Ag'84M^ ^%. United Stal 111 Departmenf C ^ Agriculture Land Resource Regions Soil Conservation Service and Major Land Agriculture Handbook 296 Resource Areas of The United States O •X3 33 o o r" r~> -0 £5 ■< • • • Land Resource Regions and Major Land Resource Areas of The United States United States Department of Agriculture Soil Conservation Service Washington. D.C. Agriculture Handbook 296 Revised December 1981 CONTENTS Pa^e Introduction 1 Northwestern Forest, Forage, and Specialty Crop Region 3 Northwestern Wheat and Range Region ' 6 California Subtropical Fruit, Truck, and Specialty Crop Region 11 Western Range and Irrigated Region 16 Rocky Mountain Range and Forest Region 30 Northern Great Plains Spring Wheat Region 35 Western Great Plains Range and Irrigated Region 40 Central Great Plains Winter Wheat and Range Region 49 Southwest Plateaus and Plains Range and Cotton Region 56 Southwestern Prairies Cotton and Forage Region 60 Northern Lake States Forest and Forage Region 64 Lake States Fruit, Truck, and Dairy Region 69 Central Feed Grains and Livestock Region 75 East and Central Farming and Forest Region 84 Mississippi Delta Cotton and Feed Grains Region 94 South Atlantic and Gulf Slope Cash Crops, Forest, and Livestock Region 95 Northeastern Forage and Forest Region 100 Northern Atlantic Slope Diversified Farming Region 106 Atlantic and Gulf Coast Lowland Forest and Crop Region 109 Florida Subtropical Fruit, Truck Crop, and Range Region 114 Hawaii Region 117 Southern Alaska Region 121 Interior Alaska Region 124 Arctic and Western Alaska Region ^27 References 130 Appendix I. Area of LRR's and MLRA's 131 Appendix II. Soil Classification 137 Appendix III. Caribbean Region 153 III INTRODUCTION This handbook is an assemblage of currently available lished major land resource areas have been divided into information about the land as a resource for farming, smaller, more homogeneous areas. The use of numbers ranching, forestry, engineering, recreation, and other and letters to identify the newly created major land uses. It is a revision of USDA Agriculture Handbook resource areas requires fewer changes in existing in- No. 296, Land Resource Regions and Major Land formation in records and in data bases. A few major Resource Areas of the United States, pubHshed in land resource areas consist of two or more parts separated 1965. Revisions consist of: (1) Refined delineations of for short distances by other land resource areas. In land resource regions (LRR's) and major land resource places one of these parts is widely separated from the areas (MLRA's), (2) identification of the soils of each main body of the major land resource area and is in an region and area according to the system of Soil Tax- adjoining land resource region. The description of the onomy, (1975), (3) a brief discussion concerning the respective major land resource aiea also appUes to these potential natural vegetation of the resource regions and outlying parts. areas, and (4) inclusion of major land resource areas Land resource regions are designated by capital and land resource regions for the states of Alaska and letters identified by a descriptive name. For example, Hawaii and the territory of Puerto Rico (Appendix III). the descriptive name for Land Resource Region A is the Information is current as of April 1978. Northwestern Forest, Forage, and Specialty Crop Re- The information in this handbook affords a basis for gion. making decisions about national and regional agricultural The dominant physical characteristics of the land concerns, identifies needs for research and resource resource regions and of the 204 major land resource inventories, provides a broad base for extrapolating the areas are described briefly under the headings land use, results of research within national boundaries, and elevation and topography, chmate, water, soils, and serves as a framework for organizing and operating re- potential natural vegetation. The state or states in source conservation programs. which an MLRA occurs and the extent of the MLRA The land resource categories used at state and na- are indicated on the first page of each description. The tional levels are land resource units, land resource area and proportionate extent of the regions and the areas, and land resource regions. MLRA's are given in appendix I. Land resource units are geographic areas, usually Land use.—The relative extent of the federally or several thousand acres in extent, that are characterized privately owned land is indicated if significant. The by a particular pattern of soils, climate, water re- extent of the land used for cropland, pasture, range, sources, and land uses. A unit can be one continuous forests, industrial and urban developments, and other area or several separate nearby areas. special purposes is indicated. These fractions or per- Land resource units are the basic units from which centages are for the entire resource area unless specifical- major land resource areas are determined. They are ly stated otherwise. Also included is a list of the also the basic units for state land resource maps. They principal crops grown and the type of farming practiced. are coextensive with state general soil map units, but Elevation and topography.