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681 Uppsatser om Soil moisture gradient - Sida 12 av 46
Tilla?ggsisolering och fuktproblem i grundkonstruktionen platta pa? mark : En fallstudie i flerbostadshus inom stadsdelen Sa?tra i Ga?vle
Between 1965 and 1974, the Swedish Parliament decided to build one million dwellings, called Million Program. The million program buildings were erected with new, untried design solutions, in a short range of time, and at low cost. The residential buildings from that time are now greatly in need of renovation. The municipal housing company, Gavlega?rdarna, renovates and improves the energy efficiency at some of it?s apartment buildings in the district Sa?tra, Ga?vle.
Hur påverkasogräsuppkomsten av jordbearbetning :
Today it is common to spray against most weeds by using very expensive weed-killers.
The goal for every farmer is to have as low costs as possible for their use of machines and weed-killers.
Therefore it is in everyones interest to find other methods to fight the weeds.
Finding a way to reduce the rise and growth of weeds already at the preparation of the soil would lower the number of laps over the field and also decrease the amount of weed-killing dose.
Tests show that by harrow in the dark it is possible to reduce the population of weeds with up to 60%, but the normal reduction would be about 20-30%.
To verify the results above we made tests by using two different methods of preparing the soil. We tested ploughing and harrowing in daylight and during night. Later we checked the number of different weeds in areas prepared in daylight and during night.
By studying the results from the different methods used we found a considerable reduction of some kinds of weeds in areas prepared during night..
Små skogliga vattendrag i Värmland - Generell beskrivning, förekomst av traktorspår samt spårens inverkan på bottenfaunan :
Modern forestry requires a high degree of machine traffic for clear felling and scarification operations. The machines most frequently used are big and the traffic often results in tracks on the forest ground. There are many small streams running through a forest, in connection to logging operations, machines might cross these frequently. These crossings could result in the erosion of fine particulate inorganic matter, which ends up in the stream. The aim of this thesis was to give a general description of small forest streams of order-one in the county of Värmland and to determine the frequency of machine tracks in small streams.
Preparatanvändning och ogräsförekomst på gårdar med olika jordbearbetningsstrategier
Reduced tillage has increased in Sweden during several years, primarily to decrease costs andincrease efficiency in crop production. Despite this, mouldboard ploughing is still the mostcommon primary tillage method on most farms. The aim with this thesis was to compare theuse of pesticides and the occurrence of weeds on ten farms in Skåne and ten farms inMälardalen that use different soil tillage systems. The object of the study was also to clarifywhy the farms had chosen their specific soil tillage system and the consequences it has had onweed occurrence and use of pesticides. The result showed a slightly higher use of pesticideson the farms that use reduced tillage.
Inventering av förorenade områden enligt MIFO-fas 1 : Erasteel Kloster AB, Söderfors
Erasteel Kloster AB Söderfors have been commissioned by the county administrative board in
Uppsala län to make an inventory of possible contaminations in theirs industrial- and landfill areas on the basis of the Swedish Environmental Protection Agency?s; ?Method of Surveying Contaminated Sites-phase 1? (MIFO-fas 1). The inventory starts with maps and archive studies, place visits and interviews, and finally a risk classification is done. A risk classification is a compilation of four categories; pollutant toxicity, contamination level, possible spreading condition of the pollutant, sensitivity and protection value of the environment.
In this paper five partial areas (Holmen- and Jörsöområdet, Järnsvampsområdet,
Ingsådeponin, Östra verken and Myrområdet) have been described from a historical point of
view. Only parts of four areas have been risk classified (Holmen- and Jörsöområdet,
Järnsvampsområdet, Ingsådeponin and Östra verken), due to that the other areas isn?t own by Erasteel Kloster AB.
Holmen- and Jörsöområdet
Holmen- and Jörsöområdet have during the entire activity time been carried out as the
production core in the company.
Phosphorus in agricultural soils around the Baltic Sea : comparisons of different laboratory methods as indices for phosphorus leaching to waters
Eutrophication of the Baltic Sea is a serious problem. A major contributing factor is diffuse losses of phosphorus (P) from agricultural land in surrounding countries. In order to estimate P losses, environmental monitoring of small agriculture-dominated catchments is being carried out in most of these countries. Evaluation of the risk of P leaching to waters is usually based on chemical tests originally developed to quantify the amount of soil P available for plant production. The tests are performed in different ways in the different countries and a number of different extraction agents are in use.
Stubblyftningens initiala effekt på emissioner av växthusgaser från en granmark i Småland :
In order to reduce greenhouse gas emissions from human activities fossil fuels will have to be replaced with renewable energy alternatives, such as bioenergy. Sweden has a great potential to produce bioenergy derived from forest products and there is currently a great interest within Sweden in using stumps for bioenergy production. However, the environmental consequences of the method need to be investigated before stump removal can be performed on a large scale. Swedish forest soils contain large carbon pools and a different land use may change conditions so that soils that presently act as sinks of carbon could potentially turn into sources of carbon release instead.
This study investigates the initial effects of stump harvesting on the emissions of three greenhouse gases, carbon dioxide, methane and nitrous oxide. The emissions were measured from the soil surface in a Norway spruce forest located in the southern part of Sweden.
