Agroforestry Research

Examples of Current HARC projects

Pitch x Loblolly Pine and Black Walnut Winter Forage Alley Cropping Study: This is the oldest agroforestry study on the farm and serves several purposes, including exploring the effects of row spacing on tree growth and tree/forage interactions in an alley cropping practice. Pitch pine / loblolly pine hybrids and black walnut planted in single, double and triple rows are grown to examine the effects of row configuration on these species, emulating an alley cropping practice.

Riparian Buffer BioFilter Livestock Trial: Assesses the value of riparian buffers in filtering nitrates and phosphates out of runoff from adjacent livestock fields.

Pitch x Loblolly Pine Progeny Testing: Pitch/Loblolly hybrid pines offer a market to Missouri landowners for both wood and pine straw, a multi-million dollar landscaping mulch crop in the southern states.

Mushroom Trials for Forest Farming: Researchers are evaluating European truffles, morels, shiitakes and other gourmet mushrooms for landowner profits.

Cottonwood Clonal Trial: Landowners may see a need for production alternatives to row crops and forage that offer potential for income and environmental benefits. This project seeks to identify poplar clones that are well-adapted to the climate of the lower Midwest and that produce substantial wood crops for fiber, chips or energy over short (4-5 year) rotations. The project also will provide estimates of total carbon sequestered by such plantations, data that will be useful in determining potential economic returns from carbon credit programs that may emerge. Cottonwood clones are being evaluated for their growth response and adaptibility to Missouri conditions. The best cultivars will be used in agroforestry to produce biomass and for pulp and paper production.

Cherrybark Oak Spacing Study: Cherrybark oak has market potential north of its native range, which extends south from the Missouri Bootheel and the USDA cold hardiness Zone 6. Seedlings have been planted at different spacings to establish uniform shade conditions for field testing promising agroforestry forages from the forage shade study laboratory.

Silvopastoral Practice: Researchers are investigating the similarities and differences in cattle performance between traditional open grazing and silvopastoral grazing practices. Factors also being evaluated include the success of electric fences as deterrents to protect young trees from grazing damage, and how grazing and forage production affect tree growth.

pine straw

Pine-Straw: The purpose of this study is to evaluate pitch x loblolly hybrid pines (Pinus rigida x taeda) for their suitability for the production of ‘pine straw’ mulch in Missouri. Pine straw, the naturally shed needles of pine trees, is an excellent mulch material used extensively in the Southeastern United States in landscape plantings. The purpose of hybridizing these two pine species was to create a pine with the cold hardiness of a pitch pine and the fast growth rate and long needles of a loblolly. Fifteen different genotypes of this hybrid are being evaluated for cold hardiness, growth rate, needle length and needle yield. Results to date indicate that some of pitch x loblolly genotypes in the plantation are hardy, fast growing, long-needled pines, suitable for commercial pine straw in Missouri.

Pot-in-Pot Nursery Stock Trial: Pine trees planted for pine straw production generally take at least ten years to begin producing a commercial yield of pine straw mulch. The purpose of this trial is to evaluate the potential for growing high value nursery stock between pines during plantation establishment using the Pot-in-Pot (PIP) production method. In PIP production, plastic “socket” pots are sunk in the ground and growing containers are nested in the sockets. Although the initial cost of establishing a PIP nursery is relatively high, the socket pots can be used for several successive crops of nursery stock. Also, PIP eliminates the costs associated with winter protection of containers using conventional container production methods. The long-term goals of this project are to estimate the profit potential for PIP production during pine plantation establishment and to evaluate a series of increasingly shade tolerant ornamental species for PIP production between the pines as the plantation matures.

Missouri Gravel Bed for Nursery Stock: The Missouri Gravel Bed (MGB) is a method, developed at HARC, that allows planting of bare root nursery stock at any time of the year. Dormant, bare rooted trees and shrubs are set into a frequently irrigated mixture of pea gravel and sand. Plants can be removed from the gravel at any time during the summer and fall and field planted bare root, in full leaf with a survival rate equal to or greater than those expected for container-grown or balled and burlapped plants. The main objective of this project is to evaluate the potential of MGB to facilitate planting of trees and shrubs in agroforestry and landscape plantings.

