Earth Sciences Commons^™

Biological Processes: Relationships Between Earthworms And Soil Temperature, Edwin C. Berry, Jerry K. Radke

Journal of the Minnesota Academy of Science

Soil fauna play important roles in many soil processes and conditions which relate to agricultural systems. Earthworms are credited with enhancing soil fertility and soil physical properties by their feeding and burrowing activities. Most research on earthworms has focused on the warmer seasons of the year and relatively little is known about earthworm activity and survival during the portion of the year with frozen soils. Earthworms may survive winter by acclimatization, aestivation, or by burrowing to deeper depths where the soil is not frozen. More research is needed on the fate of earthworms in frozen soils. Suggested research areas include: …

Freezing And Thawing Of Agricultural Soils: Implications For Soil, Water, And Air Quality, Brenton S. Sharratt, Keith E. Saxton, Jerry K. Radke

Journal of the Minnesota Academy of Science

Most agricultural lands in the USA are subject to subfreezing temperatures. Soil freezing and thawing affects both biotic and abiotic interactions and processes which vary with weather, soil type, land management, and topography. Soil fauna generally undergo physiological changes or rely on locomotion as a means of adapting to frozen soils. Managing faunal populations using soil management may be achievable with a better understanding of winter ecological processes. Many of the thermal, hydraulic, mechanical, and physical properties of soils are altered by freezing and thawing. Soil erosion may be accentuated by soil freezing and thawing as a result of changes …

Migration Of Water During Winter In West Central Minnesota Soils, Brenton S. Sharratt

Journal of the Minnesota Academy of Science

Soil freezing influences the amount and quality of our water resources, yet, little is known concerning the impacts of soil texture and water content before freezing on water migration in frozen soils. Columns of Hamerly clay loam and Sioux loam at 3 initial water contents were subjected to the vagaries of the field environment at Morris, Minnesota during the winter of 1993-1994 and then sectioned to determine changes in soil water content. Redistribution of water in the frozen soil layer became more apparent with an increase in initial water content. Little movement of water occurred at the lowest initial water …

Studies On Freezing And Thawing Soils In Iowa, Jerry K. Radke, Edwin C. Berry

Journal of the Minnesota Academy of Science

Frozen soils have a major influence on the cropping systems and farming practices in northern states. However, relatively little research has been done on the physical, chemical, and biological processes that occur in the field during the non-growing season. Experiments on frozen soils were started recently in Iowa to 1) study the effects of residue cover on soil freezing and thawing, 2) measure the movement of water and solutes and changes in soil structure due to freezing and thawing of repacked soil columns in the field, 3) test the SHAW (Simultaneous Heat And Water) model for its capability to predict …

Soil Freeze-Thaw Processes: Implications For Nutrient Cycling, C. Wayne Honeycutt

Journal of the Minnesota Academy of Science

Soil freeze-thaw processes can regulate nutrient availability to plants by influencing nutrient leakage from plant tissues, nutrient release from soil organisms, mineral weathering, various inorganic nutrient transformations, and nutrient transport in both soil solution and sediment. These aspects of freeze-thaw processes are given in this review. A frequently reported observation is that soil water content controls the extent of freeze-thaw impacts on several chemical, physical, and biological processes and components important for nutrient cycling. Practices affecting soil water content, such as tillage and crop residue management, may therefore provide opportunities for managing freeze-thaw impacts on nutrient use efficiency in crop …

Frost Tillage For Soil Management In The Northeastern Usa, Harold M. Van Es, Robert R. Schindelbeck

Journal of the Minnesota Academy of Science

Tillage during the winter is typically considered impossible, despite its desirability in some cases. Soil freezing results in net upward movement of water to the freezing zone which facilitates primary tillage or incorporation of amendments. these can be performed during a time window when the frost layer is sufficiently thin to be ripped and the underlying soil is tillable. We evaluated the feasibility of frost tillage and performed an agronomic comparison with spring-tilled soil. Soil conditions conductive to frost tillage occurred during three time windows in the 1991/1992 and two in the 1992/1993 winter at Ithaca, NY. Frost tillage resulted …

Overwinter Changes In Dry Aggregate Size Distribution Influencing Wind Erodibility In A Spring Wheat-Summerfallow Cropping System, Stephen D. Merrill, Alfred L. Black, Ted M. Zobeck

