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Long-term Agro-ecosystem Research in the Central Mississippi River Basin, USA: 1

Introduction, Establishment, and Overview 2

3

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

Kitchen, Stephen H.

Anderson, Claire

Baffaut, 4

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

Kremer, Earl D.

Vories, D. Brent Myers, 5

Robert Broz, Randall J. Miles, and Fred J. Young 6

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The material below is supplemental to the main article section titled: 8

Geophysical Setting and Anthropogenic Changes 9

Contributing to this section were the following authors listed in the main paper: 10

D. Brent Myers, Newell R. Kitchen, Stephen H. Anderson, Randall, J. Miles, Fred J. Young 11

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INTRODUCTION 13

This material is supplemental to the section of the same title in the Overview paper 14

of a series that documents data and research from the Goodwater Creek Experimental 15

Watershed (GCEW). The GCEW has been part of a larger USDA-Agricultural Research 16

Service (ARS) watershed network for more than 40 years and has a valuable store of long-17

term watershed hydrological, meteorological, and water quality data. For the data and 18

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

2), 19

selected as the Central Mississippi River Basin site in the ARS Long-Term Agro-Ecosystem 20

Research (LTAR) network, an understanding of the natural history and anthropogenic 21

influence is needed to provide a foundation for developing credible scientific interpretation. 22

The natural history, including genesis of the landscape and soil resource, is needed for a 23

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complete understanding of current natural processes active and important in the region. 24

Anthropogenic activity within the region also needs documentation in order to comprehend 25

how man’s activities have impacted soil and water resources. While much of the 26

information found here exists in the literature, it has been widely scattered. Further, this 27

summary and synthesis allows for a more comprehensive understanding of the past and 28

current interactions between watershed resources and land management, and for 29

development of future comprehensive management strategies. 30

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GEOPHYSICAL SETTING 32

Agroecosystem research must derive conclusions about best management practices 33

based on a clear picture of the soil and landscape properties, and processes at work. It is a 34

central goal of such research to manage systems in such a way to sustain productivity on 35

these irreplaceable resources. The Central Mississippi River Basin, the SRB, and the GCEW 36

occur on a post-glacial landscape along the southernmost edge of the ancient Laurentide Ice 37

sheet. The features and properties of these landscapes have interacted with management 38

systems and land uses resulting in both productive agricultural output and key failures in 39

ecosystem function. These failures are documented for Northeast Missouri, the SRB, and 40

the GCEW in this paper series and include soil erosion, stream sedimentation, and 41

ground/surface water nutrient and agrochemical pollution. Specific soil-landscape properties 42

are critical drivers for these vulnerabilities including; fractured glacial till, gently sloping 43

incised and highly erodible topography, slowly permeable argillic horizons, an intermittent 44

perched water table (episaturation) causing subsurface lateral flow, and the spatial patterns 45

of these features in the landscape. In this section we describe these features and properties 46

and discuss the landscape processes that impact agroecosystem function. 47

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Geographic and Hydrologic Context 48

The study region ranges from the field scale to large watersheds but are applicable to 49

much of Northern Missouri. The findings of these works are also potentially applicable to 50

parts of Southern Iowa, and Southern Illinois, because these regions have similar soil 51

landscapes and land uses. The Central Mississippi River Basin encompasses more area than 52

this, representing, in concept, landscapes of the southern corn belt where thin loess over till, 53

or thin loess over residuum occurs. These landscapes can be generally described as 54

dissected upland plains with alluvial benches, floodplains, and riparian corridors. The more 55

specific Northeastern Missouri context of this paper series occurs on the landscapes 56

straddling the Grand Divide of the Missouri and Mississippi rivers (Figure 1). The SRB is 57

composed of 3 major basins, the North and South Forks of the Salt, and the Salt. Within the 58

South Fork basin is the Long Branch watershed which contains the GWCEW. 59

General Chronostratigraphy 60

The character and function of Northeast Missouri’s soil-landscapes arise from three 61

key materials beginning with the underlying sedimentary bedrock, formed during the 62

Carboniferous period (359 Ma to 299 Ma). These layers help define the general topography 63

and drainage network. Above that bedrock, multiple layers of moderately dissected 64

Pleistocene epoch (2.5 Ma to 11.7 ka) glacial tills define the visible landforms. Finally, soil 65

profiles with important hydrologic control are formed in till, and mid-late Pleistocene (126 66

ka to 11.7 ka) pedisediments and loess. Pedisediments are comprised of a basal mix of 67

glacial till and loess after glacial retreat and during initial loess deposition. The loess is 68

distributed in a more or less continuous mantle of variable thickness except on areas of 69

significant slope or instability where the underlying pedisediment, till, and sometimes 70

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bedrock may outcrop. The remaining key parent materials are alluvial deposits of eroded till 71

and loess in valleys and floodplains. 72

Bedrock Geology 73

The overall topographic trends and locations of the major divides and river systems 74

in Northern Missouri are a vestige of the pre-glacial landscape (circa 2.5 Ma). That 75

landscape has been buried, but was developed in residuum of the same sedimentary geology 76

as the current bedrock. This bedrock is the remains of the Cambrian Platform which formed 77

from materials deposited beneath shallow seas which fluctuated in extent across central 78

portions of North America. The Cambrian platform in northern Missouri includes carbonate, 79

shale, and sandstone rock (Ruhe, 1969; Allaby and Allaby, 1999; Grimley, 2000) and 80

significant coal deposits, but is predominantly limestone. This bedrock outcrops on some of 81

the steeper landforms along the lower reaches of major drainages and provides some control 82

on the elevation of these channels. The Cambrian Platform in northern Missouri was 83

truncated to the Pennsylvanian or Mississippian layers by glacial activity. The hydrologic 84

function of the bedrock has very little impact on the glacial till aquifer but the bedrock 85

topography guided the route of glaciers, and their subsequent drainage networks. These 86

drainage networks still exist today. 87

Pleistocene Glacial Deposits 88

Just above the bedrock are thick deposits of glacial till and outwash sediments that 89

were laid down during the Pleistocene epoch. Glacial till accumulated in multiple layers up 90

to 100 meters thick and averages about 40 meters thick across the GCEW (Sharp, 1984). 91

