Regulations and Documents Described on this page:

Soil Types in French Prairie

French Prairie has among the best quality soils in the United States, the result of deposition of high quality soil in the Willamette Valley during the Missoula Flood some 10,000 years ago.  Generally speaking the soil quality is highest to the north (in French Prairie) and decreases to the south.  In addition to soil quality, additional factors making French Prairie land “prime farmland” is the availability of water combined with an overall mild climate.

The US Department of Agriculture defines Prime Farmland as:

Land that has the best combination of physical and chemical characteristics for producing food, feed, forage, fiber, and oilseed crops and that is available for these uses. It has the combination of soil properties, growing season, and moisture supply needed to produce sustained high yields of crops in an economic manner if it is treated and managed according to acceptable farming methods. In general, prime farmland has an adequate and dependable water supply from precipitation or irrigation, a favorable temperature and growing season, an acceptable level of acidity or alkalinity, an acceptable content of salt or sodium, and few or no rocks. Its soils are permeable to water and air. Prime farmland is not excessively eroded or saturated with water for long periods of time, and it either does not flood frequently during the growing season or is protected from flooding.

About one half of the soils in the Willamette Valley are “Willamette Silt Loam,” deep, well-drained soils with lots of organic matter.

French Prairie Zoning

The vast majority of land in French Prairie is zoned Exclusive Farm Use (EFU) due to these characteristics, as illustrated in this map from Oregon Department of Agriculture:

This map also illustrates the historic boundaries of French Prairie, the Willamette River on the north and west, the Pudding River on the east, and the Little Pudding River/Lake Labish on the south.

French Prairie Soil Maps

The agricultural capability of soils are designated by the USDA in classes, based on characteristics of the soils within specific areas and their capability to produce common cultivated crops and pasture plants without deteriorating over a long period of time.  The USDA definitions of soil Classes is:

Class 1 soils have few limitations that restrict their use.

Class 2 soils have moderate limitations that reduce the choice of plants or that require moderate

conservation practices.

Class 3 soils have severe limitations that reduce the choice of plants or that require special

conservation practices, or both.

Class 4 soils have very severe limitations that reduce the choice of plants or that require very careful

management, or both.

Class 5 soils are subject to little or no erosion but have other limitations, impractical to remove,

that restrict their use mainly to pasture, rangeland, forestland, or wildlife habitat.

Class 6 soils have severe limitations that make them generally suiitable for cultivation and that restrict their use mainly to pasture, rangeland, forestland, or wildlife habitat.

Class 7 soils have very severe limitations that make them unsuitable for cultivation and that restrict their use mainly to grazing, forestland, or wildlife habitat.

Class 8 soils and miscellaneous areas have limitations that preclude commercial plant production and that restrict their use to recreational purposes, wildlife habitat, watershed, or esthetic purposes.

Quality classification of soils is directly correlated with available water for farming, so they are frequently mapped in terms of irrigated (dependable water supply and of adequate quality) or non-irrigated (inadequate water supply for irrigation). Regardless of availability of irrigation water, most French Prairie soils are considered prime or high value.

Irrigated Soil Types: The majority of Prime Farmland in French Prairie is Class 1, 2 and 3 soil types, as this map based on irrigated status from Oregon Dept. of Agriculture shows:

Of note, very little of French Prairie has Class 4 or worse soil types.

Non-Irrigated Soil Types: Equally striking is the view of soil types mapped by in terms of non-irrigated status:

The status of soil classification changes very little between the two maps because most of French Prairie ag land is comprised of Class I, 2 and 3 soils irrespective of irrigation.

back to top

Oregon Department of Agriculture, Agriculture Land Inventory in Metro

In support of the Oregon Dept. of Land Conservation and Development hearings re: proposed New and Amended Administrative Rules establishing a process and criteria for Metro Area Urban and Rural reserves, pursuant to 2007 legislation (SB 1011), the Oregon Dept. of Agriculture completed a land survey and published the Agriculture Land Inventory and Analysis map in March, 2008.  As seen below, this map defines all land surrounding metro Portland considered to be of high enough quality to be designated as “Foundation Agriculture Land.”

back to top

Oregon Department of Land Conservation and Development documents

A. Excerpts from a DLCD document on allowable agricultural uses on EFU zoned land.

  • The definition of farm use serves a dual purpose. It identifies both the uses allowed in a farm zone and the uses which receive special farm use property tax assessment. In ORS 215 it reads: “As used in this section, “farm use” means the current employment of land for the primary purpose of obtaining a profit in money by raising, harvesting and selling crops or the feeding, breeding, management and sale of, or the produce of, livestock, fur-bearing animals or honeybees or for dairying and the sale of dairy products or any other agricultural or horticultural use or animal husbandry or any combination thereof. “Farm use” includes the preparation, storage and disposal by marketing or otherwise of the products or by-products raised on such land for human use or animal use.
  • Because the distinction between “preparation” and “processing” is not always easy to determine, LCDC adopted a rule (OAR 660-033-0020(7(b)) to further define the term “preparation” as it is used in the definition of “farm use.” It reads:

“Preparation of products or by-products includes but is not limited to the cleaning, treatment, sorting, composting or packaging of the products or by-products.”

