Physical Sciences and Mathematics Commons^™

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 …

Soil Conservation/Water Quality Wetlands And Symposium

Journal of the Minnesota Academy of Science

No abstract provided.

Influence Of Vegetated Wetlands On The Water Quality Of Two Glacial Prairie Lakes, Lois Haertel, Walter G. Duffy, Daniel E. Kokesh

Journal of the Minnesota Academy of Science

We investigated the influence of vegetated wetlands on water quality of two eastern South Dakota glacial prairie lakes. Surface water from a 5,880 ha pastured basin drains into a 90 ha upstream Typha wetland and enters Lake Enemy Swim passing 400 m through Typha-Scirpus littoral wetland. A second 1,290 ha basin characterized by row crops and pasture drains into a 260 ha open water slough entering L. Enemy Swim adjacent to Typha-Scirpus littoral wetland. Water enters Lake Cochrane from two smaller drainage basins. Water from a 180 ha basin consisting of a pasture and wet meadow enters the lake after …

Wetlands/Groundwater Quality In Agricultural Landscapes, D. H. Rickerl, D. E. Kringen, T. A. Machacek

Journal of the Minnesota Academy of Science

In the Prairie Pothole Region (PPR - SO, NO, MN, IA), wetlands classified as "semi-permanent" or "seasonal" can act as groundwater recharge sites. The nutrient filtering capacity of wetlands has been investigated for both natural and constructed wetlands linked to surface water, but there is little information available on their subsequent impact on groundwater quality. This study investigates four seasonal and two semi-permanent wetlands in the PPR of eastern South Dakota. Transitional no-till (TNT) and organic farm (ORG) management systems border the wetlands. The objective is to determine the effects of farm management system on wetland surface water and groundwater …

Restoring Agricultural Drained Wetlands: A "Reinvest In Minnesota" (Rim) Initiative, Thomas A. Wenzel, David H. Behm

Journal of the Minnesota Academy of Science

Minnesota possessed about 18.5 million acres of wetlands in 1950; by the 1980s, the acreage had been reduced to 7.5 million acres. An innovative, locally-administered state program is helping to bring back a part of this heritage.

The wetland restoration component of the Reinvest In Minnesota (RIM) Reserve Program acquires perpetual conservation easements from landowners to restore drained wetlands and convert them back to their natural state. The program provides limited funding to cover costs associated with restoring drained wetlands and establishing vegetative cover on adjacent uplands. The Board of Water and Soil Resources (BWSR) administers the program through local …

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 …

Minnesota Wetland Conservation Act: Wetland Banking System, John Jaschke, Greg Larson

Journal of the Minnesota Academy of Science

The Minnesota Wetland Conservation Act (WCA), is a "no-net-loss" state wetland protection program that became law in June 1991. The WCA prohibits the draining and filling of wetlands unless replaced by restored or created wetlands of equal or greater public value under an approved replacement plan. Local government units (LGUs) administer this state program that includes a comprehensive yet simple wetland function and value assessment to achieve wetland replacement. The WCA also was the impetus for the development of a state wetland banking system which allows both public and private sector project sponsors to participate.

The resultant system evaluates existing …

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 …

The Role Of Economic, Management And Public Policy Factors On Post-Contract Conservation Reserve Program Land Use Decisions, Larry L. Janssen, Tecleberhan Ghebremicael

Journal of the Minnesota Academy of Science

Most Conservation Reserve Program (CRP) contracts will expire from 1996 to 2001 , directly affecting land use of 36.4 million acres of highly erodible cropland enrolled in this land retirement program. The major objective of this study is to estimate the role of economic, management, and public policy factors on post-contract CRP land use decisions in South Dakota, a Northern Plains state with 2.1 million acres of enrolled land, 10% of the State's cropland base.

The major data source is a 1993 CRP survey sent to a random sample of 8.33 %of South Dakota CRP contract holders and completed by …

Influence Of Vegetated Wetlands On The Water Quality Of Two Glacial Prairie Lakes, Lois Haertel, Walter G. Duffy, Daniel E. Kokesh

Journal of the Minnesota Academy of Science

We investigated the influence of vegetated wetlands on water quality of two eastern South Dakota glacial prairie lakes. Surface water from a 5,880 ha pastured basin drains into a 90 ha upstream Typha wetland and enters Lake Enemy Swim passing 400 m through Typha-Scirpus littoral wetland. A second 1,290 ha basin characterized by row crops and pasture drains into a 260 ha open water slough entering L. Enemy Swim adjacent to Typha-Scirpus littoral wetland. Water enters Lake Cochrane from two smaller drainage basins. Water from a 180 ha basin consisting of a pasture and wet meadow enters the lake after …

How A Refocused Crp Could Be Administered In Minnesota, David H. Behm

Journal of the Minnesota Academy of Science

Reinvest In Minnesota (RIM) Reserve and Permanent Wetland Preserves (PWP) are state conservation easement programs designed to keep certain marginal agricultural land, including drained restorable wetlands, and existing types 1, 2, 3, or 6 wetlands out of crop production to protect soil and water quality and enhance fish and wildlife habitat.

The Minnesota Board of Water and Soil Resources (BWSR) suggests an alternative approach to administering a refocused Conservation Reserve (CRP) and the new Wetland Reserve Programs (WRP), in Minnesota. BWSR could enter into a delegation agreement with the U. S. Department of Agriculture to transfer easement acquisition, practice establishment, …

Singularity Of Super-Brownian Local Time At A Point Catalyst, Donald A. Dawson, Klaus Fleischmann, Yi Li, Carl Mueller

Mathematics and Statistics Faculty Publications

No abstract provided.

