A secondary and a pioneer tree species can with advantage be included in a mixed stand to increase the use of sunlight. Nitrogen-fixing plants have been shown to increase the supply of Nitrogen in the soil by, for example, litter fall. This deposition acts as a biological fertilization, which may be used by non-fixing plants. Alder is a Nitrogen-fixing, pioneer tree species that loses its Nitrogen-rich leaves late in the autumn. The aim of this study was to examine the effect on the total volume of production, when different proportions of Nitrogen-fixing Alder were part of spruce stands.

Within agriculture it is important to optimize the use of Nitrogen, not only from an economic point of view but also to minimize damage to the environment. This can sometimes be difficult, especially within organic farming. Organic farmers are using increasing amounts of waste products from the food industry to cover their Nitrogen needs. These different organic fertilizers release Nitrogen at different rates and under specific soil conditions. Because of this, it would be beneficial to have a standardized method to measure the amount and rate of Nitrogen mineralization from organic fertilizers. This project contributes to this knowledge by investigating whether relatively simple and repeatable laboratory methods can be used to estimate the Nitrogen fertilizer value of organic fertilizers.

The last decades have shown increased Nitrogen leeching from soil to water recipients. This is inSweden mainly due to over-manuring of agriculture land, effectivization of drainage systems and thedeclining extent of wetlands. The accumulated amount of Nitrogen in water doesn?t only make itunsuitable for use by humans and cattle, but also decreases the biological diversity as well as negativelyaffect tourism and fish industry. In the most severe cases shallow maritime grounds can be completelydepleted of oxygen due to decomposition of the increased amount algae and plankton growth.This study have the aim to describe and quantify the Nitrogen leeching from the Genevad drainagebasin, located in southern Halland, Sweden.

The Nitrogen cycle in freshwater bodies is complex and consists of many separate processes affected by a number of important factors for example oxygen concentration in the water, temperature and circulation. Knowledge of the different components of the Nitrogen cycle exists; however, a complete and comprehensive picture is difficult conceptually as well as theoretically. The available literature illustrates that the research on Nitrogen and the related freshwater processes is still associated with high uncertainty of how much of the supplied Nitrogen from the catchment is transported with the water versus and how much is lost due to denitrification, sedimentation or uptake by plants. This report is an interdisciplinary survey of Nitrogen discharge permitting. The research focuses in particular on the decision-making process, the levels of scientific standard and the administrative framework.Application for Nitrogen discharge permits are decided by the Environmental Court with council from their own experts as well as relevant government authorities and organisations.

Construction of wetlands in the agricultural landscape may reduce Nitrogen and phosphorus transfer to streams, thereby reducing the eutrophication of lakes and seas. The agriculturalstream Lillån, a tributary to stream Sagån, ends up in Lake Mälaren and is transporting large amounts of these plant nutrients. The aim of this study was to estimate how hypothetical wetlands of different size and location may reduce Nitrogen and phosphorus load from stream Lillån. Estimated nutrient retention in several small wetlands was compared to retention in a single large wetland based on existing data from the agricultural stream and from a nearby smaller stream. Retention in the stream was suggested to decrease along with the nutrient concentration in the water.

Due to excess precipitation that cause runoff, all soils in Sweden naturally leaches Nitrogen.High leaching from arable land is an environmental problem when the runoff reacheswaters. In the international agreement, Baltic Sea Action Plan, the aim is to reduce therunoff of nutrients. Sweden has agreed to reduce its load of e.g. Nitrogen to the Baltic Sea.One of the proposed measures is an increased use of site-specific N-fertilization, which hasbeen shown to increase Nitrogen use efficiency and therefore also reduce the Nitrogen runoff.Either yields are increased with the same total amount of Nitrogen, or the total quantityof Nitrogen is reduced with preserved yield levels, which is profitable for the farmers.The dynamics of Nitrogen leaching differs between top dressing applications above orbelow the economical optimum. There is a consensus about a difference in the dynamics,but not about its magnitude.

The euthropthication of the Baltic Sea is a threat that is beginning to be taken seriously by the governments concerned. In Sweden, regulations concerning the allowed Nitrogen (N) concentration in the effluent water from wastewater treatment plants are being tightened up. The Rimbo wastewater treatment plant has been imposed to reduce the annual mean concentration of total N in the effluent water to levels below 15 mg l-1. A more and more common way to reduce the Nitrogen level in wastewater is to let the water pass through a wetland. This study investigates the possibility to build this kind of wetland at the outlet of the Rimbo wastewater treatment plant.A prestudy of the topography, soil characteristics and groundwater flow indicates that the land area in question is well suited for the construction of a wetland.

