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158 Uppsatser om Grass weeds - Sida 1 av 11

Klimatförändringar och dess effekter på ogräsfloran i Sverige :

Land management for food production is a fundamental human activity and one of the greatest challenges of the 21st century will be to increase the global food to accommodate a world growing to 10 billion or more people, while undergoing climate change. The increasing temperature and the current and projected increase in concentrations of CO2 lead to concern over possible impacts on agricultural pests. This assay is summarizing the knowledge of weeds in a changing climate in Sweden. Global warming and other climatic changes will affect the growth, phenology, and geographical distribution of weeds. The climate change will also affect the weed composition indirect by causing changes in the agriculture.

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..

Kvickrotsstudier: 1. Kvickrotens reaktion på myllningsdjup, kvävemängd och kväveplacering i konkurrens med gröda. 2. Reducerad glyfosatanvändning på trädad åkermark :

1. Reaction on burial depth and nitrogen availability and placement in competition with a crop In this trial it was investigated how couch grass (Elymus repens) changes its ability to compete in stands of wheat and barley with different burial depth and different amounts and placement of nitrogen. More knowledge in this area can be valuable in the attempt to decrease the use of herbicides and still keep the weeds under control. The trial was carried out in the summer of 2004 as an outdoor pot experiment. The pots contained 15 litres of soil with a surface of 0,06 m2.

Undervegetation : användning av vedartade marktäckare i anläggning

The use of the robust and durable woody ground covers is increasing, not in the least in public places. The group includes low shrubs of different height that effectively build low, tight vegetation that covers the ground. Despite all the good qualities the knowledge about them is quite low and there are ideas about them of being dull. The woody ground covers manage to struggle against weeds effectively by competing for nourishment and water, but above all, by the canopy of the ground covers that prevent the weeds from getting enough light. In that way the woody groundcovers can effectively compete with the annual weeds.

Vilken effekt har lärkrutor på ogräsfloran vid ekologisk höstveteodling? :

This study forms part of the R&D project "Improved survival of bird chicks in organic fields" managed by the Rural Economy & Agricultural society in Uppsala. The skylark (Alauda arvensis) is a species that has decreased drastically in Sweden as a consequence of more intensive cropping. Studies in England have shown that skylark reproduction can be greatly improved within conventional fields, at a low cost, by establishing patches of bare ground (skylark plots). Within conventional farming, herbicides can be used in case a weed problem arises due to implementation of these skylark plots, whereas this is not allowed in organic farming. This study examined the effects of skylark plots on the weed culture in organic autumn-sown (winter) cereals and whether weeds might cause long-term problems to farmers. The study was conducted in two parts; a field study and a review of the literature regarding the weeds observed. The field study was carried out in 2007 during three weeks in June and three weeks in July, on eleven organic fields with winter cereal in the vicinity of Uppsala.

Alternativa stråbränslen i växtföljden :

The purpose of this report is to find out which crops, that are good for strawfuel, and can be grown i the area around the city of Lund. The background of this report it that Lunds energy is planning to bild a biofuelheated thermal power station in Örtofta outside of Lund. I have in the report limited me to the crops hemp, whole crop (triticale), reed canary grass, elephant grass and jerusalem artichoke. I have through a documentary research checked the crops, cultivabillity in the south of Sweden, and how they should fit, in the Scanian crop sequence. Hemp is an annual crop which probably could manage in the Scanian crop sequence. Whole crop often triticale because of it´s high yield and low rate of shed seed. Could also fit into the crop sequence of crop in Scanian. Triticale is annual, and could be grown at the same kind of fields as used to wheat, whith is why it would be possible to grow it in Scania. Reed canary grass is a reedlike grass that is easy grown at most soils.

Strängluftning av vallfoder : Inverkan på ensilagets torkningförlopp, spill och smörsyratillväxt

When harvesting ley you hope to get a fast drying and a faster harvest. If there is a system with round bales, you need to have a dry matter close to 45 %. To make this as fast as possible, there is made a machine which pick up the grass with an pick-up. It turn the grass over and put it behind the machine (figure 2 and 4). There are few tests to prove the efficiency of this machine.

En jämförelse mellan får- och nötkreatursbetade hagmarker med avseende på populationsstorlek samt artsammansättning hos dagfjärilar och örter

Many of Europe?s day-living butterflies have shown decreasing populations during the last decades and many species are threatened. Many butterflies are dependent on managed semi-natural grasslands because of their richness in nectar sources and host plants for the butterfly larva. Swedish pastures are mostly managed through grazing. The number of cattle in Sweden have been decreasing while the number of sheep in the country increased by 30%.

