Response of Eight Maple Cultivars (Acer spp.) to Soil Compaction and Effects of Two Rates of Pre-plant Nitrogen on Tree Establishment and Aboveground Growth

Abstract

This study assessed soil compaction effects on aboveground growth of maple cultivars, and compared two nitrogen rates applied pre-planting for their influence on establishment and growth of trees planted into compacted soils. Eight commonly used maple cultivars of Acer rubrum and Acer × freemanii were evaluated. During container production, plants received either 25 or 100 mg·L-1 nitrogen through fertigation twice per day. Trees were planted into non-compacted field plots with a mean bulk density of 1.40 g·cm-3, or into compacted plots with a mean bulk density of 1.60 g·cm-3. In 2002, researchers randomly selected half of the compacted plots and applied an additional soil treatment. At the completion of this treatment, mean bulk density was 1.55 g·cm-3. Trees growing in higher density soils had significantly smaller aboveground biomass measures (P < 0.05), than those growing in non-compacted plots. There was a significant difference between cultivars (P < 0.0001); for example, ‘Celzam’ and ‘Fairview Flame’ had greater aboveground biomass values than other cultivars when grown in compacted soils, but compaction still affected growth. The 100 mg·L-1 nitrogen rate increased leaf dry weight and area, but did not impact height and caliper growth or stem dry weight.