Road salt and other products used for winter maintenance in the Northeastern United States and Canada can impact ecosystems, pose risks to aquatic life, and create human health concerns. In response to these impacts and rising cost of materials, many municipalities have adopted preventative best management practices (BMPs) that reduce the amount of application materials used, save money, and/or provide a similar level of service and safety. Private companies that maintain parking lots and private roadways also contribute to the increasing chloride concentrations seen in the northeastern United States and Canada, but the practices of these companies have largely not been previously assessed. This mixed-methods study focused on private contractors in the Lake Champlain Basin in Vermont and New York who maintain parking lots, driveways, and roadways. A census and interviews were used to characterize practices used by private contractors and to identify key factors that drive their decision-making processes. A literature review was conducted to understand winter maintenance practices including recommended BMPs, potential environmental impacts and ways that contractors may be incentivized to adopt reduced-salt practices. The literature review informed the development of a census of winter maintenance companies in the Lake Champlain Basin. Contractors most often reported maintaining parking lots and roadways, and most commonly applying sand and salt. Physical snow removal techniques and adjustable material application rates were commonly adopted BMPs. Other BMPs including proactive applications, calibrating equipment, and using brine were infrequently adopted. In addition, the study examined the motivations and barriers contractors have to adopt recommended BMPs through qualitative and quantitative methods. Commonly reported motivations included perceived liability or safety concerns, customer request or expectations, and cost. Commonly reported barriers included cost, time, and customer requests or expectations. Across census and interview results, companies that focus on commercial lots and individuals who learn management practices through in-person trainings or online resources were found to use more recommended BMPs than other groups. Results of the study informed the development of outreach recommendations to increase private contractors’ adoption of BMPs and to lessen road salt use. These included: developing online resources, annual conferences, and reoccurring in-person trainings.

Wheat is one of the major crops of Utah and for more than 50 years farmers have been raising wheat on the dry lands of the state. The system they use is known as the alternate cropping or crop-follow system and consists of one year of crop alternating with one year of clean cultivation known as fallow. Wheat removes a considerable amount of the natural plant food elements from the soil each year. This is especially true of nitrogen. According to Bracken and Greaves (9) the original low supply of nitrogen in most Utah soils together with the depleting effects of alternate wheat and fallow has the possibility of making nitrogen rather than moisture the limiting factor of crop production in certain dry-farm areas. The amount of nitrogen removed from the soil by the wheat crop is only a portion of the total supply. Such factors as leaching to a lower depth beyond the feeding range of the plant, erosion, denitrification, and volatilization through biological and possibly chemical action are thought to be responsible for the loss of nitrogen unaccounted for by crop removal. The results of several investigators indicate that this loss is approximately twice as much as was removed by the crop. Since nitrogen is one of the major factors responsible for high yields and high quality of wheat, it naturally follows that any reduction of the amount of nitrogen in the soil produces a corresponding reduction in yield and quality of wheat. Recent reports show that this condition exists in Utah as well as in other areas. As a result of this reduction in yield and quality of wheat, processors are concerned about the problems. The seriousness of the problem cannot be over-emphasized. Ways and means of checking these losses and subsequently increasing the yield and quality are being studied. Three possible procedures for increasing soil nitrogen have been suggested: 1. the use of legumes, especially alfalfa, in a rotation program; 2. non-symbiotic nitrogen fixation: and 3. the use of commercial fertilizers. Since legumes have not been grown to any great extent, the only other natural source of nitrogen has been non-symbiotic fixation. Evidence in this field of investigation, however, indicates that this source is inadequate and that other sources must be bad. Also, the data indicate that no effective methods have been found which increase non-symbiotic fixation. Limited information suggests that further study is needed on the use of legumes for increasing the nitrogen and organic matter content of dry farm soils. This investigation is confined to the use of commercial fertilizers as one solution to the general problem.

