Compositional nutrient diagnosis (CND) applied to strawberry soilless

Soluble fertilizers are among the main costs in strawberry production, so knowing the nutrients balance in plant tissue is essential. In this sense, the Compositional Nutrient Diagnosis (CND) method is presented as a multivariate analysis tool for the nutritional diagnosis of the crop. The main goal of this paper was to establish CND standards and critical nutrient levels in strawberries cultivated in a soilless system. This study uses the Compositional Nutrient Diagnosis (CND) method to analyze nutrient levels grown in a soilless system. Commercial production greenhouses were evaluated for yield and leaf nutrients contents to develop the standards. Data were collected from 52 plots, each consisting of diagnostic leaves from 10 plants, and subsequently analyzed to determine critical nutrient deficiencies and excesses. The CND methodology was sensitive in diagnosing the differences between high and low-yield populations. Thus, adjusting the critical nutrient levels for soilless strawberry cultivation was possible. Due to deficiency, the most limiting nutrients for strawberry production were N, Mg, and S, and Zn and Cu due to excess. Results indicate specific nutrient thresholds, with significant findings from the integration of all indices, it was possible to calculate the sufficiency ranges for soilless strawberry: N = 26–31, P = 4–7, K = 8–11, Ca = 10–15, Mg = 3–4, S = 0.3–0.5 in g kg−1, and B = 18–95, Cu = 1–2, Fe = 46–96, Mn = 80–203, Zn = 1–40, Mo = 1.3–2.7, Ni = 0.1–0.4 in mg kg−1.