Browsing by Subject "kasvualusta"

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  • Heiskanen, Juha; Laitinen, Jukka (Suomen metsätieteellinen seura, 1992)
  • Pousi, Tomi (Helsingin yliopisto, 2017)
    In previous studies of Natural Resources Institute Finland it was noticed that Sphagnum moss had almost as good growing media properties as the white horticultural peat. In addition the Sphagnum moss based growing media prevented efficiently seed-borne Alternaria seedling blight and mosses were not molded with Peziza ostracoderma Korf that appears commonly on white horticultural peat. This thesis was part of the project of Natural Resources Institute entitled “Disease suppressive features of Sphagnum mosses”. The research aimed to survey the existence and applicability of fungistasis of Sphagnum moss as growing media. In the greenhouse experiments comparisons were made between mosses from six different sphagnum bog origins in their ability to suppress damping-off caused by Alternaria, Rhizoctonia and Pythium. Disease suppressive features of four sphagnum bogs mosses from three harvest depths were also determined. In the end of experiments the coverage by molds was determined and the fresh weights of seedlings were measured. In laboratory the amounts of common antagonist microbes in Sphagnum mosses were studied using different selective growth media. Results of different experiments were compared to white peat. In greenhouse experiments it was noticed that disease suppressive features varied a lot depending on the origin of the mosses and had different effects against different damp-ing-off pathogens. Mosses in the uppermost layers had best disease suppressive features against all three pathogens. The healthiest and biggest seedlings were obtained in growing media that contained mainly Sphagnum mosses and only a minimum amount of other peatland vegetation. There were only small amounts of molds on the top of Sphagnum moss growth media but also some phytotoxicity on seedlings was obtained Sphagnum mosses had only small amounts of antagonistic microbes as compared with peat. The results indicated that Sphagnum mosses have potential as growing medium that could efficiently prevent damping-off diseases and molds. However variation of disease suppressive was observed, which calls for more experiments to verify these effects. Minor amounts of antagonistic microbes detected in Sphagnum, as compared with white peat, suggests that disease suppressiveness may be caused by the phenolic compounds of Sphganum mosses.
  • Korhonen, Teija (Helsingfors universitet, 2007)
    Helicobacter pullorum was originally isolated from chickens at the beginning of the 90s. The bacterium has also been isolated worldwide from patients suffering from symptoms of the intestinal tract and it is suspected to be zoonotic. H. pullorum may infect chickens at the time of slaughtering, and hence it may create a risk for alimentary hygiene. Altogether over twenty helicobacteria are known, and they have been found in the gastrointestinal tract of various mammals and chicken. The importance of some species, such as Helicobacter pylori, as human pathogens has been proved. The clinical part of this study was conducted in spring 1999, at which point there was relatively little information and research done on H. pullorum. This study compares the applicability of different culture media as well as the filter method in isolating H. pullorum, and detects the occurrence of the bacterium in poultry samples. There were no notable differences in the applicability of studied culture media for the cultivation of H. pullorum, whereas the filter method could not be considered reliable. The poultry samples consisted of liver samples and the content of the caecum of egg-laying hens. The samples collected at a slaughterhouse provided 22 bacterial strains that can be identified as either Campylo- or Helicobacteria on the basis of their phenotypic features. With current knowledge these strains could be identified more specifically, using for instance PCR method. Notwithstanding the Helicobacter pylori bacterium, the isolation of Helicobacteria especially by cultivation methods has been shown to be demanding due to their specific growth/colonization factors. This is why Helicobacteria may have a greater influence both in veterinary and human medicine than is known so far. However, to estimate the pathogeneticity and zoonotic nature of Helicobacter pullorum requires further research.
