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Long-term Agro-ecosystem Research in the Central Mississippi River Basin, USA:

Introduction, Establishment, and Overview

E. John Sadler, Robert N. Lerch, Newell R.

Kitchen, Stephen H.

Anderson, Claire

Baffaut,

Kenneth A. Sudduth, Anthony A. Prato, Robert J.

Kremer, Earl D.

Vories, D. Brent Myers,

Robert Broz, Randall J. Miles, and Fred J. Young

The material below is supplemental to the main article section titled:

Geophysical Setting and Anthropogenic Changes

Contributing to this section were the following authors listed in the main paper:

D. Brent Myers, Newell R. Kitchen, Stephen H. Anderson, Randall, J. Miles, Fred J. Young

INTRODUCTION

This material is supplemental to the section of the same title in the Overview paper of

a series that documents data and research from the Goodwater Creek Experimental

Watershed (GCEW). The GCEW has been part of a larger USDA-Agricultural Research

Service (ARS) watershed network for more than 40 years and has a valuable store of long-

term watershed hydrological, meteorological, and water quality data. For the data and

research from the GCEW and the broader Salt River Basin (SRB) (6,417 km2 or 2478 mi

2),

selected as the Central Mississippi River Basin site in the ARS Long-Term Agro-Ecosystem

Research (LTAR) network, an understanding of the natural history and anthropogenic

influence is needed to provide a foundation for developing credible scientific interpretation.

The natural history, including genesis of the landscape and soil resource, is needed for a

complete understanding of current natural processes active and important in the region.

Anthropogenic activity within the region also needs documentation in order to comprehend

how man’s activities have impacted soil and water resources. While much of the information

found here exists in the literature, it has been widely scattered. Further, this summary and

synthesis allows for a more comprehensive understanding of the past and current interactions

between watershed resources and land management, and for development of future

comprehensive management strategies.

GEOPHYSICAL SETTING

Agroecosystem research must derive conclusions about best management practices

based on a clear picture of the soil and landscape properties, and processes at work. It is a

central goal of such research to manage systems in such a way to sustain productivity on

these irreplaceable resources. The Central Mississippi River Basin, the SRB, and the GCEW

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occur on a post-glacial landscape along the southernmost edge of the ancient Laurentide Ice

sheet. The features and properties of these landscapes have interacted with management

systems and land uses resulting in both productive agricultural output and key failures in

ecosystem function. These failures are documented for Northeast Missouri, the SRB, and the

GCEW in this paper series and include soil erosion, stream sedimentation, and

ground/surface water nutrient and agrochemical pollution. Specific soil-landscape properties

are critical drivers for these vulnerabilities including; fractured glacial till, gently sloping

incised and highly erodible topography, slowly permeable argillic horizons, an intermittent

perched water table (episaturation) causing subsurface lateral flow, and the spatial patterns of

these features in the landscape. In this section we describe these features and properties and

discuss the landscape processes that impact agroecosystem function.

Geographic and Hydrologic Context

The study region ranges from the field scale to large watersheds but are applicable to

much of Northern Missouri. The findings of these works are also potentially applicable to

parts of Southern Iowa, and Southern Illinois, because these regions have similar soil

landscapes and land uses. The Central Mississippi River Basin encompasses more area than

this, representing, in concept, landscapes of the southern corn belt where thin loess over till,

or thin loess over residuum occurs. These landscapes can be generally described as dissected

upland plains with alluvial benches, floodplains, and riparian corridors. The more specific

Northeastern Missouri context of this paper series occurs on the landscapes straddling the

Grand Divide of the Missouri and Mississippi rivers (Figure 1). The SRB is composed of 3

major basins, the North and South Forks of the Salt, and the Salt. Within the South Fork basin

is the Long Branch watershed which contains the GWCEW.

General Chronostratigraphy

The character and function of Northeast Missouri’s soil-landscapes arise from three

key materials beginning with the underlying sedimentary bedrock, formed during the

Carboniferous period (359 Ma to 299 Ma). These layers help define the general topography

and drainage network. Above that bedrock, multiple layers of moderately dissected

Pleistocene epoch (2.5 Ma to 11.7 ka) glacial tills define the visible landforms. Finally, soil

profiles with important hydrologic control are formed in till, and mid-late Pleistocene (126 ka

to 11.7 ka) pedisediments and loess. Pedisediments are comprised of a basal mix of glacial

till and loess after glacial retreat and during initial loess deposition. The loess is distributed in

a more or less continuous mantle of variable thickness except on areas of significant slope or

instability where the underlying pedisediment, till, and sometimes bedrock may outcrop. The

remaining key parent materials are alluvial deposits of eroded till and loess in valleys and

floodplains.

