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Ecological site F131AY313MS

Yazoo – Pleistocene Valley Train Braid Bar Woodland

Last updated: 6/10/2025
Accessed: 10/19/2025

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General information

Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.

MLRA notes

Major Land Resource Area (MLRA): 131A–Southern Mississippi River Alluvium

The Southern Mississippi River Alluvium (MLRA 131A) is the largest of 4 MLRAs within Land Resource Region O, the Mississippi Delta Cotton and Feed Grains Region. It occurs in portions of 7 states including Louisiana (32 percent), Arkansas (26 percent), Mississippi (26 percent), Missouri (12 percent), Tennessee (3 percent), Kentucky (1 percent), and Illinois (less than 1 percent). The MLRA is comprised of 29,555 square miles and extends roughly 650 miles from an area near Cape Girardeau, Missouri in the north to the MLRA’s transition to the Gulf Coast Marsh (MLRA 151) in the south. Average elevations range from 330 feet in the north to sea level in the southern part of the area. For much of the north-south distance, the MLRA is bounded to the east by an abrupt rise in elevation of loess-capped bluffs and hills, the Southern Mississippi Valley Loess (MLRA 134). West of the Mississippi River, the boundary is less distinct except to the northwest where the MLRA abuts the Ozark Plateaus and Ouachita province (MLRAs 116A, 117, and 118A). South of the Ozark and Ouachita escarpment, the MLRA adjoins the Southern Mississippi River Terraces (MLRA 131D), which includes the fabled Grand Prairie and merges with the valleys of the Arkansas and Ouachita rivers (MLRA 131B) and the Red River (MLRA 131C). Occurring within or bordering the Southern Mississippi River Alluvium are three separate loess-capped, upland remnants: Crowley’s Ridge, Macon Ridge, and Lafayette Loess Plain, which are western units of MLRA 134 (USDA-NRCS, 2006a).

MLRA 131A is characterized by landscapes that were created and influenced by the current and earlier paths of the Mississippi River and its tributaries. Waters transporting the materials that formed the area originate from as far west as the east slope of the Continental Divide to the western edge of the Appalachian Divide in the east. This comprises a drainage basin of roughly 1,245,000 square miles and includes all or parts of thirty-one U.S. states and two Canadian provinces (Elliott, 1932). The drainage basin of the Mississippi River roughly resembles a funnel, which has its spout at the Gulf of America. Waters from as far east as New York and as far west as Montana contribute to flows in the lower extent of the river (USACE, 2017). The soils of these alluvial landscapes are very deep, dominantly poorly and somewhat poorly drained, and have textures that are mostly loamy or clayey. Principal soil orders are Alfisols, Vertisols, Inceptisols, and Entisols (USDA-NRCS, 2006a).

The fluvial processes that shaped the area were highly dynamic, diverse, and complex. During the Pleistocene epoch, multiple continental glacial-interglacial cycles resulted in extreme fluctuations in river discharge and sediment loads. A braided river regime characterized the fluvial dynamics of the Mississippi River through much of the last glacial cycle (Autin et al., 1991; Rittenhour et al., 2007). Rapid aggradation of glacial outwash led to the development of prominent valley train features over a large portion of the area (Autin et al., 1991; Saucier, 1994; Aslan and Autin, 1999; Blum et al., 2000; Rittenour et al., 2007). A changing climate, meltwater withdrawal, and sea-level change induced a transition from a braided river regime to a predominantly single-channeled, laterally migrating river system during the Holocene epoch (Rittenhour et al., 2007; Shen et al., 2012) – characteristics that continue today. Fluvial dynamics of the migrating river resulted in the development of broad meander belts, backswamp environments, and extensive deltaic complexes (Saucier, 1994; Klimas et al., 2011).

Tremendous expanses of bottomland hardwood forests once covered much of the area. Today, the land base is largely in agriculture production, and soybeans, cotton, corn, and rice are the principal crops with sugarcane rising in importance in the southernmost portion of the MLRA (USDA-NRCS, 2022).

Due to its size and biophysical variability, the technical team advised subdividing the MLRA into six subregions: Western Lowlands, St. Francis Basin, Yazoo Basin, Tensas Basin, Delta Plain, and Batture.

LRU notes

There are no agency-approved and established Land Resource Units (LRUs) for MLRA 131A. However, the characteristics of each of the six subregions in this MLRA warrant noting and are presented here for each associated ecological site. This provisional ecological site occurs in the Yazoo Basin.

The Yazoo Basin is in northwest Mississippi and is the largest tributary basin within MLRA 131A. The MLRA boundary of the basin extends some 200 miles (north to south) from Memphis, Tennessee to Vicksburg, Mississippi; is about 60 miles wide (east to west) at its widest point; encompasses roughly 7,600 square miles; and is bounded by the Loess Hills to the east and the current Mississippi River channel to the west (Saucier, 1994; Klimas et al., 2011). Elevations range from 210 feet in the northern portions of the basin to about 85 feet in the south near Vicksburg (Kirchner et al., 1992).

The basin’s geomorphic features are dominated by abandoned Mississippi River meander belts and backswamp environments. The higher elevations of natural levees and point bar deposits (meander scrolls) form an alluvial ridge, which directs local drainage and floodwaters to the intervening flood basins or backswamps. Additional meander belt landforms that are quite common include abandoned channels (oxbow lakes) and courses (Saucier, 1994; Klimas et al., 2011). A minor feature of the Yazoo Basin is the Pleistocene-age valley train terraces, which comprise less than 5 percent of the total area (Saucier, 1994).

The movement of water through the Yazoo Basin is heavily influenced and controlled by the complex sequence of abandoned Mississippi River meander belts and distributary channels. Most surface water originates as precipitation (Berkowitz et al., 2020) or runoff from the uplands to the east, which are conveyed by the Coldwater, Yocona, Tallahatchie, and Yalobusha rivers in addition to several smaller streams. These systems, along with streams draining the interior portions of the basin (e.g., Big Sunflower River, Bogue Phalia, and the distributary Deer Creek), all flow to the only significant outlet for the basin, the Yazoo River, which enters the Mississippi River near Vicksburg (Saucier, 1994; Klimas et al., 2011).

Historically, large floods on the Mississippi River and in the Yazoo tributary system inundated most, if not all, of the Yazoo Basin (Moore, 1972). These periodic floods and the ponding aftereffects oftentimes lasted for very long durations (Berkowitz et al., 2020), delivering nutrient-rich sediments that are critical to the production and maintenance of the dominant natural vegetation, bottomland hardwood forests (Taylor et al., 1990; MMNS, 2015). Since settlement, the biophysical environment of the area has been vastly altered. Perhaps the most notable change entails extensive modification of the basin’s natural hydrology, which includes hundreds of miles of constructed levees along the mainstem of the Mississippi River and basin tributaries; channel modifications on many streams; water control structures; land leveled areas; and an extensive network of surface drainage systems (Kirchner et al., 1992). Even with these measures, widespread backwater flooding occurs in the southern portion of the area (Yazoo Backwater Area) when high stages are reached on the Mississippi River. The extensive modifications to the basin’s hydrology coupled with increased access (Hudson, 1979) set the stage for broadscale conversion of former forestland to a variety of land uses with agriculture production being dominant. Today, bottomland hardwood forests cover roughly 10 percent of the original forest area (Smith and Klimas, 2002).

The geographic distribution of all ecological sites within the Yazoo Basin is bounded to the west by an extensive, mainline levee system. Throughout its length, the constructed levee generally occurs within the current Mississippi River meander belt and is situated to the east of the active river channel. All lands between the river channel and the constructed levee are referred to as the Batture, and that subregion encapsulates its own complement of ecological sites due to significantly different hydrologic regimes (Smith and Klimas, 2002).

