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681 Uppsatser om Soil moisture gradient - Sida 5 av 46
Biologisk behandling av oljeförorenad jord : Abiotiska faktorers inverkan och effekter av olika uppläggningssätt på nedbrytningshastigheten.
The purpose of this report was to investigate how the abiotic factors (temperature, pH, nutrients, oxygen levels and water content) would affect the decomposition of oil-contaminated soil and how a variance in structured soil would affect the decomposition-rate. A minor field-study was made and soil where structured in five different ways (one was a default pile and was used as a reference). The study took place over 137 days and three samples were taken (start, middle, end) and analyzed for aromatic and aliphatic compounds. The result of this study shows that there is a significant difference between all methods for the aliphatic compounds and no significant difference for the aromatic compounds. The abiotic factors that affect decomposition vary from organism to organism, depending on what type of environment it will function the best.
Tid kontra pengar - Goal-gradient effekt vid valet mellan nettonuvärdesmetoden och återbetalningsregeln
Syftet med denna uppsats var att studera om det finns en målgradient vid
investeringsbedömning som medför en preferens för alternativ med kort
återbetalningstid och snabba belöningar.
Vi valde att genomföra denna studie med hjälp av en kvantitativ ansats, då vi
genomförde ett experiment med studenter vid Blekinge Tekniska Högskola. Detta
motiverar vi med att utifrån vårt syfte och vår teoretiska referensram, ger det
oss störst möjlighet att generera ett intressant och relevant resultat.
Vårt resultat visar tydligt att beslutsfattare föredrar att använda
återbetalningsregeln före nettonuvärdesmetoden i en beslutssituation, och
därmed ett fokus på tidsaspekten och när en investering är återbetald. 81 % av
våra respondenter valde tidsalternativet i minst ett av de två casen.
Vattenhaltmätning i konfektyr och sylt med Karl Fishermetoden
Abstract (in English)The task for the diploma work was to develop methods for measuring of moisture content by the Karl Fischer method, in jam, jelly sweets, and fudge.The start premises was a for the company whole new equipment, which should be started up. Then programs should be developed for different kind of samples.In the task it was as well included to develop methods for dissolving the different kind of samples, since the Karl Fischer method demands completely dissolved sample material..
Soil fertility status and Striga hermonthica infestation relationship due to management practices in Western Kenya
Striga hermonthica, a parasitic weed, has long been believed to be correlated with the
declining soil fertility status. However scientists have recently come to question this statement
since some recent studies have shown contradictive results. To investigate whether soil
fertility status and infestation of Striga hermonthica were correlated and the impact of it were
caused by farmer management, 120 farmers in Western Kenya, where Striga hermonthica
infestation is prone, participated in this study. In three districts with two sub-locations each,
farmers answered a structural questionnaire and identified two fields, one with high and one
with low soil fertility. These fields later came to be the basis for this study and soil were
therefore also sampled from them.
Kartläggning av spånprodukter vid Sävar såg
A change towards using more biofuels than fossil fuels is taking place in Sweden, and in many other parts of the world. This makes the use of fuel pellets increasingly popular, causing a greater demand for sawmill sawdust products. There is a trend towards the use of multiple types of shredders, instead of a single type in each sawmill. The purpose of the study was to characterize the different flows of saw particles that can be found at Sävar såg when cutting thick or thin wood with different cutting techniques. The saw particles size, shape, moisture content and heat value were analysed by the cutting stations: first cutting fast and slow, second cutting fast and slow, grading fast and slow and planning.
Where has the fertilizer gone? Closing the nutrient budget for a eucalyptus fertilization experiment in southern China
An increasing demand for wood products in China has resulted in large areas invested in fast-growing tree plantations of eucalyptus. Eucalyptus plantations are often associated with an intensive management including fertilization. By understanding the effects of fertilization and where in the ecosystem nutrients are accumulated a more sustainable forest management could be achieved. In this study, a nutrient budget including all biomass and soil components was created for Eucalyptus urophylla. The examined nutrients were nitrogen, phosphorus and potassium.
Effekten på nedbrytningen av rötter vid tillförsel av ammonium sulfat i en granskog i sydvästra Sverige
Decomposition of organic matter is a critical process in the ecosystem, which involves many essential biotic and physical parts. Decomposition is therefore an important process both above and below ground. The rate of decomposition is dependent of many environmental factors for example: pH, moisture and supply of oxygen. The decomposition can therefore be affected by large scaled environmental influences, such as acidification and climatic changes. The root litter in the forest is in different ways affected by acidification, liming and manuering.
Jämförelse av stenull- och polyuretanisolering : Brand- och fuktegenskaper i passivhuskonstruktion
This report compares two different types of insulation with regards to fire and moisture. The materials were tested for the company Fiskarhedenvillan AB, for a wall and a roof construction that the company currently uses in the establishment of Sweden's first certified passive house for international standards.Their current material, Rockwool, is compared to a relatively new material on the Swedish market called SEALECTION Agribalance sold by the company ISO Green AB. The material is a type of polyurethane insulation. This insulation material would result in a more efficient execution of the construction as it provides waterproofing and is applied more easily than Rockwool. From a fire standpoint, literature studies and discussions with fire experts led to results.