Bedrock Geology

The overall topographic trends and locations of the major divides and river systems in

Northern Missouri are a vestige of the pre-glacial landscape (circa 2.5 Ma). That landscape

has been buried, but was developed in residuum of the same sedimentary geology as the

current bedrock. This bedrock is the remains of the Cambrian Platform which formed from

materials deposited beneath shallow seas which fluctuated in extent across central portions of

North America. The Cambrian platform in northern Missouri includes carbonate, shale, and

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sandstone rock (Ruhe, 1969; Allaby and Allaby, 1999; Grimley, 2000) and significant coal

deposits, but is predominantly limestone. This bedrock outcrops on some of the steeper

landforms along the lower reaches of major drainages and provides some control on the

elevation of these channels. The Cambrian Platform in northern Missouri was truncated to the

Pennsylvanian or Mississippian layers by glacial activity. The hydrologic function of the

bedrock has very little impact on the glacial till aquifer but the bedrock topography guided

the route of glaciers, and their subsequent drainage networks. These drainage networks still

exist today.

Pleistocene Glacial Deposits

Just above the bedrock are thick deposits of glacial till and outwash sediments that

were laid down during the Pleistocene epoch. Glacial till accumulated in multiple layers up to

100 meters thick and averages about 40 meters thick across the GCEW (Sharp, 1984). Glacial

advances repeatedly terminated in Central Missouri, constrained by increasing elevation at

the margin of the Ozark dome. This limitation set the current course of the Missouri River.

The maximum advance of the pre-Illinoisan Laurentide ice sheet occurred about 2.4 Ma

(Rovey and Balco, 2010), but was reached multiple times during the Pleistocene, crossing the

study region with distinct layers of till deposits. Northern Missouri has been glacier free since

about 0.2 Ma ago.

The chronostratigraphic record of the Pleistocene contains several identified and dated

materials. Just above the bedrock, pre-Pleistocene residuum, fireclay deposits, a buried

gelisol (2.58 to 2.47 Ma) formed in a periglacial environment (Rovey and Balco, 2010), and

peat deposits (Blanchard and Donald, 2005) are all observed. The Atlanta till formation (2.47

Ma), represents the earliest evidence of glaciation, and is overlain by the Moberly (1.2 Ma),

and the McCredie formations (0.75 to 0.2 Ma). The Moberly formation is not currently

differentiated. Three till subunits are recognized within the McCredie formation, they are the

Fulton member (0.75 Ma) the Columbia member (0.4 to 0.2 Ma), and the Macon member

(0.2 Ma).

These periods of active glacial advances (stadia) were alternated with regressionary

interstadial periods. The most recognizable features of these warmer ice free periods are

paleosols. Paleosols are named and consistently present in the chronostratigraphic record

across the region, though their spatial coverage is intermittent and they are not well correlated

in the literature. Their preservation is dependent on the stability of the landform and the site-

specific erosion processes occurring before burial in the next glacial stage. The major

interstadials in which paleosols formed occurred between the Moberly and McCredie

deposits and on top of the McCredie formation. The most recent paleosol, the Yarmouth-

Sangamon is widely observed and represents soil formation during the middle and late

Plestocene (0.2 Ma to 12 ka). Northern Missouri remained glacier free during the Illinoisan

(0.3 to 0.12 Ma) and Wisconsinan (0.1 Ma to 25 ka) glacial stages. The current

geomorphology developed during this open period, a net erosive environment which led to

greater incision of the glacial till and caused the overprinting of the Sangamon paleosol onto

the Yarmouth.

Till composition across Northern Missouri is a mix of glacially abraded geologic

materials from local and northern latitudes. Composition of the till is vertically and spatially

heterogeneous, varying in part by the era of deposition. The older Atlanta and Moberly

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formations are more influenced by the mineralogy of local bedrock. Thus, the clast lithology

in these deeper layers is 70 to 100% sedimentary in origin (Rovey and Kean, 1996; Roy et al.,

2004). Upper till layers are influenced by mineral sources further north than central

Minnesota and contain 45 to 60% crystalline lithology. These glacial deposits were laid by a

combination of mechanical force and melt-water runoff which occurred in a complex

overlapping manner resulting in layers and pockets of material with spatially variable textures

and density. In general the till texture is loamy and structure ranges from strong, very coarse

prismatic to structureless massive. Sand lenses and fractures are sporadically present leading

to large variability in saturated hydraulic conductivity (Ksat) of the tills. Sharp (1984) reviews

the available Ksat data from studies in Northern Missouri. These studies demonstrated several

orders of magnitude range in Ksat for glacial till layers (1.2x10-9

to 2.0 x10-2

m s-1

); also

demonstrating that in-situ tests typically had larger Ksat than core samples. Blanchard and

Donald (1997) described the till in the GWCEW as ‘a fractured system with a low

permeability, high porosity matrix’. They further documented that paleosol argillic horizons

can have an impact on the hydrologic system finding that two paleosol features within the till

had relatively smaller Ksat than till layers, likely due to the larger concentrations of pedogenic

clay.

