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4205 Uppsatser om Leaf area index - Sida 1 av 281
Leaf area index in Vittelaria Paradoxa parklands in Burkina Faso estimated by light interception and leaf sampling
Burkina Faso as well as most sub-Saharan African countries struggle with providing food for a fast growing population. The dominating farming system is agroforestry parklands. Agroforestry parklands can broadly be defined as areas where scattered trees occur on farmlands as a result of selective clearing. The presence of trees in crop fields may in the long term have a positive effect on the production of annual crops. It is commonly discussed, but not proven, that the presence of trees leads to increased groundwater recharge due to higher infiltration capacity of the soil.
Modellering av reflektans från ett sockerbetsbestånd med hjälp av en strålningsmodell
The Multispectral Canopy Reflectance Model (MCRM) by Kuusk (1995) has beenused to simulate the reflectance of a sugarbeet canopy. The simulated reflectancevalues show high absorptance in the VIS area, compared to field measurements, andhigh reflectance values in the NIR area. The errors may be due to overestimation ofclorophyll content in the sugarbeet leaves and scattered light during fieldmeasurements. The estimation of the clorophyll content where carried out using thePROSPECT-model by Jacquemoud & Baret (1990).During the vegetation period, the state of the canopy moves towards a closed canopy,with sparse vegetation in spring. The MCRM-model was used to perform a ?spring?simulation, which was compared to the original simulation.
Vårvetesorters effektivitet i användningen av kväve under den huvudsakliga tillväxtperioden
Crop efficiency in utilizing available nutrients is an important factor in increasing produc-tivity and reducing the environmental impact of agriculture. Nitrogen is the nutrient that plants need in the largest quantity and wheat, along with maize and rice, is the world's most cultivated crop. In this work, the Nitrogen Use Efficiency, NUE, during the major growth period, HTP, of twelve different spring wheat varieties, were examined. The NUE was calculated as the product of uptake efficiency of nitrogen, UN, and the conversion effi-ciency of nitrogen to biomass, EN. The purpose of this work was to find if there are varietal differences in NUE and its components among the twelve varieties and to link a high NUE to specific characteristics of the varieties.
Kastanjemalen Cameraria ohridella : livscykel och utbredning i Sverige 2006
Cameraria ohridella, the chest-nut leaf miner, is a new pest in Sweden. These moths make leaf mines on chest-nut trees, preferably on Aesculus hippocastanum, which results in brown blotches on the foliage and early loss of leaves. Since the first observation in Macedonia in 1985 it has spread rapidly through Europe. The moth arrived in Sweden in 2003 when it was observed in Malmö and surrounding areas.
In this paper a literature study describes the morphology and life cycle of the chest-nut leaf miner. Further more a test with pheromone traps examining the number of generations in Sweden is shown.
Empirisk undersökning av aktieindexobligationer : Till vilken grad tar innehavaren del av underliggande index avkastning?
The purpose of this essay is to evaluate stock index bonds return to risk ratio in order to investigate to which degree an investor in a stock index bond take part of the underlying index return and what the investor must pay for the security of not losing his funds. In order to carry out this evaluation an average return per year and the Sharpe ratio will be calculated and a mean- standard deviation analysis will be made. All investigated stock index bonds are based on a Swedish underlying asset.The results show that the stock index bonds haven?t generated a higher risk adjusted return than its underlying asset. The stock index bonds took part of 57 % of the underlying assets return, and the loss of 10 percentage points per year for the stock index bonds compared to its underlying asset can be seen as the cost for the guarantee a stock index bond gives..
Redogörelse av marknadsstyrka på den svenska elmarknaden
Denna uppsats syfte är att förklara den svenska elmarknadens konkurrenssituation med Lerner index och Herfindahl index. Genom att estimera priselasticiteten med en ekonometrisk modell som logaritmerats kunde dess värde skattas fram. Vidare har denna elasticitet använts för att skatta fram Lerner index. Avslutningsvis har ett Herfindahl index beräknats för att mäta marknadens koncentration. Resultatet från empirin visar existens av marknadsstyrka på elmarknaden och att den är oligopolistisk..
Kan förändringar i bottenfaunan påvisas två år efter en bäckrestaurering?
The aim of this work is to analyze if a change in the benthic community can be detected two years after a restoration of a small stream. The samples were taken in a small stream at Tinnerö Eklandskap just south of Linköping. In addition to the restored area, two reference sites upstream and downstream of the restored area were sampled to compare to the restored site. The method used for sampling of benthic fauna in the stream was kick sampling. ASPT, Berger-Parker and Renkonen-indices were used to find out if there was any difference between the reference areas and the restored area.
Påverkar tidighetstyp fiberhalten hos rödklöver?