Glacial advances repeatedly terminated in Central Missouri, constrained by increasing 92

elevation at the margin of the Ozark dome. This limitation set the current course of the 93

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Missouri River. The maximum advance of the pre-Illinoisan Laurentide ice sheet occurred 94

about 2.4 Ma (Rovey and Balco, 2010), but was reached multiple times during the 95

Pleistocene, crossing the study region with distinct layers of till deposits. Northern Missouri 96

has been glacier free since about 0.2 Ma ago. 97

The chronostratigraphic record of the Pleistocene contains several identified and 98

dated materials. Just above the bedrock, pre-Pleistocene residuum, fireclay deposits, a 99

buried gelisol (2.58 to 2.47 Ma) formed in a periglacial environment (Rovey and Balco, 100

2010), and peat deposits (Blanchard and Donald, 2005) are all observed. The Atlanta till 101

formation (2.47 Ma), represents the earliest evidence of glaciation, and is overlain by the 102

Moberly (1.2 Ma), and the McCredie formations (0.75 to 0.2 Ma). The Moberly formation is 103

not currently differentiated. Three till subunits are recognized within the McCredie 104

formation, they are the Fulton member (0.75 Ma) the Columbia member (0.4 to 0.2 Ma), 105

and the Macon member (0.2 Ma). 106

These periods of active glacial advances (stadia) were alternated with regressionary 107

interstadial periods. The most recognizable features of these warmer ice free periods are 108

paleosols. Paleosols are named and consistently present in the chronostratigraphic record 109

across the region, though their spatial coverage is intermittent and they are not well 110

correlated in the literature. Their preservation is dependent on the stability of the landform 111

and the site-specific erosion processes occurring before burial in the next glacial stage. The 112

major interstadials in which paleosols formed occurred between the Moberly and McCredie 113

deposits and on top of the McCredie formation. The most recent paleosol, the Yarmouth-114

Sangamon is widely observed and represents soil formation during the middle and late 115

Plestocene (0.2 Ma to 12 ka). Northern Missouri remained glacier free during the Illinoisan 116

(0.3 to 0.12 Ma) and Wisconsinan (0.1 Ma to 25 ka) glacial stages. The current 117

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geomorphology developed during this open period, a net erosive environment which led to 118

greater incision of the glacial till and caused the overprinting of the Sangamon paleosol onto 119

the Yarmouth. 120

Till composition across Northern Missouri is a mix of glacially abraded geologic 121

materials from local and northern latitudes. Composition of the till is vertically and spatially 122

heterogeneous, varying in part by the era of deposition. The older Atlanta and Moberly 123

formations are more influenced by the mineralogy of local bedrock. Thus, the clast lithology 124

in these deeper layers is 70 to 100% sedimentary in origin (Rovey and Kean, 1996; Roy et 125

al., 2004). Upper till layers are influenced by mineral sources further north than central 126

Minnesota and contain 45 to 60% crystalline lithology. These glacial deposits were laid by 127

a combination of mechanical force and melt-water runoff which occurred in a complex 128

overlapping manner resulting in layers and pockets of material with spatially variable 129

textures and density. In general the till texture is loamy and structure ranges from strong, 130

very coarse prismatic to structureless massive. Sand lenses and fractures are sporadically 131

present leading to large variability in saturated hydraulic conductivity (Ksat) of the tills. 132

Sharp (1984) reviews the available Ksat data from studies in Northern Missouri. These 133

studies demonstrated several orders of magnitude range in Ksat for glacial till layers (1.2x10-

134

9 to 2.0 x10

-2 m s

-1); also demonstrating that in-situ tests typically had larger Ksat than core 135

samples. Blanchard and Donald (1997) described the till in the GWCEW as ‘a fractured 136

system with a low permeability, high porosity matrix’. They further documented that 137

paleosol argillic horizons can have an impact on the hydrologic system finding that two 138

paleosol features within the till had relatively smaller Ksat than till layers, likely due to the 139

larger concentrations of pedogenic clay. 140

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Pedisediment, Colluvium, and Alluvium 141

The cessation of glacial activity in Northern Missouri at around 0.2 Ma pre-dates 142

surface loess deposits and left a long time interval for soil formation and erosion. The result 143

of this is the commonly seen Sangamon paleosol at the till interface. Truncation of the till 144

and paleosols occurred in many places due to erosion and long exposure, leaving a pediment, 145

or erosion surface (Schaetzl and Anderson, 2005). Subsequent loess deposits occurred atop 146

this till derived material over a time frame long enough for bioturbation, soilfluction, frost 147

action, and other in-place processes to mix coarser materials up into the first increments of 148

the loess deposit. The result of this basal mixing process is a ubiquitous distribution of 149

pedisediment at the glacial till-loess contact. The pedisediment contains an increase of 3 to 5 150

percent fine sand relative to the overlying loess material, but vanishes in a diminishing 151

gradient upward into the loess. Pedisediment is quite common in most upland soil profiles in 152

the GCEW from summits to footslope positions. Colluvium is frequently seen in concave 153

footslope positions in areas with steeper dissection. These areas are influenced by 154

soilfluction and erosion occurring upslope to the immediate area. Alluvium is common in 155

the riparian corridors between the upland landforms. The alluvial fill derives from three 156

major timeframes and processes, glacial recession, post-glacial pediment formation, and the 157