Journal of the Minnesota Academy of Science

A long-term study of the wind erodibility properties of a two-year spring wheat-summerfallow cropping systems was started in 1988 in south-central North Dakota as part of an USDA-ARS led effort to construct a process-oriented soil erosion predictive model. Observations were conducted on a conservation tillage experiment established in 1984 on soil classified in the U.S. as Typic-Pachic Haploborolls and in Canada as Brown to Dark Brown Chenozemic. The experiment included four residue-management treatments defined by targeted residue coverages: no-till, > 60% cover; minimal-till, 30% to 60% cover and undercutter dominated; conventional-till, < 30% cover and disk dominated; low-residue, < 5 % cover. Fall and spring measurements of dry aggregate size distribution (ASD) of surface soil (0 to 4 cm depth), and overwinter changes in ASD are reported here. A rotary sieve produced six size fractions ranging from < 0.42 mm to > 19.2 mm diameter. Measurements of ASD are expressed as geometric …

Frozen Soils: A Perspective On Past And Future Research For Promoting Sustainable Agricultural Systems, Jerry K. Radke, Brenton S. Sharratt, W. Doral Kemper, Dale A. Bucks

Journal of the Minnesota Academy of Science

Frozen soils impact many industries which rely· on soil, water, and .air resources in developing and manufacturing products. Most noteworthy is the agricultural industry in the northern United States where soils, which sustain food and fiber production, are subjected to frequent freezing and thawing. Soil freezing and thawing influences soil erodibility, surface and ground water quality, air quality, and biological activity. Many strides toward understanding frozen soil processes and managing lands to minimize the adverse effects of freezing and thawing have been made over the last two decades. Yet, further efforts to identify frozen soil processes which influence wind and …

Relative Soil Aeration In A Cultivated Prairie Pothole, Alan Olness, J. A. Staricka, J. A. Daniel, G. R. Benoit, J. L. Rinke

Journal of the Minnesota Academy of Science

Many small prairie potholes receive surface runoff from their catchments and serve as a focal point of ground water recharge. Soil aeration controls the solubility and form of many soil chemicals. Platinum electrodes are sensitive to oxygen and provide a very sensitive indicator of its presence. Electrodes were installed at the 15-, 30-, and 45-cm depth across two transects within a shallow, cultivated depression which serves as a recharge site for groundwater. Soils on the rim of the depression remained aerobic throughout two consecutive cropping years even at 45 cm. Soils within the depression became anaerobic briefly in the first …

Morphological Indicators Of Seasonally-Saturated Soils For A Hydrosequence In Southeastern Minnesota, J. C. Bell, J. A. Thompson, C. A. Butler

Journal of the Minnesota Academy of Science

The duration and depth of seasonal soil saturation affects soil suitability for many landuses and are critical factors in the determination of hydric soil boundaries for jurisdictional wetland delineations. Biochemical processes in saturated, anaerobic soil conditions lead to the genesis of soil morphological features that indicate the duration of seasonal saturation. However, few prior studies confirm the relationships between soil hydrology and soil morphology in Minnesota landscapes. We monitored water table and piezometric elevations, soil temperature, redox potential, and soil matric potential at multiple depths for five locations along a hillslope hydrosequence of well to very poorly drained prairie soils …

Ground Water Quality And Management In Minnesota, Jeanette H. Leete

Journal of the Minnesota Academy of Science

Minnesota is known for its abundant surface water - lakes, rivers, and streams - and much emphasis is placed on managing these priceless resources, yet it is ground water that supplies drinking water to about 75 percent of the state's population, and ground water that agriculture depends on for 88 percent of irrigation water. While ground water quality can be and is impacted by activities at the land surface, the greatest proportion of Minnesota's ground water is still suitable for most uses.

Over 175 units and several levels of government are involved in water resource protection and planning. Choices are …

Analysis Of Hydrogeologic Sensitivity In Winona County, Minnesota, Michael D. Trojan, James A. Perry

Journal of the Minnesota Academy of Science

Hydrogeologic sensitivity to contamination throughout Winona County in southeastern Minnesota was assessed using the recently developed Trojan-Perry rating method. Sensitivity varied across and within three analysis regions. The Prairie du Chien Aquifer, comprising Region I, showed a wide range of sensitivity, varying from moderate to extreme. Areas of greatest sensitivity were sites where the aquifer was unconfined and overlain by a thin layer of unconsolidated material and karst bedrock. Under these conditions water may rapidly infiltrate through the soil zone and highly dissolved bedrock and into underlying aquifers. The Ironton-Galesville Aquifer, comprising Region II, was protected from surface infiltration by …

