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International Programs News & Views Volume 11

Nov. 1998

Agroforestry

Introduction

In the U. S., agriculture and forestry share many goals. Approximately 48 percent of all land (excluding Alaska) is dedicated to agricultural purposes and 32 percent of the land area is forested. Achieving social and environmental objectives, such as maintaining stream water quality and providing wildlife habitat at the landscape or watershed level, requires that forestry and agriculture practices be closely integrated.

The Secretary's Memorandum (9500-6) on Sustainable Development specifically recognized this need to better integrate USDA programs and policies related to forestry, agriculture, and rural communities. Agricultural practices can result in many direct and indirect environmental impacts that must be dealt with, while at the same time, managers work to maintain production levels to meet the demands of a growing population. Agroforestry, the intentional blending of agricultural and forestry production with conservation practices, is helping to provide cost-effective solutions. At the same time, it is simultaneously addressing the balance between environmental, economic, and social factors related to agroecosystems — a set of essential criteria in discussions of private land stewardship options.

Benefits

Benefits of agroforestry include: increased crop production, crop alternatives and diversified economies, improved soil and water quality, controlled soil erosion/sediment, filtering, sequestering and processing excess nutrients and chemicals, reduced flooding, moderated microclimates, and diversified habitats for wildlife and humans.

Practices

There are five main practices of agroforestry being promoted in the United States — alley cropping, riparian buffer strips, forest farming, windbreaks, and silvopasture.

Alley cropping generates both short- and long-term income by growing annual agricultural crops in the alleyways between rows of tree crops.

Riparian buffer strips are composed of combinations of tree, shrub, and grass plantings along streams, ponds, and wetlands to remove or intercept sediment, nutrient and pesticide runoff from adjacent land. They can also reduce bank erosion, enhance aquatic environments, and provide wildlife habitat.

Forest farming is cultivating high value specialty crops under protection of a forest canopy that has been modified to provide the appropriate amount of light and micro-environment conditions.

Windbreaks are usually designed to conserve soil, protect crops or livestock, or improve productivity. They can also be used around farmsteads to protect the home and farm buildings and decrease heating and cooling costs. Feedlot windbreaks reduce stress on livestock during times of extreme weather and can also reduce visual impacts and odors. Windbreaks along major roads or emergency routes keep snow from drifting onto roadways.

Silvopasture combines trees with forage and livestock production. The trees are grown at wide spacing to allow optimal light penetration for forage production. The trees are managed to produce high-value sawlogs, and at the same time provide shade and shelter for livestock.

In addition to the five practices, special applications of agroforestry combine tree and shrub plantings that help solve special farm concerns such as disposal of animal wastes or filtering irrigation water and also produce a wood or tree crop.

The National Agroforestry Center

The USDA National Agroforestry Center (NAC) is a partnership of the Forest Service and the Natural Resources Conservation Service (NRCS). NAC promotes agroforestry through building awareness, involving stakeholders, acting as a clearinghouse, developing concepts and principles, and leveraging resources. NAC works in concert with national and international networks of cooperators to research new ideas, transfer known technology, apply agroforestry practices locally, as well as serve the needs of natural resource managers. Primary clients of the Center are technical assistance providers who help landowners and groups with natural resource conservation planning.

NAC is comprised of three program areas: Technology Transfer & Application, Research & Development, and International Exchange.

Technology Transfer & Application Program — develops and distributes agroforestry technical information. Some of the products and services include a quarterly newsletter, how-to technical notes, training workshops, and a series of "working trees" brochures and displays. Agroforestry specialists on staff provide technical support and facilitate development of agroforestry projects and demonstrations in the field.

Research & Development Program — develops and integrates agroforestry technologies to attain more economically, environmentally, and socially sustainable ecosystems. Current areas of emphasis include: process research on how riparian and upland tree buffers maintain water quality, protect aquatic environments and sequester soil carbon, site-based restoration research to establish functioning riparian buffer systems, and landscape-scale research to optimize riparian and upland tree buffer placement in watersheds.

International Exchange Program — facilitates the development of agroforestry projects with international cooperators and selectively involves agency and university professionals for mutual benefit. Current activities include: facilitation of socio-economic study of farmer adoption of agroforestry practices in Southeast Yucatan with the International Centre for Research in Agroforestry (ICRAF)-Mexico; Forest Service and North Carolina State University; Forest Service technical assistance program for Albania with the U.S. Agency for International Development (USAID) and Albania Mission; follow-up on NRCS exchange visits to Australia and the United Kingdom; USAID-USDA Panama Canal Zone Agroforestry; collaboration with ICRAF-Southeast Asia in the Philippines; and University of Minnesota's Center for Integrated Natural Resources and Agricultural Management and the World Bank for training Ministry of Environment and Ministry of Agriculture and Natural Resources personnel in Haiti.

For more information:

If you are interested in more information about agroforestry or the USDA NAC, please visit our web site at www.unl.edu/nac.

Author: Kimberly L. Isaacson, Technology Transfer Specialist, USDA NAC, Lincoln, Nebraska

Editor: Gail C. Roane (retired), International Programs Division