Nitrogen Fertilization, Container Type, and Irrigation Frequency Affect Mineral Nutrient Uptake of Hydrangea

Abstract

Mineral nutrient uptake of Hydrangea macrophylla ‘Merritt’s Supreme’ affected by nitrogen (N) fertilization rate, container type, and irrigation frequency was investigated. Rooted liners of hydrangea plants were fertilized twice weekly with a N-free fertilizer plus five N rates including 0, 5, 10, 15, or 20 mM N from ammonium nitrate (NH4NO3), irrigated once or twice daily with the same total irrigation volume, and grown in two types of one-gallon containers: a black plastic container and a biodegradable container (biocontainer), made from recycled paper. Concentrations of calcium (Ca) and magnesium (Mg) averaged in the entire plant, and iron (Fe) and manganese (Mn) in roots had increasing trends with increasing N rate. By comparison, increasing N rate had a dilution effect on root phosphorus (P), stem and root potassium (K), stem Ca and Mg, and leaf boron (B) concentrations. In general, nutrient content of each tested element increased with increasing N rate in each structure, or total in the plant. When there was a significant container type effect, plastic containers consistently had increased nutrient concentrations and content compared to biocontainers. One irrigation per day was beneficial in increasing nutrient concentrations of P, Ca, and zinc (Zn) in different plant structures.