Classification relationships

All or portions of the geographic range of this site fall within several ecological and land classifications including:
- NRCS Major Land Resource Area (MLRA) 131A – Southern Mississippi River Alluvium (USDA-NRCS, 2006a)
- National Hierarchical Framework of Ecological Units: 234 Lower Mississippi Riverine Forest Province; 234D White and Black River Alluvial Plains Section; 234Da North Mississippi River Alluvial Plain Subsection (Cleland et al., 2007)
- Environmental Protection Agency Level III Ecoregion: 8.5.2 Mississippi Alluvial Plain, 73; Level IV Ecoregion: 73b - Northern Pleistocene Valley Trains (Chapman et al., 2004; Wiken et al., 2011)
- Mississippi River High Floodplain (Bottomland), CES203.196 (NatureServe, 2020)

Ecological site concept

This ecological site has a narrow distribution in the Yazoo Basin where it is restricted to the higher elevations or positions on valley train geomorphic features. The characteristic landform of this site consists of remnant depositional ridges and braid bars that were created during catastrophic flood releases (or pulses) of glacial outwash during the Late Pleistocene epoch. Today, these depositional features consist of a series of disjunct mounds and low, elongated ridges that are positioned beside and within the highly braided and dendritic network of remnant, glacial outwash channels. The soils of this site are described as deep, well drained to moderately well drained that formed in silty alluvium – stream and river sediments that veneered the underlying coarse outwash materials. Recent observations and a revisit of these soils strongly suggest that drainage and permeability can be more rapid than initially described. Evidence for this is expressed by plant stress and possibly poorer crop yields in some locations. The historic plant community of this site is unknown. These soils occur as small isolates within a much larger mosaic of productive soils. Hence, most occurrences of this site have been converted to agriculture production or was once under other forms of intensive land use such as grazing and human habitation. Archaeological discoveries over the past century have revealed human occupation or presence on this site for millennia. Depending on the presence and intensity of human activities, several conditions and habitat types likely existed, including local cultural and habitation sites, herbaceous openings, savannas, open woodlands, and forests. Fire was likely a historic management tool on this site. Based on forest surveys and research, the cover type most characteristic of this site may have been a diverse mixture of oaks and other bottomland hardwoods.

Associated sites

F131AY303MS	Yazoo - Low Clayey Backswamp Ridge Forest The Pleistocene valley train geomorphic features in the Yazoo Basin have been heavily veneered with Holocene alluvial deposits including the clayey soils of this site. F131AY303MS adjoins the Pleistocene braid bars (F131AY313MS) in a few areas and should be recognized as a minor associate.
F131AY307MS	Yazoo - Old Moderately Wet Natural Levee and Meander Scroll Ridge Forest The Pleistocene valley train geomorphic features in the Yazoo Basin have been heavily veneered with Holocene alluvial deposits including the loamy soils of this site. F131AY307MS adjoins the Pleistocene braid bars (F131AY313MS) in a few areas and should be recognized as a minor associate.
F131AY308MS	Yazoo - Old Wet Natural Levee and Meander Scroll Forest The Pleistocene valley train geomorphic features in the Yazoo Basin have been heavily veneered with Holocene alluvial deposits including the poorly drained, clayey and silty soils of this site. F131AY308MS broadly adjoins the Pleistocene braid bars (F131AY313MS) and should be regarded as a major associate.
F131AY301MS	Yazoo - Frequently Flooded and Ponded Oxbow and Swale Forest This site occupies depressions within remnant glacial outwash channels on Pleistocene valley trains, which adjoins the relic braid bars of site F131AY313MS.

Similar sites

F131AY109AR	Western Lowlands - Old Loamy Natural Levee and Braided Interfluve Forest This site developed under similar conditions and occurs on similar geomorphic features as site F131AY313MS. The principal difference is that F131AY109AR occurs in the Western Lowlands of Arkansas and Missouri.
F131AY204AR	St. Francis - Braid Bar Woodland This site developed under similar conditions and occurs on similar geomorphic features as site F131AY313MS. The principal difference is that F131AY204AR occurs in the St. Francis Basin of Arkansas and Missouri.

F131AY109AR

Western Lowlands - Old Loamy Natural Levee and Braided Interfluve Forest

This site developed under similar conditions and occurs on similar geomorphic features as site F131AY313MS. The principal difference is that F131AY109AR occurs in the Western Lowlands of Arkansas and Missouri.

F131AY204AR

St. Francis - Braid Bar Woodland

This site developed under similar conditions and occurs on similar geomorphic features as site F131AY313MS. The principal difference is that F131AY204AR occurs in the St. Francis Basin of Arkansas and Missouri.

Figure 1. Distribution of Site F131AY313MS.

Table 1. Dominant plant species

Tree	Not specified
Shrub	Not specified
Herbaceous	Not specified

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Physiographic features

This ecological site has a very narrow distribution and occurrence within the Yazoo Basin. It is restricted to the higher elevations or positions on Late Pleistocene valley train (braided stream terrace) landscapes. The characteristic landform of this site consists of remnant depositional ridges and braid bars that developed when vast volumes of coarse-grained glacial outwash were transported and deposited by an extensive network of braided river channels (Saucier, 1994). Today, these depositional features consist of a series of disjunct mounds and low, elongated ridges that are positioned beside and among (i.e., interfluves) the dendritic network of remnant, glacial outwash channels (see Site ID: F131AY301MS). Saucier (1994) emphasized that the Late Pleistocene valley train surfaces are positioned at or slightly below the elevations of adjoining Holocene floodplains. The circuitous migration of subsequent meander belts coupled with the effects of flooding over the millennia have reduced the extent of valley trains in the basin and have veneered most remaining surfaces with Holocene alluvium (Saucier, 1994; Klimas et al., 2011). Of note, the soils that are mapped on and representative of the remnant braid bars have been mapped on other geomorphic features such as old natural levees and meander scrolls of abandoned Mississippi River meander belts (see Site ID: F131AY306MS).

There are two disjunct valley train remnants in the Yazoo Basin. This ecological site has been identified on the west-central remnant that occurs in portions of Bolivar, Sunflower, and Washington counties, only. The characteristics of the site’s geomorphic setting, drainage, and polygonal configuration are not as well defined or represented on the valley train remnant that occurs in northeastern portion of the basin. Additional work and investigations are warranted to ascertain this site’s presence on the latter.

Figure 2. Distribution of braid bars (red; F131AY313MS) in relation to remnant glacial outwash channels (blue; F131AY301MS) on Pleistocene valley trains (yellow). Geomorphology based on Saucier (1994).

Figure 3. LiDAR imagery of the elevated braid bar soils (red delineations).

Table 2. Representative physiographic features

Landforms	(1) Alluvial plain remnant > Valley train > Bar
Runoff class	Low to medium
Flooding frequency	None to very rare
Ponding frequency	None
Elevation	115 – 150 ft
Slope	7%
Ponding depth	Not specified
Water table depth	30 in
Aspect	Aspect is not a significant factor

Climatic features

Climate of the Yazoo Basin is classified as Humid Subtropical (Koppen System), which is typified by mostly mild winters; long, hot and humid summers; and no routinely recurring wet or dry season (Smith and Klimas, 2002; NCDC, 2018). The average annual air temperature from 1980 through 2010 was 64 degrees F and the mean annual precipitation for the same period was 55 inches.

In the warmer season (and throughout much of the year), winds from the south convey moisture from the gulf leading to humid, semitropical conditions that are favorable for afternoon thunderstorms. These storms produce an average of about 25 percent of the area’s annual precipitation and are at times accompanied by locally destructive winds. A potential hazard during late summer through early fall is the tropical cyclone. While most impacts from hurricanes and tropical storms are confined along the coastal zone, heavy rainfall, severe flooding, and high winds can occur well into the basin when such systems pass through the area. To the extreme, the region is susceptible to the effects of a strong Bermuda High during the summer, which can cause devastating drought conditions for weeks and even months in some years. From 1980 through 2010, August and September were the driest months with a characteristic average monthly low of 2.5 and 2.8 inches, respectively. The hottest months of the year were July and August with characteristic average highs of 91 to 92 degrees and lows of around 72 degrees F.

In the colder season, the area’s weather is dominated by the positions of the Polar and Subtropical Jet Streams, both of which exerts strong control over the passages of cold and warm fronts. These fronts alternately bring cold continental air and warm tropical air with periods of varying length. Particularly strong cold fronts can produce large and sudden drops in air temperature; however, cold spells seldom last over a week (NCDC, 2018). The coldest month of the year is typically January with an average monthly low and high of 33 and 52 degrees, respectively. The frost-free period from 1980 to 2010 averaged 207 days basin-wide and ranged from 200 days in the northern areas to 216 days in the south. Likewise, the freeze-free period averaged 241 days and ranged from 238 in the north to 246 days in the southern part of the basin.

Snow and/or sleet falls in the area in most years with the greatest frequency and accumulations occurring in the northern extent of the basin. Winter precipitation sometimes occurs as freezing rain and damaging ice storms hit some portion of the basin on occasion. However, these wintry events are generally the exception; they are typically brief and do not persist for very long. Rain is the characteristic form of winter precipitation, and the period of greatest rainfall generally occurs from November through June with March and April being the months of greatest frequency (NCDC, 2018). Precipitation for this period typically ranges from 4.5 to around 6.0 inches per month.

