GEOGRAPHY OF SOILS FIELD TRIP

DAY ONELearning Objectives:

1. Learn how peat bogs form and how to describe and sample an organic soil.2. Observe landscapes (glacial lakes, moraines, outwash)3. Learn about Itasca State park and the headwaters of the

Mississippi River.

FIGURE ONE

First Soil Stop: PEAT BOG IN LAKE PLAIN OF GLACIAL LAKES AITKIN AND UPHAM (approx. 1 hour drive)

FIGURE TWO

Figure Two shows the extensive area in northern MN covered by the lake plain of these former glacial lakes. The resulting landscape is FLAT and poorly drained. Glacial history in this region of MN is complex. Several advances from different lobes (Wadena, Rainy, Superior and

Des Moines Lobes) of the Laurentide Ice Sheet moved through this region. See Figure Three.

FIGURE THREE

Each lobe in each advance deposited moraines. One of the advances of the Superior Lobe left the Highland and the Mille Lacs moraines. The Highland moraine acted as a dam and water was ponded to form Glacial Lakes Upham I and Aitkin I. Later, the St. Louis sublobe (of the Des Moines Lobe) stagnated and Glacial Lakes Upham II and Aitkin II formed. These lakes covered an extensive area of northeastern Minnesota. (See Figures Four and Five).

The lakes stood at several levels, and formed strandlines (beaches) at each level. The lake water also modified earlier deposits of till. On our

drive to Floodwood and Jacobson, we traverse Upham and Aitkin beaches and wave-washed tills from this basin. Eventually, the lakes drained through St. Louis River around 9000 yrs. BP. You will notice numerous peat deposits on the lake plain, where closed depressions have filled with peat.

FIGURES FOUR AND FIVE

Peat Bog : Peat forms when organic material accumulates more rapidly than it is decomposed. These old, glacial lake basins are very flat and therefore very poorly drained. The wetness encourages anaerobic decomposition, which is relatively slow and not as efficient as aerobic decomposition. This slow decomposition rate has allowed organic deposits to accumulate here for thousands of years, creating deep, peat soils.

We will examine a core of peat from one of these closed depressions in the Arlberg bog. This peatland extends over 8900 acres. The peat soil

here consists of 5-6 meters of peat above very fine sand of glacial lake origin. These soils have extremely low bulk densities (0.2 – 0.3 g/cm3) and high porosity (80%). The minerals in organic soils are tied up in organic compounds and are not plant-available, therefore only very specialized plants grow in peat bogs. Look for Black Spruce (Picea mariana), Labrador tea (Rhododendron groenlandicum), dwarf shrubs like blueberry (Vaccinium spp.), leather leaf (Chamaedaphne calyculata), and Sphagnum moss (Sphagnum spp.).

Observe the sphagnum moss here. There are hundreds of species of Sphagnum moss. It can hold 20 times its dry weight in water and used to be used as an absorbent material in bandages.

Important descriptive elements of organic soils are the botanical origin of the organic material (sphagnum, grasses, sedges, cattails, wood and leaf litter) and the extent of decomposition. A simple classification is:

Fibric (peat) <1/3 decomposed; >2/3 identifiable (Von Post H1 – H4)Hemic (mucky peat or peaty muck) moderately decomposed (Von Post H5 –H6)Sapric (muck) 2/3 decomposed; <1/3 identifiable (Von Post H7-H10)

A more detailed classification is given in the Von Post method (below). We will examine a core and use the Von Post method.

Materials: rags, peat sampler and handle and extension, field trip handout for taking notes, bulk density cans, 6 sampling bags and marker

Assignment:Learn the Von Post and simple (fibric, hemic, sapric) classification of peat. Take six samples: 2 for bulk density, 2 for water content, and 2 for organic matter content (to be analyzed in later laboratory exercises). Label the bags with initials, date, site (“Arlberg Peat Bog”), depth of sample, sample number and test for which sample is collected. (Example: “PF, Arlberg Bog, 10-4-19, 13-24 cm, Bulk Density , #1)

THE VON POST SCALE OF HUMIFICATION (source Ekono 1981)

Symbol Description

H1 Completely undecomposed peat which, when squeezed, releases almost clear water. Plant remains easily identifiable. No amorphous material present.

