Cultivar-Specific Assessments of Almond Nutritional Status through Foliar Analysis

Abstract

Mediterranean almond growing is increasing, as confirmed in Italy where new almond orchards in areas not previously interested in this nut crop have been recently established. In these new areas, as in the coastal of Latium region, the knowledge of eco-physiological behavior as a complex interaction among cultivars, pedoclimate conditions and orchard management is still poor. Optimizing fertilization strategies according to cultivar needs is one of the main key factors to guarantee high yields and nut quality, as well as to reduce environmental pollution. With this aim, an almond field collection has been established planting medium- and late-bloom cultivars. During the growing seasons 2019–2020, leaf samples were collected at 90 and 120 days after full bloom (DAFB) analyzed for biometrical and eco-physiological traits and leaf nutrients content through foliar diagnostics. Differences in foliar nutrient content depend on both cultivar and phenological stage. According to Pearson correlation heatmap, leaf nitrogen content showed a medium–high positive correlation with Nitrogen Balance Index (NBI) either at 90 or 120 DAFB, highlighting reciprocal influences among leaf nutrient contents and some eco-physiological traits. The findings of this study will help to develop novel environmentally friendly nutrition and fertigation strategies supported by foliar diagnostics which also consider accurate cultivar requirements.