Pre-bloom leaves of blackcurrant can be used to predict boron and manganese nutrition

The aim of the study was to examine the utilization of mineral analyses of pre-bloom leaves and inflorescences to forecast the nutrition of blackcurrant (Ribes nigrum L.). The study was carried out in Poland in 2 consecutive years on 8 mature ‘Tisel’ blackcurrant plantations planted in coarse- and medium-textured soils that were poor in organic matter. Within each plantation, plants were supplied with nitrogen (N), phosphorus (P) and potassium (K) at low, moderate or high doses for each nutrient. Every year, from the same bushes, the pre-bloom leaves, the inflorescences and the mid-summer leaves (as a standard diagnostic tool) were collected 3–6 days before flowering, when ca. 50% of flowers were open, and at harvest, respectively. No relationships between calcium (Ca) and zinc (Zn) in the studied tissues were significant. The pre-bloom leaf concentrations of N, P, magnesium (Mg), boron (B,) iron (Fe), manganese (Mn) and copper (Cu) were correlated with those in the mid-summer leaves. The relationships between the inflorescence concentrations of P, K, Mg, B, and Mn and those in the mid-summer leaves were also significant. However, only linear correlations between B and Mn in the pre-bloom leaves and the mid-summer leaves were sufficiently strong because the determination coefficients for those relationships were 81% for B and 62% for Mn. The calculated optimal concentrations of B and Mn in the pre-bloom leaves varied from 23 to 37 mg/kg and from 46 to 93 mg/kg, respectively.