Browsing by Subject "kierrätyslannoite"

Global growing demand to produce more food with less inputs and energy without causing greenhouse gas emissions challenges the current practice of using mineral fertilizers which are produced from new and partly non-renewable raw materials with considerable amount of energy. On the other hand recycled fertilizers made of different side streams and biomasses also need to be processed before usage or the amount needed per area is so great that the environmental advantages might be lost. The aim of this study was to discover and compare the energy consumption and greenhouse gas emissions of recycled fertilizers (ammonium sulfate, biogas digestate and meat bone meal) and mineral fertilizer in production of oat by using Life Cycle Assessment (LCA). All recycled fertilizers were found to cause less greenhouse gas emissions and consume less energy than mineral fertilizer. The least emissions caused the usage of ammonium sulfate and the best energy efficiency was achieved with biogas digestate fertilization. Considered relative to global increase in food and energy consumption and control of climate change and recycling of raw materials recycled fertilizers proved to be effective compared to mineral fertilizer. Also on the grounds of land use and yield recycled fertilizers turned out to be potential substitute for mineral fertilizers. Further studies are still needed due to large number of raw materials and constantly increasing amount of processing techniques of recycled fertilizers.

The use of fertilizers has made it possible to increase agricultural yields, enabling the world’s growing population to be fed. The use of mined phosphorus has created mostly linear phosphorus flow from mines through farms to lakes and oceans. This has clearly deteriorated aquatic ecosystems globally. USA, China and Morocco control over 85 % of global phosphorus reserves and Europe is very dependent on imported phosphorus. To gain phosphorus balance in Europe, it would be important to recycle phosphorus. Recycled fertilizers come from derived currents of agriculture, food industry, forest industry and communities. Only a few studies have been made regarding the effects different recycled fertilizers have on plant’s phosphorus uptake. The aim of this study was to find out how four different recycled fertilizer treatments (ammonium sulphate, liquid digestate, meat bone meal, vinasse) affect barley’s phosphorus uptake and soil aggregate stability, when compared to mineral fertilizer treatment and non-fertilized control treatment. Study material was collected from HYKERRYS 2 -project’s experiment field in growing season 2019. Phosphorus in dry matter was measured and biomass, phosphorus uptake to biomass, fertilizer use efficiency and phosphorus uptake from soil phosphorus reserves were calculated from barley plant samples collected at growth stage 65 (BBCH). Soil aggregate stability analyses, dry sieving and wet sieving, were made to soil samples collected after harvest. Barley’s phosphorus content in dry matter was highest with non-fertilized treatment but other treatments had no differences between them. In biomass quantity or phosphorus uptake on biomass there were no differences between treatments. Fertilizer use was most efficient with ammonium sulphate and least efficient with digestate. Phosphorus uptake from soil phosphorus reserves was least efficient with digestate and mineral fertilizer. The share of soil water stable aggregates had no differences between treatments, but water turbidity was lowest with ammonium sulphate. The results show that recycled fertilizers are fit to replace mineral fertilizers when considering plant’s phosphorus uptake, because there were no notable differences in barley’s phosphorus content, biomass, phosphorus uptake on biomass or soil aggregate stability between different recycled fertilizers and mineral fertilizer. When viewing the results, it should be considered that the soil in experimental field had high phosphorus content and high soil organic matter content to begin with, which made it more difficult to detect the differences than it probably would have been if the soil phosphorus content had been lower. There was also no information available about the forms of the phosphorus in the recycled fertilizers, which made the interpretation of the results difficult, because different forms of phosphorus are differently available for plants. In order to target the use of recycled fertilizers effectively based on crop and soil quality, more knowledge is needed on both the phosphorus forms in recycled fertilizers and recycled fertilizer’s effects on plant’s phosphorus uptake on soils with lower nutrient and organic matter contents.

Nutrient recycling has a huge potential in Finland, but the recycling fertilizer market remains immature. Recycled nutrients should be developed into fertilizers and business activity around them to develop the market as well. Fertilizers must be profitable for the manufacturer and cost-effective for the farmer. Therefore, the fertilizers must be priced correctly. The aim of this study was to find out farmers willingness to pay for different types of manure-based recycling fertilizers, which factors affect farmers fertilizer choices and what are farmers opinions on recycling fertilizer attributes and use. Moreover, the pricing of existing recycling fertilizers was compared to their attributes like nutrient content and form. According to present results, the factors affecting farmers willingness to pay were form, eligibility to organic farming and price of the recycling fertilizer, as well as cultivated area and production sector of the farm, amount of manure produced on the farm, being part of environmental compensation scheme, and also the farmers relation to farming (part-time, full-time) and how long has he been farming. Farmers preferred fertilizers with dry form, and the willingness to pay of organic farmers was higher than that of traditional farmers. Willingness to pay for different recycling fertilizers was mostly much lower than market prices, but there are potential customers to be found, especially among organic farmers.