“Preparation of a farm product is something less than “processing.” Making a new or different product from the naturally grown farm product is “processing” not “preparation” and treated as either a “processing facility” of “farm crops” in a building less than 10,000 sq. feet or a “commercial activity in conjunction with farm use. All “processing” facilities, regardless of size, where more than 75% of the product comes from other farms, are treated as “commercial” activities in conjunction with farm use.

  • Processing facilities for farm crops were allowed in 1997 in order to encourage small scale facilities on the farm... Such facilities are subject to three limitations: 1) they can only process farm crops (plants not livestock/animals or other); 2) at least one-quarter of farm crops processed must come from the farm operation on which the facility is located; and 3) the building for the processing facility cannot exceed 10,000 square feet of floor area exclusive of the floor area designated for preparation, storage or other farm use or devote more than 10,000 square feet to the processing activities within another building supporting farm uses.

Download the entire article in PDF by clicking here: Uses allowed in Farm Zones Supportive of the Agricultural Industry


B. Excerpts from a DLCD document regarding Oregon’s Statewide Planning Goals and Guidelines for Agricultural Lands:

  • Agricultural lands shall be preserved and maintained for farm use, consistent with existing and future needs for agricultural products, forest and open space and with the state's agricultural land use policy expressed in ORS 215.243 and 215.700.
  • Zoning applied to agricultural land shall limit uses which can have significant adverse effects on agricultural and forest land, farm and forest uses or accepted farming or forest practices.
  • Plans providing for the preservation and maintenance of farm land for farm use, should consider as a major determinant the carrying capacity of the air, land and water resources of the planning area. The land conservation and development actions provided for by such plans should not exceed the carrying capacity of such resources.
  • Non-farm uses permitted within farm use zones under ORS 215.213(2) and (3) and 215.283(2) and (3) should be minimized to allow for maximum agricultural productivity.

Download a PDF of the Goals and Guidelines document by clicking here.


C. Protecting farmland still a priority for Oregon Department of Agriculture and DLCD.

The protection of farmland is as important as ever in Oregon, according to two state agencies and their respective board or commission. In 2004 the State Board of Agriculture and the Land Conservation and Development Commission (LCDC) met in joint session to discuss Oregon´s land use laws and why they are still needed by agriculture

"Agricultural land can´t be viewed as an idle resource waiting to be converted to homes, office buildings, retail outlets, or other types of development," said Katy Coba, director of the Oregon Department of Agriculture. "These lands and their associated infrastructure are an integral and stable economic platform statewide, both urban and rural."

Read the entire article, click here

back to top

French Prairie Agreement

What has come to be called the French Prairie Agreement results from the adoption of a vision statement regarding the French Prairie area by Clackamas and Marion Counties and the cities of Aurora, Canby, Donald, Hubbard, Wilsonville and Woodburn in early 2006. This agreement defines an area of interest in the French Prairie area because (among other reasons):

  • Agriculture is the largest industry in Clackamas and Marion Counties;
  • The Northern Willamette Valley, commonly known as French Prairie, is home to some of the richest and most productive soil in the world;
  • The highest and best use of most lands south of the Willamette River that are not part of an existing city or an existing city’s planned growth expansion area is for agricultural and agriculture-related purposes;
  • The Willamette River provides the best natural barrier between the urban and rural areas of the Portland metropolitan region and the rich agricultural lands of the Willamette Valley;
  • There are many acres of industrial land that can be redeveloped throughout the Portland-Metro region for additional industrial needs and uses;
  • Land use policies should not be violated to benefit one entity or special interest for their financial gain at the expense of the greater good of the region’s residents and businesses

Click here to read the French Prairie Vision Statement

Municipalities formally adopting the French Prairie Agreement as of this date are:

back to top

Home  | About FOFP | Area History | Sustainable Agriculture | Branding Initiative | Current Issues | Historic Sites | Join Us | Contact