Pedisediment, Colluvium, and Alluvium

The cessation of glacial activity in Northern Missouri at around 0.2 Ma pre-dates

surface loess deposits and left a long time interval for soil formation and erosion. The result

of this is the commonly seen Sangamon paleosol at the till interface. Truncation of the till and

paleosols occurred in many places due to erosion and long exposure, leaving a pediment, or

erosion surface (Schaetzl and Anderson, 2005). Subsequent loess deposits occurred atop this

till derived material over a time frame long enough for bioturbation, soilfluction, frost action,

and other in-place processes to mix coarser materials up into the first increments of the loess

deposit. The result of this basal mixing process is a ubiquitous distribution of pedisediment at

the glacial till-loess contact. The pedisediment contains an increase of 3 to 5 percent fine sand

relative to the overlying loess material, but vanishes in a diminishing gradient upward into

the loess. Pedisediment is quite common in most upland soil profiles in the GCEW from

summits to footslope positions. Colluvium is frequently seen in concave footslope positions

in areas with steeper dissection. These areas are influenced by soilfluction and erosion

occurring upslope to the immediate area. Alluvium is common in the riparian corridors

between the upland landforms. The alluvial fill derives from three major timeframes and

processes, glacial recession, post-glacial pediment formation, and the Illinoisan and

Wisconsinan era influx of loess into the system. Terrace bench positions at valley margins are

derived consequence of the earlier processes while the current floodplains are narrower due

to less water influx in the post-glacial period, and reduced sediment delivery in the Holocene

era (Bettis et al., 2008). Alluvium in the GCEW area is silty to loamy in texture with little

sand content compared with larger river basins.

Late Pleistocene Loess

As noted above, glaciers covered much of the upper and central Midwest during the

Illinoisan and Wisconsinan glacial stages while Northern Missouri remained glacier-free.

Nevertheless, the deposits of these glaciers were eroded by the meltwater created in their

recession, making their way to Northern Missouri in the major river systems. This eroded,

silty material was moved during fluctuating melting conditions and, intermittently deposited

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on the Missouri River flood plains (Schultz and Frye, 1965; Ruhe, 1969; Follmer, 1983;

Guccione, 1983). The late Pleistocene and early Holocene periglacial environment was cold

and arid with a westerly to southwesterly paleowind (Muhs and Bettis, 2000). Exposed

fluvial sediments were transported by wind erosion and re-deposited on downwind landforms

and left as loess deposits. The chronostratigraphic result of the Wisconsin glacial regression

is the most recently deposited parent material, the Peoria loess. Many of the modern soils of

the Central Claypan Areas in both Missouri and Illinois, including the GCEW, are formed in

this layer that was deposited during the timeline of 25 to 7 ka. Smectites and mixed-layer

illite smectites are the primary clay-sized mineral component of the Peorian loess

(Nizeyimana and Olson, 1988; Burras et al., 1996; Young and Hammer, 2000).

Regionally, thickness of the silty loess veneer varies with distance from its source and

was distributed anisotropically according to prevailing paleowinds (Ruhe, 1969; Muhs and

Bettis, 2000). The study region is on the east-central side of Missouri with most of the state

separating it from the southerly course of the Missouri river on the western border of the state.

This portion of the river is perpendicular to the paleowind and loess thickness decreases from

as much as 30-meters in the deep loess hills adjacent to the Missouri and Mississippi rivers to

less than 2-meters on broad flat interfluves in the Missouri Central Claypan Region

(Guccione, 1983).

Soil-Landform Relationships

Parent materials and soil morphology in Northeast Missouri are strongly correlated to

landscape position and geomorphology (Figure 2). Key features with landscape dependence

are thickness of loess, and depth of and clay content in the argillic peak. Local landscape

processes have caused the loess cap to vary in thickness systematically with slope and

landform (Ruhe, 1969). Maximum accumulation of loess occurs at summits and on divides.

Because of the flat topography, runoff does not accelerate; thus the detachment and transport

of soil particles is minimal (Jamison et al., 1968). As slope increases from shoulder to

backslope, the surface is less stable. Gravity, soilfluction, and runoff cause slumping and

detachment, and loess thickness decreases. Loess may be eroded away entirely at some

steeper incised landforms, exposing pedisediment, or the surface of the glacial till. These

processes also caused the accumulation of colluvial hillslope sediments composed of the

eroded silt, pedisediment, and till in concave landscape positions (Young and Geller, 1995).

Clay content in these soil profiles has a peak-shaped continuous depth function

(Myers et al., 2011). The depth and amplitude of the profile peak clay content also varies

systematically in these landscapes. Summit positions exhibit the most, abrupt argillic

horizons having the greatest clay content and form entirely in loess. Down-slope positions

have a larger portion of silt and sand material arising from pedisediment and glacial till

within 1-m from the surface. The coarser pedisediment typically does not influence the

summit position until >1 m depth while the shoulder position can have pedisediment at about

75 cm. Depending on the history of erosion, the backslope position can have loess,

pedisediment, or glacial till at the surface, and frequently has all of these materials within the

top 1 m of the profile. The footslope position typically has loess-derived colluvial sediments

and pedisediments over a deeper argillic horizon.

Terrace, creek, and river bottom soils are a smaller portion of the landscape than

upland positions, but are some of the most productive soils in this region as the silts and

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loams dominate the soil profile. Terraces tend to have similar profiles to summit positions.

Though they are the result of glacial erosion and fluvial deposition, they existed as stable

landforms during the late Pleistocene (Bettis et al., 2008) and have a thick loess covering.

Below terrace positions, the current flood plains tend to have a very diverse range and

heterogeneous distribution of fluvial sediments with clayey to sandy texture.