Table 3. Representative climatic features

Frost-free period (characteristic range)	200-216 days
Freeze-free period (characteristic range)	238-246 days
Precipitation total (characteristic range)	52-57 in
Frost-free period (actual range)	195-222 days
Freeze-free period (actual range)	229-254 days
Precipitation total (actual range)	52-59 in
Frost-free period (average)	207 days
Freeze-free period (average)	241 days
Precipitation total (average)	55 in

Characteristic range

Actual range

Bar

Line

Figure 4. Monthly precipitation range

Characteristic range

Actual range

Bar

Line

Figure 5. Monthly minimum temperature range

Characteristic range

Actual range

Bar

Line

Figure 6. Monthly maximum temperature range

Bar

Line

Figure 7. Monthly average minimum and maximum temperature

Figure 8. Annual precipitation pattern

Figure 9. Annual average temperature pattern

Climate stations used

(1) CLEVELAND [USC00221738], Cleveland, MS
(2) GREENVILLE [USC00223605], Greenville, MS
(3) LAMBERT 1W [USC00224869], Lambert, MS
(4) MINTER CITY [USC00225897], Minter City, MS
(5) ROLLING FORK [USC00227560], Rolling Fork, MS
(6) STONEVILLE EXP STA [USC00228445], Leland, MS
(7) GREENWOOD LEFLORE AP [USW00013978], Carrollton, MS
(8) LAKE PROVIDENCE [USC00165090], Lake Providence, LA
(9) TUNICA 2 N [USC00228998], Tunica, MS
(10) YAZOO CITY 5 NNE [USC00229860], Yazoo City, MS
(11) CHARLESTON [USC00221606], Charleston, MS
(12) CLARKSDALE [USC00221707], Clarksdale, MS
(13) CLEVELAND 3 N [USC00221743], Cleveland, MS
(14) MOORHEAD [USC00226009], Moorhead, MS
(15) BELZONI [USC00220660], Belzoni, MS

Influencing water features

This site occurs on the highest interfluve positions among remnant glacial outwash channels on Late Pleistocene valley trains. Today, this site occurs on the protected side of the extensive Mississippi River levee system and no longer receives overland flooding on the same scale that it may have experienced prior to levee construction. For the most part, the location or position of this site is high enough in elevation that it does not flood on a frequent or predictable basis. In general, this site does not support wetland species and does not qualify as supporting hydric conditions or meeting “wetland determination” criteria.

Soil features

Please note that the soils listed in this section of the description may not be all-inclusive. There may be additional soils that fit the site’s concepts. Additionally, the soils that provisionally form the concepts of this site may occur elsewhere, either within or outside of the MLRA and may or “may not” have the same geomorphic characteristics or support similar vegetation. Some soil map units and soil series included in this “provisional” ecological site were used as a “best fit” for a particular soil-landform catena during a specific era of soil mapping, regardless of the origin of parent material or the location of MLRA boundaries. Therefore, the listed soils may not be typical for MLRA 131A or a specific location, and the associated soil map units may warrant further investigation in a joint ecological site inventory-soil survey project. When utilizing this provisional description, the user is encouraged to verify that the area of interest meets the appropriate ecological site concepts by reviewing the soils, landform, vegetation, and physical location. If the site concepts do not match the attributes of the area of interest, please review the Similar or Associated Sites listed in this description to determine if another site may be a better fit for your area of interest.

This ecological site occurs entirely on higher positions of Late Pleistocene valley trains, the remnant braid bar environment. The site has a limited geographic distribution with mapped occurrences in Bolivar and Washington counties, only. The soils that have been mapped on these features include the Dexter (fine-silty, mixed, active, thermic Ultic Hapludalfs) series and the inactive (or extinct), Pearson soil series. Neither of these soils were mapped exclusively on braid bars; they were mapped predominantly on abandoned Holocene meander belt landforms such as old natural levees and meander scroll ridges. The exception was in Washington County where a single Pearson soil map unit was mapped entirely on remnant braid bars, “Pearson silt loam, 0 to 2 percent slopes (dundee)” (USDA-SCS, 1961). Of the two series, Pearson soils are dominant on this ecological site. This soil-site environment is considered separately from the Holocene meander belt sites due to: 1) the unique physical configuration and setting of this landform relative to adjoining landforms and to all Holocene features within the Yazoo Basin; 2) questions concerning the soils and associated soil properties and characteristics, particularly Pearson soils; 3) observations of plant stress and potential decreases in crop vigor where crops have been planted on this ecological site compared to adjoining sites.

In the Yazoo Basin, both Dexter and Pearson soils were mapped in the late 1940s through the mid-1950s, and the interpretation of these soils at the time was that they originated in loess alluvium (often referred to as “water reworked loess”). The soil survey manuscripts consistently recognized and emphasized that the soils formed in parent material that was different from other Holocene deposits in the Yazoo Basin (e.g., USDA-SCS, 1961). In fact, the early description on “the blue sheets” of Pearson soils questioned whether the silty material was wind (loess) or water deposited (Soil Survey Staff, 1943). Dexter is currently described and recognized as having been formed in loess over loamy and sandy sediments (Soil Survey Staff). Collectively, these characteristics stress the differences in parent material. Where they were mapped together, the two soils were consistently placed within the same silty soil association with principal differences based on drainage characteristics. Dexter soils are well drained whereas Pearson soils are described as ranging from somewhat poorly to moderately well drained (USDA-SCS, 1958; USDA-SCS, 1959).

These very deep soils have moderate permeability, reactions ranging from strongly to moderately acid, and slopes that are dominantly 0 to 3 percent but extending to 7 percent, locally. They have prominent profile development as determined by distinct argillic (clay) accumulations in the subsoil (Bt horizon) and some pedons may exhibit contrasting texture changes or differences in subsurface layers. For instance, the description of Dexter soils in the Bolivar County soil survey manuscript suggests an abrupt change in texture from silty clay loam (presumed Bt2 horizon) to very fine sandy loam that transitions to fine sandy loam at depths below 46 inches (USDA-SCS, 1958). Dexter has been mapped in other MLRAs (e.g., 133C and 134), but its prevailing (and accepted) concept is that it consists of a thin loess cap (or loess alluvium) over older loamy and sandy valley train (Pleistocene terrace) deposits associated with the Mississippi River and its tributaries (Soil Survey Staff).

Although similar characteristics have been reported for Dexter and Pearson soils, questions remain concerning the dominant soils of this ecological site, the Pearson soil series. The broad drainage classification of somewhat poorly to moderately well drained raises some questions with respect to the position of these soils on remnant braid bar features and the plant community that would naturally develop in this environment. An additional concern arises as this extinct soil series has no taxonomic classification or lab data from which to develop sound resource and land use management interpretations.

Field investigations conducted in 2017-2018 of Pearson map unit delineations on remnant braid bars revealed a broad range of characteristics. Of the pedon descriptions generated thus far, 60 percent consisted of well drained, fine-silty soils that most closely classified to the established Dubbs (fine-silty, mixed, active, thermic Typic Hapludalfs) soil series; 30 percent were moderately well drained that classified to the Askew (fine-silty, mixed, active, thermic Aquic Hapludalfs) series; and one pedon was somewhat excessively drained, which classified to the Beulah (coarse-loamy, mixed, active, thermic Typic Dystrudepts) soil series. General features of the dominant, well drained pedons frequently consisted of a silt loam surface layer or ochric epipedon (Ap horizon) 4 inches thick; a silty clay loam subsoil or argillic horizon (Bt) that averaged 32 inches thick; a transitional zone (BC horizon) that averaged 17 inches thick and varied from silt loam to very fine sandy loam textures; and a substratum (C horizon) that averaged 26 inches thick with textures that were primarily very fine sandy loam or fine sandy loam and secondarily, silt loam. (Maximum pedon depth was 80 inches as measured from the soil surface.) Reactions ranged from very strongly acid to neutral. Apart from pH, no additional chemical analyses (e.g., base saturation, etc.) were conducted. (Note that far more variability occurred in horizon depths and thickness, horizon recurrence, textures, and other properties and characteristics than what the preceding suggests.)

A notable observation of the recent investigations were the discoveries of buried horizons associated with human-transported materials and earthen construction (i.e., mound building) in addition to the presence of cultural artifacts. The Pearson units that have been mapped on valley trains are noted for supporting pre-Columbian human activities. Connaway and McGahey (1996) specifically mentioned focusing their survey efforts on “Pearson silty loam” soils during an archaeological reconnaissance of valley train surfaces in Bolivar and Washington counties.

