Eastern Redcedar (Juniperus virginiana) as a Substrate Component Effects Growth of Three Tree Species

摘要

Sustainable and local alternative substrates are being explored for nursery crop production due to concern over pine bark (PB) supplies and costs. This study evaluated a tree species which is weedy in the Great Plains region of the United States, eastern redcedar, processed through a hammer mill equipped with a 19 mm (3/4 in) screen size to create six substrates consisting of 0, 5, 10, 20, 40, and 80% eastern redcedar chips (ERC) and 20% sand; the remaining volume was composed of PB. Each of these substrates were then used to grow baldcypress (Taxodium distichum), Chinese pistache (Pistacia chinensis), and silver maple (Acer saccharinum) under two fertilizer rates: either a 4.5 kg.m(-3) (7.5 lbs.yd(-3)) low fertilizer rate or a 8.9 kg.m(-3) (15 lbs.yd(-3)) high fertilizer rate. Substrates composed of 40 and 80% ERC had reduced container capacity, resulting in less growth of all three species. Plants responded similarly to both fertilizer rates suggesting that the limiting factor to plant growth is substrate physical properties. Plants grown in 5-20% ERC were of comparable size and quality to those grown in the control substrate. Therefore, ERC can be recommended as a PB substrate supplement, but not as a full replacement at this time.