Major Land Resource Areas

Major Land Resource Areas (MLRAs) are geographically associated land resource units, usually encompassing several thousand acres, characterized by a particular pattern of soils, geology, climate, water resources and land use.  A unit can be one continuous area or several separate nearby areas.  Following are the MLRAs within Region 16:

MLRA descriptions

116A = Ozark Highland (Arkansas, Missouri, and Oklahoma)

This area consists of two old plateau surfaces in northeast Oklahoma, northwest Arkansas and southern Missouri. These highly dissected plateaus are characterized by narrow, gently sloping to rolling ridges that break sharply to steep side slopes and narrow valleys with steep gradients. Elevations range from about 500 feet on valley floors to about to 1800 feet on the ridge tops. The soils, dominantly Alfisols and Ultisols, formed in residuum and colluvium from cherty limestone, cherty dolostone and sandstone. The steep, mountainous areas are mainly in hardwood forests. The less sloping areas are used for pasture and forage production. Orchards, vineyards and truck crops are important locally on some of the loamy, very deep, level to nearly level soils. This resource area covers approximately 26,950 square miles and contains about 17,250,000 acres.

116B = Ozark Border (Missouri)

Located in southern Missouri, this resource areas consists of limestone ridges and remnants of the Springfield and Salem plateaus. It is characterized by broad, gently sloping to moderately sloping ridge tops and strongly sloping to steep side slopes. The stream valleys are narrow to moderately wide. Elevations range from about 400 feet on valley floors to over 1400 feet in the uplands. The soils, dominantly Alfisols, formed in colluvium and residuum from limestone and dolostone, partly mantled with a thin layer of loess. The less sloping areas are cleared and used for growing forage and grain for livestock operations. The steeper areas remain in hardwood forest. This area covers approximately 13,690 square miles and contains about 8,750,000 acres.

117 = Boston Mountain (Arkansas and Oklahoma)

These mountains, remnants of an old plateau are located in northwest Arkansas and northeast Oklahoma. This highly dissected plateau is characterized by gently sloping to rolling broad mountaintops with steep side slopes and long, narrow valleys. Elevations range from about 650 feet on valley floors to about 2400 feet on the broad mountaintops. The soils, dominantly Ultisols, formed in residuum and colluvium from interbedded sandstone and shale. The steep, rugged mountainsides are mainly in hardwood forests. The less sloping mountain tops and valley floors are used for pasture and forage production. Small grains and orchards are important locally where the soils are loamy, very deep and nearly level. The area covers about 5,770 square miles and contains approximately 3,700,00 acres.

118 = Arkansas Valley and Ridges (Arkansas and Oklahoma)

This resource area roughly follows the Arkansas River through west-central Arkansas and east-central Oklahoma. It is characterized by broad valleys, narrow, low ridges and high, flat topped mountains. Valley floor elevations range from 300 to 400 feet and the low ridges are typically around 1200 feet and the flat topped mountains can range over 2500 feet high. The soils, dominantly Ultisols, formed in residuum and colluvium from interbedded sandstone and shale. The steep, rugged mountain sides and low ridges are mainly in hardwood forest. The valley floors and flat topped mountain tops are in pasture and used for forage production. Small grains, vineyards, orchards and vegetable crops are important locally where the soils are loamy, very deep and level to gently sloping. Soybeans and other row crops are important along the Arkansas River. The area covers about 10,520 square miles and contains approximately 6,750,000 acres.

119 = Ouachita Mountains (Arkansas and Oklahoma)

Located in western Arkansas and eastern Oklahoma, these rugged east-west trending mountains are characterized by narrow, winding tops and steep side slopes. Valleys are narrow with steep gradients. The mountains are underlain by folded and faulted shale, sandstone, quartzite, chert and novaculite. Elevations are typically around 300 feet on valley floors to over 2000 feet on mountain tops. The soils, dominantly Ultisols, formed in residuum and colluvium from the shale, sandstone, quartzite, chert and novaculite in very complex patterns due the folding and faulting of the bedrock. The steep, rugged mountain sides and low ridges are mainly in mixed hardwood-pine forest. The valley floors are in pasture and used for forage production. Small grains are important locally where the soils are loamy, very deep and less sloping. A great recreation area with several lakes and numerous hiking trails and camping sites. This resource area covers approximately 9,510 square miles and contains about 6,100,000 acres.

