Improving the Efficacy of the Missouri Gravel Bed as a Tool for Facilitating Bare Root Handling of Trees and Shrubs

IMPROVING THE EFFICACY OF THE MISSOURI GRAVEL BED AS A TOOL FOR FACILITATING BARE ROOT HANDLING OF TREES AND SHRUBS

Sponsoring Institution

National Institute of Food and Agriculture

Project Status

COMPLETE

Funding Source

HATCH

Reporting Frequency

Annual

Accession No.

0208698

Grant No.

(N/A)

Cumulative Award Amt.

(N/A)

Proposal No.

(N/A)

Multistate No.

(N/A)

Project Start Date

Sep 15, 2006

Project End Date

Sep 14, 2011

Grant Year

(N/A)

Program Code

[(N/A)]- (N/A)

Recipient Organization
UNIVERSITY OF MISSOURI
(N/A)
COLUMBIA,MO 65211

Performing Department
PLANT SCIENCES

Non Technical Summary
Harvesting plants bare root (without a soil ball) has several advantages over harvesting balled and burlapped (B&B) or growing in containers. Less labor and equipment are required to harvest bare root than B&B and shipping costs are much lower. Bare root handling also eliminates the costs of pots, growing medium and pot handling associated with container growing and avoids container-induced root contortion. Until recently, a major factor preventing growers, landscapers and homeowners from taking advantage of the benefits associated with bare root plants has been the necessity to plant during the dormant season only. However, recent research has shown that bare root trees and shrubs can be successfully planted in mid summer if they are placed, while dormant, with their roots in frequently-irrigated gravel, using a system called the Missouri Gravel Bed. Two factors currently limiting widespread adoption of this technique are the intensity of water management required and the limited top growth that occurs in the gravel bed. In recent studies, incorporation of clay into the rock significantly improved the growth of plants in a gravel medium while reducing the frequency and volume of water required to keep plants from wilting. The objective of this project is to determine the best type and amount of clay to incorporate into pea gravel to maximize plant growth while minimizing water and fertilizer requirements. Results of this work will allow more growers and landscapers to take advantage of the cost savings associated with bare root handling of trees and shrubs.

Animal Health Component

80%

Research Effort Categories

Basic

10%

Applied

80%

Developmental

10%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
125	0699	1060	30%
205	2110	1060	70%

Knowledge Area
205 - Plant Management Systems; 125 - Agroforestry;

Subject Of Investigation
2110 - Ornamental trees and shrubs; 0699 - Trees, forests, and forest products, general;

Field Of Science
1060 - Biology (whole systems);

Keywords

Goals / Objectives
Research has shown that the Missouri Gravel Bed is an effective tool for extending the planting season for bare root nursery stock. However, the method has not been widely adopted because, as it is currently designed, the level of management required is unacceptable to many potential users. The objectives of this project are 1) to confirm the beneficial effects of amending gravel with calcined clay on plant growth and water holding capacity of the gravel bed medium; 2) to compare the effects of amending gravel with calcined clay with those of amending with non-calcined, locally available clay materials; 3) to define the optimal frequency and volume of irrigation for maximizing plant growth in a clay amended gravel bed; 4) to determine the optimum application frequencies and rates of controlled release and soluble fertilizer for plant growth in a clay amended gravel bed; and 5) to estimate the levels of nitrate and phosphate in leachate from a clay amended gravel bed. Results of this research will allow users of the Missouri Gravel Bed to install systems that meet their production and handling needs using an economical and environmentally sound design.

Project Methods
Greenhouse and field studies will be conducted in which plants of Gymnocladus dioicus and Forsythia are grown in mixtures of pea gravel and calcined or non-calcined clay materials. In the initial study, Gymnocladus seedlings will be grown in the greenhouse in pots containing gravel mixed with 0-40% calcined clay. Seedling height, caliper and dry weight will be measured and the moisture release characteristics of the mixtures will be determined using the pressure plate method. In subsequent studies, Forsythia plants will be grown outdoors in 7-l plastic pots filled with various mixtures of rock and calcined or non-calcined clay to determine the mixtures allowing the most rapid plant growth. Once the optimal mixture of gravel and clay is determined, studies will be conducted to determine the effects of irrigation schedule and level of fertilization on growth of Forsythia. The concentration of nitrate in the leachate from gravel and clay mixtures will also be determined.

