Land use: Most of this area is in farms; a small acreage is federally owned. About 35 percent of the area is cropland, but the proportion varies greatly from county to county, depending on the soils and the topography. This is largely a cash-crop area. Cotton, corn, soybeans, and wheat are major crops, but rice is important locally in Arkansas and in Louisiana, and strawberries are important in Louisiana. Feed grains and forage are grown on dairy farms. About 16 percent of the area is in pasture or hay. About 46 percent is in forest of mixed pine and hardwoods. Lumber is the major forest product, and some pulpwood is harvested. The present trend is toward the conversion of the pasture and forest to cropland. About 3 percent of the area is used for urban development or other purposes. There is an increase in urban development near the metropolitan areas.
Elevation and topography: Elevation ranges from 25 to 100 m. The sharply dissected plains have a thick loess mantle that is underlain by unconsolidated sand, silt, and clay, mainly of marine origin. Valley sides are hilly to steep, especially in the west. The intervening ridges are mostly narrow and rolling, but some of the interfluves between the upper reaches of the valleys are broad and flat. Stream valleys are narrow in the upper reaches but broaden rapidly downstream and have wide, flat flood plains and meandering stream channels. Local relief is mainly several meters to 25 or 50 m.
Climate: Average annual precipitation-1,150 to 1,525 mm, increasing from north to south. Maximum precipitation is in winter and in spring, decreasing gradually through summer to autumn except for a moderate increase in midsummer. Average annual temperature-16 to 20 C, increasing from north to south. Average freeze-free period-200 to 280 days, increasing from north to south.
Water: Precipitation and ground water are abundant. On the uplands shallow wells, cisterns, ponds and rural water systems are the main sources of water for domestic use and livestock. Shallow wells provide small quantities of water, but deep wells in underlying sand and gravel yield large quantities. Most steams are small and flow intermittently. They flow most of the time in winter and in spring but only during and immediately after storms in summer and in autumn.
Soils: Most of the soils are Udalfs. They are deep, medium textured soils that have a thermic temperature regime, an udic moisture regime, and mixed mineralogy. Well drained, nearly level to very steep Hapludalfs (Memphis series) are on uplands. Moderately well drained, nearly level to strongly sloping Fragiudalfs (Grenada and Loring series) are on ridgetops, side slopes, and terraces. Somewhat poorly drained Fragiudalfs (Calloway series) and poorly drained Udifluvents (Morganfield and Vicksburg series), moderately well drained Udifluvents (Adler and Collins series), and somewhat poorly drained Fluvaquents (Falaya series) are on flood plains. In the east where the loess mantle thins, well drained Paleudalfs (Lexington series), moderately well drained Fragiudalfs (Dulac and Providence series), well drained Hapludults (Brandon and Silerton series), and well drained Paleudults (Smithdale series), all of which are gently sloping to steep, are on ridgetops and side slopes. Well drained Dystrochrepts (Ariel series), moderately well drained Udifluvents (Collins series), moderately well drained Dystrochrepts (Oaklimeter series), and somewhat poorly drained Fluvaquents (Falaya and Gillsburg series) are on the flood plains.
Potential natural vegetation: This area supports hardwood and pine forest vegetation. Cherrybark oak and Shumard oak are widely distributed. Yellowpoplar, white ash, cottonwood, and black walnut are important species on the flood plains. Loblolly and shortleaf pines are on a wide variety of sites, mainly the eroded soils of the uplands and ridges. Other hardwood species that commonly grow in this area are white oak, basswood, sweetgum, water oak, American elm, blackgum, sycamore, sassafras, southern red oak, chinkapin oak, American beech, and hickory.
(From "Land Resource Regions and Major Land Resource Areas of the United
States". United States Department of Agriculture Soil Conservation Service
Handbook 296. Dec. 1981. page 96 - 97.)