Illinoisan and Wisconsinan era influx of loess into the system. Terrace bench positions at 158

valley margins are derived consequence of the earlier processes while the current 159

floodplains are narrower due to less water influx in the post-glacial period, and reduced 160

sediment delivery in the Holocene era (Bettis et al., 2008). Alluvium in the GCEW area is 161

silty to loamy in texture with little sand content compared with larger river basins. 162

Late Pleistocene Loess 163

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As noted above, glaciers covered much of the upper and central Midwest during the 164

Illinoisan and Wisconsinan glacial stages while Northern Missouri remained glacier-free. 165

Nevertheless, the deposits of these glaciers were eroded by the meltwater created in their 166

recession, making their way to Northern Missouri in the major river systems. This eroded, 167

silty material was moved during fluctuating melting conditions and, intermittently deposited 168

on the Missouri River flood plains (Schultz and Frye, 1965; Ruhe, 1969; Follmer, 1983; 169

Guccione, 1983). The late Pleistocene and early Holocene periglacial environment was cold 170

and arid with a westerly to southwesterly paleowind (Muhs and Bettis, 2000). Exposed 171

fluvial sediments were transported by wind erosion and re-deposited on downwind 172

landforms and left as loess deposits. The chronostratigraphic result of the Wisconsin glacial 173

regression is the most recently deposited parent material, the Peoria loess. Many of the 174

modern soils of the Central Claypan Areas in both Missouri and Illinois, including the 175

GCEW, are formed in this layer that was deposited during the timeline of 25 to 7 ka. 176

Smectites and mixed-layer illite smectites are the primary clay-sized mineral component of 177

the Peorian loess (Nizeyimana and Olson, 1988; Burras et al., 1996; Young and Hammer, 178

2000). 179

Regionally, thickness of the silty loess veneer varies with distance from its source 180

and was distributed anisotropically according to prevailing paleowinds (Ruhe, 1969; Muhs 181

and Bettis, 2000). The study region is on the east-central side of Missouri with most of the 182

state separating it from the southerly course of the Missouri river on the western border of 183

the state. This portion of the river is perpendicular to the paleowind and loess thickness 184

decreases from as much as 30-meters in the deep loess hills adjacent to the Missouri and 185

Mississippi rivers to less than 2-meters on broad flat interfluves in the Missouri Central 186

Claypan Region (Guccione, 1983). 187

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Soil-Landform Relationships 188

Parent materials and soil morphology in Northeast Missouri are strongly correlated 189

to landscape position and geomorphology (Figure 2). Key features with landscape 190

dependence are thickness of loess, and depth of and clay content in the argillic peak. Local 191

landscape processes have caused the loess cap to vary in thickness systematically with slope 192

and landform (Ruhe, 1969). Maximum accumulation of loess occurs at summits and on 193

divides. Because of the flat topography, runoff does not accelerate; thus the detachment and 194

transport of soil particles is minimal (Jamison et al., 1968). As slope increases from 195

shoulder to backslope, the surface is less stable. Gravity, soilfluction, and runoff cause 196

slumping and detachment, and loess thickness decreases. Loess may be eroded away 197

entirely at some steeper incised landforms, exposing pedisediment, or the surface of the 198

glacial till. These processes also caused the accumulation of colluvial hillslope sediments 199

composed of the eroded silt, pedisediment, and till in concave landscape positions (Young 200

and Geller, 1995). 201

Clay content in these soil profiles has a peak-shaped continuous depth function 202

(Myers et al., 2011). The depth and amplitude of the profile peak clay content also varies 203

systematically in these landscapes. Summit positions exhibit the most, abrupt argillic 204

horizons having the greatest clay content and form entirely in loess. Down-slope positions 205

have a larger portion of silt and sand material arising from pedisediment and glacial till 206

within 1-m from the surface. The coarser pedisediment typically does not influence the 207

summit position until >1 m depth while the shoulder position can have pedisediment at 208

about 75 cm. Depending on the history of erosion, the backslope position can have loess, 209

pedisediment, or glacial till at the surface, and frequently has all of these materials within 210

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the top 1 m of the profile. The footslope position typically has loess-derived colluvial 211

sediments and pedisediments over a deeper argillic horizon. 212

Terrace, creek, and river bottom soils are a smaller portion of the landscape than 213

upland positions, but are some of the most productive soils in this region as the silts and 214

loams dominate the soil profile. Terraces tend to have similar profiles to summit positions. 215

Though they are the result of glacial erosion and fluvial deposition, they existed as stable 216

landforms during the late Pleistocene (Bettis et al., 2008) and have a thick loess covering. 217

Below terrace positions, the current flood plains tend to have a very diverse range and 218

heterogeneous distribution of fluvial sediments with clayey to sandy texture. 219

Claypan Genesis 220

The claypan feature prominent in the study area is an extreme variant of the peak 221

shaped accumulation of clay content in argillic horizons commonly seen in many Alfisols. 222