Claypan Genesis

The claypan feature prominent in the study area is an extreme variant of the peak

shaped accumulation of clay content in argillic horizons commonly seen in many Alfisols.

This argillic peak is formed due to chemical and physical weathering processes. Subsequent

to deposition, weathering of these collected materials has occurred in the temperate,

subhumid environment of the Holocene epoch (Ruhe and Scholtes, 1956). Because of the thin

loess deposit (1 - 2 m), flat topography, finer particle size, and the Holocene climate, the soil

minerals have undergone intensive weathering (Bray, 1935; Jamison et al., 1968) relative to

thick loess deposits.

The claypan feature has both physical and chemical provenance. Chemical weathering

processes include chemical transformation of primary and secondary minerals, and neo-

formation in-situ from dissolved mineral components left behind as evapotranspiration

seasonally dessicated the profile (Bray, 1935; Nikiforoff and Drosdoff, 1943; Whiteside,

1944; Wambeke, 1976). Physical translocation and accumulation of clay sized particles also

occurs. A constructive interference develops in the argillic horizons, whereby illuviated clay

films plug successively larger and larger pores and gaps between structural peds (Thorp et al.,

1959; Yaalon, 1983).

The accumulation of clay in argillic horizons (450 to 650 g kg-1

) is complemented by

eluviation in the superior E or BE horizon (200 to 300 g kg-1

) (Bray, 1935; Jamison et al.,

1968). Seasonal impermeability of the argillic zone causes a perched water table to form

directly above it. Solvent action and a fluctuating redox state are dominant in this part of the

soil profile. The felsic and mafic primary minerals found in the loess parent material are rich

in base cations, but they are largely weathered away from this portion of the profile and

degradation components of secondary minerals are shifted towards acid cations (Bray, 1935;

Albrecht, 1967; Lindsay, 1979). The remaining material in the eluviated zone has a larger

proportion of silt-sized quartz and other stable aluminosilicates with small CEC. Due to the

production of acid cations in weathering the eluviated zone has a pH of about 4.5. Large iron-

manganese concretions form here due to seasonally alternating redox state concomitant with

saturation and dessication. The coarser texture of the E horizon and impermeability of the

underlying clay leads to subsurface lateral flow (episaturation) and seepage downslope. These

are key hydrologic features of this landscape that have important impacts on water quality

and crop productivity.

ANTHROPOGENIC CHANGES

Historical information relative to settlement and associated land management changes

is critical for an accurate understanding of how water and soil quality changes occur in

watersheds. This history represents the Central Mississippi River Basin but primarily draws

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upon historical records written for the SRB (6,417 km2 or 2478 mi

2), of which the GCEW is a

sub-basin. Further, this historical sketch is not intended to cover all human activities, but is a

description of those elements having the most significant impact on land use, watershed

hydrology, soil and water resource impairment, and response with conservation practices.

Human Activity During Prerecorded History

Prior to European settlement, Native American habitation of the SRB likely followed

the archeological-derived timeline found in much of the U.S. Midwest area: 1) Paleo –

Indian period (ca. 12,500-10,000 B.P.) characterized with nomadic bands of hunters of ice-

age mammals (early only), deer, elk, buffalo, and turkey, and later in this period gatherers of

berries and nuts; 2) Archaic Culture period (ca. 10,000-3,500 B.P.) with predominantly small

upland villages where hunting, fishing, and foraging were replaced by some agricultural food

production; and 3) Woodland Culture period (ca. 3,500-700 B.P.) characterized by increased

advancement and utilization of pottery, weaving of plant fibers, and agriculture cultivation

practices, leading to long-term settlement and inter-tribal trading (Chapman and Chapman,

1983). Artifacts of all three periods were documented prior to construction of the Clarence

Cannon Dam that created Mark Twain Lake within the SRB (Henning, 1975). Leading up to

and overlapping with the time when European fur trappers and settlers arrived in the SRB,

various tribal groups occupied the area, surviving mostly on hunting and gathering, and less

on agriculture. Of note were the Sauk and Fox tribes that had migrated to the basin from the

Great Lakes region in the mid-1600s (Chapman and Chapman, 1983). As a result of the 1803

Louisiana Purchase, these Indian tribes relinquished rights to the U.S. Government in an 1804

treaty a large area west of the Mississippi River that included the SRB. Significant tribal

factions ignored the treaty for several decades and therefore land ownership was reaffirmed

by a second treaty in 1824 with the State of Missouri.

Early 1800’s Anglo-European Settlement

When Anglo-European settlers first moved into the SRB area, it was a combination of

deciduous forests (oak-hickory) and prairie grasses. However, what attracted the first settlers

was the presence of salt springs (salt being a scarce commodity on the frontier), and from

such the river received its name (O’Brien, 1984). The small salt mining operations, however,

never provided lasting strongholds. These operations were frequently attacked by Indians and

later failed because of less-expensive salt imports. Compared to other parts of the region,

movement of settlers into the basin was inhibited because of poor transportation routes. For

many years un-mapped game and Indian trails were all that were available (Henning, 1975).

In the 1820’s these trails were gradually worn into wagon roads and sparse settlement became

widespread throughout the Basin. Land purchase and settlement expanded rapidly from 1827-

1836 (a period of national economic prosperity), with ~80% of the public land within the

Basin purchased during this decade (O’Brien, 1984). Additional sale of public lands to

settlers was completed by 1860.