One final characteristic of the Pearson soils warrants noting. The demands for efficient cultivation and irrigation across valley train surfaces have resulted in extensive land leveling of surface irregularities, including the elevated braid bar environment. Where these geomorphic features are being leveled into a uniform grade, brighter red hues of the former subsoil and subsurface materials become exposed and are very evident on bare surfaces. The red hues are so apparent that the former outline of a leveled braid bar feature is discernible on the surrounding landscape (as viewed in aerial imagery). One plausible interpretation of these characteristics may suggest that this soil-site environment is very old and very weathered – a feature that has supported life for many, many centuries.

The cultural significance coupled with the gaps in our knowledge of the inactive Pearson soil series and remnant braid bar features underscores the urgency in continuing the survey work in this soil-site environment. Urgency is evermore emphasized as these elevated features are rapidly being leveled for production purposes.

Figure 10. Soil core of Pearson soils, Washington County, MS.

Table 4. Representative soil features

Parent material	(1) Alluvium
Surface texture	(1) Silt loam (2) Silty clay loam
Drainage class	Somewhat poorly drained to well drained
Permeability class	Moderately slow to moderate
Soil depth	80 in
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	Not specified
Available water capacity (Depth not specified)	7.1 – 7.9 in
Calcium carbonate equivalent (Depth not specified)	Not specified
Electrical conductivity (Depth not specified)	Not specified
Sodium adsorption ratio (Depth not specified)	Not specified
Soil reaction (1:1 water) (Depth not specified)	5.3 – 5.9
Subsurface fragment volume <=3" (40in)	Not specified
Subsurface fragment volume >3" (40in)	Not specified

Ecological dynamics

Historically, this ecological site was part of a vast forested landscape with processes and functions directly connected to the highly dynamic nature of the Mississippi River (Gardiner and Oliver, 2005). Widespread changes to the landscape occurred long before any intensive studies of the historic natural communities were conducted. Accordingly, reference conditions and associated natural communities of this ecological site are still under review and consideration.

Landforms of the Late Pleistocene valley trains are among the oldest geomorphic features in the Yazoo Basin. The silty materials, possibly a mixture of eolian and alluvial deposits, that blanket the braid bars (this site) have provided a medium for plant growth and production for millennia. However, the vegetation that was historically or naturally associated with this site has a long history of manipulation.

The elevated positions and improved drainage of this site likely were a focal area for cultural and habitation complexes (per Mehta, 2015) and certainly provided a refuge for both wildlife and humans during catastrophic flood events. The soils associated with this site, particularly the inactive Pearson soil series, are noted for supporting pre-Columbian human activities. Earthen mounds, depicted on USGS 7.5-minute topographic quadrangles, occur within local delineations of Pearson map units. Joint soil and archaeological investigations of one such complex led to the discovery and confirmation of Baytown Plain potsherds (personal communication, Cliff Jenkins, State Archaeologist, Mississippi NRCS), indicative of the Late Woodland Baytown period (ca. 400 to 800 AD; chronology after Bitgood, 1989). Connaway and McGahey (1996) specifically mentioned focusing their survey efforts on “Pearson silty loam” soils during an archaeological reconnaissance of valley train surfaces in Bolivar and Washington counties. Artifacts and elements of cultural magnitude dating from the Paleo-Early Archaic period (ca. 12,000 to 8,000 years Before Present) through more recent cultural chronologic eras of the Woodland, Mississippian, and Historic periods (ca. 500 BC to 1900s AD) have been discovered on these braided stream landscapes in the Yazoo Basin (Connaway, 1988; Buchner et al., 1996; Connaway and McGahey, 1996; cultural chronologies after McGahey, 2004; personal communication, Cliff Jenkins, State Archaeologist, Mississippi NRCS).

Locations supporting human occupancy and development necessitated intensive construction and management activities along with continual maintenance. Local areas were cleared of trees and maintained in an open state, which likely included fire as a choice management tool. Food, clothing, building, and cultural materials needed for subsistence were cultivated, harvested, and gathered from surrounding environments. Favored mast and fruit producing trees, in addition to shrubs, vines, and herbs, were selectively established, retained, and managed. Plants considered as competitive nuisances likely were culled from local sites or used as fuel or other purposes (Delcourt and Delcourt, 2004; Abrams and Nowacki, 2008; Mehta, 2015). This complex backdrop of human subsistence and influences on the surrounding landscape must have contributed to a “shifting mosaic” of biological communities as human populations moved about, increased, and waned.

Although the natural vegetation of this site may have received considerable local manipulation and management, forest surveys and research conducted over the past century provide an account of tree species and forest types associated with major geomorphic features in the Southern Mississippi River Valley. Putnam and Bull (1932), and later Putnam (1951), characterized the “white oaks – red oaks – other hardwoods” cover type as most commonly occurring on high loamy ridges of old terraces. Utilizing the description of forest types from Putnam (1951), the soil survey manuscript of Sunflower County, Mississippi (USDA-SCS, 1959) attributed the occurrence of Putnam’s “white oaks – red oaks – other hardwoods” type as occurring on both Dexter and Pearson soils in addition to other well drained loamy soils. Important or key species comprising the type include swamp chestnut oak (Quercus michauxii), white oak (Q. alba), bottomland (Delta) post oak (Q. similis), cherrybark oak (Q. pagoda), Shumard’s oak (Q. shumardii), southern red oak (Q. falcata), white ash (Fraxinus americana), hickory (Carya spp.), blackgum (Nyssa sylvatica), and winged elm (Ulmus alata) (Putnam, 1951). Additional forest associates that are important components in some locations include sweetgum (Liquidambar styraciflua), water oak (Q. nigra), willow oak (Q. phellos), and American elm (U. americana) (Eyre, 1980; MMNS, 2015). Putnam (1951) added that this association produces some of the highest valued species and products among the southern bottomland forest types.

Putnam’s white oaks – red oaks – other hardwoods type was later absorbed into more broadly accepted forest types such as the swamp chestnut oak – cherrybark oak type (Society of American Foresters, SAF, Type No. 91; Eyre, 1980) or simply renamed the red oak – white oak – mixed species association (see Meadows and Stanturf, 1997) or the oak – mixed hardwood ridge bottom forest (see MMNS, 2015).The diversity of tree species and other community associates are reportedly high for this system (NatureServe, 2020). Meadows and Stanturf (1997) regards this forest association as a late sere in the succession of southern bottomland forests, whereas others consider it a climax community (e.g., Eyre, 1980; Hodges, 1997). Although there are no known examples of this diverse forest type currently occurring on this site, the preceding accounts strongly suggest that this association may have been the representative cover type.

Today, where braid bar features have not been leveled, remaining areas are mainly under production, although a very few spots support ruderal vegetation such as dense growths of honeylocust (Gleditsia triacanthos), chinaberry (Melia azedarach), wisteria (Wisteria sp.) vines, persimmon (Diospyros virginiana), and privet (Ligustrum sp.) (Buchner et al., 1996). A secondary use on this site is pasturage.

Following this narrative, a “provisional” state and transition model is provided that includes the “perceived” reference state and several alternative (or altered) vegetation states that have been observed and/or projected for this ecological site. This model is based on limited inventories, literature, expert knowledge, and interpretations. Plant communities may differ from one location to the next depending on the severity of local land use activities and rates of deposition. Depending on objectives, the reference plant community may not necessarily be the management goal.

The environmental and biological characteristics of this site are complex and dynamic. As such, the following diagram suggests pathways that the vegetation on this site might take, given that the modal concepts of climate and soils are met within an area of interest. Specific locations with unique soils and disturbance histories may have alternate pathways that are not represented in the model. This information is intended to show the possibilities within a given set of circumstances and represents the initial steps toward developing a defensible description and model. The model and associated information are subject to change as knowledge increases and new information is garnered. This is an iterative process. Most importantly, local and/or state professional guidance should always be sought before pursuing a treatment scenario.