Three-Dimensional Fabry-Perot Imaging Spectroscopy Of The Crab Nebula, Cassiopeia A, And Nova Gk Persei, Stephen S. Lawrence, Gordon M. Macalpine, Alan Uomoto, Bruce E. Woodgate, Larry W. Brown, Ronald J. Oliversen, James D. Lowenthal, Charles Liu

Astronomy: Faculty Publications

Three-dimensional spatial models of the line-emitting gas in the Crab Nebula, Cassiopeia A, and the nova remnant of GK Persei have been developed from imaging spectroscopy taken with the Goddard Fabry-Perot Imager mounted on the McGraw-Hill 1.3 m and Hiltner 2.4 m telescopes of the Michigan-Dartmouth-MIT Observatory. The spatial model of the Crab Nebula in [O III] λ5007 emission reveals the thin, annular morphology of the "high-helium torus," the association of this torus and other bright filament loops with north-south bipolar asymmetry of the remnant shell, the structure of the filamentary shell at the boundary with the inner synchrotron cavity, …

Transient Data Sharing Among Mobile Programs, Jerome Plun, Gruia-Catalin Roman

All Computer Science and Engineering Research

Mobile computing represents a major point of departure from the traditional distributed computing paradigm. The potentially very large number of independent computing units, a decoupled computing style, frequent disconnections, continuous position changes, and the location-dependent nature of the behavior and communication patterns present designers with unprecedented challenges in the areas of modularity and dependability. This paper describes a modular approach to specifying and reasoning about of mobile computing. Its novelty rests with the notion of allowing transient (location-dependent) data sharing among programs which move in space. The notation is a direct extension of that used in UNITY and reasoning about …

An Efficient Signaling Structure For Atm Networks, Dakang Wu

All Computer Science and Engineering Research

As ATM becomes widely accepted as the communication standard for high speed networks, the signaling system structure and protocols that support ATM become more and more important. To support existing, future and unknown applications, the signalign system has to be very flexible and efficient. In this paper we define the signaling problem, present several possible signaling system structures, compare the advantages and disadvantages of these systems, and then we propose a new signaling system structure. The fundamental idea of the new signaling system is the logical separation of the signaling system structure from the underlying communication network, even though they …

Building Interactive Distributed Applications In C++ With The Programmers' Playground, Kenneth J. Goldman, T. Paul Mccartney, Ram Sethuraman, Bala Swaminathan And Todd Rogers

All Computer Science and Engineering Research

No abstract provided.

Efficient Demultiplexing Of Network Packets By Automatic Parsing, Mahesh Jayaram, Ron K. Cytron

All Computer Science and Engineering Research

Packet filters are a mechanism for efficiently demultiplexing network packets to application endpoints. There is currently no general, formal specification method for packet filters that allows for easy or efficient composition of specifications. In this paper we present an automatic approach that achieves all of these goals. We approach packet filter specification as a language recognition problem: each filter is represented by a context-free grammar, whose language is the set of packets the filter should accept. Thus, packet filters can be formulated through a general, well defined specification; further, the grammar-based approach simplifies filter composition, which is essential where scalability …

Table Of Contents Volume Six, Number One, Winter 1995, Risk Editorial Board

RISK: Health, Safety & Environment (1990-2002)

Table of contents for the journal RISK: Health, Safety & Environment (ISSN: 1073-8673)

Perceived Risks Of Emfs And Landowner Compensation, Linda J. Orel

RISK: Health, Safety & Environment (1990-2002)

Although public concerns about EMFs may eventually prove groundless, they can nevertheless depress the market value of residential property near powerlines. Ms. Orel argues that the scientific truth, as courts increasingly recognize, should play no role in determining whether or how much landowners should recover.

Getting Through The Door: Threshold Procedural Considerations In Right-To-Die Litigation, Sharon F. Dipaolo

RISK: Health, Safety & Environment (1990-2002)

Ms. DiPaolo explains how judges may use mootness, ripeness and standing to avoid getting involved in right-to-die cases. She argues that this may interfere with private decision making and be counterproductive.

A Survey Of Residual Cancer Risks Permitted By Health, Safety And Environmental Policy, March Sadowitz, John D. Graham

RISK: Health, Safety & Environment (1990-2002)

The authors describe permitted U.S. residual cancer risks, focusing on numerical levels specifically and implicitly authorized by statute or regulation. They also discuss potential changes.

The Greening Of Technology Transfer: A Conference Summary, William O. Hennessey

RISK: Health, Safety & Environment (1990-2002)

Dr. Hennessey briefly reports on an international conference that explored the relationship between patent and other intellectual property laws and those designed to protect the environment and maintain biodiversity.

Senator Johnston's Proposals For Regulatory Reform: New Cost-Benefit-Risk Analysis Requirements For Epa, Linda-Jo Schierow

RISK: Health, Safety & Environment (1990-2002)

Dr. Schierow compares provisions designed to improve the development of regulations and promulgated by Reagan and Clinton Executive Orders with those in the Johnston Amendments.

Review Of: Lawrence J. Kaplan & Rosemarie Tong, Controlling Our Reproductive Destiny: A Technological And Philosophical Perspective, Sophie M. Sparrow

RISK: Health, Safety & Environment (1990-2002)

Review of: Lawrence J. Kaplan & Rosemarie Tong, Controlling Our Reproductive Destiny: A Technological and Philosophical Perspective (The MIT Press 1994). Appendix (basic biochemistry), illustrations, index, notes, preface, series foreword by Samuel Goldberg, tables. CIP 93-38060, ISBN 0-262-11176-4 [418 pp. Cloth $29.95. 55 Hayward St., Cambridge MA 02142.]