Examining Nutrient Treatments Used on Balled and Burlapped Colorado Spruce Trees to Maintain Postharvest Quality

Abstract

The goal of this study was to examine the effectiveness of several nutrient treatments to maintain or enhance the growth and foliar nutrition of Colorado spruce (Picea pungens Engelm.) trees while they were in a mulch holding bed. Sixty 1.5 to 1.8 m tall Colorado spruce trees with 61 cm (24 inch) diameter root balls were heeled into a holding bed of fresh pine bark mulch. The treatments applied to the root balls were a control (pine bark without fertilizer), Osmocote 15-9-12 distributed over the top of the ball at 114.2 g (label rate) per root ball, one Ross Gro-Stake 10-10-10 Evergreen fertilizer spike per ball, one-half cartridge of Ross Root Feeder 10-12-12 evergreen fertilizer injected into the root ball at four points, or a 50:50 mixture (by volume) of Eko Compost mixed with pine bark. Trunk diameters and tree heights were measured and foliar samples for nutrient analyses were collected before applying these treatments and at the end of the growing season 17 weeks later. Overall, the Colorado spruce trees appeared quite normal throughout the study. Changes in tree height and trunk diameter by the end of the growing season were unaffected by the nutrient treatments. By fall, needles from trees treated with the mixture of 50:50 compost:bark had the highest levels of foliar N, Mg, Ca, S, MN and B. Trees treated with one fertilizer spike had the second highest levels of foliar N and S, and these levels were significantly higher than those of trees receiving the other fertilizer treatments. Even though all nutrient treatments failed to influence increases in tree heights and trunk diameters during the first growing season after digging, the compost:bark mixture and to some extent the fertilizer spike improved foliar nutrition during this time.