  • Ikonen, Liisa (Helsingin yliopisto, 2019)
    Tutkin tässä pro gradu -tutkielmassani eräiden suomalaisten ruohovartisten kasvilajien ja biohiilen vaikutuksia huleveden määrään ja laatuun. Tutkimuksessa järjestettiin koekasteluita, joiden avulla oli tarkoitus selvittää kasvilajien kykyä vähentää huleveden määrää ja poistaa siitä ravinteita sekä biohiilen vaikutusta huleveden määrään ja laatuun. Kasvillisuuden ja biohiilen vaikutusta on tutkittu aikaisemminkin, mutta erityisesti tiettyihin kasvilajeihin liittyviä tutkimuksia ei ole tehty Suomessa. Tutkimus on osa Luonnonvarakeskuksen Hulevesialueiden kasvit ja kasvualustat (HuleKas) -projektia. Kaupungistuminen lisää talojen, parkkipaikkojen ja teiden rakentamista. Tämä kasvattaa läpäisemättömien pintojen määrää, ja se puolestaan estää veden imeytymisen maan läpi. Kaupungeissa ongelma on ratkaistu rakentamalla hulevesiviemäriverkostoja, mutta erityisesti muuttuva ilmasto lisää sateiden ja sitä kautta huleveden määrää. Rankkasateilla kaupunkien hulevesiviemärit osoittautuvat usein riittämättömiksi. Lisäksi hulevesi huuhtoo epäpuhtaudet kaduilta, ja hulevesi onkin todettu yhdeksi tärkeimmistä hajakuormituksen aiheuttajista. Nyttemmin on kehitetty perinteisten sadevettä pois johtavien viemäriverkostojen rinnalle ekologisempia ja kestävämpiä ratkaisuja. Hulevesi pyritään käsittelemään sen syntysijoilla, ja tähän voidaan päästä rakentamalla erilaisia hulevesirakenteita, kuten hulevesipainanteet tai sadepuutarhat. Hulevesirakenteiden tärkeimmät osat ovat kasvualusta ja kasvillisuus. Hyvällä kasvualustavalinnalla voidaan pidättää mm. fosforin yhdisteitä ja kuparia, kun taas nitraatin pidättyminen vaatii rakennetta peittävää kasvillisuutta ja hapettomia olosuhteita. Kasvillisuuden avulla voidaan myös hidastaa huippuvirtaamia, pidättää kiintoainesta ja poistaa metalleja ja ravinteita hulevedestä. Myös kasvualustan mikrobeilla on tärkeä merkitys ravinteiden sitojina. Tutkimusasetelmani oli astiakoe. Astioihin oli istutettu seitsemää suomalaista luonnon kasvilajia, nurmea ja kontrollina toimivat kasvittomat astiat. Osaan astioista oli lisätty biohiiltä. Tutkimusjakson aikana järjestettiin kolme koekastelua, joissa liuoslannoitteilla lisättyä tekohulevettä kaadettiin jokaiseen astiaan sama määrä. Tämän jälkeen kirjattiin ylös tietyin aikavälein, paljonko vettä astiasta on valunut ulos. Tutkielman aineisto koostuu kahdesta osasta. Ensimmäinen osa muodostuu koekasteluiden valuntatiedoista ja kolmas osa koekasteluiden vesinäytteiden laboratorioanalyyseistä. Parhaita kokonaistypenpidättäjiä olivat viiltosara, jänönsara, korpikaisla, luhtakastikka ja rantatyräkki. Kokonaisfosforin pidätyksessä puolestaan erottuivat viiltosara, korpikaisla, ja rantatyräkki. Kaikki kasvikäsittelyt alensivat tekohuleveden kokonaisfosforin konsentraatiota. Biohiili paransi kaikkien edellä mainittujen kasvilajien ravinteenpidätyskykyä. Myös mikrobitoiminnan merkitys ravinteiden sidonnassa on tärkeä. Eniten vettä koekastelussa käyttivät viiltosara, luhtakastikka sekä jänönsara. Jänönsaran suorituskyky on kiistanalainen johtuen epätasaisesta kastelusta kolmannen jakson aikana. Jaksojen aikaisessa veden käytössä tehokkaina veden käyttäjinä nousevat esiin viiltosara, jänönsara, korpikaisla, luhtakastikka ja rantatyräkki. Kaikki kasvikäsittelyt tuottivat vähemmän valuntaa, kuin kontrolli. Biohiilen avulla voidaan hidastaa valunnan alkamista ja kertymistä.