This argillic peak is formed due to chemical and physical weathering processes. Subsequent 223

to deposition, weathering of these collected materials has occurred in the temperate, 224

subhumid environment of the Holocene epoch (Ruhe and Scholtes, 1956). Because of the 225

thin loess deposit (1 - 2 m), flat topography, finer particle size, and the Holocene climate, 226

the soil minerals have undergone intensive weathering (Bray, 1935; Jamison et al., 1968) 227

relative to thick loess deposits. 228

The claypan feature has both physical and chemical provenance. Chemical 229

weathering processes include chemical transformation of primary and secondary minerals, 230

and neo-formation in-situ from dissolved mineral components left behind as 231

evapotranspiration seasonally dessicated the profile (Bray, 1935; Nikiforoff and Drosdoff, 232

1943; Whiteside, 1944; Wambeke, 1976). Physical translocation and accumulation of clay 233

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sized particles also occurs. A constructive interference develops in the argillic horizons, 234

whereby illuviated clay films plug successively larger and larger pores and gaps between 235

structural peds (Thorp et al., 1959; Yaalon, 1983). 236

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

) is complemented by 237

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

) (Bray, 1935; Jamison et al., 238

1968). Seasonal impermeability of the argillic zone causes a perched water table to form 239

directly above it. Solvent action and a fluctuating redox state are dominant in this part of the 240

soil profile. The felsic and mafic primary minerals found in the loess parent material are rich 241

in base cations, but they are largely weathered away from this portion of the profile and 242

degradation components of secondary minerals are shifted towards acid cations (Bray, 1935; 243

Albrecht, 1967; Lindsay, 1979). The remaining material in the eluviated zone has a larger 244

proportion of silt-sized quartz and other stable aluminosilicates with small CEC. Due to the 245

production of acid cations in weathering the eluviated zone has a pH of about 4.5. Large 246

iron-manganese concretions form here due to seasonally alternating redox state concomitant 247

with saturation and dessication. The coarser texture of the E horizon and impermeability of 248

the underlying clay leads to subsurface lateral flow (episaturation) and seepage downslope. 249

These are key hydrologic features of this landscape that have important impacts on water 250

quality and crop productivity. 251

252

ANTHROPOGENIC CHANGES 253

Historical information relative to settlement and associated land management 254

changes is critical for an accurate understanding of how water and soil quality changes 255

occur in watersheds. This history represents the Central Mississippi River Basin but 256

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

2), of 257

which the GCEW is a sub-basin. Further, this historical sketch is not intended to cover all 258

human activities, but is a description of those elements having the most significant impact 259

on land use, watershed hydrology, soil and water resource impairment, and response with 260

conservation practices. 261

262

Human Activity During Prerecorded History 263

Prior to European settlement, Native American habitation of the SRB likely 264

followed the archeological-derived timeline found in much of the U.S. Midwest area: 1) 265

Paleo – Indian period (ca. 12,500-10,000 B.P.) characterized with nomadic bands of hunters 266

of ice-age mammals (early only), deer, elk, buffalo, and turkey, and later in this period 267

gatherers of berries and nuts; 2) Archaic Culture period (ca. 10,000-3,500 B.P.) with 268

predominantly small upland villages where hunting, fishing, and foraging were replaced by 269

some agricultural food production; and 3) Woodland Culture period (ca. 3,500-700 B.P.) 270

characterized by increased advancement and utilization of pottery, weaving of plant fibers, 271

and agriculture cultivation practices, leading to long-term settlement and inter-tribal trading 272

(Chapman and Chapman, 1983). Artifacts of all three periods were documented prior to 273

construction of the Clarence Cannon Dam that created Mark Twain Lake within the SRB 274

(Henning, 1975). Leading up to and overlapping with the time when European fur trappers 275

and settlers arrived in the SRB, various tribal groups occupied the area, surviving mostly on 276

hunting and gathering, and less on agriculture. Of note were the Sauk and Fox tribes that 277

had migrated to the basin from the Great Lakes region in the mid-1600s (Chapman and 278

Chapman, 1983). As a result of the 1803 Louisiana Purchase, these Indian tribes 279

relinquished rights to the U.S. Government in an 1804 treaty a large area west of the 280

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Mississippi River that included the SRB. Significant tribal factions ignored the treaty for 281

several decades and therefore land ownership was reaffirmed by a second treaty in 1824 282

with the State of Missouri. 283

284

Early 1800’s Anglo-European Settlement 285

When Anglo-European settlers first moved into the SRB area, it was a combination 286

of deciduous forests (oak-hickory) and prairie grasses. However, what attracted the first 287

settlers was the presence of salt springs (salt being a scarce commodity on the frontier), and 288

from such the river received its name (O’Brien, 1984). The small salt mining operations, 289

however, never provided lasting strongholds. These operations were frequently attacked by 290

Indians and later failed because of less-expensive salt imports. Compared to other parts of 291

the region, movement of settlers into the basin was inhibited because of poor transportation 292

routes. For many years un-mapped game and Indian trails were all that were available 293

(Henning, 1975). In the 1820’s these trails were gradually worn into wagon roads and sparse 294

settlement became widespread throughout the Basin. Land purchase and settlement 295

expanded rapidly from 1827-1836 (a period of national economic prosperity), with ~80% of 296

the public land within the Basin purchased during this decade (O’Brien, 1984). Additional 297

sale of public lands to settlers was completed by 1860. 298

Most settlements started as clusters of three-to-five, usually-related families. Two 299

natural resources guided these settlers for homestead site selection: year-round water and 300

abundant timber. Because of high-water flooding in the bottomlands adjacent to streams, 301

homesteads were usually upslope from waterways in or adjacent to timber (O’Brien, 1984). 302