—A range in height some general soil map units are subdivided into land above sea level and significant exceptions, if apphcable, resource units because of significant geographic differ- are provided for the area as a whole. The topography of ences in climate, water resources, and land use. Land the area, including natural and cultural features, is resource units are not described in this handbook, and described. they are not shown on the national map. Climate.—Climatic data discussed are: (1) A range Major land resource areas (MLRA's) are geographically of the annual precipitation for the driest parts of the associated land resource units. Identification of these area to the wettest and the seasonal distribution of large areas is important in statewide agricultural plan- precipitation and (2) a range of the average annual ning and has value in interstate, regional, and national temperature and the average freeze-free period charac- planning. teristic of different parts of the resource area. In this handbook major land resource areas are Water.—Information is provided concerning surface designated by Arabic numbers and identified by a des- streamflow and i^ound water and the source of water criptive geographic name. For example, MLRA1 (North- for municipal use and for irrigation. Also, land resource ern Pacific Coast Range, Foothills, and Valleys) is on areas dependent on other areas for water supply and the west coast; MLRA 157 is on the east coast; and those that furnish water to other areas are specified. MLRA 175 (Kuskokwim Highland) is in Alaska. Soils.—The dominant soils of the major land re- Some major land resource areas are designated by an source area are identified according to the principal Arabic number and a letter because previously estab- suborders, great groups, and representative soil series. 1 General descriptions of the soil orders, suborders, and sources, mainly from the Soil Conservation Service, great groups are provided in appendix IL U.S. Department of Agriculture. Most information Potential natural vegetation.—The plant species about land use is based on recent reports of state soil that the major land resource area can support are and water conservation needs. For additional sources, identified by their common names. refer to the list of references. The descriptions are based on information from many A—NORTHWESTERN FOREST, FORAGE, AND SPECIALTY CROP REGION 204,080 km^ (78,790 mi^) Steep mountains and narrow to broad, gently sloping valleys and plains characterize this region. The average annual precipitation ranges from 1,025 to 1,775 mm in much of the region, but it is 375 mm or less in some valleys and as much as 5,075 mm in some of the higher mountains. All this region is dry during the summer. The average annual temperature is 10 to 13°C in most of the region, but it is 2°C or less in some of the mountains. The freeze-free period is more than 200 days in most valleys, as long as 300 days along the coast in the southern part, and less than 115 days in the mountains. Umbrepts, Ochrepts, Humults, Xerults, Andepts, and Orthents are the principal soils in the mountains and on uplands. Fluvents, XeroUs, Xeralfs, AquoUs, and Aquents are extensive in the valleys. The mountains are heavily forested, and lumbering is a major industry. Dairy farming is an important enterprise in the valleys that have abundant rainfall. Grain crops, grass and legume seeds, fruits, and horticultural specialties are grown extensively in the drier valleys. 1—Northern Pacific Coast Range, chrepts (Dabob and Hoko series) formed in glacial Foothills, and Valleys drift. The nearly level Udifluvents (Belfast, Greha- Oregon and Washington lem, and Hoh series) formed on flood plains. 41,020 km^ (15,840 mi^) Potential natural vegetation: This area supports for- est vegetation. The coniferous forest stands are dense, Land use: About 90 percent of this area is pri- tall, and highly productive. Western hemlock, west- vately owned. The area is densely forested, and lum- ern redcedar, Douglas-flr, and Sitka spruce are com- bering is the chief industry. About 9 percent is cleared mon, and grand fir grows in places. Red alder is ag- and used for general agriculture. The cleared areas are gressive on disturbed sites. Lodgepole pine is com- mainly in the narrow valleys and on coastal terraces. mon along the coastal dunes. Mature forests have Hay, pasture, and some grain for cattle are the prin- cipal crops. About 1 percent of this area, mainly land lush understories with dense growths of shrubs, herbs, bordering water, is used for urban development. Recre- ferns, and cryptograms.