  • Kuisma, Eero (Helsingfors universitet, 2013)
    The use of peat as a growing-medium has raised concerns globally, because it is not ecologically sustainable. Coir is an ecologically friendly alternative, but it is transported very long way to Finland. Therefore, a substitute for peat and coir as a growing-medium in soilless culture is needed. The aim of this research was to find out, whether Finnish plant fibre medium can replace peat or coir in greenhouse production of strawberry. In the experiments four substrates were compared: coir, peat, plant fibre and peat/plant fibre mix. Water holding capacity, pH-buffer capacity and mineralisation of nitrogen were determined, and vegetative and generative growth of strawberries on different substrates were measured. In strawberry cultivation experiment the pH of plant fibre (6,5-7,7) was very close to that of peat (6,4-7,6). Coir and plant fibre had considerably lower pH-buffer capacity than the media that contained peat. The water holding capacity (613 % per dw) of plant fibre was considerably lower than in other media. Plant fibre medium´s water content (32-42 % v/v) was however closest to strawberry´s optimum (25-34 % v/v) during almost the whole experiment. Plant fibre (23:1) and peat/plant fibre mix (29:1) had optimal C/N- ratios in this experiment. The amount of soluble nitrogen was highest in plant fibre medium in the beginning of the experiment. The EC of plant fibre medium was very low in the beginning (0,5 mS/cm), but it increased quickly being 1,2-2,1 mS/cm, so it was second closest to the optimum during the rest of the experiment. The vegetative growth of strawberry plants was more vigorous in peat compared to other substrates. The growth of the root system was weakest in peat. Medium had no significant influence on the amount of yield, and had only minor influence on the quality of the yield. In conclusion, the plant fibre medium could replace peat or coir in the soilless cultivation of strawberry.
  • Simpanen, Suvi-Marja (Helsingfors universitet, 2017)
    Viherkattojen määrä on kasvanut räjähdysmäisesti eri puolilla maailmaa viime vuosina niiden jatkuvan tutkimisen myötä. Monet kaupungit haluavatkin lisätä viherkattojen määrää ja rakentamiselle on tarjolla erilaisia tukia sekä helpotuksia. Viherkattoja rakentaessa ongelmaksi muodostuu usein viherkaton aiheuttama lisäpaino, jota saneerauskohteiden rakenteet eivät välttämättä kestä. Ratkaisuksi voi nousta sammalkatto, joka voi olla perinteisiä viherkattoja ohuempi ja siten kevyempi. Sammalet ovat putkilokasveihin verrattuna kevyempiä ja ne kestävät myös paremmin kuivuutta. Sammalkattoja ei ole kuitenkaan tutkittu tarpeeksi, jotta niitä voitaisiin suunnitella ja rakentaa uusiin kohteisiin. Tämän tutkimuksen kohteena toimi Meilahden liikuntakeskuksen sammalkatto, jossa sammalten kasvua tutkitaan eri paksuisilla ja erityyppisillä kasvualustoilla. Tutkielman tarkoituksena oli selvittää, minkä tyyppinen kasvualusta edistää parhaiten sammalten kasvua koekatolla. Materiaali koostui sammalkatolta otetuista kuvista, joita muokattiin myöhemmin Photoshop -kuvankäsittelyohjelmalla sammalpeitteisyyden selvittämiseksi. Tutkimus aloitettiin syksyllä 2015 ja saatiin päätökseen syksyllä 2016. Tutkimuksen aikana osa katosta kärsi pahasti kevään 2016 kuivasta jaksosta sekä rankkasateista. Ohuimmat koealat huuhtoutuivat pois katolta, mutta paksuimmilla koealueilla sammaleet kehittyivät tasaisesti. Maaseoksista erityisesti kivituhkaa sisältävät seokset edistivät sammalten kehitystä, kun taas hiekan sekaisesta kuoresta/turpeesta koostuneilla kasvualustoilla peitteisyys pieneni. Pääkäsittelyiden, eli kasvualustan koostumuksen ja paksuuden, lisäksi tarkasteltiin myös taustalla vaikuttavia tekijöitä, kuten katon ilmansuuntaa sekä näytealan sijaintia suhteessa korkeuteen, mitkä vaikuttivat omalta osaltaan sammalpeitteisyyteen. Sammalkattojen jatkotutkimusten tarve on suuri. Tietoa tarvitaan enemmän erityisesti kasvualustasta sekä eri lajien soveltuvuudesta katolle. Tämän tutkimuksen tulokset antavat suuntaa katolle soveltuvasta kasvualustan paksuudesta sekä koostumuksesta, mutta tutkimus tulisi toistaa useammalla katolla sekä uusilla maaseoksilla.
