Establishment of Leaf Tissue Nutrient Sufficiency Ranges of Two Perovskia Selections by Chronological Age

Abstract

<jats:p>The objective of this study was to determine optimum fertilizer concentrations, identify leaf tissue nutrient sufficiency ranges by chronological age, and establish leaf tissue nutrient standards of containerized Russian sage (<jats:italic>Perovskia</jats:italic> sp.). Common Russian sage (<jats:italic>P. atriplicifolia</jats:italic> Benth.) and ‘Crazy Blue’ Russian sage were greenhouse-grown in a soilless substrate under one of six constant liquid fertilizer concentrations [50, 75, 100, 200, 300, or 400 mg·L<jats:sup>−1</jats:sup> nitrogen (N)] with a constant level of a water-soluble micronutrient blend. Fertilizer concentrations sufficient for optimal plant growth and development were determined by analyzing plant height, diameter, growth index, primary shoot caliper, axillary shoot number, and total dry mass; they were found to be 100 to 200 mg·L<jats:sup>−1</jats:sup> N after a 6-week crop cycle. Recently, mature leaf tissue samples were collected from plants fertilized with 100 to 200 mg·L<jats:sup>−1</jats:sup> N and analyzed for elemental contents of 11 nutrients at 2, 4, and 6 weeks after transplant (WAT). An overall trend of increasing foliar nutrient concentrations over time was observed for all elemental nutrients. For instance, at 2 WAT, the total N concentrations of common Russian sage and ‘Crazy Blue’ Russian sage ranged between 3.68% and 5.10% and between 3.92% and 5.12%, respectively, and increased to ranges of 5.94% to 5.98% and 5.20% to 5.86% at 6 WAT, respectively. Before this study, no leaf tissue concentration standards have been reported; therefore, this study established leaf tissue concentration sufficiency ranges for the trialed <jats:italic>Perovskia</jats:italic> selections.</jats:p>

A Data-driven Approach for Generating Leaf Tissue Nutrient Interpretation Ranges for Greenhouse Lettuce

“…The SRA has been used to increase the number of crops for which recommended leaf tissue ranges have been defined, including numerous ornamental species such as coral bells [(Heuchera hybrida L.) (Owen 2019a)], perennial hibiscus [(Hibiscus hybrid L.) (Owen 2019b)], osteospermum [(Osteospermum ecklonis DC) (Papineau and Krug 2014), geranium [(Pelargonium ×hortorum Bailey) (Krug et al 2010), and Russian sage [(Perovskia sp.) (Owen 2020)]. These studies were based on the maximization of growth as the determining factor for establishing the tissue standard ranges.…”