Stream water was needed for human and livestock consumption, as well as used for washing 303

purposes. Fish also helped meet food needs. Hand-dug, rock-lined wells were often 304

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constructed near the homestead for a cleaner drinking water source than stream water. 305

Readily-available timber was essential since it was the principle resource used for home and 306

barn construction, tools, cooking, and heating. Early homesteading on the nearly-flat prairie 307

was mostly absent since these grasslands lacked critical water and wood resources. 308

Since transportation was restricted, commerce was also limited and settlers generally 309

lived a simple agrarian lifestyle growing corn (Zea mays), wheat (Triticum aestivum), rye 310

(Secale cereale), pumpkin and squash (Cucurbita spp.), and garden vegetables. Typically 311

each homestead also had a few livestock serving as work animals and helping meet food 312

needs. Because an ample timber source was a necessity for settlement through much of the 313

1800’s, cropping first occurred on land cleared of timber or on prairie adjacent to woodlands. 314

Much of this land was adjacent to riparian areas, had significant slope, and thus was highly 315

vulnerable to erosion after plowing (Bratton and Smith, 1928). The thick turf of the broad 316

flat prairies was viewed less valuable for many decades and was mainly used for free-roam 317

grazing of livestock. Only as transportation means and roadways improved and alternative 318

building materials for making homes became more available did settlers move away from 319

the timbered riparian corridors and onto the prairie grasslands (O’Brien, 1984). 320

321

Landscape Transformation during the Late 1800’s 322

For the beginning of the second half of the 1800’s, a simple agrarian lifestyle was 323

still predominant throughout the SRB. Settlements remained small. Most families survived 324

on land parcels 10 to 40 acres (4 to 16 ha) in size (Bratton and Smith, 1928), though a few 325

wealthy landowners had emerged. Much of each family’s food continued to be raised or 326

grown on their own farm or was obtained by barter with nearby neighbors. Along with grain 327

production, almost every farm also had a small orchard and garden plot. Close by timber 328

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sources were still heavily relied on for heating and construction. However, during the mid- 329

to late 1800’s mechanization was quickly advancing and allowed for more aggressive land 330

clearing and larger farming operations. Primary grain crops grown were corn, oats (Avena 331

sativa), wheat, and sweet sorghum (Sorghum vulgare). This mechanization period also led 332

to an ability to develop roadways that stimulated commercialization and economic 333

diversification, including grist mills, lumber mills, brick yards, and cash crops such as 334

tobacco (Nicotiana spp.), hemp (Cannabis sativa), and cotton (Gossypium spp.) (O’Brien, 335

1984). Frame and brick houses began replacing log cabins. Small villages and towns 336

emerged throughout the region, with Paris, Missouri, becoming the main commercial center 337

of the SRB. Growth and commercialization was also stimulated starting in the late 1850s 338

with the completion of the Hannibal and St. Joseph Railroad line in northern Missouri. Even 339

with transportation developments, little evidence exists of grain being shipped outside of the 340

basin in the 1800’s. During this time, cattle were fattened with locally-grown grain and 341

herded into the St. Louis, Missouri area for market (O’Brien, 1984). 342

Up through the Civil War, the wealthiest landowners owned slaves and had the 343

largest livestock and grain operations. While slave ownership was less than in other parts of 344

Missouri, the slave population in 1860 for the SRB counties was between 15-25% of the 345

total population (Howard, 1980). 346

347

1900’s to Modern Times 348

Land Use Intensification Promotes Erosion 349

Early in the 1900s, the face of the Midwest rural landscape, including the SRB, 350

began a major transformation. People began migrating to the larger metropolitan cities, 351

seeking for a higher standard of living than what rural life offered. This resulted in shrinking 352

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communities and increased farm size (Bratton and Smith, 1928). Investment in rural 353

infrastructure slowed and some smaller communities turned into ghost towns. At the same 354

time, improvements in agricultural mechanization helped affluent farmers expand their 355

enterprises, becoming wealthier. Poorer, less-efficient farmers went out of business. The 356

larger farms integrated grain feed production and livestock (cattle, hogs, and sheep) 357

operations. Extensive flat grasslands were plowed and put into grain production for the first 358

time. During this period, corn, oats, wheat and a new crop, soybean (Glycine max) was 359

typically grown. During World War I, corn grain prices soared, and so did corn acreage. 360

These changes in the agricultural landscape resulted in major shifts in land use and 361

cultivation intensity for all of Northeast Missouri. Intensified grain crop agriculture had an 362

immediate and dramatic increase on soil erosion that impacted total runoff and water quality 363

into rivers and streams of the SRB. Prior to the Civil War, much of the Salt River was noted 364

to have clear, clean water during most of the year (Howard, 1980). Fish and mussels were 365

plentiful. By the 1930’s, the streams were sediment filled and fish life was disappearing. 366

Not by coincidence, the first soil erosion plot research in the U.S. was initiated in 1917 on 367

similar soils on the campus of University of Missouri in Columbia, Missouri (just 80 km, or 368

50 miles SE of the SRB) (Troeh et al., 1980). Multiple and damaging rainfall events caused 369

severe flooding, soil erosion, and property damage between 1926 and 1936. The impact was 370

devastating for croplands. An erosion survey in 1934 disclosed that 25% of cropped acres in 371

this region had lost from 75% to all of its topsoil, exposing the subsoil claypan (Bennett, 372