Geographic Information Systems, Data, And Water Resources, Dwight A. Brown, Philip J. Gersmehl

Journal of the Minnesota Academy of Science

ABSTRACT-We evaluate three data handling methods for use in a GIS analysis of land-cover change impacts on runoff. A universe of 2560 point samples is analyzed to provide runoff calculations that would se1:7e _as a comparison base to evaluate different attribute logic systems. The attribute logics ~e evaluate are two va~1at1ons of tag and one of count. We chose a two by five mile area of Dakota County, Mmnesota as the test site, and prepared raster GIS maps of soil hydrologic groups and two plausible land covers. The count 1:1~thod for handling the generalization of data produced results that were …

Landscape Assessment Of Soil Erosion And Nonpoint Source Pollution, Ian D. Moore, John L. Nieber

Journal of the Minnesota Academy of Science

ABSTRACT-The hydrologic processes occurring in the landscape are a manifestation of its topographic attributes. Spatially variable topographic-based attributes permit the distribution of hydrologic and nonpoint source pollution processes to be mapped within catchments. They can be derived from Digital Elevation Models (DEMs) using a variety of Terrain Analysis Methods (TAMs). The relationships between topographic indices and the spatial distribution of the potential for surface runoff, groundwater recharge, soil erosion, and evapotranspiration are graphically illustrated.

Water Quality In Southeastern Minnesota Streams: Observations Along A Gradient Of Land Use And Geology, Nels H. Troelstrup Jr., James A. Perry

Journal of the Minnesota Academy of Science

ABSTRACT-Surface water quality in southeastern Minnesota's driftless area exhibits subregional and local spatial patterns which are highly correlated with subsurface geology and land-use practices. Some variables appear to respond on subregional or watershed scales. Nitrate, specific conductance, alkalinity, and surface water atrazine concentrations were lower in streams originating from the Prairie Du Chien or Jordan sandstone ~quifers of easte:n Fillmore and Houston Counties than those originating from the Galena limestone aquifer m west-central Fillmore County. In addition, the numbers of pollution intolerant and functionally specialized invertebrates in the benthic community were higher in the eastern streams. Gross primary production on …

Origin And Developmental History Of Minnesota Lakes, H. E. Wright Jr.

Journal of the Minnesota Academy of Science

ABSTRACT-Most lakes in Minnesota owe their origin directly or indirectly to glacial deposition or erosion 10,000 to 20,000 years ago. The lakes' shapes have since been modified by waves and currents near the shores and by the deposition of sediment off-shore-principally the sediment produced by growth of algae and other organisms. This sediment is a receptacle for pollen grains blown into the lake from the surrounding vegetation, and the stratigraphic succession of pollen grains records the postglacial vegetational and thus climatic history of the area. The sediment also preserves the fossils of microorganisms that reveal by their chemical composition the …

Nitrogen Management Related To Groundwater Quality In Minnesota, James L. Anderson, Gary L. Malzer, Gyles W. Randall, George W. Rehm

Journal of the Minnesota Academy of Science

ABSTRACT-Minnesota ranks fifth in overall fertilizer nitrogen (FN) use. Nitrogen is essential for crop production; however, there are concerns about this use relative to profitability and potential impacts on groundwater. There are many sources and sinks of nitrogen in ecosystems. The impact of agricultural management practices on groundwater requires that all sources and fates be considered before FN rates are determined. Research is underway to evaluate relationships between FN application for continuous com and movement of nitrate through soil profiles. Growers making N management decisions have to be able to evaluate the complex nature of N in the environment when …

Natural And Anthropogenic Forces Acting On A Forest Lake, M. C. Whiteside, M. B. King, K. Pulling

Journal of the Minnesota Academy of Science

ABS1RACT-Lak~ Itasca, Minnes~ta is located within one of the more popular state parks. Since the turn of the centmy, loggmg, fire protection, and development within the watershed have put modest pressures on the ecosystem. The presence of the University of Minnesota's Biological and Forestry Station on the lake has encouraged research in this region. Consequently there are numerous research reports and papers which are available _at the station's library. We examined data collected over the past 25 years to see if we could detect changes ~~ the lake. We detected no changes in phytoplankton, macrophyte, zooplankton, or zoobenthos com~urnues, but …

The Water Quality And Management Of Lakes In The Twin Cities Metropolitan Area, Richard A. Osgood, Gary L. Oberts