H2 Almost entirely undecomposed peat which, when squeezed, releases clear or yellowish water. Plant remains still easily identifiable. No amorphous material present.

H3 Very slightly decomposed peat which, when squeezed, releases muddy brown water, but from which no peat passes between the fingers. Plant remains still identifiable, and no amorphous material present.

H4 Slightly decomposed peat which, when squeezed, releases very muddy dark water. No peat is passed between the fingers but the plant remains are slightly pasty and have lost some of their identifiable features.

H5 Moderately decomposed peat which, when squeezed, releases very “muddy” water with a very small amount of amorphous granular peat escaping between the fingers. The structure of the plant remains is quite indistinct although it is still possible to recognize certain features. The residue is very pasty.

H6 Moderately highly decomposed peat with a very indistict plant structure. When squeezed, about one-third of the peat escapes between the fingers. The residue is very pasty but shows the plant structure more distinctly than before squeezing.

H7 Highly decomposed peat. Contains a lot of amorphous material with very faintly recognizable plant structure. When squeezed, about one-half of the peat escapes between the fingers. The water, if any is released, is very dark and almost pasty.

H8 Very highly decomposed peat with a large quantity of amorphous material and very indistinct plant structure. When squeezed, about two-thirds of the peat escapes between the fingers. A small quantity of pasty water may be released. The plant material remaining in the hand consists of residues such as roots and fibres that resist decomposition.

H9 Practically fully decomposed peat in which there is hardly any recognizable plant structure. When squeezed it is a fairly uniform paste.

H10 Completely decomposed peat with no discernible plant structure. When squeezed, all the wet peat escapes between the fingers.

B1 Dry peat

B2 Low moisture content

B3 Moderate moisture content

B4 High moisture content

B5 Very high moisture contentNote: The moisture regime of each peat sample is estimated using the above scale of 1-5 and symbol “B” (derived from Swedish blöthet = wetness).

Proceed to Continental Divide and LUNCH STOP: JacobsonWe will proceed to Jacobson by continuing west on Highway 2, then turning onto Route 200. At approximately 4 miles after we turn left on 200 (around Mile Marker 197), we cross a continental divide between Great Lakes drainage and Mississippi drainage. We will stop and eat lunch by the Mississippi River.

FIGURE SIX

DRIVE to Itasca State Park, UNIVERSITY OF MINNESOTA FIELD STATION : (about 2.5 hours)

THINGS TO NOTICE ABOUT THE LANDSCAPE AS WE DRIVE TOWARDS HILL CITY:

As we drive west, we continue through the expansive, flat lake basin. The peat bogs are evident by the expanses of black spruce trees which look like dead trees, but are actually alive and well. Eventually we approach Hill City, presumably so-named because of the relatively high relief in the Des Moines Lobe end moraine, the “Sugar Hills Moraine”, in which Hill City lies. (See Figure Five).This high relief topography(steep hills with bogs or lakes between the hills) is typical of an end moraine landscape.

We enter Leech Lake Reservation before the town of Remer. (Look for signs of Big Foot)! You will notice Leech Lake on your right. Leech Lake formed by being dammed on all sides by moraines. As we drive, you can observe the rocky moraine landscape.

