Normal nutrient ranges and nutritional monitoring of 'Pêra' orange trees based on the CND method in different fruiting stages

Abstract

-The objective of this work was to determine reference values for evaluating the nutritional status of 'Pêra' orange (Citrus sinensis) trees in different fruiting stages, using the compositional nutrient diagnosis (CND) method. The study used 243 leaf samples from 81 plots, with samplings performed in plants bearing fruits with three and six months of age, and also in the main harvest (nine months). Plots with productivity higher than 30 Mg ha -1 were selected for the establishment of reference standards. Three normal ranges were evaluated for each nutrient in the reference population, comprehended by the confidence interval (CI) of the foliar content averages, by the mean±standard deviation (±SD), and by the mean±⅔SD. Regardless of the normal range of nutrients used, the leaf sampling periods interfered with the nutritional status of 'Pêra' orange tree. The normal ranges obtained from the criteria CI and ±⅔SD of the nutrient contents observed in the reference population frequently provided similar nutritional diagnoses. Zn, Ca, and Fe are the elements that most often limit the production of 'Pêra' orange in the state of Amazonas, Brazil.

Efficiency of critical level and compositional nutrient diagnosis methods to evaluate boron nutritional status in soybean

“…Several authors have used the DA as a criterion to indicate the most appropriate method to assess nutritional status, opting for the methods with high DA between themselves (Politi et al, 2013;Dias et al, 2017). Therefore, the CLREF and CLRND methods should be the most recommended (100% DA) due to their higher DA followed by the CND method.…”

Addressing DRIS (Diagnosis and Recommendation Integrated System) norms with potentially toxic elements for assessing the nutritional status of Eucalyptus amended with sewage sludge

“…Orange tree (Dias et al, 2017), Eucalyptus cuttings (Morais et al, 2019), sugarcane (Calheiros et al, 2018;Silva et al, 2020) soybean and cotton (Kurihara et al, 2015) oil palm (Matos et al, 2018), acai palm (Ribeiro et al, 2020), 'Thompson' atemoya Rozane, 2017), mango (Pinto et al, 2010), coffee (Wadt, 2005) and Eucalyptus ssp. (Silva et al, 2005;Wadt, 2004).…”