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492 Uppsatser om Non-cohesive soil - Sida 1 av 33

Spetsbärförmåga hos betongpålar slagna i friktionsjord

The purpose of this study was to build a database for point-bearing piles in dense noncohesive soil, predominantly moraine. Further, the database was analysed and areas with difficult geotechnical conditions was identified.The database includes for point-bearing piles driven to refusal in moraine. Piles with mainly shaft friction have been excluded. Only concrete piles have been included. Geographically the database covers almost all geotechnical conditions of Sweden.

Kvävemineralisering från stallgödsel beroende på olika grad av inblandning i mark

The impact of the distribution in the soil volume of two farm manures on the net mineralization and immobilization processes of nitrogen were studied in an incubation experiment. Cattle slurry and broiler litter were placed in the soil with three procedures for incorporation including placement on top of the soil (TOP), in the middle of the soil (MID) and mixed homogenously with the soil (MIX). During the two weeks of incubation, few significant differences in net mineralization were seen between TOP, MID and MIX. However, there was a tendency that MIX led to a larger net immobilization of N than placement at one point (TOP and MID). This is also the result in the literature.

JB-TOTALSONDERING : Jämförande sonderingar och utvärdering av egenskaper i isälvsavlagringar kring Igelstaviken

The main purpose of this thesis has been to find a way to evaluate the soil parameters for the Total sounding method (TS), such as the inner friction angles and settlement modules. This study only includes an analysis of soil profiles from the Stockholm region. The chosen location for the study is a proposed residential area east of Igelstaviken in Södertälje. Presently, the subject plot is located in a residential area and is also adjacent to a school area.Total sounding is originally a Norwegian soil testing method. The differences between the sounding methods (weight-, ram-, CPT-sounding) are for instance how the sound is driven into the ground and what kind of parameters that are registered.

Markskadefri avverkning - från traktplanering till plantering

This study is made for Södra skog and is concerning how to minimize soil damage from planning to plantation. The purpose of the study is from the respondent?s perspectives; their own ideas and approaches. What emerged from the interviews is that the communication between the different organization levels can be improved. It is also important to prevent damage on the soil and to have in mind that the process of planning tracks to plantation continues for a long time and because of that, the soil condition meanwhile will change..

Långsiktig förändring av fosforhalt och skördenivåer för jordar med höga P-AL-tal : en analys av försöksserien "Exploatering av höga fosfortillstånd"

The field trial Exploatering av höga P-AL-tal (Exploiting P in heavily P dressed soils) started in 1982-1983 and included seventeen study sites placed across Sweden. Each site included three treatments, one unfertilized control (A), one aiming at replenishment of harvest removal, i.e. fertilized with 15 kg P ha-1 year-1 (B) and one over-fertilized (C) with 30 kg P ha-1 year-1. In this thesis data from the five longestrunning study sites are analysed based on four hypotheses. The hypotheses stated that in soils with high P-AL values and a pH over 6.0 P-AL will not decrease over time in the control (A) or in the replenishment treatment (B), that P-AL and P-HCl in the top soil will increase at all sites for the over-fertilized treatment (C) and that yields will not decrease as long as the P-AL is above 12 mg P 100 g-1 soil. My conclusions from the analysis of data from the selected sites are as follows: - A pH above 6.0 cannot guarantee a stable P-AL value in an unfertilized but phosphorus-rich soil. - The P-AL of unfertilized soils decreased faster at lower soil pH than at higher pH. - In the replenishment treatment (B) the rate of P-AL decrease seems to fall at a pH of 6.5. However, the influence of the soil type cannot be ignored. - P-AL and P-HCl did not increase in all over-fertilized treatments.

Vinster med björkinblandning i granbestånd i syfte att höja markens pH-värde

The soil acidification and the pH-value of the soil have been discussed for many years. Many observations of the tree species effects on the soil pH have been done. We have discussed the effects on the soil surface pH-value with a birch (Betula spp. L.) admixture in Norway spruce stands (Picea abies L.).We have used data from the Swedish National Forest Inventory. We have also discussed how the wood production and the biodiversity can be increased in mixed stands, in according to the Swedish forestry act Skogsvårdslagen. Our sampling areas are located in Norrland, Sweden. The results show a significant correlation between an increased birch admixture and an increased pH-value of the soil.

Strukturkalkningens möjlighet att hindra fosforutlakning : en litteraturstudie

The purpose of this essay is to find out if liming with Ca(OH2) and CaO can reduce leachingof phosphorus from agricultural land and the problem with eutrophication. This purpose alsoincludes getting knowledge about how to make the phosphorus retained in the soil and beaccessible for the plants. This essay is supposed to show if more research is needed in thissubject. There has not been much research about this subject and therefore the amount ofmaterial to study is limited in this literature review. The research reports that have beenstudied have similar results.

Olika metoder och tekniska hjälpmedel för att bestämma bevattningstidpunkt :

This examination work on studies and research in articles is mostly from other countries. The purpose of the examination work have been to find out if there are any means you can work with to find out when its time to start irrigation, how they works and if they are credible. In Sweden there is not many means for decide when it?s time to irrigate and how much water you should appear. Swedish farmers think they have so much experience that they don?t need techniques like this.