Reduced recruitment rates in Utah mule deer (Odocoilus hemionus) showed that significant losses in production were accruing during pregnancy, the neonatal period or during the first few months after birth . The primary objectives of the study were to determine the time, extent and possible causes of these losses. Corpora luteal and fetal rates were estimated by examining the reproductive tracts of 125 carcasses collected on selected herd units in Utah and by observing the reproductive tracts of 136 female deer captured in Spanish Fork Canyon. A laparotomy was performed on each captured female to allow visual examination of the reproductive tract without sacrificing the doe. Live-birth rates were estimated by observing and monitoring pregnant wild does held captive during the fawning period, and by observing free - ranging does tagged with radio- transmitters . Fawn mortality was estimated by monitoring radio-tagged fawns, captured shortly after birth until fawn:doe ratios were observed the following fall. The greatest loss in production occurred during the post-natal period. Annual fawn losses averaged 26.4 percent, while a 3.7 percent interuterine loss occurred before midpregnancy and a 9.5 percent fetal loss was recorded between midpregnancy and parturition. No single mortality factor appeared to be responsible for most of the fawn losses. Condition of the pregnant doe on the winter range was investigated as the cause of reduced recruitment. The condition of the doe had to be accurately estimated while the doe was alive, before the relationship between condition and reproductive success could be evaluated. The condition of 43 carcasses, based upon a modified nutritional status index that included weight corrected for size and age, was highly significantly correlated to condition of the same carcasses estimated by amount of kidney fat (r=0.70, P Weights and sizes of fawns captured shortly after birth were not significantly related to subsequent survival.

Two areas of research are reported: an experiment on the effects of warm temperature prestratification treatments on seed dormancy and a new chill unit model. Crabapple seeds (Malus sargentii Rehd.) were allowed to imbibe water and were given warm pretreatments at temperatures of 16, 20, 24 and 28C for periods of 3, 10, 20 or 30 days before cold stratification at 4C for 20, 40, 60, 80 or 100 days. Pretreatments resulted in increased chilling requirements for seedling emergence. A short chilling period (20 days) also altered the leaf area, shoot length, internodal length and root/shoot ratio of the resulting seedlings. The new chill unit model was developed from data from seed experiments and tested with records of 11 years. A three-dimensional model for the transition through apple tree dormancy is proposed. The new model evaluates the effectiveness of different temperatures for the transition between dormancy induction and dormancy release according to physiological time. The standard of measurement for this model is the chill unit (CU), which is defined as the equivalent of one-hour exposure to the optimal temperature during the optimal physiological time for dormancy development. The general pattern of temperature activity for dormancy development is sigmoidal; and temperature effectiveness through the process varies according to length of exposure, temperature cycling and time. The new model permits a more accurate prediction of dormancy development under subtropical conditions than previous models and will predict the amount of leafing that will occur in spring. The prediction efficiency of leafing under subtropical conditions was improved from an r2 of 0.66 for the Utah Chill Unit Model to an r2 of 0.74 for the new model when compared under Mexican conditions.

Zugl.: Karlsruhe, Univ., Diss., 2006

Winter wheat fields provide upland nesting habitat for migrating birds. Duck nests built in winter wheat croplands experience lower probabilities of nest mortality due to farming practices compared to nests built in spring wheat croplands. Two dynamic optimization models are specified in order to measure economic (producer’s profit) and environmental benefits (mallard population) derived from increases in winter wheat acreage in the Prairies. The first model, maximizes the farmer’s revenue due to spring and winter wheat production, subject to mallard population dynamics. The second model uses a social planner point of view to maximize both the farmer’s revenue obtained from wheat production, and social benefit associated with mallard population. The connection between duck population and winter wheat is specified using a logistic growth function where the intrinsic growth rate is a function of winter wheat acreage, and carrying capacity sets the maximum numbers of ducks in a specific area. / Agricultural and Resource Economics

Two experiments measured winter feed waste when cows were fed forage on snow. In the first experiment, feed waste was different (P<0.01) when alfalfa meadow brome mixed hay was fed by bale unroller or bale processor; waste was12.9% vs.19.2%, protein losses were 23.3% and 21.5% respectfully. Feed waste, nutrient replacement and additional equipment costs increased winter feeding costs by $52.50 and $56.25 per head respectfully for a 175 day feeding period. Hay processed into portable bunk feeders, experienced 0% feed waste. In the second experiment, feed waste when barley cereal silage fed either as high moisture round bale silage or chopped pit silage was fed on snow was not different (P>0.05) at 23.2% and 26.8% respectfully. When chopped barley cereal silage or high moisture round bale silage was fed into bunks, feed waste was 0%. Protein losses were 27.1% and 24.2% for the pit and round bale silage. Feed waste, nutrient replacement and additional equipment costs increased winter feeding costs by $164.50 for pit silage and $126.00 for bale silage over a 175 day feeding period. / Animal Science

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Timothy E. Targett, College of Marine and Earth Studies. Includes bibliographical references.