Progress 09/15/06 to 09/14/11

Outputs
OUTPUTS: As a result of field days, publications and previous speaking engagements, I was invited to make presentations to two green industry groups in 2009 on use of the Missouri Gravel Bed to facilite urban tree planting. The first presentation was at the annual convention of the Western Landscape and Nursery Association in Overland Park Kansas and the other was at the Inland Turf, Tree and Landscape conference in Spokane Washington. These presentations generated requests for further information from ten individuals who indicated that they planned to establish gravel beds in their operations. PARTICIPANTS: Partner organizations included the cities of Columbia and St. Peters in Missouri and Overland Park in Kansas. Personnel in the park departments in these cities have installed gravel beds to facilitate tree planting and have provided valuable input on the function of their beds with minor modifications. I am also collaborating with Dr. Gary Johnson at the University of Minnesota on a cost/benefit analysis of the gravel bed technique for urban tree planting programs in the Midwest. Training of nursery producers, city foresters and urban horticulture managers occurred during presentations at the Western Landscape and Nursery Association convention and the Inland Tree, Turf and Landscape conferences. TARGET AUDIENCES: Target audiences included professionals in the nursery and landscape industry as well as arborists, city foresters and municipal horticulturists. The main efforts to reach these audiences were presentations at the Western Landscape and Nursery Association convention in Overland Park, Kansas and the Inland Tree, Turf and Landscape Conference in Spokane, Washington. I also worked directly with such as Chad Herwald and Bret O'Brien, forestry and natural resource supervisors with the City of Columbia parks department as they developed a gravel bed operation. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Several cities in the region have established gravel beds to facilitate their tree planting programs. St. Peters, MO installed a bed in 2008 and plans to move and expand the operation in 2011 based on planting success with bare root trees from the gravel. City of Columbia Missouri expanded its gravel bed in 2010 to allow continued trees planting in parks despite a 50% budget cut, based on experience with a small, experimental bed in 2009. Overland Park Kansas also plans to expand its gravel bed operation based on previous success.

Publications

No publications reported this period

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: As a result of field days, publications and previous speaking engagements, I was invited to make presentations to two green industry groups in 2009 on use of the Missouri Gravel Bed to facilite urban tree planting. The first presentation was at the annual convention of the Western Landscape and Nursery Association in Overland Park Kansas and the other was at the Inland Turf, Tree and Landscape conference in Spokane Washington. These presentations generated requests for further information from ten individuals who indicated that they planned to establish gravel beds in their operations. PARTICIPANTS: Partner organizations included the cities of Columbia and St. Peters in Missouri and Overland Park in Kansas. Personnel in the park departments in these cities have installed gravel beds to facilitate tree planting and have provided valuable input on the function of their beds with minor modifications. I am also collaborating with Dr. Gary Johnson at the University of Minnesota on a cost/benefit analysis of the gravel bed technique for urban tree planting programs in the Midwest. Training of nursery producers, city foresters and urban horticulture managers occurred during presentations at the Western Landscape and Nursery Association convention and the Inland Tree, Turf and Landscape conferences. TARGET AUDIENCES: Target audiences included professionals in the nursery and landscape industry as well as arborists, city foresters and municipal horticulturists. The main efforts to reach these audiences were presentations at the Western Landscape and Nursery Association convention in Overland Park, Kansas and the Inland Tree, Turf and Landscape Conference in Spokane, Washington. I also worked directly with such as Chad Herwald and Bret O'Brien, forestry and natural resource supervisors with the City of Columbia parks department as they developed a gravel bed operation. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Several cities in the region have established gravel beds to facilitate their tree planting programs. St. Peters, MO installed a bed in 2008 and plans to move and expand the operation in 2011 based on planting success with bare root trees from the gravel. City of Columbia Missouri expanded its gravel bed in 2010 to allow continued trees planting in parks despite a 50% budget cut, based on experience with a small, experimental bed in 2009. Overland Park Kansas also plans to expand its gravel bed operation based on previous success.

Publications

No publications reported this period

Progress 01/01/07 to 12/31/07

Outputs
A gravel bed was installed at the Horticulture and Agroforestry Research Center (HARC) in New Franklin Missouri, containing 40 tons of gravel and 10 tons of calcined clay. A similar bed was also installed utilizing non-calcined, subsoil clay. Bare root oak seedlings have been placed in these beds to compare seedling growth in gravel containing 10% sand (the standard MGB medium) with that in media containing calcined and non-calcined clay. These research tools will allow assessment of effects of adding calcined clay to a pea gravel medium on growth of woody plants on a field scale to verify results of greenhouse studies.

Impacts
Based on preliminary data on growth of oak seedlings in the field scale, experimental gravel beds, it appears that amending pea gravel with non-calcined clay may be nearly as effective as amending it with calcined clay in enhancing plant growth relative to that in the standard MGB medium. This is important, since calcined clay costs approximately ten times as much as non-calcined material.

Publications

No publications reported this period