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763 Uppsatser om Soil carbon - Sida 2 av 51
Biochar as soil amendment in flow-through planters - for increased treatment of zinc roof runoff
In times of increased flooding, enhanced by climate change, polluted stormwater poses an increased threat to the environment through contaminated water entering waterways. Bioretention utilizes natural processes in soil and vegetation to treat pollutants and combat this threat. Biochar produced through pyrolysis, has a high cation exchange capacity (CEC) and could therefore increase treatment in bioretention systems. This research applies a literature review, interview, and a model to explore the benefits and disadvantages of biochar in order to specify a soil-mix through an understanding of the production process and preferred application rate. High purification through CEC, increased water holding capacity, and carbon sequestration being the benefits discussed.
Koldioxidutsläpp vid vägbyggnad - en fallstudie med jämförelse av alternativa byggnadssätt
Abstract This degree project examines how much carbon dioxide that emits during the construction phase of a road project. This is to make it possible to compare how the amount of carbon dioxide differentiates between traditional road construction and Swepave construction, which is PEAB?s alternative way to design roads. To make the comparison a calculation tool has been produced. To compare the amount of carbon dioxide emissions a reference project was needed.
Ökad kollagring i boreal skog : Kan blädningsbrukad skog lagra mer kol än trakthyggesbrukad skog?
This study was conducted to test the hypotheses that a forest managed by selective cutting can store more carbon than a forest managed by clearcutting. The study was carried out as a meta-analysis. The data that was found was analyzed by performing t-tests on the proportional effect that the two silvicultural methods had on the driving factors of CO2-efflux and carbon stores in coniferous boreal forest. In all areas tested, an effect in favor of selective cutting was found, but not all of them significant however. The soil respiration following selective cutting was significantly lower than that of clearcutting, and the primary production of a clearcut area cannot according to reason exceed that of an area post-selective cutting.
En analys av nattliga koldioxidflöden i en boreal barrskog avseende spatial och temporal variation
Carbon dioxide in the atmosphere contributes to the greenhouse effect, which is essential tolife on our planet. Furthermore, it plays an important part of the photosynthesis andrespiration of the world?s organisms. Since the start of the industrial revolution the amount ofcarbon dioxide in the atmosphere has increased exponentially. The main source is theextensive burning of fossil fuels.
Effects of biogas residues on respiration and denitrification in arable soil : evaluation of methods, microbial activity and agronomic implications
Agricultural soils constitute the base in human food production and soil content of organic matter and plant nutrients together with soil microbial activity are all important parameters for high crop yield of good quality. These parameters are dependant on proper fertilization.Anaerobic digestion of organic wastes for biogas production generates a liquid residue called biogas residue (BR). It contains organic material and plant nutrients which makes ita potential fertilizer for arable cropping. However, it also contains heavy metals and toxic organic compounds and it is therefore in need of evaluation before usage.Microbial tests were performed aiming to evaluate the agronomic traits of four different BR and to find a viable procedure for evaluating slurry fertilizers. Two experiments where soil respiration and soil potential denitrification activity (PDA) was measured at fertilizer addition were performed.
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.
Aggregatstabilitet, jordbearbetning och fosforförluster i ett typområde på jordbruksmark :
Large amounts of phosphorus (P) are lost from the arable land due to water erosion. Both phosphorus attached to particles and dissolved phosphorus (mainly phosphate) are transported away with drainage-water and surface runoff. Good soil structure is important in minimizing these losses.
In this study, soils from 50 fields were analysed with respect to aggregate stability as measured by dispersion of clay together with the content of total phosphorus (TotP), particulate phosphorus (PP) and phosphate phosphorus (PO4P) in the water phase. All soils were clay soils with clay content varying between 21 and 54%.