State and transition model

More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective text

Ecosystem states

1. Reference: Loamy Bottomland Forest

2. Cropland

3. Land Formed Cropland

4. Pastureland/Grassland

5. Forest Recovery

6. Conservation (Herbaceous)

States 2, 5 and 6 (additional transitions)

2. Cropland

5. Forest Recovery

6. Conservation (Herbaceous)

T1A	-	Vegetation/stump removal (mechanical/chemical); preparation for cultivation
T1B	-	Vegetation/stump removal (mechanical/chemical); seedbed preparation; establishment of desired forage; manage for grazing
T2A	-	Precision land leveling
T2B	-	Vegetation/stump removal (mechanical/chemical); seedbed preparation; establishment of desired forage; manage for grazing
T2C	-	Natural succession (Community 5.1) or prep area (plow pan breakup, fertilizing, etc.) and plant species appropriate for site (Afforestation - Community 5.2)
T2D	-	Establish select native species suitable for site; prepare for planting (herbicide and/or mechanical)
T4A	-	Vegetation/stump removal (mechanical/chemical); preparation for cultivation
T4B	-	Natural succession (Community 5.1) or prep area (plow pan breakup, fertilizing, etc.) and plant species appropriate for site (Afforestation - Community 5.2)
T4C	-	Establish select native species suitable for site; prepare for planting (herbicide and/or mechanical)
T5A	-	Vegetation/stump removal (mechanical/chemical); preparation for cultivation
T5B	-	Vegetation/stump removal (mechanical/chemical); seedbed preparation; establishment of desired forage; manage for grazing
T6A	-	Vegetation/stump removal (mechanical/chemical); preparation for cultivation
T6B	-	Vegetation/stump removal (mechanical/chemical); seedbed preparation; establishment of desired forage; manage for grazing
T6C	-	Natural succession (Community 5.1) or prep area (plow pan breakup, fertilizing, etc.) and plant species appropriate for site (Afforestation - Community 5.2)

State 1 submodel, plant communities

1.1. Mixed Bottomland Hardwoods

State 2 submodel, plant communities

2.1. Conservation Management

2.2. Transitional Conservation Management

2.3. Conventional Management

2.1A	-	Soil disturbance (tillage); reduction of soil health.
2.1B	-	Conventional tillage, seeding, and fertility management for crops.
2.2A	-	No-till, cover crops, reduced till-soil health improvements.
2.2B	-	Conventional tillage, seeding, and fertility management for crops.
2.3A	-	Reduced till, no-till, and cover crops with soil health improvements as a goal.

State 3 submodel, plant communities

3.1. Land Leveled Cropland

State 4 submodel, plant communities

4.1. Monoculture Grassland

4.2. Mixed Species System

4.3. Mixed Species, Non-seeded

4.4. Early Woody Succession

4.1A	-	Seeding and/or management for desired species composition.
4.1B	-	Species management without overseeding.
4.2A	-	Seeding, fertilizing, management/removal of undesirable species.
4.2B	-	Species management without overseeding
4.3A	-	Seeding, fertilizing, management/removal of undesirable species.
4.3B	-	Seeding and/or management for desired species composition.
4.3C	-	Lack of disturbance; no (infrequent) mowing, herbivory, or brush management; natural succession of woody species.
4.4A	-	Brush management/removal of unwanted species.

State 5 submodel, plant communities

5.1. Ruderal/Opportunistic Regrowth

5.2. Afforestation

5.1A	-	Remove undesirable competitors; final soil preparation; establish site-appropriate species (favored in management).

State 6 submodel, plant communities

6.1. Pollinator Planting/Native Grasses

State 1
Reference: Loamy Bottomland Forest

Removal of the historic natural communities of this site occurred long before thorough studies and investigations were conducted. Accordingly, reference conditions for this site have yet to be confirmed, but they are perceived to consist of mature forest stands that support a diverse mix of southern bottomland hardwoods adapted to the moderately well and well drained soils of this site. Once assigned or identified, the reference community will not represent the pre-settlement forest community, but it should identify an assemblage of naturally occurring species that reflects and contributes to regional biodiversity and local forest ecology. Implicated in the latter is that the “local” geomorphic features and drainage patterns of this soil-site environment should not have been drastically altered or removed (e.g., land leveled). Based on literature accounts, natural vegetation that may be most representative of this soil-site environment include components of Putnam’s (1951) “white oaks – red oaks – other hardwoods” forest type. This is corroborated by the species list for Dexter and Pearson soils in the Sunflower County, Mississippi soil survey manuscript (USDA-SCS, 1959). The current state and transition model does not have a return or transition pathway from the altered states back to reference conditions. Former land uses (alternate states) that result in soil compaction (increased bulk densities), lower soil organic matter content, altered fertility, and smaller available rooting volume can reduce forest site productivity by 10 to 20 percent, if not more, for some species (Groninger et al., 1999) and may result in high seedling mortality. Attempts to establish reference conditions under these soil-site constraints could result in poor establishment and response, colonization by undesirable taxa, or failure. These soil-site impacts, however, can be ameliorated through various “afforestation” techniques such as plow pan breakup (subsoil or deep plowing), fertilization, and fallowing fields before stand establishment (Emile Gardiner, USFS Research Forester, personal communication). State 5 (Forest Recovery) is representative of forest establishment and growth on locations where soil compaction and reduction of nutrients have occurred. Once a previously affected location has recovered its site potential, transition to the reference state may be possible. Realistically, it may not always be possible to return to a “perceived” reference state from a former altered condition. While planting and establishing trees appropriate for a site may be possible, achieving restoration of the understory and other system functions present challenges that may never be realized (Stanturf et al., 2001; Flinn and Vellend, 2005). That potential transition is still under review and is currently not shown or addressed in the state and transition model.

Community 1.1
Mixed Bottomland Hardwoods

Characteristic species of the “white oaks – red oaks – other hardwoods” forest type include swamp chestnut oak, white oak, bottomland post oak, cherrybark oak, Shumard’s oak, southern red oak, white ash, hickory, blackgum, and winged elm (Putnam, 1951). This list of species coincides with the swamp chestnut oak – cherrybark oak forest type (SAF No. 91) in Eyre (1980). Additional components of the type that may be locally important or dominant in some cases are sweetgum, water oak, willow oak, green ash (Fraxinus pennsylvanica), American elm, and sugarberry (Celtis laevigata) (Eyre, 1980; MMNS, 2015). Nuttall oak (Quercus texana), which is generally associated with wetter sites, is listed by some as an additional component of this site (Meadows and Stanturf, 1997). Meadows and Stanturf (1997) emphasized that hickory may represent the largest non-oak component in some stands. Hickory reportedly occurring in this community include shagbark (Carya ovata), shellbark (C. laciniosa), mockernut (C. tomentosa), and bitternut (C. cordiformis). Understory components may consist of pawpaw (Asimina triloba), American hornbeam (Carpinus caroliniana), and possumhaw (Ilex decidua) (Eyre, 1980). Ground cover is reportedly dense and diverse with herbaceous components consisting of sedges (Carex spp.) and various grasses and forbs including dense growths of the fabled giant cane (Arundinaria gigantea) within some canopy openings. Vines can be prevalent in the understory and may be represented by eastern poison ivy (Toxicodendron radicans), trumpet creeper (Campsis radicans), and Virginia creeper (Parthenocissus quinquefolia) (NatureServe, 2020).

Dominant plant species

swamp chestnut oak (Quercus michauxii), tree
white oak (Quercus alba), tree
bottomland post oak (Quercus similis), tree
cherrybark oak (Quercus pagoda), tree
Shumard's oak (Quercus shumardii), tree
southern red oak (Quercus falcata), tree
white ash (Fraxinus americana), tree
hybrid hickory (Carya), tree
blackgum (Nyssa sylvatica), tree
winged elm (Ulmus alata), tree
pawpaw (Asimina triloba), shrub
American hornbeam (Carpinus caroliniana), shrub
possumhaw (Ilex decidua), shrub
eastern poison ivy (Toxicodendron radicans), shrub
trumpet creeper (Campsis radicans), shrub
Virginia creeper (Parthenocissus quinquefolia), shrub
giant cane (Arundinaria gigantea), shrub

State 2
Cropland

This state is representative of the dominant land use activity on this ecological site, agriculture production. The dominant crops grown on this site are cotton (Gossypium hirsutum), corn (Zea mays), soybeans (Glycine max), and wheat (Triticum aestivum) (USDA-SCS, 1959; Snipes et al., 2005). Minor crops, such as some specialty crops (e.g., fruits, vegetables, and tree nuts such as pecans), may be grown locally. The soils of this site are well suited to agriculture production. Tilth is reportedly good with a surface layer that is very friable and easily tilled and managed over a wide range of moisture content. Management concerns are largely centered on erosion, plow pan development, soil compaction under equipment traffic, crusting and packing following heavy rain, and low organic matter content (USDA-SCS, 1959; Snipes et al., 2005). Each of these factors could affect yields or impede optimum operation. Management measures to ameliorate some of these issues may include implementing a conservation tillage or management system and subsoiling to breakup plow pans (USDA-NRCS, 2006b). Major components that producers generally develop and plan are proper selection of crop cultivar, pest control, cropping system, tillage methods, nutrient management, and water management (Snipes et al., 2005). Key practices of some cropping systems often include two or more crops grown in a multiyear rotation, which has been documented to disrupt pest cycles. Leaving crop residue on the surface can help to maintain tilth, fertility, and organic matter content – all critical elements of soil quality and health. For monoculture cropping systems, the implementation of well-designed pest and nutrient management systems are imperative (Pringle et al., 2017). (For assistance, interested parties are advised to visit their local NRCS Field Office.) Three separate management phases comprise this state: Conservation Management (2.1), Transitional Conservation Management (2.2), and Conventional Management (2.3). The three phases consist of varying tillage methods and approaches to soil health management systems.