Most settlements started as clusters of three-to-five, usually-related families. Two

natural resources guided these settlers for homestead site selection: year-round water and

abundant timber. Because of high-water flooding in the bottomlands adjacent to streams,

homesteads were usually upslope from waterways in or adjacent to timber (O’Brien, 1984).

Stream water was needed for human and livestock consumption, as well as used for washing

purposes. Fish also helped meet food needs. Hand-dug, rock-lined wells were often

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constructed near the homestead for a cleaner drinking water source than stream water.

Readily-available timber was essential since it was the principle resource used for home and

barn construction, tools, cooking, and heating. Early homesteading on the nearly-flat prairie

was mostly absent since these grasslands lacked critical water and wood resources.

Since transportation was restricted, commerce was also limited and settlers generally

lived a simple agrarian lifestyle growing corn (Zea mays), wheat (Triticum aestivum), rye

(Secale cereale), pumpkin and squash (Cucurbita spp.), and garden vegetables. Typically

each homestead also had a few livestock serving as work animals and helping meet food

needs. Because an ample timber source was a necessity for settlement through much of the

1800’s, cropping first occurred on land cleared of timber or on prairie adjacent to woodlands.

Much of this land was adjacent to riparian areas, had significant slope, and thus was highly

vulnerable to erosion after plowing (Bratton and Smith, 1928). The thick turf of the broad flat

prairies was viewed less valuable for many decades and was mainly used for free-roam

grazing of livestock. Only as transportation means and roadways improved and alternative

building materials for making homes became more available did settlers move away from the

timbered riparian corridors and onto the prairie grasslands (O’Brien, 1984).

Landscape Transformation during the Late 1800’s

For the beginning of the second half of the 1800’s, a simple agrarian lifestyle was still

predominant throughout the SRB. Settlements remained small. Most families survived on

land parcels 10 to 40 acres (4 to 16 ha) in size (Bratton and Smith, 1928), though a few

wealthy landowners had emerged. Much of each family’s food continued to be raised or

grown on their own farm or was obtained by barter with nearby neighbors. Along with grain

production, almost every farm also had a small orchard and garden plot. Close by timber

sources were still heavily relied on for heating and construction. However, during the mid- to

late 1800’s mechanization was quickly advancing and allowed for more aggressive land

clearing and larger farming operations. Primary grain crops grown were corn, oats (Avena

sativa), wheat, and sweet sorghum (Sorghum vulgare). This mechanization period also led to

an ability to develop roadways that stimulated commercialization and economic

diversification, including grist mills, lumber mills, brick yards, and cash crops such as

tobacco (Nicotiana spp.), hemp (Cannabis sativa), and cotton (Gossypium spp.) (O’Brien,

1984). Frame and brick houses began replacing log cabins. Small villages and towns emerged

throughout the region, with Paris, Missouri, becoming the main commercial center of the

SRB. Growth and commercialization was also stimulated starting in the late 1850s with the

completion of the Hannibal and St. Joseph Railroad line in northern Missouri. Even with

transportation developments, little evidence exists of grain being shipped outside of the basin

in the 1800’s. During this time, cattle were fattened with locally-grown grain and herded into

the St. Louis, Missouri area for market (O’Brien, 1984).

Up through the Civil War, the wealthiest landowners owned slaves and had the largest

livestock and grain operations. While slave ownership was less than in other parts of

Missouri, the slave population in 1860 for the SRB counties was between 15-25% of the total

population (Howard, 1980).

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1900’s to Modern Times

Land Use Intensification Promotes Erosion

Early in the 1900s, the face of the Midwest rural landscape, including the SRB, began

a major transformation. People began migrating to the larger metropolitan cities, seeking for

a higher standard of living than what rural life offered. This resulted in shrinking

communities and increased farm size (Bratton and Smith, 1928). Investment in rural

infrastructure slowed and some smaller communities turned into ghost towns. At the same

time, improvements in agricultural mechanization helped affluent farmers expand their

enterprises, becoming wealthier. Poorer, less-efficient farmers went out of business. The

larger farms integrated grain feed production and livestock (cattle, hogs, and sheep)

operations. Extensive flat grasslands were plowed and put into grain production for the first

time. During this period, corn, oats, wheat and a new crop, soybean (Glycine max) was

typically grown. During World War I, corn grain prices soared, and so did corn acreage.

These changes in the agricultural landscape resulted in major shifts in land use and

cultivation intensity for all of Northeast Missouri. Intensified grain crop agriculture had an

immediate and dramatic increase on soil erosion that impacted total runoff and water quality

into rivers and streams of the SRB. Prior to the Civil War, much of the Salt River was noted

to have clear, clean water during most of the year (Howard, 1980). Fish and mussels were

plentiful. By the 1930’s, the streams were sediment filled and fish life was disappearing. Not

by coincidence, the first soil erosion plot research in the U.S. was initiated in 1917 on similar

soils on the campus of University of Missouri in Columbia, Missouri (just 80 km, or 50 miles

SE of the SRB) (Troeh et al., 1980). Multiple and damaging rainfall events caused severe

flooding, soil erosion, and property damage between 1926 and 1936. The impact was

devastating for croplands. An erosion survey in 1934 disclosed that 25% of cropped acres in

this region had lost from 75% to all of its topsoil, exposing the subsoil claypan (Bennett,

1939). Grain crop yields for many fields actually declined by more than 50% below yields

obtained in the late 1800’s.