A common perception is that fungicide treatments increases yield, but that the Nitrogen of the particular grain is diluted so that the overall removal of grain Nitrogen from the field remains unchanged. The aim of this paper is to demonstrate that a healthy crop reduces the risk of nutrient loss from agricultural land. The results from genotype and plant protection trials often show constant Nitrogen content in the grain, although the yield has been increased. Results from such experiments are therefore processed in order to confirm this and show that it is no statistically significant difference between the protein content (and also Nitrogen content) in crops which have undergone fungicide treatment compared to crops which remained untreated. The trials processed have been carried out in the southernmost part of Sweden and are distinguished to concern winter wheat production.The explanation to the results is that a healthy crop is able to maintain the biological functions of the plant in a more efficient way than a crop damaged by a fungal infection.

Wetlands play an important role in the ecosystem. They reduce the impact of flow flux in the drainage area, acts as upholder of biodiversity, as an esthetic and recreational component in the landscape and they have the ability to reduce nutrients such as Nitrogen, and help preventing eutrophication in costal areas.The number of wetlands in Scania have, due to the intensified agriculture been reduced to maximize the area suitable for crops.However since the mid 80th the consequences of this has been acknowledged, and many wetlands have been restored.This master?s thesis aim to see what impact this development have had on wetlands in Scania over the last 60 years. And also look at some of those factors important for the efficiency of Nitrogen removal in wetlands. During the process a detailed manual for inventories of this sort was created.The material used to execute the inventory of wetlands where aerial photographs over Scania from the 1940th, 1980th and 2000.

The price trend on rapeseed the latest years has led to an increasing interest to grow the crop among many farmers in Sweden. The price trend has resulted in more than a doubling of the oilseed area since the early 2000s. For many farmers it is an advantage to increase cultivation of rapeseed because of the high proportion of cereals in the crop rotation on many farms, but it is not just benefits. The risk of the fields being infected by clubroot increases within frequent rapeseed cultivation and it often leads to subtantial economic losses. Clubroot is caused by Plasmodiophora brassicae that is a soilborne pathogen in genus Protozoa and its resting spores can be found in the soil for up to 18 years.

The purpose with this report was to compare three commonly occurring methods for measuring plant available Nitrogen in soils. The methods extraction, incubation and Plant root simulator (PRS) probe - an ion exchange membrane (Western Ag Innovations, Inc., Saskatoon, Canada) method were used and comparison between these methods were conducted. A full factorial experiment were set up in northern Finland with the treatments excluding herbivores, warming and fertilization to see how the inorganic Nitrogen content in the soil was effected by the treatments. Soil cores were taken and from them a subsample was incubated for 18 days and thereafter analyzed for inorganic N in laboratory. PRS- probes were in the ground for 1 month.

The purpose of this report is to examine the possibilities to decrease the number of insects and other pathogens in a crop of pak choi (Brassica rapa), grown with different types of cover and living mulches. Included in the report is a study of literature where amongst others, a summary on the vegetable pak choi and theories of living mulches and different kind of covers are to be found. To examine the amount of predators in the field, traps were used. During the autumn 2002 the tests were conducted in Alnarp. The pak choi and the living mulches were planted/sawn at the same time, the different covers were also applied at this time. The total experiment was divided into six different treatments (plus control) of which three were with covers and three were with living mulches. Once a week the number of leaves, the height and damages were read on ten of the plants from each parcel.

Lichens are adapted to bright and sparse forests on oligotrophic ground. Due to a slow growth rate and high light demand lichens will suffer from competition in eutrophic environments. Therefore, lichens have disappeared from managed forests where the forest industry has increased the productivity. A reduced abundance of lichens will affect both biodiversity of the forest and the reindeer winter graze lands. It is important to understand how and for how long fertilization affects the abundance and diversity of lichens in order to protect lichen rich ecosystems. We have registered the biomass and number of lichen species in eight plots (four Nitrogen rich and four Nitrogen deficient) and compared fertilized Sami settlements with their oligotrophic surroundings in the nature reserves of Tjeggelvas.

This study was made as a part of a feasibility study on a polishing wetland at Rimbo wastewater plant (wwp) in Norrtälje municipality. The wwp had to decrease the Nitrogen discharge to reach the limit 15 mg tot-N/l. The Nitrogen in the outlet was mainly in the form of nitrate, hence the wetland mainly ought to support denitrification. The proposed area for the wetland was situated right next to the wwp and was already in the municipalitys posession. One aim of this study was to examine what spieces of plants needed to achieve highest possible denitrification.

The relatively poor economy in European dairy farming might be improved from efficient feeding systems and dietary management. Increasing herd sizes and transition to loose housing systems in Sweden, increases the possibilities for other feeding systems than separate feeding that is the traditional feeding system in Sweden. Other possible feeding systems are partial mixed ration (PMR) and total mixed ration (TMR), where the TMR system sometimes is associated with overfeeding and thereby increased environmental impact and high feed cost. Diets providing nutrients above or below animal requirements are considered as unbalanced, which in turn are associated with reductions in health, fertility and milk production. On the other hand, a balanced feed ration improves feed efficiency, Nitrogen utilization and profitability.