Fiberföstärkning av Limträbalkar
Glulam is a product that was engineered to make use of timber in a more efficient way. Bychoosing timber of similar quality and discarding natural defects during production, thedevelopment of a stronger cross-section is achieved.Carbon fiber is a relatively new material with a high tension capacity. This feature is used toexamine how the bending capacity of the beams improve by adhering carbon fiber laminateson the lower edge of the beamsThe strength of the material is tested with three experiments: carbon fiber on the bottom of thebeam (a), carbon fiber attached to the lower sides of the beam (b) and carbon fiber in thebeam, covered with a layer of wood (c)The results show that the first case, where the carbon fiber is attached to the bottom of thebeam, gave the best result with an increase in capacity of 59 % compared to the nonreinforcedcontrol. The other two cases also show an improvement in capacity, beam-type 3had a capacity increase of 47% and beam-type 4 increased with 25 %Tests were also made with glulam beams reinforced with fiberglass, but these tests were notanalyzed in depth because the purpose was to compare the capacity to carbon fiber. Thisbeam improved its capacity by 40.3%.The tests show that carbon fiber as a reinforcement material for glulam is a good choice whenthere is a requirement for stronger cross-sections in both new production and renovation ofold buildings.
Utsläpp av växthusgaser under islossning i små boreala sjöar
Freshwater ecosystems have long been neglected as an important part of the global carbon cycle. However, research shows that most of the world?s lakes are net-heterotrophic and consequently emitters of greenhouse gases to the atmosphere. In many boreal and north-temperate lakes, most of the yearly emissions usually occur in spring, shortly after ice-thaw. The aim of this study was to quantify the flux of carbon dioxide (CO2) and methane (CH4) in three boreal lakes, during this annual event.
Sapa Heat Transfers koldioxidspår : En kartläggning av verksamhetens koldioxidutsläpp
Sapa Heat Transfer is a company that produces aluminum heat-exchanger strips for the automotive industry. Sapa Heat Transfer wish to chart their emissions of carbon dioxide in order to meet future demands on carbon dioxide reporting. They also would like to examine the meaning of the term ?green electricity? which is marketed as carbon dioxide free, and the sort of electricity that they purchase. This report includes both direct (liquefied petroleum gas and diesel) and indirect (water, process-water, long distance heating, waste) emissions from their company.
En jämförelsestudie av koldioxidsläpp för en byggnad med trä- respektive betongstomme ur ett livscykelperspektiv
The goal with this examination thesis is to investigate the difference in carbon dioxide emissions between a building with a wooden versus concrete carcassing from a life cycle perspective. The huge amounts of carbon dioxide released into air from human activities must be reduced to prevent serious consequences. A way to limit this issue is through performing a comparative study where the result shows which of two products with the same function has the lowest emission of carbon dioxide, whereof the product with the lowest carbon dioxide pollution can be chosen.To be able to perform a study like this an object has been chosen and studies about life cycle analyses have been done. The rental square meter, the thermal conductivity value, the energy requirements and the placement of the building has been set equal in both framework types. There were solely dissimilarities of the two buildings taken into account when this comparison study was performed.The result of the study is that a building constructed with a wooden carcassing has the lowest amount of carbon dioxide emissions.
The legacy of the mill : a metal polluted forest soil in Gusum
Soils in a metal contaminated site on Stångberget in Gusum in southeastSweden were investigated and compared to relatively unaffected soils a fewkilometres away. Pollution came from historical release of untreated flue gasesfrom a brass mill. The objective was to find information on how high the metalconcentrations are, if metals from the polluted soil affect the surroundings andif the metal contamination affects the microbial community. The soil wasinvestigated using several different methods, such as field XRF measurements,chemical analysis of metal, carbon and nitrogen content, pH, acid neutralizingcapacity, texture, soil depth, field leach tests, sequential extraction and microbialfunctional profiles. The study showed that copper and zinc concentrationswere above Swedish Environmental Protection Agency guidelines for lesssensitive land use on the entire investigated area.
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.
Do 25 years old skid tracks restrict growth and survival? : a study on growth conditions for the planted regeneration in a rainforest rehabilitation project
The rainforests of the world are important not only to the countries in which they grow but to the world as a whole. They influence oxygen and water circulation as well as carbon sequestration which in turn affect global radiation and global warming. The forest also have great value and in Malaysia as in many other tropical countries large volumes are harvested which leaves great areas of degraded forest with little growth and biological diversity. Due to their low financial value these forests are often transformed and used for other purposes than forestry such as oil palm plantations.
The trees are often transported out of the forest using large bulldozers. They are heavy which causes compaction of the forest floor and during transport the top soil layers are moved to improve mobility.