131 = Southern Mississippi Valley Alluvium (Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee)

This area consists of broad flood plains and low terraces in the lower Mississippi River valley. This large resource area runs north and south along the Mississippi River from its confluence with the Ohio River to the Gulf of Mexico. It covers parts of southeast Missouri, eastern Arkansas and Louisiana and western Mississippi, Tennessee and Kentucky, and also includes the flood plains and terraces of the Arkansas and Red Rivers in Arkansas and Louisiana. Elevations range from sea level in southern Louisiana to approximately 600 feet in western Kentucky and southeastern Missouri. The level to gently sloping soils, mainly, Alfisols, Inceptisols, Entisols and Vertisols developed in very deep, loamy, clayey and sandy alluvial sediments. Mostly cropland, important crops include soybeans, rice, cotton, wheat and sugar cane. Small tracts of woodland, mainly bottom land hardwoods, are important for wildlife habitat. This highly productive agricultural area covers approximately 36,140 square miles and contains about 23,150,000 acres.

133B = Western Coastal Plain (Arkansas, Louisiana, and Texas)

This area consists of rolling, dissected upland and broad level to nearly level stream valleys in southwestern Arkansas, southeastern Oklahoma, northeastern Texas and northwestern Louisiana. Elevations increase from south to north and range from less than 100 feet in the south to over 500 feet in the north. The nearly level to rolling upland soils, mainly Ultisols, developed in very deep, loamy, clayey and sandy marine sediments. The level to nearly level soils in stream valleys, mainly Alfisols and Inceptisols, developed in very deep, loamy local alluvium. Used extensively for timber production, this resource area also has small areas in pasture and forage production. Row crops are also important in some of the larger stream valleys with soybeans the main crop. The areas cover approximately 54,300 square miles and contains about 34,750,000 acres.

134 = Southern Mississippi Valley Silty Uplands (Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee)

This area consists of highly dissected uplands and broad terraces covered with a thick mantle of loess. Scattered throughout the lower Mississippi valley, the largest areas are along the east side of the valley in western Kentucky, Tennessee, Mississippi and Louisiana. These areas have a thick mantle of loess over unconsolidated marine sediments. Crowleys Ridge and Macon Ridge, erosional remnant that run north to south in eastern Arkansas and northeastern Louisiana have a similar make up. Also included in this resource area are broad, level to nearly level outwash terraces covered with a thick mantle of loess. The largest of these terraces are west of Crowleys Ridge and Macon Ridge in Arkansas and Louisiana. Elevation range from around 100 feet on terraces in southern Louisiana to over 800 feet on uplands in western Kentucky. The soils, mainly Alfisols, formed in the deep loess. The steep, dissected uplands are mainly in hardwood forests. Less sloping areas are used for pasture and forage production. High value crops such as tobacco are grown locally. Row crop are the main land use on the terraces with corn, cotton, soybeans and rice the major crops. These areas cover approximately 19,850 square miles and contain about 12,700,000 acres.

135 = Alabama, Mississippi, and Arkansas Blackland Prairie (Arkansas)

Small outliers of this resource areas are scattered across southwestern Arkansas. This area consists of rolling uplands with elevations ranging from 200 to 450 feet. The soils, mainly Alfisols and Vertisols, developed in residuum form chalk and marly clays. Only small areas of the former prairie vegetation remains. Most areas are in mixed hardwood-pine forests. Forage production is also important. Small areas are in row crops with corn, soybeans and grain sorghum in the main crops. These scattered areas cover approximately 550 square mile and contain about 350,000 acres.

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