ITASCA STATE PARK

Itasca is the oldest state park in Minnesota. The park was established in 1891 to protect the drainage basin around the source of the Mississippi River (Lake Itasca) and virgin stands of red and white pine, 100-300 years old. Hunters were here 8500 years ago; the Dakota people were here 3000-350 years ago and the Ojibwe were here from approximately 300 ? years ago to today. The park used to be called Omushkos, the Ojibwe word for “elk”. The first white explorer called it Itasca as a combination of “veritas” and “caput”, Latin for “true head”. We will look at some interesting things in the park, including the headwaters of the Mississippi. Ozawindib, an Ojibwe guide brought Henry Schoolcraft to the headwaters in 1832 Mississippi Facts:

The Mississippi River flows 2,340 miles from Lake Itasca to the Gulf of Mexico.

The first 50 miles, navigable only by canoe, are the last vestige of the wild Mississippi.

It takes a raindrop approximately 90 days to travel from Lake Itasca to the Gulf of Mexico.

The river's watershed drains 41 percent of the continental United States, or between 1.2 and 1.8 million square miles.

Most of Itasca State Park is in the Itasca Moraine, an end moraine of the Wadena Lobe of ice.

DAY TWOLearning Objectives:

1. Learn about soil health practices that are used at a family farm in Wadena. 2. Observe erosion simulators to learn how various cropping methods lower the impacts of both water erosion and wind erosion of soils.3. Learn about Wadena outwash deposits and Wadena till, we will compare Wadena deposits to the Des Moines lobe deposits we will see on Sunday. 4. Learn about the formation of drumlins and observe drumlins in the Wadena drumlin field.

STOP ONE: REINKE FAMILY FARM: The Reinke family has agreed to host us and tell us about the soil health principles they are using on their farm. The farm is on sandy soil because the parent material is Wadena lobe outwash. We will see some water erosion and wind erosion simulators that will show us the effect of differing crop techniques on soil erosion. We will have lunch at the farm.

“STOP” TWO: A DRIVING TOUR OF THE DRUMLIN FIELD(1.5 hour drive from Itasca)The Wadena drumlin field is in the Wadena lobe till. The provenance (or origin) of the Wadena Lobe is the Hudson Bay area of Canada. The stones in the Wadena till are limestone and granite. The till color is buff to yellowish brown and is coarse-textured with a lot of stones and boulders in it. The Des Moines Lobe had a provenance slightly west of the Wadena Lobe in Canada and contains shale in addition to limestone and granite. It is a more fine textured till with few boulders and a buff to yellowish brown color.

Drumlins are elongated hills of glacial till, like upside-down spoons, that form under the ice sheet and always occur in swarms, rather than as isolated individual hills. (See Figure Eleven). There are approximately 1200 drumlins in the Wadena drumlin field. The moving ice plastered the underlying sediment into these features. They are quite evident on the topographic map. The long axes of drumlins are oriented in the direction of ice movement, with the less steep side of the drumlin pointing in the direction of ice movement.

FIGURE ELEVEN

FIGURE TWELVE

FIGURE THIRTEEN

DAY THREELearning Objectives: 1. Learn about Glacial Lake Agassiz and the extensive lake plain landscape. Observe these lake clay soils.2. Observe the extensive agricultural ditching of this region of Minnesota, draining what would otherwise be wetlands. 3. Observe and learn about the sugar beet harvest.4. Visit a beach ridge of Glacial Lake Agassiz and learn about beach ridge formation.5. Study the soil signature of a native grassland and describe a grassland soil. Practice soil description skills.6. Observe the characteristics of a typical forest soil.7. Learn the differences in till from lobes of ice with differing provenances (Compare Des Moines lobe deposits today with the Wadena lobe deposits we saw yesterday).

FIRST STOP: Glacial Lake Agassiz clays near Ada, MN (soybean field) (Drive about 1.5 hours from Itasca)

After leaving Itasca, about 6-7 miles west of the Park Entrance, on Highway 71/200, we cross another Continental Divide (around mile marker 76-78), separating the Mississippi drainage from the Red River drainage.

As we leave Itasca and drive west towards Ada, we will pass through Wadena Lobe moraine deposits and then Des Moines Lobe moraine. As we approach Ada, you will notice the end of the hilly moraine landscape and the beginning of a vast, flat landscape, the lake plain of Glacial Lake Agassiz. See Figure SEVEN below.