Marktillstånd och borbrist på åkermark planterad med gran i Västerbottens län :
This study was made on former agricultural areas that had been planted with spruce or pine, in the county of Västerbotten. The goal of the project was to investigate suspected deficiency of boron in these areas. Several objects have been reported for possible deficiency and some of these have the characteristic symptoms of boron-deficiency. The hypotheses are that
1) Boron deficiency is present at several of the investigated objects.
2) Planting of forest on cultivated postglacial sediments leads to a successive podzolisation with a decreasing content of organic matter in the mineral soil, due to decomposition, and a decreasing pH in the soil, even on locations that have been added lime.
To be able to confirm or reject the hypotheses a number of tests were performed.
Kvävestatus och risk för nitrifikation i två avverkade skogsområden i Halland
Nitrogen deposition leads to environmental damage in areas where the nitrogen deposition is high. Southwest Sweden receives an annual nitrogen deposition of up to 20 kg N/ha. Nitrogen that is not assimilated by the vegetation is accumulated in the soil, which may lead to nitrogen saturation and an elevated risk of nitrogen leaching. Nitrogen leaching from forest areas in southern Sweden has proven to be higher than from agricultural areas, which have been thought to be the main contributors to elevated nitrogen levels in rivers and lakes. The amount of nitrogen that leaches depends on the fraction of the total nitrogen in the soil that consists of nitrate, since nitrate is easily transported through the soil.
Effekt på mark och gröda av olika bearbetningssystem, med och utan CTF
Swedish agriculture has gone through big changes in the latest 60 years. The farm sizes have increased, which has led to raised tractor and machinery sizes and therefore
increasing problems with soil compaction. A method to reduce these problems is to implement controlled traffic farming, CTF. All field operations are then concentrated
to specific tracks by using GPS guidance.
The aim of this work was to study how the tillage regime, with or without CTF, affects the soil, with the main focus on macroporosity. In Säby close to Uppsala, and Alnarp close to Malmö, randomized block trials has been carried out, and the data has mainly been taken from these trials.
Utvärdering av fosforläckageefter stallgödsling med hjälp av lysimeterteknik : Evaluation of phosphorus leaching aftermanure application using lysimeter techniques
Based on laboratory studies with lysimeters, the concentrations of dissolved reactive phosphorus(DRP) and particulate phosphorus, which is the main part of other P (OVRP), has been studied inpercolating water. The experiment was conducted through irrigation of small soil columnscontaining clay topsoil from an experimental field in Västergötland. Three rain simulations wereconsecutively performed. DRP concentrations in the percolating water ranged between 0.2 - 0.3mg·Lclearly related to the phosphorus concentration in the soil, measured in a soil extract ofammonium lactate (P-AL). Concentrations of OVRP were relatively low and ranged between0.12 and 0.16 mg·Lwas not proven and the experiment may reflect how a relatively slow percolation of water mayrelease DRP.
Vindfällning i naturliga och skapade bryn och kanter :
The aim of this work was to study if the edge of the forest is more resistant to heavy winds than the trees located further in from the edge, and how this edge effect changes between different types of tree species and site types.
The data was collected from an electric power line going from the north to the south of
Sweden. The mean value of the clearcutted area around the power line was 120 meters. The
main direction of the storm in January 2005 was west-southwest and thus the power line was a perfect place for gathering a large data set.
The main parameter studied was the damage frequency at the edge of the forest compared to
the trees located further in from the edge (up to 100 m from the power line). Tree species mixture, soil moisture class, soil type, topography, stand height, stand height of the stand on the other side of the power line and wind exposition was estimated.
The results showed a distinct edge effect. The edge of the forest had clearly lower damage frequency for all tree species.
A marked difference was observed between tree species and damage frequency.
Ants and termites in small-scale plantain farms in Uganda : a comparison between agroforestry and non-agroforestry farms
This study was conducted in Kkingo district, west of Masaka, Uganda. It compared soil macrofauna abundance in non-agroforestry farms with that of agroforestry farms. The agroforestry farms had participated in the Vi Agroforestry´s program between 1995 and 2006, and continued on their own after 2006, when Vi Agroforestry left the area. The soil macrofauna is important for soil structure and processes that are contributing to soil organ-ic matter decomposition and nutrient mineralization. They are also predators of potential pests.
Fosforläckage från växtodling - orsaker och ågärder :
Phosphorus is essential to all plants and is taken up from the soil as the ion H2PO4 - (and to some extent HPO42-). Plant availability depends on, among other factors, the soil pH. In order to provide for plant available phosphorus, it is applied as mineral fertilizers and farmyard manure. However, that causes phosphorus leaching from arable land to surrounding surface waters and lakes and contributes to the eutrofication. There are three types of soils in Sweden that are at higher risk of contributing to phosphorus leakage.