There is always an endeavor to govern the initial products in the plant cultivation with precision in order to keep down the expenditure and in order to decrease environmental impact. Initial phosphorus fertilizer can then be one possibility in order to keep down the fertilizer cost and to decrease environmental impact. This exam study includes a literature study about location of fertilizer and which effects this give and two field experiments. The aim with initial phosphorus fertilizer to autumn wheat is to accelerate the root growth and to give the crop a big root system before the growth stagnates before the winter. Easy to access phosphorus favours the root growth.

Cassava (Manihot esculenta Crantz) is a root crop that plays an important role in many households in Africa. It is sometimes called ?Africa´s food insurance?. The advantages with the crop are that cassava is drought-resistant and it can grow in a semi-dry land. It is a perennial crop and does not require much labor.

This pre-study investigates the possibility of U-value measurements through an acoustic method. A hypothesis about an acoustic model built on acoustic theories combined with U-value theories is presented to answer the questions: ? Can U-value theory be combined with acoustic theories? ? Can the coefficient of heat be affirmed trough an acoustic measurement? The idea for this dissertation begun with a logical idea in mathematical similarity, between the coefficient of heat transmission units and sound intensity units. The U-value theory is based on assumptions such as initial resistance for inner walls and initial resistance for outer walls. The resistance in the material is interpreted through sound intensity theory. The argument is built upon mass law theory, which means if the frequency or thickness of the material layer doubles it implies an increase of sound reduction by 6 dB.

The organic farmland is increasing all the time and the goal is that 15 % of the Swedish farmland will be in organic production in year 2010. The organic production needs new and more effective ways to control weeds, and there is the row harrowing coming as a good complement to the conventional weed harrowing. In this experiment is weed harrowing whit different row spaces and row harrowing with a spacing of 25 cm compared. Then are the weed picked and the weight taken of them. The yield is compared in the 7 different ways of treatment. The results is not showing any significant differences in yield even when the row spacing is 25 cm instead of 12,5 cm. Even the spring wheat that is a sensitive crop and has bad tillering is doing well in this experiment. Now with modern technology where the row harrow is controlled by a camera that making the row harrow to follow the rows is it the soil coverage of the crop that is the limit for the speed. With wide machinery is the very good coverage even with a row harrow..

Field balances based on supply and removal of trace elements from the topsoil have been calculatedfor farms specialized in crop, dairy and pig production in Sweden. Today's field balances have beencompared with the field balances of 1990 in order to examine if, and then how, the situation haschanged. Studied trace elements are arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu),mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn).The balance calculations show that the stores of Cu and Zn are depleted with an average rate of -15% and -6 % over a 100-years period on crop farms when only commercial fertilizers are being used.The concentrations of Hg and Pb tend to increase in the topsoil on crop farms with more than 3 % forHg and with 2 % for Pb in 100 years. There is today balance between supply and removal of the traceelements As, Cd, Cr, Mn and Ni. In the south of Sweden, on crop farms with sugar beets in the croprotation, one can see a decrease in the concentration of Cd in the top soil by -6 % over a period of100 years.

The objective of this M. Eng. Diploma work was to validate the new version, CASMO-5M, and compare the results with CASMO-4E, by using the same input in both programs. The tasks that were included in this work was to compare TIP-measures, k-effective curves (warm), k-effective curves (cold), the effect of void on k-effective, the isothermal temperature coefficient (ITC), the moderator temperature coefficient (MTC), damping ratio calculations, internal effect in a fuel bundle of a BA-rod, the speed of BA-out burn, impact of xenon, falling control rod, margins and isotopes.The TIP-measures showed that the differences were small for all reactors, at most, 6% nodal improvement by C5M (Casmo-5M) for Oskarshamn 3. The warm measurements of k-effective showed that C5M had a higher value for all cycles of Oskarshamn 1, 2 and 3 in comparison to C4E (Casmo-4E).

The agriculture is today in a development that leads to bigger and bigger units in the primary production. To be able to follow this development many companies chooses to cooperate in different ways. The most radical change is when farmers fuses with other farmers and merge into to a big collectively owned operation firm. The reason behind this idea is that the firms achieve the big companies advantages by being complement to each other. The purpose of this essay is to make an economic analysis of two crop production companies who works together in an operation firm.

The conditions for a good silage process start with good wheather and choice of crop, then choice of harvesting machinery. The shorter and more mechanically treated crop, the better quality of the forage. (Pauly 1994). This study has examined the variations in chopping length depending on harvest method. Precision choppers works with a rotating chopping cylinder, where the crop is cut into pieces.