Channelization and Drainage

While sod busting on the broad upland prairies for expanding cropland undoubtedly

had a major role in increased runoff and accelerated erosion, it coincided with other

significant hydrology-altering human activity, namely timber clearing, drainage, and

channelization. Spring and early summer floods commonly vexed farmers and homesteaders

on the bottomlands of northeast Missouri rivers, including the Salt. Their natural courses

tended to be tortuous and the common resolve was to develop straight ditches or canals

centrally located in the valleys for enhanced drainage. These were primarily occurring in the

forested bottomlands of the Salt River and its tributaries. Drainage projects in Northeast

Missouri began sometime in the first decade of the 20th

century when drainage districts were

formed for the major Northeast Missouri Mississippi River tributaries such as the Fabius, and

Wyaconda (Ball, 1913) and the Chariton (available from the Missouri Department of

Conservation at http://mdc.mo.gov/landwater-care/stream-and-watershed-

management/missouri-watersheds/chariton-river). Drainage districts were empowered by

State law (Missouri, State of, 1909) to authorize drainage districts organized by landowners.

These districts organized the tasks of surveying, designing, and commissioning the work to

be done by private dredging companies (Mason, 1984). Drainage districts were formed prior

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to 1909 on the Chariton (White, 1910), in 1908 on the North Fabius (Roberts and Bumbarger,

1908), and around 1913 on the Wyaconda (Ball, 1913). These local drainage authorities

levied taxes on landholders in the drained areas for repayment of bonds sold to subsidize

these projects.

For the SRB, enhanced drainage through channelization was especially focused on the

North Fork, one of the largest of the Salt River tributaries. Major sections of the river were

bypassed by drainage canals through the bottomlands, straightening out the meandering

natural stream system. Dredging in the main Salt River channel also occurred around this

period (Schrader et. al., 1917) (See Figures 3 and 4). Dredging produced a corresponding

increase in flow gradient that accelerated stream scouring. Channelization continued beyond

1950 as additional stream sections were straightened in more difficult terrain using modern

construction equipment.

These artificial drainage canals, now considered the actual channel of the river, are

now much different than they would have been at the time of construction. Design

specifications for ditches dug on the Salt River tributaries were probably similar to those for

the Chariton (White, 1910) and North Fabius (Roberts and Bumbarger, 1911). These were

dug to a depth of 2.5 m with a 6 m bottom width and having sides sloping at a 1:1 pitch. Now,

because of bank erosion and scouring, these channels are typically 3 to 5 m deep and 30 to 80

m wide with nearly vertical banks. It was the intent of those involved in these projects that

the artificial channels would increase in dimension and flow capacity and they have

succeeded. In the case of the Chariton River, the base level of the canal was already below

that of the original riverbed in less than ten years (White, 1910).

Altogether, these alterations in the length and base level of the Salt River and its

tributaries created significant change in the hydrology and stability of the landscape. Though

the overall goal of allowing excessive runoff to quickly move into and through stream

systems seemed necessary as agriculture intensified, there have been many unintended

consequences to the Basin. The most obvious impact has been the promotion of erosion due

to accelerated runoff. Channelization for improved drainage, working in concert with deep-

tillage cultivation practices on cropped fields, promoted severe erosion in many areas of the

landscape. With enhanced water flow in streams and ditches, deep gouges in the topography

have been caused by headcutting (or sometimes called “nickpoints”) backwearing up into the

landforms. Some of these headcuts unchecked by modern era conservation measures have

migrated into the upper reaches of the landscape. The straightened channels and unnatural

curves continue to promote severe bank erosion (Willet, 2010).

The GCEW is one of the headwater tributaries of the Salt and did not receive

significant channelization. However, major channelization and dredging occurred

downstream, and in other nearby watersheds. The degree to which these impacts have

propagated into GCEW is not clear. Like similar river systems in the region such as the

Blackwater (Emerson, 1971) and the Chariton (available from the Missouri Department of

Conservation at http://mdc.mo.gov/landwater-care/stream-and-watershed-

management/missouri-watersheds/chariton-river), the Salt River has not stabilized from the

channelization and drainage work that was initiated about a century ago. These landscape

alterations will likely continue to cause sediment-related water quality problems into the

foreseeable future.

11

Early Conservation Initiated

Government-directed public works projects addressing national erosion issues

resulted in the creation of the Soil Erosion Service within the Department of Interior in 1933.

That program was made permanent and transferred in 1935 to the newly formed Soil

Conservation Service (SCS) within the Department of Agriculture (Troeh et al., 1980).