Soil carbon, pH and yield development in a long-term humus balance trial

Agriculture has to be performed in a sustainable way in order to sustain high yields and to support a globally growing population. Functional soil properties are fundamental for high yields and in order to achieve good soil conditions sustainable management is a key. Loss of soil organic material and increased soil acidity are problems associated with degradation of soils and hence less sustainable agriculture. In this thesis, the effect of different agricultural systems on soil organic matter, pH and yield was examined. The systems examined are a cereal system with straw removal or returning and a ley system, all with different nitrogen levels.

Hur en ökad marktemperatur påverkar fotosyntes och markrespiration i en boreal skog

During the year of 2008, a powerful earthquake hit the southern part of Iceland, which changed the geothermal conditions in the area around the city of Hveragerdi. Elevated soil temperatures in a nearby forest plantation have contributed to a unique opportunity for researchers to study how an increased soil temperature affects the boreal forest ecosystem, something that partly can be connected to the climate changes which are happening today. The boreal forest is representing a carbon sink and a buffert for the emissions that occurs. Changes in this ecosystem will for that reason contribute to major impact for the global carbon cycle. To study the impact of how elevated soil temperatures affects different processes in a plantation of Sitka spruce, studies were made on the photosynthesis of the trees and the respiration from the soil.

Bok- och grankonkurrens i Sydsverige - markegenskaper och naturlig föryngring :

In southern Sweden, beech (Fagus silvatica) and spruce (Picea abies) are two species with similar demands on soil properties. With increased global warming and high acid deposition the future may bring larger areas were the two species are overlapping, competing for the same soil. The aim of this study was to compare spruce and beech concerning distribution, cultivation and soil properties. From available data comparisons were made between spruce and beech forests in Sweden. Soil analyses were made on samples from beech forest in southern Sweden, with and without natural regeneration of spruce.

Metodutveckling för analys av klorfenoler i jord samt analys av förorenad jord från ett sågverk

In this final thesis, an existing method for analysis of chlorophenols (CP) in bottom sediments has been updated and adjusted for analysis of chlorophenols in soil. The covalent bonds between the chlorophenols and the soil matrix were broken through basic hydrolysis and the chlorophenols were then separated from the water phase through addition of sulphuric acid followed by ether extraction. The chromatography was improved through extractive acetylation of the chlorophenols.The updated method was then applied on soil samples from a contaminated area (a former sawmill in Hyttsjö, Östergötland, Sweden).The analyse was preformed by GC/MS with respect to 2-MonoCP, 4-MonoCP, 2,4-DiCP, 2,6-DiCP, 2,4,6-TriCP, 2,3,4,6-TetraCP and pentachlorophenol (PCP).Contamination of chlorophenols in nature can be explained by the former use of wood preservative chemicals based on chlorophenols. In the 1960s and the 1970s these chemicals were used in Sweden, but due to their toxicity they were banned by the Swedish government in 1978.In Hyttsjö a pentachlorophenol-based product named Santobrite was used for several years. The concentration of PCP in the soil samples from Hyttsjö varied from 0.2->1.8 ng/mg dry substance.

Siktning som saneringsmetod för metallförorenad mark

Toxic metals contaminate soil worldwide and thus serve as sever environmental threat. Therefore the purposes of this study were to investigate in which soil fractions that different heavy metals (Fe, As, Cu, Zn and Pb) could be found in contaminated soils and if it is possible to use sieving as a method for decontamination. Soil samples were collected from three different locations, the Nasa silver mine, the Blaiken-mine and Svalget environmental station. The samples were oven dried and later on sieved into six different fractions 8mm, 4 mm, 0.5 mm, 0.250mm, 0.063 mm and <0.063 mm. The fractions 4 mm, 0.5 mm and <0.063 mm from each location were analyzed in an x-ray fluorescence detector.

Fördjupad miljöriskbedömning av förorenade markekologiska system. : Integrering av kemisk, toxikologisk och ekologisk information.

AbstractThe research project Liberation, supported by the European Commission under the Environment and Sustainable Development Programme (Fifth RTD Framework Programme) aimed at developing a decision support system for ecological risk assessment of contaminated sites has proposed a tiered system including the triad method. This method integrates contaminant chemistry and bioavailability analyses with observed ecotoxicological effects in soil and groundwater. In this study the triad method was used to perform a risk characterization of a former surface treatment and metal industry, now used for the student union buildings of the Mälardalen University in Eskilstuna, Sweden. On the site, high concentrations of copper, zinc and nickel have been detected in the soil in a preliminary investigation of contaminant levels with XRF. For performing the risk assessment of the site according to the triad method, contaminant bioavailability, soil metal concentrations and soil toxicity were determined and an ecological assessment was carried out on four selected soil samples (one reference soil and three samples with low (B), medium (C) and high (D) contaminant levels). Contaminant bioavailability was measured through leaching (ISO TC 190/S7) and biouptake tests (DGT).

Tankar om plöjningsfri odling :

The margin in crop production is more and more less and it forces the producer to check out how to reduce the cost of establishment of new crop. One way to reduce the cost in establishment is to begin with plough less farming. It saves money and time compares to conventional soil preparation with plough and harrow. Not all soil types are god for plough less farming and should be continued with ploughing (mainly light soil), but other soil types working very well with plough free farming. If you want to success with plough less farming you have to think in new lanes. One of the things you have to think about is to not grow too much cereal after cereal. Low stubble is important when you harvest the crop and also to spread and chop the straw well. I have in this work interviewed some farmers and farm advisers in Östergötland to see which thoughts they have about plough less farming.

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