Tillämpning av en markprofilmodell för hydrologiska beräkningar i avrinningsområdesskala
There is a great need to reduce nutrient leaching from arable land into lakes and oceans. By using several different types of models it has previously been possible to describe nutrient losses in a catchment area with a minimum unit of sub-catchment level. At present, it is instead desirable to model a smaller catchment with an opportunity to re-connect the results to the corresponding fields in the catchment. Such models already exist but they are not fully able to properly describe Swedish conditions and land characteristics in our region.With the approach of creating such a model, SLU has developed a project with this work as its first stage. The model is expected to be created under the working name SWE-model which stands for Soil Water Environment and is in this first stage supposed to apply the SOIL model in catchment scale. During the procedure to describe the first step in the process of developing such a model adapted to Swedish conditions and which works in the catchment scale with an area of about 10-30 km2, focus has been set on calculating the transport of water flow from different hydrological response units. Regardless of the processes occurring in the soil after the water has been added, it is assumed that all the water which flows from each simulated unit is drained.In the first step the hydrologic response units were identified based on land use and soil type in the study area. With the help of a script with functions that retrieve and transform data, certain units were chosen for simulation. The script was also created in this project. Finally, the model results were aggregated and summarized for each unique unit, for each sub-catchment, and also for the whole catchment.From the results it is possible to see similarities in the flow dynamics between modeled and measured data. The efficiency coefficient has been calculated to correspond to the mean of the measured values for the whole simulation period. With an automated calibration process the model should be able to perform better. The volume error gives an indication of overestimation from the model..
Fuktåterföring i roterande värmeväxlare
För att ha en chans att ändra trenden med ökande utsläpp av växthusgaser är internationella samarbeten nödvändiga. Därför har EU genom miljökvalitetsmålet Begränsad Miljöpåverkan satt krav på högsta tillåtna utsläpp av växthusgaser. Att sänka energianvändningen för upp- värmning är ett steg i att även sänka utsläpp av koldioxid, som är en av växthusgaserna. Sänkning av energianvändning kan göras på flera sätt, bl.a. genom att öka tjockleken på isoleringen eller återvinna värmen i frånluften. Men dessa åtgärder ska inte helt okritiskt göras.
Förekomsten av sura sulfatjordar i Mälardalen : -en pilotstudie utförd åt SGU
Acid sulphate soils is a wide spread problem along the northern coast of Sweden. This is causing great damage through low pH and leaching of metals out into the streams. These soils are estimated to be found in several places in Sweden but also in many other areas in the world. One of these areas in Sweden that are believed to contain these sediments is Mälardalen. The purpose of this study is to evaluate the extension of the acid sulphate soils in this area.
Undersökning av självspridning av contortatallen i norra Sverige
Over the past 40 years 600 000 ha of lodgepole pine (Pinus contorta ssp. latifolia (Engelm.) Critchf.) has been planted in Sweden (280 000 ha on SCA's forest land alone which represents about 15% of the company's total forest land area). In the early 70's SCA situated a number of experimental stands in order to investigate different aspects of the exotic tree, primarily growth rate. To be able to compare the two species plots with scots pine (Pinus sylvestris L.), this species was also planted at the same time and under the same conditions.
A number of questions should always be raised when exotic species are introduced in an ecosystem. Invasiveness, the pathogen situation and purely ethical issues should be discussed.
Trä och fukt ? Mätmetoder för fuktrelaterade dimensionsförändringar hos trä och deras användbarhet, med två fallstudier inom konservering
This thesis deals with different methods for measuring moisture-related dimensional changes ofwood. Typically relative humidity is measured to determine if the ambient climate around anobject is harmful to it or not. Values between 40 to 65% RH are recommended for hygroscopicmaterials. To know how a wooden object actually reacts to changes in the surroundingenvironment requires methods that involve the object itself. Because of the wood anisotropy,differences in wood structure, finishes and other restraints, it is not always possible to predict themovements.This paper addresses various measurement methods, primarily methods that have been testedin the field of conservation, with examples of their use.
Nutrient effects on microorganism communities in nutrient poor soils
Better, more efficient fertilizers with great productivity and economic returns are needed, but it is important today to find fertilizers that are also sustainable. It is also important to carefully monitor their impact on the environment, including potential side-effects. In this context, the microbial communities that carry out numerous essential functions contributing to a functional ecosystem are of particular interest.
The present study is a complement to a pot experiment that investigated the potential of different waste products for use as fertilizers and how they affect the microbial community. In the pot experiment, the clearest treatment change in microorganism community function was found in the fully fertilized treatment used as a positive control. The question was whether this was indirect, i.e.
Produktivitet vid stubblyftning :
Stump wood was used between 1850 and 1950 for production of tar and as firewood. In the 1950s the use decreased because of the introduction of the cheap fossil oil. In the 1970s stump wood became an interesting issue again as a raw material for the pulp industry. Stump lifting has today become a possible source for bioenergy. The objectives with this study were to investigate the productivity of stump lifting and stump extraction, and to analyse the economy.
Bokhögstubbar i Klåveröds strövområde : utbredning, egenskaper och betydelse för rödlistade vedlevande skalbaggar
Lack of dead wood is the main cause of decaying or loss of populations for many
forest species. To increase the amount of dead wood is a prerequisite to maintain
biodiversity in forests of northern Europe. In summer 2006 the recreation area
Klåveröd, at Söderåsen in Skåne, Sweden, has been inventoried for high stumps
(snags) of beech, (Fagus sylvatica). The result of the inventory has been compared
with data of the real estate and forest management directories from the owner,
region Skåne. The results have also been matched with the results from an
inventory of saproxylic beetles in 2005, performed with windowtraps on selected
snags both in the area and the adjacent national park Söderåsen.
594 snags were found on 747 ha.