1939). Grain crop yields for many fields actually declined by more than 50% below yields 373

obtained in the late 1800’s. 374

Channelization and Drainage 375

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While sod busting on the broad upland prairies for expanding cropland undoubtedly 376

had a major role in increased runoff and accelerated erosion, it coincided with other 377

significant hydrology-altering human activity, namely timber clearing, drainage, and 378

channelization. Spring and early summer floods commonly vexed farmers and homesteaders 379

on the bottomlands of northeast Missouri rivers, including the Salt. Their natural courses 380

tended to be tortuous and the common resolve was to develop straight ditches or canals 381

centrally located in the valleys for enhanced drainage. These were primarily occurring in the 382

forested bottomlands of the Salt River and its tributaries. Drainage projects in Northeast 383

Missouri began sometime in the first decade of the 20th

century when drainage districts were 384

formed for the major Northeast Missouri Mississippi River tributaries such as the Fabius, 385

and Wyaconda (Ball, 1913) and the Chariton (available from the Missouri Department of 386

Conservation at http://mdc.mo.gov/landwater-care/stream-and-watershed-387

management/missouri-watersheds/chariton-river). Drainage districts were empowered by 388

State law (Missouri, State of, 1909) to authorize drainage districts organized by landowners. 389

These districts organized the tasks of surveying, designing, and commissioning the work to 390

be done by private dredging companies (Mason, 1984). Drainage districts were formed prior 391

to 1909 on the Chariton (White, 1910), in 1908 on the North Fabius (Roberts and 392

Bumbarger, 1908), and around 1913 on the Wyaconda (Ball, 1913). These local drainage 393

authorities levied taxes on landholders in the drained areas for repayment of bonds sold to 394

subsidize these projects. 395

For the SRB, enhanced drainage through channelization was especially focused on 396

the North Fork, one of the largest of the Salt River tributaries. Major sections of the river 397

were bypassed by drainage canals through the bottomlands, straightening out the 398

meandering natural stream system. Dredging in the main Salt River channel also occurred 399

18

around this period (Schrader et. al., 1917) (See Figures 3 and 4). Dredging produced a 400

corresponding increase in flow gradient that accelerated stream scouring. Channelization 401

continued beyond 1950 as additional stream sections were straightened in more difficult 402

terrain using modern construction equipment. 403

These artificial drainage canals, now considered the actual channel of the river, are 404

now much different than they would have been at the time of construction. Design 405

specifications for ditches dug on the Salt River tributaries were probably similar to those for 406

the Chariton (White, 1910) and North Fabius (Roberts and Bumbarger, 1911). These were 407

dug to a depth of 2.5 m with a 6 m bottom width and having sides sloping at a 1:1 pitch. 408

Now, because of bank erosion and scouring, these channels are typically 3 to 5 m deep and 409

30 to 80 m wide with nearly vertical banks. It was the intent of those involved in these 410

projects that the artificial channels would increase in dimension and flow capacity and they 411

have succeeded. In the case of the Chariton River, the base level of the canal was already 412

below that of the original riverbed in less than ten years (White, 1910). 413

Altogether, these alterations in the length and base level of the Salt River and its 414

tributaries created significant change in the hydrology and stability of the landscape. 415

Though the overall goal of allowing excessive runoff to quickly move into and through 416

stream systems seemed necessary as agriculture intensified, there have been many 417

unintended consequences to the Basin. The most obvious impact has been the promotion of 418

erosion due to accelerated runoff. Channelization for improved drainage, working in concert 419

with deep-tillage cultivation practices on cropped fields, promoted severe erosion in many 420

areas of the landscape. With enhanced water flow in streams and ditches, deep gouges in the 421

topography have been caused by headcutting (or sometimes called “nickpoints”) 422

backwearing up into the landforms. Some of these headcuts unchecked by modern era 423

19

conservation measures have migrated into the upper reaches of the landscape. The 424

straightened channels and unnatural curves continue to promote severe bank erosion (Willet, 425

2010). 426

The GCEW is one of the headwater tributaries of the Salt and did not receive 427

significant channelization. However, major channelization and dredging occurred 428

downstream, and in other nearby watersheds. The degree to which these impacts have 429

propagated into GCEW is not clear. Like similar river systems in the region such as the 430

Blackwater (Emerson, 1971) and the Chariton (available from the Missouri Department of 431

Conservation at http://mdc.mo.gov/landwater-care/stream-and-watershed-432

management/missouri-watersheds/chariton-river), the Salt River has not stabilized from the 433

channelization and drainage work that was initiated about a century ago. These landscape 434

alterations will likely continue to cause sediment-related water quality problems into the 435

foreseeable future. 436

Early Conservation Initiated 437

Government-directed public works projects addressing national erosion issues resulted in 438

the creation of the Soil Erosion Service within the Department of Interior in 1933. That 439

program was made permanent and transferred in 1935 to the newly formed Soil 440

Conservation Service (SCS) within the Department of Agriculture (Troeh et al., 1980). 441

Because of the severe gully and sheet erosion that quickly stripped away the limited topsoil 442

of the SRB, H.H. Bennett declared the need for conservation practices on these soils as 443

“urgent” (Bennett, 1939). In the late 1930’s the “McCredie project” (near present day 444