FIGURE SEVEN

Glacial Lake Agassiz was formed as the retreating ice, towards the end of the Wisconsin glaciation, blocked the northward flowing drainage towards Hudson Bay. During this time, the lake had multiple stages and multiple outlets. The maximum extent of this enormous

Ada

lake is shown in Figure Eight below. The lake existed, in various sizes from 11,700 – 9400 years ago. Lake of the Woods and the Upper and Lower Red Lakes are remnants of this ancient, huge lake.

11,700 years ago, the Des Moines Lobe of ice melted back north of the continental divide, trapping meltwater between the ice to the north and the moraines to the south. The lake got deep enough to overtop the glacial till and cut a valley which is now occupied by Big Stone Lake.

FIGURE EIGHT

LAKE CLAY:In the former lake bed of this enormous lake, we can see deep lacustrine sediment of Glacial Lake Agassiz. Locally, these clayey soils are called “gumbo soils” because they are very sticky and gummy when wet. During dry periods, they dry out and develop deep cracks.

The lake sediments themselves form Vertisols in deep deposits of silty clay. The lake plain itself is extremely flat, with relief in some places only one inch per mile. Ditching in this region can be seen on the topo maps. Ditches remove water from the surface, which has led to productive agriculture, especially of sugar beets and small grains. But

the ditching has increased peak flows to the Red River and may be partly responsible for severe flooding in recent years.

MATERIALS: Materials needed:Field trip handout, lab book, pencil, and soil equipment for two groups: two shovels, two augers, spray bottles, distilled water, pH kits, soil description kits, sampling bags, Sharpies.. ASSIGNMENT: Working in two groups, auger as deep as you are able in this sticky clay soil and fill troughs to do a soil description. Remember to keep track of the depths using the auger hole. Record observations on a Soil Profile Description sheet.

Take samples of each horizon for later laboratory analysis.

The remaining three stops on our field trip will look at the effect of vegetation on soils. We will visit two prairies and then look at a forest soil. All three of these soils we will see have the same parent material: Des Moines Lobe till, or wave-deposited beach gravel. The differences that you will see in these three soils are due to vegetation changes.

There are many theories attempting to explain the abrupt transition in Minnesota from forest to prairie. These theories range from climate change to fire patterns to changes in topography. Prairie and forest vegetation have existed in Minnesota since the Pleistocene glaciation. The prairie/forest transition was very dynamic and ever-changing before European settlement. The changing border was dictated by the frequency and severity of fires and weather patterns. Several different kinds of communities existed along this transition zone, including brush prairie and savanna. (See Figure Nine).

Before settlement, the “Big Woods” (deciduous forest) , existing south and west of the Twin Cities, covered over 2 million acres in Minnesota. Currently the remaining acreage of the Big Woods is mainly comprised of the late-successional species of maple and basswood referred to as maple-basswood forest. The first trees to invade the prairies were oak, aspen and willow, followed later by elm.

Fires started by lightning and by American Indians were originally the primary obstacles to forest invasion into the prairie. Frequent fires spread easily over the prairie, killing most invading trees and shrubs, but were extinguished when they reached the moister forest regions. The prairie grasses would quickly regenerate after the burns. The large

burr oaks were resistant to fire, and the willow and aspen regenerated quickly after burns at the transition. A later shift in climate to cooler, wetter conditions in the Big Woods likely ushered in the shift from oak and aspen to elm.

FIGURE NINE

Settlement of the transition area brought with it extensive fire control to protect buildings, crops, livestock, and the surrounding woodlands. Constructed railroads and highways served as fire breaks. This fire suppression has and continues to lead to the invasion of the forest into the remaining native prairie lands. Prescribed burning is now used to manage the remaining native prairies.

