Research — Dr. Bert Cregg, Associate Professor

Current Research Projects

 

Nursery establishment and physiology of difficult to transplant ash alternative species

 

Co-PI’s: Bob Schutzki, Tom Fernandez, Pascal Nzokou

Graduate Student: Dana Ellison

 

Background and objective: Many tree species that are commonly recommended as replacements for ash trees lost due to the emerald ash borer (EAB) are difficult to establish in nurseries and landscapes.  The physiological basis for poor initial growth of these species is not completely understood but may be related to poor initial root growth following transport and handling from liner production nurseries on the west coast.  In this project we will examine the effects of pre-plant handling on transplant stress of ash alternative species in nursery production.  The long-term goal of the project is to improve the overall availability and success of important ash alternative species in production nurseries and as street and landscape trees. 

 

Support:

  • Michigan State University Project GREEEN
  • J. Frank Schmidt Family Charitable Foundation
  • Scotts, Inc.
  • J. Frank Schmidt and Sons Nursery
  • Renewed Earth, Inc.
  • Nursery Supplies, Inc.

 

Sustainable nutrient and water management for container tree production

Co-PI’s: Tom Fernandez, Pascal Nzokou

 

Cregg, B., D.Ellison, R.T. fernandez, and P. Nzokou. 2011.  MSU Research Update: Water and nutrient management for container tree production.  Michigan Landscape 54(5):39-43.

 

Background and objective: Landscape tree nurseries in Michigan are faced with several challenges.  These include adapting to a shift in the industry from traditional field production to container production, optimizing nutrition and water management to maximize growth while reducing costs and potential environmental impacts, and meeting rising consumer demands for sustainably- or organically-produced landscape materials.  For the past four years we have conducted research trials on improving nutrient and water management of landscape conifers and shade trees in Pot-in-Pot container production. (Klooster et al., 2010; Taylor et al., 2009).  The overall goals of the current phase of our Pot-in-Pot production research are to expand the capabilities of the system and evaluate components of production systems for container-grown conifers and shade trees that will enable growers to market plants as certified Organic or certified Naturally-grown. 

 

The specific objectives of this project are to:

  1. Increase the research capacity of the MSU Pot-in-Pot research nursery by adding an automated drainage measuring system; making it a state-of-art facility for water and nutrient management research on container-grown landscape trees.

  2. Compare the growth and quality of landscape shade trees and conifers grown with conventional fertilizers and organic-approved fertilizers.

  3. Develop whole-crop water and nutrient budgets for shade tree and conifer crops grown with conventional and organic-certified fertilizers.

 

Support:

  • USDA SCRI Block Grant
  • Michigan Department of Agriculture
  • Michigan Nursery and Landscape Association
  • Scotts, Inc.
  • J. Frank Schmidt and Sons Nursery
  • Renewed Earth, Inc.
  • Nursery Supplies, Inc.
  • Peterson’s Riverview Nursery

 

Effect of nitrogen source on physiology and growth of Fraser fir and blue spruce

Co-PI’s Pascal Nzokou and David Rothstein

 

Background and objectives: Proper nutrition management and fertilization are essential to enhancing productivity and maintaining tree quality, especially for high-value species such as Fraser fir and Colorado blue spruce.  Moreover, nitrogen source (ammonium vs. nitrate) has been shown to affect nutrient uptake and physiology of Fraser fir (Rothstein and Cregg 2005).  The relative amount of nitrate to ammonium may also affect coning in conifers (Ebell 1972 and Ebell and McMullan 1970).  The objective of this project is to determine the effect of nitrogen source (100% ammonium vs. 100% nitrate) on growth and physiology of Fraser fir and blue spruce trees in a test Christmas tree plantation at the MSU Southwest Michigan Research and Extension Center (SWMREC).

 

Support:

  • MSU SWMREC
  • Michigan Christmas Tree Association
  • Peterson’s Riverview Nursery
Dr. Bert Cregg, Associate Professor

Dr. Bert Cregg
Associate Professor

A214 Plant & Soil Sciences Building
East Lansing MI 48824-1325

Phone: (517) 355-5191 x 1335
Fax: (517) 353-0890

Email: cregg@msu.edu