  • Turpeinen, Laura (Helsingin yliopisto, 2019)
    Tomaatit ovat tärkeimpiä luomutuotteita Suomessa. Pohjoismaisissa oloissa luomutomaatteja kasvatetaan pääasiassa kasvihuoneissa rajoitetussa kasvualustassa. Luomukasvihuonetuotanto eroaa tavanomaisesta tuotannosta eniten kasvinravinteiden käytössä. Tutkimuksen tavoitteina oli selvittää luonnonmukaisen kasvualustojen ja kasvinravitsemuksen vaikutusta tomaatin satoon ja sadon laatuun. Kasvihuonetutkimuksessa kirsikkatomaatilla (Solanum lycopersicum) tutkittiin kolmea kaupallista luomukasvualustaa ja kahta kokeeseen suunniteltua luomujakojuurikasvualustaa, joita verrattiin tavanomaiseen kivennäislannoitettuun kontrollialustaan. Luomukasvualustoja lannoitettiin pelkästään siipikarjanlannasta valmistetuilla kiinteillä lannoitteilla. Jakojuurialustat erosivat toisistaan vain lannoituksen määrän suhteen. Kokeessa seurattiin kasvualustojen ravinnepitoisuuksia, sadon määrää ja laatua ja tomaattien vegetatiivista kasvua. Kasvualustoista kerättiin satoa 28 viikon ajan. Yhtä kaupallista kasvualustaa lukuun ottamatta kaikki luomukasvualustat tuottivat yhtä suuren sadon kuin kivennäislannoitettuun kontrolli. Heikoimmat sadot ja vegetatiivisen kasvun tuotti kasvualusta, jonka rakenne ei tukenut lisättyjen ravinnepanosten liukenemista ja mineralisoitumista kasveille helposti käytettävään muotoon. Kontrolli tuotti tilastollisesti eniten kauppakelvottomia hedelmiä. Kasvualusta ja lannoiteratkaisut eivät vaikuttaneet hedelmien liukoisten kuiva-aineiden pitoisuuteen, mutta kontrollin hedelmien titrautuva happamuus oli 25 – 30 % luomukasvualustoja suurempi kasvukauden alussa. Titrautuvan happamuuden kasvu alentaa tomaattien sokeri/happo -suhdetta, mikä viittaa kontrollissa olevan huonomman makuisia tomaatteja. Kokeessa käytetyt jakojuurialustat eivät eronneet tilastollisesti toisistaan sadon määrän, laadun tai vegetatiivisen kasvun suhteen. Kasvualustan rakenne on erityisen tärkeää lannoituksen onnistumisen kannalta. Luomukasvualustoilla ja luomulannoituksella voidaan saada samansuuruinen ja laadukkaampi sato tavanomaiseen tuotantoon verrattuna, jos kasvualustan ravinteiden riittävyydestä pidetään huoli.
  • Kämäräinen, Antti (Helsingfors universitet, 2014)
    Street trees are an important part of a comfortable urban environment. Their beneficial effects in the built environment have been documented in a number of ways around the world. In urban environment tree roots are often grown in limited volumes of soil and competing for space with artificial construction materials and technical structures. Low oxygen concentrations in urban soils are considered as one of the major growth limiting factors, particularly under street pavements. The terrestrial growth conditions are difficult to alter in urban environment. By improving below-ground conditions, tree well-being and sustainability can be significantly increased. Increased ensign of growing conditions and the awareness of the value of urban trees have contributed to the creation of landscaping applications such as structural soil. This study compared gas concentrations in the air of structural and conventional soils, used in roadside tree plantings in the City of Helsinki. Soil air samples were collected during growing seasons 2012 and 2013. Proportions of nitrogen, oxygen, carbon dioxide and methane in soil air were determined by a gas chromatograph. CO?-fluxes were used to evaluate the effect of the soil surfacing material to ground ventilation. Structural soil contained more oxygen in all depths compared to conventional tree soil. A strong correlation existed between oxygen and carbon dioxide concentrations. It seems that cobblestone coating with wide seams does not impair the ground ventilation compared to soil covered with cast-iron grate. Atmospheric growth conditions were more favorable in the structural soil; however the oxygen concentrations in conventional soil were also high.