Community 2.1
Conservation Management

This cropland phase utilizes long term, continuous conservation management systems that include reduced till and cover crops; no-till with cover crops; crop residue retention; and perennial cropping systems. The guiding principles of this system are minimizing soil disturbance and maximizing soil cover, biodiversity, and the presence of living roots. Implementing diverse crop rotations while maintaining these principles can lend to the development of an integrated pest management plan and contribute to overall system resilience. Of caution, the above-ground crop growth or yields may not be the best tracking mechanism for assessing the efficacy or presence of this management phase. Indicators of these systems are generally determined via soil-site assessments with outcomes that may include enhanced soil aggregate stability, increased soil biological activity, higher organic matter content, and improved water holding capacity and infiltration rates while also alleviating soil compaction and reducing runoff and erosion (Chessman et al., 2019). Additional advantages to this system that have been noted by some producers are reductions in fuel and labor costs and less wear and tear on machinery and equipment. There are challenges to this management system, especially in situations where tillage may be considered and/or needed to repair weather damage or other detrimental impacts. Implementation of conventional tillage even after long term conservation practices (e.g., no-till) can reset the affected area back to a conventional cropping system. However, those changes can be reversed and a return to a conservation management system is achievable. Critical conservation practices associated with this phase include cover crops, no-till, and reduced till as the foundational practices. Additionally, this phase may include supporting and site-specific practices to address conservation needs for a given location.

Community 2.2
Transitional Conservation Management

This cropland phase utilizes a hybrid approach that combines conventional methods with conservation practices at specific periods and under specific situations. Practices under this phase may include a combination of conventional till, reduced till, strip till, and the inclusion of cover crops. For instance, perennial crop species could be in a continuous transitional phase where conventional tillage is implemented at the time of planting followed by reduced tillage during the rotation. Planted forage crops could also be included in this phase, especially when part of a crop rotation that utilizes reduced tillage for one crop followed by conventional tillage for a succeeding crop. The development, implementation, and refinement of nutrient and pest management plans throughout component operations are imperative. Additionally, this phase may include supporting and site-specific practices to address conservation needs for a given location.

Community 2.3
Conventional Management

This management phase is representative of conventional cropland where tillage is implemented as an annual component of the production system. As crucial elements of the system, conservation practices such as nutrient and pest management are needed to address fertility requirements and pest concerns within the crop cycle. It is important to note that this phase may develop when tillage is implemented to address damage or for other purposes while under a conservation management system (Community Phase 2.1). There could also be associated, supporting, and site-specific practices that are needed to address specific conservation needs. Specific needs may include grade stabilization structures to control gully erosion, grassed waterways to trap sediment from sheet and rill erosion, or implementing reduced till.

Pathway 2.1A
Community 2.1 to 2.2

Soil disturbance (tillage); reduction of soil health.

Pathway 2.1B
Community 2.1 to 2.3

Conventional tillage, seeding, and fertility management for crops.

Pathway 2.2A
Community 2.2 to 2.1

No-till, cover crops, reduced till-soil health improvements.

Pathway 2.2B
Community 2.2 to 2.3

Conventional tillage, seeding, and fertility management for crops.

Pathway 2.3A
Community 2.3 to 2.2

Reduced till, no-till, and cover crops with soil health improvements as a goal.

State 3
Land Formed Cropland

This gently sloping ecological site typically adjoins nearly level to level landscapes. It is bordered by soils of varying textures and drainage characteristics. Accordingly, inconsistencies in wetness, ease of operation, and production or yields may occur across a cropped location. An increasingly common practice on this site consists of land forming or leveling surface irregularities into a predetermined and engineered, uniform slope. This practice removes the drier and higher features of this site, which are then used to fill wetter and lower positions (e.g., depressions or swales) across the targeted area. Advantages of land leveling may include reduced hazards of erosion and runoff rates, improved surface drainage, and enhanced distribution and conservation of irrigation water. Disadvantages of the practice is a churning of various surface and subsurface materials (former soil horizons) that no longer occur in a predictable or regular pattern. Organic matter content in the surface layer is generally low, and the surface tends to crust and pack after heavy rains (USDA-NRCS, 2006b). One potential hazard that appears to be emerging in some areas is an effective management of surface water runoff. As both irrigated and stormwater runs off leveled fields at uniform rates, surface water tends to collect cumulatively and simultaneously, which places tremendous demands on local drainage networks. Without “in field” structures (natural or artificial) to stagger runoff, the downslope (or lower) ends of some fields tend to back flood thereby contributing to more flooding overall in local watersheds (personal observations). Immediately following land leveling, the constituent elements of soil health are likely to be absent. In some areas, producers have initiated practices such as applying organic residues (e.g., poultry litter) or growing rice crops for one to two years to rapidly boost fertility and introduce organic matter (via rice biomass) in the surface layer. Over time, the full complement of the management (or community) phases of State 2 may be possible on land leveled fields. They are not repeated or indicated here. Currently, this state serves as an endpoint in the state and transition model because the ability to predict vegetation response when transitioning to a different state is no longer possible without soil-site investigations for each area of interest. The former soils of this ecological site, including surface and subsurface horizons, will have been redistributed as particles among other former soils.

Community 3.1
Land Leveled Cropland

Some of the crop species and management practices indicated and discussed in State 2 (including all three management phases) may be suitable for establishing on land leveled areas that once supported the soils of this site. However, the type of crops suited for newly leveled areas may ultimately depend on the prevailing soil particle-size distribution and internal drainage characteristics. Former studies on precision leveled fields have noted variabilities and inconsistencies in soil particle-size distributions, bulk density, soil biological properties, and nutrients (Brye et al., 2003; Walker et al., 2003; Brye et al., 2006). Management concerns for this phase may consist of restricted permeability, low organic matter content, and crusting and packing (USDA-NRCS, 2006b). These impacts may be improved by implementing conservation tillage, cover crops, retaining crop residue, and nutrient and pest management strategies.

State 4
Pastureland/Grassland

This state is representative of areas that have been converted to and maintained in pasture or grassland. The soils of this site correspond to Pasture Suitability Group 8a for the State of Mississippi and are considered well suited to most commonly grown perennial forage species. Available water capacity is moderate to high, and production on this site is generally high when areas are adequately fertilized and properly managed. The very strongly to moderately acid reactions of these soils usually require lime for many forage species. Given that this ecological site adjoins lower, wetter sites, some forage operations may utilize the higher elevations of this site as a protected area. This site may be suitable for the storage of harvested forage or holding of livestock when wet or flooded conditions occur on lower areas. Establishing an effective pasture management program can help minimize degradation of the site and assist in maintaining growth of desired forage. An effective pasture management program includes selecting well-adapted grass and/or legume species that will grow and establish rapidly; maintaining proper soil pH and fertility levels; using controlled grazing practices; mowing at proper timing and stage of maturity; allowing new seedings to become well established before use; and renovating pastures when needed (Rhodes et al., 2005; Green et al., 2006). This state consists of four community phases that represent a range of forage management options and pasture and hayland condition scenarios. Options range from establishing a forage monoculture for haying to a broad mixture of forage species for production and grazing. It is strongly advised that consultation with local NRCS Service Centers be sought when assistance is needed in developing management recommendations or prescribed grazing practices.