Kingdom City, in Callaway County, MO) was initiated by the SCS on 25,000 acres (10,000 445

ha) to assess and then implement soil conservation practices on 100 different farms (Bennett, 446

1939). This project was adjacent to the southern edge of the SRB and undoubtedly helped 447

20

stimulate new conservation practices within the Basin. Practices employed were diverse and 448

targeted the most obvious problems. They included contour tillage, contour strip cropping, 449

buffer strips, terracing, contour furrowing within pastures, gully control, impoundment, 450

fencing, construction of vegetated channels for runoff mitigation, liming, manure 451

applications, cover crops, green manuring, and retiring of highly eroded lands to trees, grass, 452

or native plants (Bennett, 1939). Additionally, the SCS established in 1937 a soil 453

conservation experiment station called the Midwest Claypan Experimental Farm near 454

McCredie, MO (Jamison et al., 1968), that became a primary runoff and erosion research 455

location for the University of Missouri Experiment Station and the USDA Agricultural 456

Research Service for the next 60 years. A major contribution of this station was data used in 457

implementing the Universal Soil Loss Equation (USLE) and its derivatives (Wischmeier and 458

Smith, 1960), which continue to impact conservation in the SRB and elsewhere. Results 459

from these demonstrations and research projects were recognized by famers and business 460

leaders within the region (Bennett, 1939). 461

Modern Era Farming Practices and Specialization 462

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

century as 463

motorized equipment increased in size and efficiency. In 1950, agriculture employed 33% 464

of the labor force in the Salt River area (Clarence Cannon Dam and Reservoir: 465

Environmental Statement, 1975). Over the next two decades, the number of cropped acres 466

increased almost 10% while the labor force employed by agriculture decreased to less than 467

15%. During the 1970’s and early 1980’s, many small to medium-sized farms abandoned 468

animal operations because of poor profitability and focused on grain production. For 469

Missouri farmers, debt nearly tripled during the 1970’s and 80’s, resulting in a nation-470

leading number of farm bankruptcies in 1985 (Demissie, 1986). Also during this period, a 471

21

much higher percentage of farmland became leased instead of owner-farmed. Predominant 472

crops grown during this time were soybean, corn, sorghum, and wheat. 473

During the last four decades of the 20th

century, farming operations evolved in 474

response to newer cost- and time-efficient technologies, and better-engineered equipment. 475

Further, awareness grew for enhanced soil and water conservation (addressed in next 476

section). Important changes that had direct impact on the landscape included: 1) seed bed 477

preparation changed from plow/disk to mulch till or no-till; 2) crop selection changed from 478

rotations that included three or more crops that often used cover crops to two-crop rotations 479

(often corn-soybean, sorghum-soybean, or wheat-soybean); 3) weed control changed from 480

mechanical cultivation to herbicides, with plant-active herbicides replacing many soil active 481

herbicides in the later years; 4) farm tractors and combines changed from 4-6 row power 482

capacity and size to 12-24 row power capacity and size; 5) crop genetics changed to include 483

cultivars and varieties with higher yield performance, greater pest resistance, and 484

genetically-engineered protection from certain herbicides to allow for a broader spectrum of 485

weed control; and 6) more synthetic fertilizers and less manure nutrients, wide-spread use of 486

soil and plant diagnostic tools, and better application equipment with more accurate control 487

of rates (See Figure 5). 488

Modern Era Environmental Challenges Identified and Response 489

In the latter half of the 20th

century, understanding of environmental issues 490

nationally evolved to include many challenges other than just runoff and erosion. These new 491

challenges became apparent in part because of active public-funded support for research and 492

monitoring programs. This awareness was also made possible because of advancement in 493

scientific instrumentation that allowed for quantification of chemical contaminants at 494

smaller and smaller concentrations. Measurement of chemicals in air, soil, and water 495

22

mediums went from parts per thousand to parts per billion in just a few decades. Increased 496

concern for environmental issues led to the formation of the U.S. Environmental Protection 497

Agency in 1970. In 1972 major enhancements were made to the federal Water Pollution 498

Control Act, later renamed the Clean Water Act. This legislation more clearly defined the 499

federal regulatory structure for defining water quality standards, developing control 500

programs, permitting of discharge, and planning that addressed point and nonpoint source 501

problems of pollutants within U.S. waters (available from U.S. EPA at 502

http://www.epa.gov/lawsregs/laws/cwahistory.html). Since then the Clean Water Act has 503

been amended on numerous occasions, and other legislation was signed into law, which 504

expanded legal authority for addressing these concerns. Initially legislation focused on 505

human health, but with time broadened to embrace numerous ecological balances disrupted 506

by anthropogenic activity. 507

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

century, 508

more comprehensive education, extension, and farmer programs and services followed the 509

improved scientific understanding of human interactions with the environment. This was 510

evidenced by the renaming of the SCS in 1994 to the Natural Resource Conservation 511

Service (NRCS), to reflect a broadened scope of landscape and watershed concerns this 512

agency now addressed (available from the USDA NRCS at 513

http://www.nrcs.usda.gov/wps/portal/nrcs/main/national/about/history). Earlier in the 514

century, the model of empowering local farmers and ranchers to develop and implement 515

practical and specific conservation practices was promoted through organizing conservation 516

districts, an idea conceived by H.H. Bennett when Chief of the SCS. His philosophy was 517

land owners have the experience and resolution to make necessary management changes to 518

preserve their lands, and given the technical help and engineering suggestions, they should 519

