Abstract
•DRIS and CND detect rose crop nutrient imbalances better than traditional methods.•Corrections to supplies of Fe, Zn, Cu and Mn improved length in rose flower yields.•A significant Fe:Mn interaction was identified on ‘Natal Briar’-grafted rose crops.
Efforts to optimize fertilizer use efficiency in intensively managed greenhouse rose crops led to studies to establish and validate norms for their integrated nutrient diagnosis. The present study experimentally validates the practical usefulness of previously established DRIS (Diagnosis and Recommendation Integrated System) and CND (Compositional Nutrient Diagnosis) norms for soil-grown roses in the Bogota Plateau of Colombia. Corrective fertilization treatments, based on a control fertigation solution, were designed based on preliminary diagnosis by DRIS methodology, and applied over two growth and flowering flushes in an experimental plot within a commercial rose crop. These integrative nutrient diagnoses methods detected microelement imbalances in rose leaf tissues, including excesses of iron (Fe) and deficiencies of zinc (Zn), copper (Cu) and manganese (Mn). Conventional soil and foliar analyses had some contrasting interpretation diagnoses on these nutrients. Implementation of corrective changes, based on DRIS results, to the supply of these micronutrients in fertilization treatments improved the elemental (individual) and mean nutrient balance indices in rose leaf tissues, and led to gradual increases in average stem length and the fraction of harvested flowers with longer stems (>70 cm) over the course of two flowering cycles. These DRIS and CND methods highlighted a significant Fe:Mn interaction in rose crops, likely affected by the supply and ratio of micronutrients in the fertigation solutions, inherently low Mn levels in the soils of the region, and a major role of the dominant rootstock in use. The use of integrative nutrient diagnosis methods, based on relationships between all nutrient elements and flower yield as the primary response criterion, offer an enhanced capacity to identify those elements with the highest probability of generating a positive flower yield response when correcting their supply in rose fertilization programs.