Community 4.1
Monoculture Grassland

This phase is mainly characterized by planting forage species for hay production. Forage plantings generally consist of a single grass species. Native and non-native forage species can be seeded. Forage is usually harvested as hay or haylage, although grazing may occur periodically. These sites are highly productive for forage and can provide ecological benefits to control soil erosion. Allowing for adequate rest and regrowth of desired species is required to maintain productivity. Maintenance of monoculture stands also requires control of unwanted species, which will require pest and nutrient management. Generally, the application of fertilizer and lime is needed to establish and maintain improved desirable pastures. Exceptions do occur for bahiagrass (Paspalum notatum) and common bermudagrass (Cynodon dactylon), which can be sustained under natural fertility and pH levels. Introduced grasses, such as hybrid bermudagrass, require a higher level of sustained fertility, pH above 6.0, and good surface drainage to persist. An additional measure to aid production may include prescribed grazing. Implementing limited and monitored grazing can promote deeper root penetration of grasses with the added benefit of greater nutrient and moisture uptake. This synergistic approach can lead to increased production of and may sustain desirable forages. Conservation practices should include prescribed grazing, or forage harvest management, nutrient and pest management, and potentially other site-specific practices.

Dominant plant species

Bermudagrass (Cynodon dactylon), grass
bahiagrass (Paspalum notatum), grass
dallisgrass (Paspalum dilatatum), grass

Community 4.2
Mixed Species System

This community is characterized by mixed species composition of grasses and legumes. Components of this forage system are either planted or they established naturally. Typically, perennial warm-season grasses are the foundation of the stand that are periodically overseeded with adapted cool-season forages. The latter creates an added benefit of extending the grazing season. This community phase can be highly productive for grazing and haying operations and can provide beneficial habitat for some wildlife species. Maintenance of grass stands also requires a series of management practices such as prescribed grazing, brush management, pest management, and nutrient management to maintain production of the desired species. Prescribed grazing includes maintaining proper grazing or forage heights, timing, and stocking rates. Supporting or facilitating practices such as fences, water lines, and watering facilities could be part of the system that maintains this phase.

Dominant plant species

Bermudagrass (Cynodon dactylon), grass
bahiagrass (Paspalum notatum), grass
dallisgrass (Paspalum dilatatum), grass
white clover (Trifolium repens), other herbaceous
red clover (Trifolium pratense), other herbaceous
crimson clover (Trifolium incarnatum), other herbaceous

Community 4.3
Mixed Species, Non-seeded

This community is characterized by a mixture of native and naturalized non-native species. Forage is usually grazed and/or harvested as stored forage, hay or haylage. Common established species may include Bermudagrass, bahiagrass, dallisgrass, and carpetgrass (Axonopus sp.). Stands are generally productive, and forage and grazing management can maintain the community. Healthy stands provide additional benefits by protecting soils from excessive runoff and erosion. However, a common peril associated with this phase is overgrazing, which lowers production and favors less palatable weedy species, especially in areas where livestock congregate. Proper stocking rates or grazing systems that allow for adequate rest and plant regrowth are required to maintain productivity. When forage species are afforded adequate recovery time between grazing intervals, they develop deeper root systems and greater leaf area. Conversely, when plants are not allowed to adequately recover, root development will be restricted leading to lower forage and biomass production. Additionally, maintenance of grass stands requires implementing pest management practices to control unwanted weedy and woody species.

Community 4.4
Early Woody Succession

This community is characterized by a diverse composition of grasses and forbs with an increasing presence of woody species (both native and non-native) that are immature and of low stature. Woody species grow quickly on this site and can be difficult and expensive to control. One potentially problematic species may be honeylocust. Putnam (1951) reported honeylocust as being common on old pastures, and the species can be difficult to remove once established. Management to transition this phase to other forage communities of this state is still possible without excessive inputs and effort, particularly if stem diameters remain below 2 inches and are widely scattered (e.g., a density of less than 100 stems per acre). However, if diameters become greater than 3 inches and densities exceed 300 stems per acre, far more investment, effort, and inputs will be required. If brush management measures are not undertaken, the plant community will transition to the Ruderal/Opportunistic Regrowth (Community Phase 5.1) of State 5. Of note, this community phase is often very beneficial habitat for some wildlife species, especially a specific guild of resident and Neotropical migratory bird species that depend on old field to young tree stand habitats.

Dominant plant species

honeylocust (Gleditsia triacanthos), tree

Pathway 4.1A
Community 4.1 to 4.2

Seeding and/or management for desired species composition.

Pathway 4.1B
Community 4.1 to 4.3

Species management without overseeding.

Pathway 4.2A
Community 4.2 to 4.1

Seeding, fertilizing, management/removal of undesirable species.

Pathway 4.2B
Community 4.2 to 4.3

Species management without overseeding

Pathway 4.3A
Community 4.3 to 4.1

Seeding, fertilizing, management/removal of undesirable species.

Pathway 4.3B
Community 4.3 to 4.2

Seeding and/or management for desired species composition.

Pathway 4.3C
Community 4.3 to 4.4

Lack of disturbance; no (infrequent) mowing, herbivory, or brush management; natural succession of woody species.

Pathway 4.4A
Community 4.4 to 4.3

Brush management/removal of unwanted species.

State 5
Forest Recovery

This state is representative of forest recovery in areas that were once under former intensive land use such as long-term row crop cultivation. Characteristics that distinguish this state from other forest states on this site include a suite of soil-site properties that reportedly affect tree growth such as higher soil bulk density due to compaction, presence of a plow pan, lower organic matter content, and reduced fertility (Baker and Broadfoot, 1979; Groninger et al., 1999). Two community phases are provisionally recognized for this state. Community Phase 5.1 represents natural colonization of tree and shrub species without management. Community Phase 5.2 is representative of intentional forest establishment by artificial regeneration or planting. For Community Phase 5.2, determining the objectives and goals of the future stand is imperative to increase the probability of successful establishment and production of the afforested area. These decisions will ultimately determine the species to be established, preparation requirements, planting density, and post-planting operations (e.g., competitor control, future improvement cuttings and thinnings, regeneration methods, and overall stand health). Since each area targeted for afforestation may have unique or different land use histories, having a clear understanding of the soil-site conditions are essential. Some areas may necessitate a series of soil improvement actions prior to planting. These actions may include subsoiling or deep plowing to breakup plow pans and fertilizing the targeted area. An additional option is to allow the area to undergo fallowing for a predetermined period (Community Phase 5.1) to potentially increase soil organic matter content, enhance soil aggregate stability, increase soil biological activity, and improve water holding capacity and infiltration rates. Controlling competing vegetation (chemical and mechanical treatment) will most likely be critical. Post-planting operations and maintenance of the stand can enhance survival, future development, and achieve goals and objectives (see Gardiner et al., 2002). Finding the appropriate approach for a given environment necessitates close consultation with trained, experienced, and knowledgeable forestry professionals. If there is a desire to proceed with this state, it is strongly urged and advised that professional guidance be obtained and a well-designed afforestation and silvicultural plan developed in advance of any work conducted. For an exceptional review and summarization of the afforestation literature, techniques, and practices within the Southern Mississippi River Alluvium, interested parties are directed to Gardiner et al. (2002).

Community 5.1
Ruderal/Opportunistic Regrowth

This community phase is representative of former working lands (e.g., cropland and possibly high concentration areas of former pastureland) that have fallowed and subsequently undergone natural colonization by vegetation. A profusion of growth will likely initiate within five to ten years of becoming idle – one that typically includes grasses, forbs, woody seedlings and shrubs, and an increasing presence and covering of vines. Initial colonization may be dominant in annuals followed by a shift to perennial vegetation. Shrubs and tree seedlings may appear very early following abandonment, however the rate of colonization and period to stand establishment likely depends on the proximity of established mature stands (Battaglia et al., 1995; Battaglia et al., 2002). If established stands consisting of light-seeded species adjoin fallow fields, colonizing tree species will likely be comprised of those taxa (e.g., green ash, elm, sycamore, and cottonwood) (Allen, 1990; Stanturf et al., 2001). Some areas may be far removed from established forest stands. Under this scenario, establishment of woody species (especially overstory tree species) may be very slow, and years may be required before stand establishment is reached (Battaglia et al., 1995; Allen, 1997). In fact, natural colonization by some species may be delayed indefinitely with some stands or areas being understocked (Allen, 1997; Battaglia et al., 2002; Groninger, 2005). Heavy-seeded species like oaks and hickory may not have an opportunity to colonize available areas due to distance and lack of a dependable dispersing agent (e.g., wildlife and water). For those areas close to a viable seed source, oaks may be a component of the developing stand, although in the early stages of stand development oaks are likely to be a minor component (Meadows, 1993). Non-native invasive species may become part of the developing stand given the proliferation of exotic plant species over the past century. It is extremely difficult, if not impossible, to predict the future composition and structure of an abandoned field on this site. Many different environmental factors will influence initial colonization and development trajectories. The following projections are simply based on native plant species reported to occur on the soils of this site. As the young stand matures and eventually enters the stem exclusion stage (crown or canopy closure), composition may include American elm, green ash (Fraxinus pennsylvanica), American sycamore (Platanus occidentalis), sweetgum, persimmon, honeylocust, and American hornbeam. Oaks that may occur in the young stand include cherrybark, swamp chestnut, water, willow, and possibly Nuttall (Quercus texana) but these will likely be rare or uncommon components, if present at all. Problematic non-native species that may occur include Japanese honeysuckle (Lonicera japonica), Chinese privet (Ligustrum sinense), Chinese tallow (Triadica sebifera), Chinaberrytree, and possibly Callery pear (Pyrus calleryana). Vines common in the young, developing stand may include greenbrier (Smilax spp.), eastern poison ivy, trumpet creeper, and wisteria. As the stand matures decades into the future and the overstory stratifies (i.e., the understory reinitiation stage), shade tolerant species may rise to prominence in the stand.