The high feeding value of red clover makes it into an important species in Swedish agriculture. There are three different maturity types grown in Sweden, early, medium late and late. The time for heading, regrowth and winter hardiness is affected by the maturity type, but there can also be other factors that are affected by the maturity type, for instance fiber content. In a greenhouse experiment three red clover varieties of different maturity types were compared; early Titus, middle late SW Nancy and late SW Torun. The features compared were fiber content and differences in development rates.
Muddring i Ireån : indirekta effekter på bottenfaunan nedströms
This research aims to investigate the effects that dredging may have on benthic fauna. The dredging took place in the stream Ireån on northern Gotland during the early summer 2010. My area of research was taking place in a scenic area downstream in Ireån close to the Baltic Sea. I chose this area due to the dredging that started just upstream of this area and continued further upstream. Thus it is not the direct impact of the dredging that is the focus for this paper but the side-effect the dredging may have on the area downstream.
Vikten av ett oviktat index
Syftet med denna uppsats är att undersöka ett oviktat index relevans som jämförelsemått för aktivt förvaltade fonders avkastning och förvaltares förmåga att hitta vinnaraktier. Arbetet använder sig av en kvantitativ metod för framtagning av ett oviktat index (SUWX 100) som inkluderar de 100 största företagen på Stockholmsbörsen. Analysen av kvantitativa data är av induktiv karaktär, och använder sig av de Sverigefonder som finns i PPM-systemet för att dra slutsatser kring det oviktade indexet som jämförelsemått. Vår slutsats är att det finns aspekter av ett oviktat index som gör det användbart som jämförelsemått för Sverigefonder..
Biologin hos svenska Lilioceris arter och åtgärder för att begränsa deras skadeverkningar :
Summary
The leaf beetles, Lilioceris lilii and L. merdigera have existed in Asia, Europe and in North Africa for a long time, but have become much more abundant the last twenty-five years. Even North America has been affected during the last years.
The purpose of this investigation of Lilioceris species in Sweden, is to give advice to gardeners, which type of control measures is the most effective in order to restrict their damage to lilies.
Lilioceris species overwinter normally as pupae in the soil under the host or close by.
Literature and contact with advisors have described the life cycle and spreading of Lilioceris. Under favourable conditions these leaf beetles have two generations/year in the south of Sweden. Both the adults and the larva eat the foliage, and by strong attacks even flowers can be eaten and only the stem is remaining.
My own observations include different treatments of both lily foliage and of the leaf beetle.
Alternativa index - En studie av mean-variance-effektiviteten hos index baserade på fundamentalvärde kontra börsvärde
Finansiella index är viktade genomsnitt av olika tillgångars avkastning från en bestämd tidpunkt. Traditionella index är börsvärdeviktade. Problemet med denna typ av index är att börsvärdet tidvis kraftigt kan överdrivas på grund av spekulation. Alternativa index bygger på företags fundamentalvärden. De viktas därmed efter företags faktiska redovisade siffror i balans- och resultaträkningar.
Två år efter restaurering:Vad har förändrats i bottenfaunan?
The aim of the study was to examine if the benthos in a restored portion of a small lowland stream south of Linkoping differed from two non restored reference areas two years after restoration. The reference areas were one stretch downstream and one upstream stretches of the restored stream. The benthic invertebrates were collected using standardized kick sampling. In order to classify the communities and estimate any differences, three different indices were exercised. In addition rank-abundance curves and checklists were used to get a picture of species composition.
Sjukdomar i vallgräs : uppdatering av Faktablad om växtskydd -Sjukdomar i vallgräs (95 J)
In Sweden, 2011, ley was grown almost as much as cereals, which means that in terms of area, ley is an important crop. A lay can consist of either grass or grass combined with legumes e.g. clover. Forage grasses can be affected by many differ- ent diseases, some during the winter and some during the growing season. The diseases which do damage during the winter are called snow mold and can make large areas perish.
Rehabilitation in a tropical secondary rain forest in Malaysian Borneo : early effects of canopy properties on light conditions at the forest floor
Tropisk regnskog i Sydostasien är ett av de områden som hyser störst biodiversitet i världen, av vilken stora ytor är hotat. Ön Borneo drabbades av en katastrof åren 1982-1983 efter att väderfenomenet El Niño orsakat torka med vidsträckta skogsbränder som följd. Detta lämnade stora ytor av Borneos skogar i ett undermåligt, sekundärt tillstånd. På grund av detta startades INIKEA projektet med syfte att rehabilitera skogar i regionen kring Tawau vid östkusten av delstaten Sabah i Malaysia. I denna studie undersökte jag resultatet av rehabiliteringsarbetet på krontaket i tre olika skogstyper genom att ta hemisfäriska foton med en digital systemkamera (DSLR).