Because of the severe gully and sheet erosion that quickly stripped away the limited topsoil

of the SRB, H.H. Bennett declared the need for conservation practices on these soils as

“urgent” (Bennett, 1939). In the late 1930’s the “McCredie project” (near present day

Kingdom City, in Callaway County, MO) was initiated by the SCS on 25,000 acres (10,000

ha) to assess and then implement soil conservation practices on 100 different farms (Bennett,

1939). This project was adjacent to the southern edge of the SRB and undoubtedly helped

stimulate new conservation practices within the Basin. Practices employed were diverse and

targeted the most obvious problems. They included contour tillage, contour strip cropping,

buffer strips, terracing, contour furrowing within pastures, gully control, impoundment,

fencing, construction of vegetated channels for runoff mitigation, liming, manure applications,

cover crops, green manuring, and retiring of highly eroded lands to trees, grass, or native

plants (Bennett, 1939). Additionally, the SCS established in 1937 a soil conservation

experiment station called the Midwest Claypan Experimental Farm near McCredie, MO

(Jamison et al., 1968), that became a primary runoff and erosion research location for the

University of Missouri Experiment Station and the USDA Agricultural Research Service for

the next 60 years. A major contribution of this station was data used in implementing the

Universal Soil Loss Equation (USLE) and its derivatives (Wischmeier and Smith, 1960),

which continue to impact conservation in the SRB and elsewhere. Results from these

demonstrations and research projects were recognized by famers and business leaders within

the region (Bennett, 1939).

Modern Era Farming Practices and Specialization

The trend of fewer and larger farms continued through much of the 20th

century as

motorized equipment increased in size and efficiency. In 1950, agriculture employed 33% of

the labor force in the Salt River area (Clarence Cannon Dam and Reservoir: Environmental

Statement, 1975). Over the next two decades, the number of cropped acres increased almost

10% while the labor force employed by agriculture decreased to less than 15%. During the

1970’s and early 1980’s, many small to medium-sized farms abandoned animal operations

because of poor profitability and focused on grain production. For Missouri farmers, debt

nearly tripled during the 1970’s and 80’s, resulting in a nation-leading number of farm

bankruptcies in 1985 (Demissie, 1986). Also during this period, a much higher percentage of

farmland became leased instead of owner-farmed. Predominant crops grown during this time

were soybean, corn, sorghum, and wheat.

During the last four decades of the 20th

century, farming operations evolved in

response to newer cost- and time-efficient technologies, and better-engineered equipment.

Further, awareness grew for enhanced soil and water conservation (addressed in next section).

Important changes that had direct impact on the landscape included: 1) seed bed preparation

changed from plow/disk to mulch till or no-till; 2) crop selection changed from rotations that

included three or more crops that often used cover crops to two-crop rotations (often corn-

soybean, sorghum-soybean, or wheat-soybean); 3) weed control changed from mechanical

cultivation to herbicides, with plant-active herbicides replacing many soil active herbicides in

12

the later years; 4) farm tractors and combines changed from 4-6 row power capacity and size

to 12-24 row power capacity and size; 5) crop genetics changed to include cultivars and

varieties with higher yield performance, greater pest resistance, and genetically-engineered

protection from certain herbicides to allow for a broader spectrum of weed control; and 6)

more synthetic fertilizers and less manure nutrients, wide-spread use of soil and plant

diagnostic tools, and better application equipment with more accurate control of rates (See

Figure 5).

Modern Era Environmental Challenges Identified and Response

In the latter half of the 20th

century, understanding of environmental issues nationally

evolved to include many challenges other than just runoff and erosion. These new challenges

became apparent in part because of active public-funded support for research and monitoring

programs. This awareness was also made possible because of advancement in scientific

instrumentation that allowed for quantification of chemical contaminants at smaller and

smaller concentrations. Measurement of chemicals in air, soil, and water mediums went from

parts per thousand to parts per billion in just a few decades. Increased concern for

environmental issues led to the formation of the U.S. Environmental Protection Agency in

1970. In 1972 major enhancements were made to the federal Water Pollution Control Act,

later renamed the Clean Water Act. This legislation more clearly defined the federal

regulatory structure for defining water quality standards, developing control programs,

permitting of discharge, and planning that addressed point and nonpoint source problems of

pollutants within U.S. waters (available from U.S. EPA at

http://www.epa.gov/lawsregs/laws/cwahistory.html). Since then the Clean Water Act has

been amended on numerous occasions, and other legislation was signed into law, which

expanded legal authority for addressing these concerns. Initially legislation focused on human

health, but with time broadened to embrace numerous ecological balances disrupted by

anthropogenic activity.