23

be trusted to do so (available from the Missouri Department of Conservation at 520

http://www.maswcd.net/historydoc.htm). Relative to many states in the Union, Missouri’s 521

use of conservation districts has been stellar. This has in large part been because of a one-522

tenth-of-one-percent parks, soils, and water sales tax passed by Missouri voters in 1984, and 523

renewed three times since (available from the Missouri Department of Conservation at 524

http://www.dnr.mo.gov/env/swcp/history.htm). The majority of the soil and water portion of 525

this tax has been used to assist agricultural landowners through voluntary programs, 526

prioritized by the statewide Soil and Water Districts Commission, but administered through 527

the 114 county-level Soil and Water Conservation district boards. This tax along with other 528

state and federal soil conservation programs and education initiatives (e.g., conservation 529

tillage and NRCS’s Conservation Reserve Program), have been credited for helping 530

Missouri to have the greatest decline in soil erosion rates when compared to other states (i.e., 531

171 million tons in 1982 to 95 million tons in 1992) 532

(http://www.maswcd.net/historydoc.htm). Prior to 1982, Missouri had the second highest 533

rate of erosion in the nation and now it ranks seventh. 534

These modern-era descriptions of federal and state soil and water conservation 535

initiatives are applicable for what has taken place in the runoff-prone landscape of the SRB. 536

With current grain cropping on about ~45% of the Basin acres (Lerch et al., 2005), 537

excessive runoff and the associated environmental problems persist in this watershed. 538

Notable issues from these grain crop acres include sediment movement into waterways and 539

the Mark Twain Lake, nutrient loss off fields resulting in eutrophication of lakes and 540

streams, decreased crop productivity with lost topsoil, and pesticide movement from fields 541

into water bodies. Livestock grazing occurs on ~30% of acres, with associated 542

environmental issues. Unprotected streams within grazed lands result in damage to stream 543

24

banks, loss of riparian habitat, and bacterial and nutrient contamination of steam water. 544

Concentrated animal feeding operations (CAFOs) and their associated challenges have also 545

increased since 1990, with over 15 facilities rated at 3000+ animal unit equivalents in the 546

SRB in 2010 (available from the Missouri Department of Conservation at 547

http://www.dnr.mo.gov/env/wpp/afo.htm). 548

549

CONCLUSION 550

Examination of the genesis of the soil landscapes and how human activity has 551

greatly altered landscape resources is valuable for interpreting watershed research as found 552

in this series of papers on GCEW and SRB. Attempting to understand current land use 553

activities and condition of natural resources and formulating future management plans 554

without the historical context is like beginning a novel by opening it at the middle. Here we 555

have described how key landscape-dependent soil features, including thickness of loess and 556

depth of and clay content in the argillic peak, are important hydrologic drivers for watershed 557

vulnerability. Soil loss from erosion has significantly altered many fields cultivated for grain 558

crop production. Soil resources lost cannot be restored to pre-European settlement 559

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

560

century, when intensive rainfall followed deep tillage and/or extended drought periods, and 561

major changes in stream channels destabilized the landscape. Research and demonstration 562

projects have been essential for understanding the relationships of soil landscapes, 563

hydrology, weather, and anthropogenic activity. Early conservation responses focused on 564

poor practices and determining land use alternatives to help prevent further landscape 565

resource degradation while later responses also included a goal of restoring lost ecosystem 566

25

function into the landscape. Soil and water conservation practices have undoubtedly 567

improved watershed soil and water quality, but signs of impairment persist. 568

569

26

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Missouri watersheds, M.S. Thesis, University of Missouri, Columbia. 671

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31

681 Figure 1. 682

Geographic and hydrologic context of long term agroecosytem research in the Goodwater 683

Creek Experimental Watershed and the Salt River Basin. (Columbia, Missouri, Lat. 38.95°, 684

Lon -92.33°; Hannibal, Missouri, Lat. 39.71°, Lon -91.35°). 685

32

686

687

Figure 1. 688

The three primary parent materials in the study region are loess, glacial till, and alluvium. 689

Thick deposits of glacial till up to 100 meters are overlain with windblown loess. Sediments 690

from these sources are found in alluvial fill in valleys and floodplains. 691

692

33

693

Figure 3. 694

An aerial image taken Oct 14, 1950 from a portion of the North Fork of the Salt River 695

northeast of Clarence, MO shows a continuous 5.4 km section of channel dug in the early 696

1900’s. The channel length was reduced to less than half of the original 13.6 km. Compared 697

to Photo 2, part of the river had not been channelized by this date. 698

699

700

34

701

702

Figure 4. 703

A 2010 aerial image of the same area as Photo 1 showing channelization of the North Fork 704

of the Salt River. A comparison of these two photos shows the extent of channelization after 705

1950. After 1950, an additional 5.2 km section of canal was dug, which straightened 12.7 706

km of original stream channel. In all, more than 65 km of channel were dug on the North 707

Fork above Clarence Cannon Dam, reducing overall channel length by about twice that 708

amount. 709

710

711

35

1939 1956 1968

1982 1990

1939 1956 1968

1982 1990

712

Figure 5. 713

A sequence of aerial photos obtained from the USDA Farm Service Agency archives 714

illustrate some of the important changes that occurred between 1930 and 1990 for a typical 715

quarter section field (~160 acres, 64 ha) in the Salt River Basin: 1) larger fields were created 716

by merging of smaller fields; 2) loss of farmsteads as farmers managed larger acreages; 3) 717

loss of integrated grain and animal production systems; and 4) return of indigenous trees 718

along waterways and field boundaries. 719