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Browsing by study line "Maaperä- ja ympäristötiede"

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  • Lind, Noora (2021)
    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.
  • Mattila, Tomi (2021)
    Tämän työn tarkoituksena oli tutkia kuinka eri lannoituksen muodot ja määrät vaikuttavat nurmiviljelyyn käytettävän maaperän typpi (N)- ja hiili (C)-pitoisuuksiin. Pyrkimyksenä oli löytää tilastollisia eroavaisuuksia orgaanisen ja epäorgaanisen lannoituksien vaikutuksista nurmialueen kasvihuonekaasupäästöihin. Kasvillisuuden, maahengityksen ja yhteyttämisen mittaukset suoritettiin neljälle eri käsittelylle (lannoittamaton, epäorgaaninen 30 kg N/ha, epäorgaaninen 60 kg N/ha ja orgaaninen 60 kg N/ha). Maaperästä otetiin näytteet analyysiä varten kasvukauden jälkeen syvyyksiltä 0–10 cm ja 20–30 cm. Maaperänäytteille suoritettiin mineraalityppi-määritys sekä kokonais- hiilen ja – typen määritykset. Kasvillisuudesta mitattiin maanalainen ja maanpäällinen biomassa sekä lehtipinta-ala indeksi eli LAI. Maahengitys ja yhteyttäminen mitattiin suljetuilla kammiomenetelmillä. Mittauksissa saatu CO2-pitoisuuden muutos sijoitettiin lineaariseen yhtälöön, josta muodostettiin hiilidioksidin vuo. Maahengityksen ja yhteyttämisen tuloksista mallinnettiin vielä koko kasvukauden hiilitaseet. Kasvillisuuden mittauksissa suurimmat biomassat esiintyivät läpi mittauskauden korkeimman lannoitustason saaneilla epäorgaanisella (700–800 g/m2) ja orgaanisella (700–1000 g/m2) käsittelyillä. Yhteyttämispotentiaalin sekä maahengityksen tuloksissa eroja oli ainoastaan lannoittamattomien ja lannoituksen saaneiden käsittelyiden välillä. Hiilitaseiden mallinnuksessa selvisi, että kokeen kaikki käsittelyt toimivat hiilenlähteinä ja vähiten hiiltä vapautui epäorgaaniselta 30 kg N/ha saaneelta lannoitukselta. Maaperäanalyyseissä käsittelyiden C- ja N- pitoisuuksissa ei ollut eroavaisuuksia. Mineraalitypen määrityksissä pohjamaiden NO3- ja NH4- pitoisuuksissa oli tilastollisia eroavaisuuksia orgaanisen ja epäorgaanisen käsittelyiden välillä. Orgaanisella lannoituksella pintamaan sekä pohjamaan NO3-pitoisuudet ovat lähellä toisiaan, kun taas epäorgaanisella lannoituksella pohjamaan pitoisuudet ovat selkeästi korkeammat. Tuloksien perusteella ei pystytä selkeästi sanomaan, kumpi lannoitemuodoista olisi hiilen sitoutumisen kannalta parempi vaihtoehto. Tutkimuksen aihealue on kuitenkin merkittävä ilmaston sekä viljelijöiden kannalta. Tästä syystä jatkotutkimuksien tekeminen olisikin suotavaa, jotta nurmiviljelystä pystytään muokkaamaan hiiltä sitovaksi ja samalla parantamaan peltojen kasvukuntoa.
  • Pietiläinen, Karoliina (2022)
    Declining trend of carbon content in croplands has been reported in Finland as well as globally and at the same time soil degradation has risen to a significant threat for food production. Increasing soil carbon content for example with carbon rich fertilizers may improve soil water retention properties, soil structure, and increase soil carbon sink. The aim of this thesis was to study if the usage of carbon-rich fertilizers (pulp mill sludge, liquid vinasse, bone meal and biowaste compost with biochar) increase soil carbon content, soil water retention and water stable aggregates compared to usage of inorganic fertilizers or unfertilized control in a four-year time period (2016-2019). Material for water retention curve and water stable aggregate measurements was collected in HYKERRYS-project field experiment after harvest in august 2019. Existing data were utilized for determination of soil total carbon content, which had been collected every year after harvest in the topsoil (0-20 cm). The total carbon content was determined with Variomax CN-analyser in 2016-2018 and with LECO CN-analyzer in 2019. Water retention curve was determined by underpressure method in sandbox (for pF 1,5, 1,8 and 2,0) and overpressure method in pressure plate extractor (for pF 2,7, 3,4 ja 4,2) using undisturbed and disturbed (pF 4,2) soil samples collected in topsoil. Water-stability of aggregates was determined with wet sieving method for aggregate size fraction 2-5 mm. Before wet sieving, samples were dry sieved on fraction classes > 5 mm, 2-5 mm and < 2 mm. Soil carbon content (soil C) in the composted pulp mill sludge treatment was by +0,5 % statistically significant (p < 0,05) higher than that in the mineral fertilizer treatment in 2019. Statistically significant regression between added C and measured soil C content supported the view that added C increased soil C contents also in other treatments even if no significant differences between these treatments were detected. None of the treatments significantly improved the water retention or water stable aggregates (p > 0,05). The results of this thesis indicated that adding composted pulp mill sludge over 22 000 kg DM ha 1 (8000 kg C ha-1) in four years is enough to significantly raise the carbon content of a humic clay loam soil, but it is not enough to improve soil water retention properties or the water stability of soil aggregates.