Prairie vegetation dominates landscapes to the west on Des Moines lobe ground moraine, which has relatively low relief. Here the landscape is complex and consists of beach ridges, inter-ridge complexes and lacustrine sediments. The topographically higher landscapes are dominated by forests and are composed of Itasca End Moraine (from the Wadena Lobe) and the Big Stone Stagnation Moraine (from the Des Moines Lobe).

SECOND STOP: Beach Ridge, Twin Valley Prairie(30 minute drive from Ada)

As the ice retreated North, the lake covered the land. As the ice advanced and retreated over several hundred years, the water level in the lake varied. At each constant level of the lake, beaches, sand spits and sand bars developed on the shore and near shore, just as they do in modern-day lakes. The waves of the lakes were moving and depositing moraine (till) deposits so the beaches are composed of sand and gravel. The beaches of this enormous lake are about 500 feet wide but only about 10-15 feet high. Today, they remain as very subtle rises on an otherwise very flat landscape, but the deposits in these subtle rises differ significantly from their surroundings.

Dotted lines on the map below represent beach ridges.

FIGURE TEN

Twin Valley Prairie is a Nature Conservancy Preserve and a Scientific and Natural Area (SNA) of 499 acres on a prominent beach ridge. The site is an important staging area for sandhill cranes. The site is considered a “biodiversity hotspot” because it contains species of both dry and wet prairies. According to the Nature Conservancy’s website, the “site was selected because it contains many of the plant communities found in abundance prior to agricultural expansion in

northwestern Minnesota. The site has a narrow band of dry prairie only yards away from bulrush and cattail marshes, meeting the habitat needs of a wide variety of plant, insect and bird species… the Conservancy has reclaimed a former gravel pit, reseeded a portion of the preserve, that was formerly farmed, to native prairie species and removed numerous mature trees…Tree rows in the midst of open prairie provide habitat for predators such as raccoons, skunks and birds of prey, which can diminish the ability of grassland birds to successfully nest”.

We will observe the gravel and sand deposits in this beach ridge and describe the soil.

ASSIGNMENT: Working as a class, we will auger, fill a trough or two and describe this soil. Record observations on a Soil Profile Description sheet.

Lunch at Ulen Wayside (15 minute drive from prairie)(Here we are able to examine Agassiz clay in the bank of Wild Rice River, a tributary of the Red River).

STOP THREE: ZIMMERMAN PRAIRIE

This is another prairie preserve belonging to the Nature Conservancy. According to the prairie’s website, “Northern tallgrass prairie is one of the rarest ecosystems in North America. Once a vast sea of grasses and wildflowers, much of the remnant prairies have been converted to crop fields. Zimmerman Prairie preserves a small portion of unbroken tallgrass prairie. Many prairie plants and animals thrive at this unique site…Periodic controlled fire and mowing help keep brush and trees from invading and out competing the prairie wildflowers and grasses. Unfortunately, some introduced species are found on the site”.

ASSIGNMENT: The prairie soil that we will look at is a Mollisol, with the typical deep, dark, mollic epipedon (a HORIZON) characteristic of grassland soils. Working in groups, we will describe a prairie soil here.

MATERIALS: Field trip handout, lab book, pencil, and soil description equipment for two groups, 2 shovels, 2 augers, spray bottles, distilled water, 2 pH kits, sampling bags and markers.

STOP FIVE: FOREST SOIL (ALFISOL) IN DES MOINES LOBE DEPOSIT (short drive)This alfisol formed in a forest in an area that has been dominated by forest vegetation for thousands of years. Note all the features of this soil that make it a forest soil: shallow A horizon, weak E horizon, Bt argillic horizon.

MATERIALS: field trip handout, lab book, shovel, Munsell, acid bottle, sand chart, hand lens, spray bottles, spray bottle, distilled water, pH kit

ASSIGNMENT: We will complete a Soil Profile Description sheet together as a class. Everyone should complete a sheet as we go through this exercise.

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