUM  aFlavonols meter  aFluorimeter  aNitrogen Nutrition Index  aVegetable crops  aYield1 aPEÑA-FLEITAS, M.T.1 aTHOMPSON, R.B.1 aGALLARDO, M.1 aGRASSO, R.1 aPADILLA, F.M.  tPrecision Agriculture, 2021, OPEN ACCESS. Doi: https://doi.org/10.1007/s11119-021-09837-4