Journal of the Minnesota Academy of Science

ABSTRACT-We have detected a slow degradation in the water quality of Twin Cities Metropolitan Area lakes du~ to phospho_rus enrichment. While the water quality of the lakes does not appear to limit most uses, nmsances do exist. We have further discovered that commonly-used watershed treatments such as wetland diversions and ponding, are ineffective ~t reversing or completely mitigating the degradati~n following land development. Th_erefore, we are su~gestmg that lake managers reduce the external loading of phosphorus to the greatest ~oss_1ble extent; then, 1f further water quality improvements are necessary, that measures which treat eutroph1cat1on-related symptoms be considered for the long-term …

Lake Mixing Dynamics And Water Quality Models, Heinz G. Stefan

Journal of the Minnesota Academy of Science

ABSTRACT-To forecast water quality changes or to evaluate the potential success of restoration measures in lakes, it is necessary to formulate "models" which relate lake water quality to the inflows and outflows of materials and energy. Concepts of dynamic deterministic (cause-effect) models and examples are presented. The relationship between internal thermo-hydraulic processes and water quality is stressed. Stratification mixing, and nutrient kinetics are included in these models.

Viruses And Drug Resistant Bacteria In Groundwater Of Southeastern Minnesota, Sagar M. Goyal, Daniel Amundson, Robert A. Robinson, Charles P. Gerba

Journal of the Minnesota Academy of Science

ABSTRACT-Karst topography of soils in southeastern Minnesota is responsible for the formation of sinkholes, subsurface cracks, and underground rivers which may enhance the transportation of surface contaminants into groundwater. The present study was conducted to determine the presence of human pathogenic viruses, coliforms, fecal coliforms and coliphages in private rural wells of this area. The occurrence of drug resistance in bacteria isolated from groundwater also was studied. Coliform bacteria were detected at least once from 22 of the 26 sites sampled over 34 months. Water from 10 sites yielded drug-resistant indicator bacteria; 25 of 38 (65.8 percent) total coliforms and …

Susceptibility Of Northern Minnesota Lakes To Acid Deposition Impacts, Clifford J. Twaroski, J. David Thornton, Rick L. Strassman, Patrick L. Brezonik

Journal of the Minnesota Academy of Science

ABSTRACT-lake chemistry surveys indicate a large number of lakes with acid neutralizing capability (ANC) below 200 μeq/L occur in northeast Minnesota where shallow soils over bedrock and exposed rock outcrops predominate, and in moraine areas having rolling to steep topography in north-central and east-central Minnesota. In the Boundary Waters area, lake chemistry is strongly associated with bedrock geology. lakes with ANC <100 μeq/L are associated with granite, basalt, and gabbro formations, while lakes with ANC of 100- 200 μeq/L are associated with slate and greenstone formations. In the rest of the state where soils are deep, landform, soil type, and lake hydrology determine lake chemistry. Most low ANC lakes are found in terminal moraine areas. These lakes are generally small ( <40 ha in area), have limited groundwater inflow, and typically classed as precipitation-dominated seepage lakes. Higher ANC lakes (>400 μeq/L) are often associated with agricultural and residential land uses. Relationships found between ANC and bedrock geology, and between ANC and landform and soils, provided the basis for mapping the distribution of low ANC surface waters in Minnesota. …

Residence Times Of Minnesota Groundwaters, Scott C. Alexander, E. Calvin Alexander Jr.

Journal of the Minnesota Academy of Science

ABSTRACT-Tritium, 14C, and nitrate analyses for eighty groundwater samples from selected Minnesota aquifers indicate a range of residence times from a few days or weeks to tens of thousands of years. The presence of significant nitrate contamination in groundwater is confined to recent or mixed groundwaters. Isotopic studies can yield information that will be useful in the design of effective groundwater protection plans in Minnesota.

The Regional Nature Of Lake Water Quality Across Minnesota: An Analysis For Improving Resource Management, Steven A. Heiskary, C. Bruce Wilson

Journal of the Minnesota Academy of Science

ABSTRACT-The diversity and number of lakes in Minnesota may be better understood by the use of regional characterizations of lake and watershed information. Recent efforts have utilized the ecoregion approach to define seven regions across Minnesota, four of which contain 98 percent of our lake resources. Typical land use patterns vary regionally as do lake water quality patterns. Understanding these patterns will assist lake managers to develop realistic goals and minimize false expectations. Regional assessments facilitate the definition of reasonable goals, expressed in terms of: average summer nutrient concentrations, probability of nuisance conditions ( e.g., estimates of algal bloom frequency), …