National Arboretum / NC-7 Trials: The purpose of this planting is to serve as a germplasm repository and evaluation site for newly introduced and rare woody plants with potential ornamental value. A cooperative agreement in 1996 designated HARC as the U.S. National Arboretum Midwest Research and Education Site. Since then, many National Arboretum introductions have been planted, including red maples, alders, disease resistant elms, ‘Green Giant’ arborvitae, viburnums and many others. The National Arboretum/ NC-7 trial plantings provide a unique opportunity for Missouri nursery producers, landscapers and interested individuals to observe mature specimens of new and unusual plants.

Forage Shade Study: In 1994, researchers began this project by examining 27 forage species (native and exotic legumes, warm season and cool season grasses) for the effect of shade on dry weight production and nutritional value. During the intervening years, additional species have been studied. All species are evaluated under 3 shade levels: 0% (full sun), 55% shade and 80% shade. The goal is to determine their growth and development under different shade levels when grown as companion crops in agroforestry practices or for savanna and woodland restoration.

Evaluating the MDC quail cover bundle shrubs: Bare root seedlings of false indigo, wild plum, fragrant sumac and dogwood were established in 2001. These shrubs were chosen for their potential to provide quality escape cover and food for bobwhite quail. The main objective is to compare their growth and development with moderate management under field conditions.

Flood Tolerance: A Flood Tolerance Laboratory was constructed along Sulphur Creek in the Missouri River floodplain at HARC. This facility provides a unique field laboratory for studying the response of plant species to the periodic flooding common to mid-western floodplains. The laboratory has 12 channels, each approximately 20-ft wide by 600-ft long. Each channel can be independently adjusted for water depth, standing or flowing water, and duration of flooding. Selected grasses, legumes, and tree species are being evaluated for flood tolerance. The flood tolerance of hardwood planting stock and genetic variation in ecotypes from seed collected from bottomland and upland stands is also being evaluated.

flood tolerance lab

Bioterracing Demonstration: This project demonstrates the value of bioterracing on highly erodible soils. Bioterraces are a combination of trees, shrubs and grasses planted in rows along the corridor to help trap soil and debris as they move down a slope in surface water flow.

Tree Improvement: The tree improvement program focuses on identifying and testing selections of black walnut (Juglans nigra), pecan (Carya illinoensis) and chestnut (Castanea mollissima) for incorporation into agroforestry plantings. Major components of this research include (1) testing cultivars on various sites; (2) identifying superior rootstocks for grafting; (3) developing improved vegetative propagation techniques; and (4) creating a breeding program to develop improved selections. A significant component of the tree improvement research program at HARC is nut tree repositories, which serve as germplasm collections to study the adaptation and commercial potential of various cultivars of nut bearing trees to Missouri. Repositories at HARC include walnut (Juglans nigra), pecan (Carya illinoensis), Chestnut (Castanea mollissima and Castanea hybrids), and Hazelnut (Corylus hybrids). UMCA is conducting the nation’s most extensive programs to develop the northern pecan, Chinese chestnut and the eastern black walnut as profitable agroforestry orchard crops.

National ties

A cooperative program begun in 1996 with the U.S. National Arboretum establishes the center’s ties to national horticultural efforts. Designated the Midwest Plant Research and Education Site by the National Arboretum, the center serves as a germplasm repository for newly introduced and rare plant materials with commercial and ornamental value. It is also the Midwest site for evaluating ornamental trees and shrubs for cold hardiness and resistance to disease and insects, with particular emphasis on plant materials in the Missouri and Mississippi River bioregions.

Extension role

In addition to its traditional role as a teaching facility, the center supports University Extension programs such as field days and workshops for the general public and various commodity or industry groups. Local county or regional extension personnel use the center occasionally as a stop on Extension-sponsored tours for growers and producers.

Community connections

Public education is an important part of the center’s mandate. A self-guided driving tour highlights the center’s cultural features, natural resources, and research activities. Interpretative trails throughout the site are planned. Display gardens feature both perennial and annual flowering plants especially suited to Missouri’s growing conditions.

Thomas Hickman House

The center has strong historical links to its surrounding community. One of Missouri’s oldest intact brick houses, the Thomas Hickman House built in 1819, stands on the property. The 1,800-square-foot house represents the southern “Georgian” cottage design a distinctive architectural style during the early development of the Boonslick region of Missouri. Hickman, one of the original settlers of Howard County, was a local businessman. The restored house will be used as a visitor education center to display botanical collections and exhibits of local natural history, plant science research at the center, and period artifacts from the early 1800s.