Increasing cycling as a means of personal travel couldgenerate environmental benefits if associated with acorresponding decrease in car-based transport. In seeking topromote cycling in wintertime, it is desirable to understandhow important the road surface condition is compared to otherfactors in people's decision to cycle or not. In this thesis,the possibility of increasing the number of cyclists byimproving the winter maintenance servicelevel on cycleways isexamined. The attitudes towards cycling during winter ingeneral, and in relation to winter maintenance of cycleways inparticular, is studied through questionnaire surveys. Bicyclemeasurements are related to weather data from Road WeatherInformation System, in order to know the influence on cycleflow during winter from different weather factors. Fieldstudies are performed testing unconventional winter maintenancemethods, in order to see if a higher service level could beachieved on cycleways and if that would lead to an increase inwinter cycling frequency. The field studies are evaluatedthrough road condition observations, measurements of friction,bicycle counts, a questionnaire survey and interviews. A visualmethod to assess winter road conditions on cycleways isdeveloped, in order to compare the service levels achievedusing different winter maintenance methods. There is a clear difference in mode choice between seasons.With improved winter maintenance service level it could bepossible to increase the number of bicycle trips to work duringwinter with, at the most, 18 %, and decrease the number of cartrips with 6 %. However, it could not be concluded with bicyclemeasurements, that an enhanced service level in fact, generateda higher winter cycling frequency. To increase cycling during winter, snow clearance is themost important maintenance measure. Skid control is not assignificant for the choice of mode but is important to attendto for safety reasons. Winter road condition propertiesimportant both with regard to safety and accessibility ofcyclists, are icy tracks formed when wet snow freezes, snowdepths greater than about 3 cm of loose snow or slush,unevenness in a snow covered surface, loose grit on a baresurface. Weather factors with negative influence on winter cyclingfrequency, are temperatures below +5 ° C,precipitationand strong winds. Only the occurrence of precipitation, not theamount of rain or snow, is significant for the cycle flow. Lowtemperatures are more important in reducing the cycle flow thanprecipitation. Temperatures around 0 ° C seem to be extracritical for cyclists, probably due to the larger influence ofprecipitation and slippery road conditions at thesetemperatures. An unconventional method using a power broom for snowclearance and brine or pre-wetted salt for de-icing, provides ahigher service level than winter maintenance methodstraditionally used, but it is about 2 to 3 times moreexpensive. The method has great potential in regions, such assouthern Sweden, with low snow accumulations but with major iceformation problems. To assess the maintenance service level,the visual assessment method developed and tested in thisproject is adequate for the purpose, however, furtherimprovements are desirable. As a complement to the visualassessment, a Portable Friction Tester can be used to measurethe surface friction on cycleways during wintertime. Keywords:Cycleways, winter maintenance, maintenanceservice level, mode choice, winter cycling frequency, wintermaintenance equipment, winter road condition assessment,bicycle measurements, friction measurement.

In temperate climate with pronounced seasonality, ice and snow cover reduces light conditions during winter which in turn reduce search efficiency for visual feeding consumers like fish. Furthermore, a suggested major effect of future climate change is an increased input of allochtonous DOC to aquatic systems which causes an increased brownification and hence reduced overall light conditions. In this study, I sampled YOY three-spined sticklebacks (Gasterosteus aculeatus) of different sizes overwintering in clear and brown water model ecosystems to examine if consumption were dependent on light conditions (natural light variability over winter) and if consumption were reduced in brown water. Three-spined sticklebacks were able to feed at different winter conditions and the prey biomass in stomachs was higher in clear- than in brown water despite higher resource levels in brown water treatments. Moreover when light intensity increased in late winter compared to midwinter conditions prey biomass in stomachs increased in both clear and brown water systems. Dominated prey taxa in the diet were chironomids and copepods. Results from this study suggest that when fish species are able to feed at low temperature and resource availability are sufficient light conditions during winter can be an important factor affecting overwinter survival in YOY fish because visual prey encounters and hence consumption rates are affected by light conditions. Future climate change scenarios with predicted increased brownification may therefore affect over winter survival in fish because of the negative effect of low light intensity (brownification) on prey consumption in fish in turn potentially changing recruitment success and densities of fish.