County-Based Priority Assessment Methodology For Phasing Of Wellhead Protection Programs, H. O. Pfannkuch, M. E. Campion, D. C. Mccaa, J. M. Palenberg

Journal of the Minnesota Academy of Science

ABSTRACT-Setting priorities to schedule and implement wellhead protection programs for municipal and community drinking water supplies is presented in the framework of a general risk assessment approach. This includes a hazard identification procedure representing the likelihood of contaminants being released to the surface environment, a hydrogeologic vulnerability assessment representing the risk of contaminants entering the groundwater supply, and an impact assessment, strongly linked to the population at risk. A methodology was developed to aggregate information on a county basis for Minnesota. The resulting composite risk index map shows a number of counties in the central part of the state roughly …

Factors Affecting Water-Supply Potential Of The Twin Cities Metropolitan Area Aquifer System, Michael E. Schoenberg

Journal of the Minnesota Academy of Science

ABSTRACT-The Twin Cities aquifer system in Minnesota contains five aquife~s and fou: confining units that together consist of fourteen geologic units. Unconsolidated sand and gravel aqmfers overlie bedrock sandstone and carbonate aquifers. Between 1880 and 1980, groundwater wi_thdrawals have c_aused long-term wate~ level declines of as much as 90 feet in the Prairie du Chien-Jordan aquifer and 240 feet m the deeper Mount S~monHinckley aquifer-the two major sources of groundwater supplies in the ar~a .. The estimated max1mu1:1 continuous withdrawal rate from the aquifer system is about 650 Mgal/d (million gallons per day). This compares with an average daily groundwater …

A Hydrologic Model For Minnesota Peatlands, Kenneth N. Brooks, Dawn R. Kreft

Journal of the Minnesota Academy of Science

ABSTRACT-The Peatland Hydrologic Impact Model (PHIM) is a continuous simulation computer model developed over a twelve-year period to aid hydrologists in understanding the hydrologic functions of peatlands and upland-peatland watersheds. An initial conceptual model defined the research needed to create the working m?del. The re~e_arch has become an iterative process of model design, field work, model refinement, ~ode! test1?g, an~ add1t1?nal field work. The model is as physically-based as possible while relying on data mput that 1s readily available to the natural resources community. It simulates streamflow response of peatlands, upland-peatland systems, mined peatlands, and a combination of these watershed …

Human Impacts To Minnesota Wetlands, Carol A. Johnston

Journal of the Minnesota Academy of Science

ABSTRACT-Minnesota's 3.6 million ha of wetlands have been impacted by a variety of human activities, including agricultural drainage, urbanization, water control, and nonpoint source pollution. More than half of Minnesota's wetlands have been destroyed since the first European settlers arrived, an average loss of about 35,600 ha/yr. Drainage for agriculture is the major cause of wetland loss in Minnesota, particularly in southern Minnesota and the Red River Valley. In addition to impacting wetlands directly, wetland drainage affects downstream areas by increasing flood flows, and releasing sediment and nutrients. Urban development and highway construction affect a smaller proportion of Minnesota's wetlands, …

Hydropower Research And Development In Minnesota, Roger E. A. Arndt, John S. Gulliver

Journal of the Minnesota Academy of Science

ABSTRACT-Although hydropower development in Minnesota accounts for a relatively small percentage of its total electricity production (2-3% ), it has a very favorable impact on Minnesota's economy. Every dollar saved on fuel purchases outside of Minnesota is the equivalent, considering the average economic turnover of money in Minnesota, to spending three dollars within the State. In addition, an estimated 320 million dollars of possible new construction of economical hydropower installations would also represent a significant boost to the local economy since hydropower is a technology that can be developed with Minnesota-based engineering firms and construction contractors. This paper summarizes the …

The Comprehensive County Water Planning Process In South Central Minnesota, Henry W. Quade, Robert A. Barrett

Journal of the Minnesota Academy of Science

ABS~CT-Development of co_unt)_' comprehensi~e water plans is underway in a majority of Minnesota counties as a result of recent leg1slat1on. The planning process requires the fashioning of new relationships and r~les for local and st~te _government, agen':Y personnel, and interdisciplinary technical teams. Early water planning efforts reve~I. s1gmfi~ant problerI:s with the adequacy and applicability of existing water resources da~. Assessment of e1t1Zen attitudes regarding water resource issues was found necessary to link support with policy and develop public education activities. Analysis of water resources data combined with citizen and stat~ agency attitudes has enabled counties in south central Minnesota to …