  • Pekkala, Kati (University of Helsinki, 1994)
  • Punkka, Eetu (Helsingin yliopisto, 2019)
    Substrate producers are interested in new climate-friendly alternatives due to the problematic nature of the peat life cycle and the uncertain status. The Sphagnum moss has good properties for substrate production and, due to its productivity, is a potential alternative to peat harvesting. Indeed, the Sphagnum moss has been harvested for this purpose for several years. Exploitation of the new natural resource involves many issues to take care of in order to consider sustainable use. One of these is the impact on climate. Of the greenhouse gases, carbon dioxide and me-thane play a role in the climate emissions of ombrotrophic mires. Nitrous oxide is not considered here. In the case of carbon dioxide, it is important to study the carbon stocks of the decaying material and, in the case of methane, vege-tation restoration and plant species relationships are considered carefully. The aim of this Master's thesis was to study observations on the climatic effects of Sphagnum harvesting for possi-ble further research. Climate effects were compared with untreated reference areas and, in addition, the differences in emissions between peatland types were provisionally investigated. The climatic effects of Sphagnum harvesting were also compared with the corresponding figures of horticultural peat. Carbon dioxide was studied by the carbon content of drilled peat samples. The climate impact of the peat that wasn’t formed as a result of the harvesting was also taken into account in the calculations. Methane emissions were examined on the basis of restoration of cover from vegetation analysis and plant species relationship data. The Sphagnum harvesting areas were also examined about general information of the harvesting area for example harvesting marks in the ground, tree stand and ditch conditions. Field work was carried out in summer 2019 in Kihniö area on 12 bogs. In general, the vegetation of the harvesting areas was characterized by a strong pioneer effect on Eriophorum vagi-natum. The most recent harvesting areas were still nearly plant-free, but at the time of the study, the harvesting areas that had recovered three growing seasons had already begun to clearly recover in terms of vegetation. Within 10 years, the vegetation had completely recovered. In relative terms, the proportion of Eriophorum vaginatum in the oldest areas was clearly higher than in the reference areas and the regenerated vegetation in the harvesting areas was poorer than in the reference areas. However, the presence of Eriophorum vaginatum also seems to contribute to the spread of Sphagnum sp. In addition, the harvesting marks of the harvesting seems to be important above all for the recovery of Sphagnum sp. The flat surface facilitates recovery, but also the unharvested spots within the harvesting areas. Based on the greenhouse gas calculations, the emission of the Sphagnum harvesting area was 10.26 kg/m2 CO2 in 13 years. Comparing the differences between the different bog types, it was found that the harvesting is more climate friendly in Sphagnum-bogs than in cottongrass-bogs. The Sphagnum harvesting is clearly a better alternative to harvesting peat from a climate point of view, when emissions are distributed on the dry masses of the growing media produced. When reducing climate emissions, the major part of total emissions is generated by the specific decontaminated substrate. The importance of the vegetation is less significant in the overall result. In this study, the climate effects of the Sphagnum harvesting were tentatively mapped, as the topic has not been studied previously in Finnish conditions. More research is needed with wider sampling and long-term follow-up.
  • Lehto, Anniina (Helsingin yliopisto, 2019)
    Peat is currently the most important raw material for growing media in horticulture. For a while now, alternative raw materials have been tested since there is a demand for more sustainable substrates for horticultural production. The aim of this research was to determine the effects of different Sphagnum L. biomass containing growing media on the vegetative and generative growth on Pelargonium L´Hér and Begonia L., and to determine how the different growing media affect the longevity of the plant in water deficit. There were two types of Sphagnum biomass used for the study and there were eight different compositions of Sphagnum based growing media in total. The growing media consisted of varying amounts of Sphagnum fibre and peat. Peat was amended with either 100%, 75%, 25% or 0% of Sphagnum fibre. 47 days from the beginning of the experiment some of the Begonias and Pelargoniums were transferred to a water deficit treatment in national plant phenotyping infrastructure (NaPPI) for non-destructive imaging. The results showed that the Pelargoniums cultivated in Sphagnum-based growing media had higher fresh and dry weights than the ones cultivated in 100% peat. With Begonia, there were no differences in fresh or dry weights of the plants between the treatments. The leaf areas were in trend with the fresh and dry weights. The higher the fresh and dry weights, the higher was the leaf area. There were no differences in the onset of flowering or the number of flowers in the plants between the different growing media for Pelargonium or Begonia. There were no notable morphological differences in the plants between the treatments either, which indicates that the Sphagnum fibre did not affect the ornamental value of Pelargonium and Begonia. In the water deficit treatment, there were no differences between the growing media in any of the values measured. The results indicate that the vegetative and generative growth of Pelargonium and Begonia on Sphagnum-based growing media was on acceptable level for production. Considering these results, Sphagnum biomass could be used in the growing media to replace peat, either partially or completely, for at least certain ornamentals.