Location: Floral and Nursery Plants Research Unit
Project Number: 8020-21000-062-00
Start Date: Apr 14, 2013
End Date: Apr 13, 2018
New plants or underutilized native plants in a range of environments will be evaluated to identify superior landscape qualities, environmental sustainability, and production potential. Traits to be evaluated include flowering characteristic and duration, growth rate and habit, fruit development, foliage characteristics, cold and heat tolerance, drought tolerance, susceptibility to insect and disease pressure, possible invasiveness, and nutrient and irrigation management. Traditional cylinder-style containers will be compared to novel containers that are modular and low profile with air root pruning capabilities that allow a more natural spreading root growth. Plant responses, including photosynthesis, trunk diameter increase, and shoot growth, will be documented for a two-year period and determined by nondestructive measurements. Destructive measurements will include root and shoot biomass and a quality rating to determine kinked, circling, or girdling roots. Transplant success of bare root harvested ornamental trees will be examined as compared to the quality and mass of the root system as affected by root uptake of neonicotinoid insecticides for control of flatheaded appletree borer. The primary role of ARS in this cooperative project will involve root pruning treatments on bare root trees, assessing root regrowth, and determining the optimal chemical application timing for maximum root uptake. Root quality will be assessed by the number of main lateral roots generating from the shoot transition zone, the branching structure of the main lateral roots and secondary root formation, and the amount of fibrous roots present. Phloem and leaf tissue will be collected over time to determine insecticide uptake. The effect of fertilizer coating and fertilizers with lower ratios of nitrogen and phosphorus will be studied in conjunction with micro-cyclic irrigation in large container production systems. The interaction of irrigation management with the nutrient release from low nutrient formulations of controlled release fertilizers will be tested in large nursery containers (7 to 25 gal). Container substrate moisture levels will be monitored using a gravimetric technique. Weekly container leachate analysis will be conducted during the growing season to determine the effect of irrigation treatments on nutrient release.