Liming and micronutrient requirements for containerized landscape tree seedling production

Abstract

Nine species of landscape trees were grown from seed in two pine barks with a pH 4.7 and 5.1. Preplant amendment treatments to each pine bark were: with or without dolomitic limestone [3.6 kg m-3 (6 lb yd-3)] and with or without micronutrients [0.9 kg m-3 (1.5 lb yd-3) Micromax™]. The experiment was repeated using two of the nine original species and pine barks with pH 5.1 and 5.8. In a second experiment, one of the species used in both above experiments was grown from seed in pine bark amended with [0, 1.2, 2.4, or 3.6 kg m-3 (0, 2, 4, or 6 lb yd-3)] dolomitic limestone and 0 or 0.9 kg m-3 (0 or 1.5 lb yd-3) Micromax™ to determine the effect of micronutrient fertilization over a wide substrate pH range. Lime rates resulted in initial pine bark pH values of 4.0, 4.5, 5.0, and 5.5, respectively. In all experiments, micronutrient fertilization increased shoot dry weight and shoot height for all species, while lime amendments decreased shoot dry weight and shoot height for all species. Pine bark solution nutrient element concentrations increased when micronutrients were added, decreased when lime was added, and were higher in low pH bark than in high pH bark. In all experiments, adding micronutrients was necessary regardless of pine bark pH, while adding lime was not necessary.