Dominant plant species

winged elm (Ulmus alata), tree
American elm (Ulmus americana), tree
green ash (Fraxinus pennsylvanica), tree
American sycamore (Platanus occidentalis), tree
sweetgum (Liquidambar styraciflua), tree
red maple (Acer rubrum), tree
boxelder (Acer negundo), tree
honeylocust (Gleditsia triacanthos), tree
common persimmon (Diospyros virginiana), tree

Community 5.2
Afforestation

This community phase is representative of areas planted in tree species that are suited for and favored in management on this ecological site. Preparation of this phase may be initiated immediately following a former land use activity (e.g., State 2) or it may be started following a fallow period (Community Phase 5.1). If afforestation is initiated immediately following years of conventional tillage without soil-site preparation and improvement efforts, potential productivity of the targeted area could be less than optimal if soil compaction, plow pan presence, degraded fertility, and/or depleted organic matter content are existing factors (Baker and Broadfoot, 1979; Groninger et al., 1999; Gardiner et al., 2002). Over the years, various afforestation innovations have increased the likelihood of success in addition to soil-site amelioration such as planting large, high-quality seedlings with well-developed root systems in an appropriate cover crop (Dey et al., 2010); interplanting seedlings within a fast-growing pioneer species nurse crop (e.g., cottonwood) (Gardiner et al., 2001); and planting companionable species combinations for mixed species stands (Lockhart et al., 2008). The cover crop and nurse crop approaches reportedly help to control rapid overtopping and crowding by competing vegetation and wildlife herbivory (Dey et al., 2010). Finding the appropriate strategy for a given location requires matching the species to the local hydrologic and soil-site environment; determining short- and long-term objectives and goals; and implementing the appropriate management actions at the required intervals. Several species that are favored in management (see State 1) are appropriate for planting on this ecological site. Extremely important components such as swamp chestnut oak, cherrybark oak, Shumard’s oak, and water oak are included as naturally occurring species on these higher and drier “ridge soils” and warrant consideration (Putnam, 1951; Eyre, 1980; MMNS, 2015).

Dominant plant species

swamp chestnut oak (Quercus michauxii), tree
cherrybark oak (Quercus pagoda), tree
Shumard's oak (Quercus shumardii), tree
water oak (Quercus nigra), tree
sweetgum (Liquidambar styraciflua), tree

Pathway 5.1A
Community 5.1 to 5.2

Remove undesirable competitors; final soil preparation; establish site-appropriate species (favored in management).

State 6
Conservation (Herbaceous)

This state is representative of the range of conservation actions that may be implemented and established on this ecological site. Apart from planting trees and managing for forest, one may elect to establish native herbaceous species and manage for predominantly a native grassland; a complex mixture of native grasses and forbs; or a pollinator planting whereby native forbs dominate the mix. In each of these options, it is strongly advised (possibly a programmatic requirement) that the species comprising the planting or seed mix consist of spring, summer, and fall flowering species. Depending on goals and objectives, various conservation programs and practices may be available. For additional information and assistance, please contact or visit the local NRCS Field Office.

Community 6.1
Pollinator Planting/Native Grasses

This community phase represents the establishment of native forbs or wildflowers for pollinator habitat or native grasses. The seed mix for planting may be quite varied depending on objectives and goals. Ideally, the mix includes a wide range of species that flower at various times of the growing season (spring, summer, and fall). Plant species in some pollinator mixes may include but are not limited to beebalm (Monarda spp.), milkweeds (Asclepias spp.), beardtongue (Penstemon spp.), vervain (Verbena spp.), various legumes such as native lespedeza (Lespedeza spp.), Illinois bundleflower (Desmanthus illinoensis), partridge pea (Chamaecrista fasciculata), and a broad assortment of composites such as asters (Symphyotrichum spp.), tickseed (Coreopsis spp.), blazing star (Liatris spp.), coneflower (Rudbeckia spp.), sunflower (Helianthus spp.) among many others. If goals and objectives are to establish native grasses within a forb mix or in a grass-dominant stand, species suitable for planting may include big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium) and Indiangrass (Sorghastrum nutans). Key to the establishment of this phase is initial preparation, seeding rate, planting period, follow-up treatment, and maintenance of the planting. The selection of species to establish on any given area may ultimately depend on size and conditions of the location where the planting will occur, landowner/manager goals and objectives, and the advice and knowledge of the conservation practitioner.

Transition T1A
State 1 to 2

Actions include mechanical removal of vegetation and stumps; herbicide treatment of residual plants; and preparation for cultivation.

Transition T1B
State 1 to 4

Actions include mechanical removal of vegetation and stumps; herbicide treatment of residual plants; seedbed preparation; and establishment of desired forage.

Transition T2A
State 2 to 3

Precision land leveling

Transition T2B
State 2 to 4

Vegetation/stump removal (mechanical/chemical); seedbed preparation; establishment of desired forage; manage for grazing

Transition T2C
State 2 to 5

Natural succession (Community 5.1) or prepare area (e.g., plow pan breakup, fertilizing, etc.) and plant tree species appropriate for site (Afforestation - Community 5.2)

Transition T2D
State 2 to 6

Establish select native species suitable for site; prepare for planting (herbicide and/or mechanical)

Transition T4A
State 4 to 2

Actions include mechanical removal of vegetation; herbicide treatment of residual plants; and preparation for cultivation.

Transition T4B
State 4 to 5

Natural succession (Community 5.1) or prepare area (e.g., plow pan breakup, fertilizing, etc.) for planting tree species appropriate for site (Afforestation - Community 5.2)

Transition T4C
State 4 to 6

Establish select native species suitable for site and prepare area for planting (herbicide and/or mechanical).

Transition T5A
State 5 to 2

Cropland establishment: vegetation/stump removal (mechanical/chemical) and preparation for cultivation.

Transition T5B
State 5 to 4

Vegetation/stump removal (mechanical/chemical); seedbed preparation; establishment of desired forage; manage for grazing

Transition T6A
State 6 to 2

Cropland establishment: vegetation removal (mechanical/chemical) and preparation for cultivation.

Transition T6B
State 6 to 4

Establish desired forage species and manage for grazing.

Transition T6C
State 6 to 5

Natural succession (Community 5.1) or prepare area (e.g., plow pan breakup, fertilizing, etc.) for planting tree species appropriate for site (Afforestation - Community 5.2).

Additional community tables

Supporting information

Inventory data references

The information provided on the states and community phases in this provisional description report were generated from literature reviews, conversations with technical specialists, and limited personal observations and experience on this soil-site environment. Intensive vegetation inventories were not conducted during the development of this provisional report. Those tasks will occur during future phases of ecological site development.

Other references

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Contributors

Barry Hart
Rachel Stout Evans

Approval

Charles Stemmans, 6/10/2025

Acknowledgments

We are sincerely grateful to the MLRA 131A Technical Team for their assistance and input in the development of this report. Special recognition is owed to Tom Foti (Ecologist, Arkansas Natural Heritage Commission, Retired) and Henry Langston (Wetland Ecologist, Arkansas Department of Transportation, Retired) for their time, personal travel expenses, and willingness to share their vast knowledge of the region. Their assistance with field reconnaissance, identifying sites and locations for investigating, and verifying ecological factors across multiple Mississippi River basins has led to a deeper understanding of the ecological sites and their associated states and community phases in the Southern Mississippi River Alluvium.

Rangeland health reference sheet

Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.

Author(s)/participant(s)
Contact for lead author
Date	06/10/2025
Approved by	Charles Stemmans
Approval date
Composition (Indicators 10 and 12) based on	Annual Production