Vildsvinstammen har ökat snabbt i södra och centrala Sverige sedan några individer rymde ifrån fångenskap på 1970-talet. Vildsvin har aptit för jordbruksgrödor vilket resulterar i en konkurrens om dessa grödor mellan arterna människan och vildsvin i en s.k. interspecifik konkurrens. Detta utgör i sin tur en konflikt mellan jordbrukare och vildsvin. Denna konflikt verkar även förvärras av jägares förvaltningsmetoder som, enligt lantbrukare, innefattar ett bristande jakttryck och utfodring i för stor skala.

The purpose of this study was to investigate how the content of glucose, fructose, sucrose and fructan (WSC) varied in silage, haylage and hay harvested from the same field and at the same time of harvest. The study also investigated if differences in the WSC-fraction in the forages caused differences in composition of WSC in the colon of horses fed the forages. Hay, haylage and silage were harvested in the first week of June 2005 and stored for about nine months before feeding. Horses that were fistulated in right ventral colon and caecum were used, but only the colon fistula was used for sampling. The fresh crop and the conserved hay, haylage and silage were analyzed for chemical composition and WSC-fraction.

Fusarium graminearum is one of the most important pathogens on cereals and causes major crop losses around the world. The most cultivated cereal in Sweden is winter wheat. F. graminearum produces both sexual and asexual spores for dispersal. Multiple factors affect the production of these spores.

The agricultural sector accounts for about 13 percent of the total load of greenhouse gas emissions from Sweden (Swedish Environmental Protection Agency, 2007). The Swedish objective to reduce the greenhouse gas emissions with 40 percentage units to the year of 2020, based upon the year of 1990, might imply stricter regulations for Swedish farmers. A regulation or other forms of economic incentives is probably necessary to reduce the emissions originating from the agricultural sector. This study aims to investigate the economic and managerial impact on two agricultural firms with differing production system given that a constraint on green house gas emissions is introduced. Gases included in this study are carbon dioxide, methane and nitrous oxide.

The Kverneland Ecomat and The Ecomat Seeder has been tested in three different field studies. All the studies were conducted on soils with different clay content during 2005 in Säby outside Uppsala. In one of the trial spring ploughing with the Ecomat and spring ploughing and seeding with Ecomat Seeder were compared with conventional autumn mouldboard ploughing and spring mouldboard ploughing to conventional depth (22-23 cm). In this study the quality of the seedbed, the number of emerged plants and weeds, the pentration resistance and the yield were examined. Shallow spring ploughing (10 cm) with the Kverneland Ecomat has shown to be a good alternative to conventional autumn ploughing when growing spring crops. During the season 2005 tilling with the Ecomat resulted in a higher yield than conventional ploughing. In 2002-2005 the average yield for shallow spring ploughing was 4 percent higher than after conventional autumn mouldboard ploughing and 10 percent higher than after spring mouldboard ploughing to conventional depth (22-23 cm). In the other two studies, ploughing to different depth in the autumn with the Ecomat was compared with conventional mouldboard ploughing and stubble discing.

Today, high-yielding leys of good quality are a must for Swedish dairy and beef enterprises if they are to become profitable. Thus, it is of interest to evaluate the quality of the recently released high-yielding Festulolium hybrids ((Festulolium braunii (K.Rich.) A.Camus). The aim of this project was to determine at what phenological stage three different Festulolium hybrids should be cut in order to get the highest nutritional value. The hybrids studied were Hykor, Perun and Paulita. In the study I also investigated if leaf proportion of the crop could be useful for predictions of the crop content of metabolizable energy. The cultivars were grown in plots within a variety trial with ryegrasses.

The aims of the silvicultural method natural regeneration of spruce (Picea abies L. Karst) in birch (Betula pendula and pubescens) shelterwoods are to establish a new stand of tree seedl-ings and to protect those from high groundwater levels, frost damages and grass competition during its first life years. The aim of this work has been to (i) describe how shelterwood and stand characteristics influ-ence the results from using natural regeneration of spruce protected by a shelterwood of birch, and to (ii) compare those regeneration results with planting of spruce after soil scarification in clear-cut areas. Totally 17 harvesting sites have been inventoried and 15 of those included natural regenera-tion in birch shelterwoods, and two were subjects to soil scarification and planting of spruce. The sites represented 7-10 year old final cuts and are located in the coastal (eastern) region of the province of Norrbotten in Sweden. In all areas shelterwood and stand characteristics, as well as the number of main crop seedlings and the height of the highest main crop spruce seedling, were estimated and registered in all areas.