Vad orsakar höga ammoniumvärden i ensilage? :

High levels of ammonia in grass silage have been up for discussion by Swedish advisers. One reason is that it is more difficult for the rumen-microbes to utilise high levels of ammonia. A low level of ammonia is also good because if the cattle can use more of the protein in the silage, they don?t need so much protein concentrate. That is very good for the economy at the farm, and it is also good for the environmental problems caused by high levels of ammonia. In this project, 24 samples of silage have been taken at 20 different farms in the south west of Sweden.

Drankgivans och vallfoderkvaliténs effekt på konsumtion och produktion hos mjölkkor :

The coproduct, dried distillers grains + solubles (DDGS) from ethanol production based on wheat contains much rumen degradable protein and fiber with low digestibility. To compliment this quality in an effective way a grass silage low in protein and much digestible fiber is needed. The aim of the study was to investigate the effects of adjusting the crude-protein concentration and fiber quality of the silage when feeding DDGS and of varying the inclusion level of DDGS, when feeding the adjusted grass silage, on intake, milk yield and composition, faecal traits and feed efficiency. Four different total mixed rations were compared. The normal grass-clover silage had a crude protein content of 17,8 % and an NDF content of 46,2 % of dry matter. The adapted grass silage had a crude protein content of 14,6 % and an NDF content of 52,9 % of dry matter. The diets were formulated to have similar nutritional content except for A + 4 which had a higher content of rumen degradable crude protein and a lower concentration of NDF.

Grazemore DSS för att optimera utnyttjandet av bete i mjölkproduktionen :

The aim of the study was to investigate if the Grazemore Decision Support System (DSS) is able to provide a grazing management strategy that gives a high utilisation of grazed grass in milk production in the north of Scandinavia. To do this, a grazing experiment was planed and performed during the summer 2005. Simulations in the DSS were run to get a suggestion of how the cows should graze, grazing calendar 1. Deviations and updates during the season resulted in the simulated grazing calendar 2. During the experiment, the actual milk yield was recorded twice weekly. The difference between actual and predicted milk yield by Grazemore DSS was analysed statistically with regression analysis and the mean square prediction error (MSPE) was estimated.

Grovfodermajs : från odling till utfodring av växande nötkreatur

The use of forage maize has increased over the last years. The aim of this litterateur review was to summarize a part of the research that has been conducted on forage maize for growing cattle, including cultivation and conservation of the maize. The forage maize is planted in April or the beginning of May when the temperature in the soil is between 6 and 10°C. Maize needs high temperatures and much water. Maize is harvested in the autumn when the dry matter (DM) is more then 30% or the plants have been exposed to the first frost in the autumn.

Controlled traffic for grass silage production : an economic evaluation for dairy farmers

The farm management system controlled traffic farming (CTF) aims to reduce soil compaction by restricting the field traffic from agricultural machinery to permanent traffic lanes. Literature and empirical findings show that soil compaction and field traffic from heavy machinery may affect crop growth negatively, reducing crop yields. If grass-clover leys are subject to heavy field traffic the botanic composition might be altered, providing a lower clover content in the forage. Clover as a silage feed is rich in protein providing good conditions for high yielding dairy cows. Grass-clover silage production is generally associated with intensive field traffic.

Majs till mogen skörd :

Corn is an important food and feed crop in the world, in Sweden it?s up till now grown on limited acreages mainly for silage. But I think it can get more important if you can grow it also for grain, because it?s a good animal feed for example, for life stock-, pigsand poultry. On of corns advantage is that it can produce the same amount of dry matter as for example wheat, barley and rise but with 25% less water. I will examine if it possible to grow corn for grain production in the south of Sweden.

Methane production from dairy cows : relations between enteric production and production from faeces and urine

Methane (CH4) is a greenhouse gas (GHG) that contributes to the global warming. One of the largest sources of methane is livestock, preferably ruminants which alone counted for 30% of the total agricultural anthropogenic methane emissions in the year of 2000. The reason to why ruminants are such large contributors of methane are that the gas is produced in the rumen by enteric formation and leaves the animals by belching, exhaling or by the excreta.Diets high in concentrates can result in a lower emission of methane. Also diets with a high content of starch, such as alfalfa-grass, have a methane-decreasing. It is profitable to reduce enteric methane formation since that form of methane is unavoidably lost.

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