Comparison of Conventional and Alternative Nursery Field Management Systems: Tree Growth and Performance

Abstract

Abstract The effects of 5 nursery field maintenance systems (cultivation, herbicide management, legume (bird's-foot trefoil) companion crop, winter cereal (rye) cover crop/mulch, and mixed grass sod) on the growth and performance of field-grown trees were investigated. Six tree species were included in this study: Fraxinus pennsylvanica ‘Marshall's Seedless’; Malus ‘Red Splendor’; Gleditsia triacanthos var. inermis ‘Skyline’; Acer rubrum ‘Northwood’; Thuja occidentalis ‘Techny’; and Picea glauca var. densata. Height, lateral branch extension, and caliper growth were measured each year for 7 years. Plant quality was assessed at the end of the study. All growth parameters were affected by field management treatment. Field management treatment effects on growth were influenced by differences in climate between years and were species dependent. Caliper growth was more sensitive to cover crop competition than height growth. Height and caliper growth were initially reduced for deciduous trees grown together with cover crops, but treatment differences in height became less significant over time. Caliper of evergreens was also reduced, but field management treatment effects on height were variable. Trees grown under bare soil conditions (cultivation and herbicide management) were more densely branched than those grown with cover crops. Herbicide management and cultivation generally supported the most vigorous growth and resulted in the best quality plants. Of the cover/companion crops evaluated, the rye cover crop/mulch treatment only slightly reduced plant performance compared to cultivated and herbicide management treatments while bird's-foot trefoil and grass companion crops proved to be too competitive. A winter rye cover crop/mulch field management system appears to have potential as an alternative to conventional field production systems. Using such a system, quality plants can be produced with fewer inputs and fewer negative impacts on the environment and long term productivity.