Afonso, SandraArrobas, MargaridaFerreira, Isabel Q.Rodrigues, M.A.2018-02-092018-02-092018Afonso, Sandra; Arrobas, Margarida; Ferreira, Isabel Q.; Rodrigues, M.A. (2018). Assessing the potential use of two portable chlorophyll meters in diagnosing the nutritional status of plants. Journal of Plant Nutrition. ISSN 0190-4167. 41:2, p. 261–2710190-4167http://hdl.handle.net/10198/15660The SPAD-502 and the FieldScout CM 1000 chlorophyll meters were compared in their performance in diagnosing the nutritional status of plants. Leaves of a wide range of greenness were used to push the sensitivity of the tools to their limits. Both devices showed high reproducibility when used by different operators. The SPAD-readings were well-correlated with leaf nitrogen (N) concentrations, since leaves from heavily fertilized plants were not included in the sample population. The FieldScout-readings showed a marked saturation curve with the leaf N concentration, thus it cannot be used as a reliable N nutritional status index. The results also showed that the use of SPAD-502 in the diagnosis of the nutritional status of an orchard requires the establishment of specific critical concentrations for cultivars and sampling dates. The SPAD-502 appeared to have potential in the diagnosis of the nutritional status of the orchard for nutrients other than N.engFieldScout CM 1000 NDVILeaf greennessResults reproducibilityLeaf N concentrationSPAD-502journal article10.1080/01904167.2017.1385798