Concurrent with regulatory steps taken during the latter half of the 20th

century, more

comprehensive education, extension, and farmer programs and services followed the

improved scientific understanding of human interactions with the environment. This was

evidenced by the renaming of the SCS in 1994 to the Natural Resource Conservation Service

(NRCS), to reflect a broadened scope of landscape and watershed concerns this agency now

addressed (available from the USDA NRCS at

http://www.nrcs.usda.gov/wps/portal/nrcs/main/national/about/history). Earlier in the century,

the model of empowering local farmers and ranchers to develop and implement practical and

specific conservation practices was promoted through organizing conservation districts, an

idea conceived by H.H. Bennett when Chief of the SCS. His philosophy was land owners

have the experience and resolution to make necessary management changes to preserve their

lands, and given the technical help and engineering suggestions, they should be trusted to do

so (available from the Missouri Department of Conservation at

http://www.maswcd.net/historydoc.htm). Relative to many states in the Union, Missouri’s use

of conservation districts has been stellar. This has in large part been because of a one-tenth-

of-one-percent parks, soils, and water sales tax passed by Missouri voters in 1984, and

renewed three times since (available from the Missouri Department of Conservation at

http://www.dnr.mo.gov/env/swcp/history.htm). The majority of the soil and water portion of

this tax has been used to assist agricultural landowners through voluntary programs,

prioritized by the statewide Soil and Water Districts Commission, but administered through

13

the 114 county-level Soil and Water Conservation district boards. This tax along with other

state and federal soil conservation programs and education initiatives (e.g., conservation

tillage and NRCS’s Conservation Reserve Program), have been credited for helping Missouri

to have the greatest decline in soil erosion rates when compared to other states (i.e., 171

million tons in 1982 to 95 million tons in 1992) (http://www.maswcd.net/historydoc.htm).

Prior to 1982, Missouri had the second highest rate of erosion in the nation and now it ranks

seventh.

These modern-era descriptions of federal and state soil and water conservation

initiatives are applicable for what has taken place in the runoff-prone landscape of the SRB.

With current grain cropping on about ~45% of the Basin acres (Lerch et al., 2005), excessive

runoff and the associated environmental problems persist in this watershed. Notable issues

from these grain crop acres include sediment movement into waterways and the Mark Twain

Lake, nutrient loss off fields resulting in eutrophication of lakes and streams, decreased crop

productivity with lost topsoil, and pesticide movement from fields into water bodies.

Livestock grazing occurs on ~30% of acres, with associated environmental issues.

Unprotected streams within grazed lands result in damage to stream banks, loss of riparian

habitat, and bacterial and nutrient contamination of steam water. Concentrated animal feeding

operations (CAFOs) and their associated challenges have also increased since 1990, with

over 15 facilities rated at 3000+ animal unit equivalents in the SRB in 2010 (available from

the Missouri Department of Conservation at http://www.dnr.mo.gov/env/wpp/afo.htm).

CONCLUSION

Examination of the genesis of the soil landscapes and how human activity has greatly

altered landscape resources is valuable for interpreting watershed research as found in this

series of papers on GCEW and SRB. Attempting to understand current land use activities and

condition of natural resources and formulating future management plans without the

historical context is like beginning a novel by opening it at the middle. Here we have

described how key landscape-dependent soil features, including thickness of loess and depth

of and clay content in the argillic peak, are important hydrologic drivers for watershed

vulnerability. Soil loss from erosion has significantly altered many fields cultivated for grain

crop production. Soil resources lost cannot be restored to pre-European settlement conditions.

Greatest devastation to the landscape occurred during the first half of the 20th

century, when

intensive rainfall followed deep tillage and/or extended drought periods, and major changes

in stream channels destabilized the landscape. Research and demonstration projects have

been essential for understanding the relationships of soil landscapes, hydrology, weather, and

anthropogenic activity. Early conservation responses focused on poor practices and

determining land use alternatives to help prevent further landscape resource degradation

while later responses also included a goal of restoring lost ecosystem function into the

landscape. Soil and water conservation practices have undoubtedly improved watershed soil

and water quality, but signs of impairment persist.

14

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Figure 1.

Geographic and hydrologic context of long term agroecosytem research in the Goodwater

Creek Experimental Watershed and the Salt River Basin. (Columbia, Missouri, Lat. 38.95°,

Lon -92.33°; Hannibal, Missouri, Lat. 39.71°, Lon -91.35°).

19

Figure 1.

The three primary parent materials in the study region are loess, glacial till, and alluvium.

Thick deposits of glacial till up to 100 meters are overlain with windblown loess. Sediments

from these sources are found in alluvial fill in valleys and floodplains.

20

Figure 3.

An aerial image taken Oct 14, 1950 from a portion of the North Fork of the Salt River

northeast of Clarence, MO shows a continuous 5.4 km section of channel dug in the early

1900’s. The channel length was reduced to less than half of the original 13.6 km. Compared

to Photo 2, part of the river had not been channelized by this date.

21

Figure 4.

A 2010 aerial image of the same area as Photo 1 showing channelization of the North Fork of

the Salt River. A comparison of these two photos shows the extent of channelization after

1950. After 1950, an additional 5.2 km section of canal was dug, which straightened 12.7 km

of original stream channel. In all, more than 65 km of channel were dug on the North Fork

above Clarence Cannon Dam, reducing overall channel length by about twice that amount.

22

1939 1956 1968

1982 1990

1939 1956 1968

1982 1990

Figure 5.

A sequence of aerial photos obtained from the USDA Farm Service Agency archives

illustrate some of the important changes that occurred between 1930 and 1990 for a typical

quarter section field (~160 acres, 64 ha) in the Salt River Basin: 1) larger fields were created

by merging of smaller fields; 2) loss of farmsteads as farmers managed larger acreages; 3)

loss of integrated grain and animal production systems; and 4) return of indigenous trees

along waterways and field boundaries.