Potential of the slow pyrolysis products birch tar oil, wood vinegar and biochar in sustainable plant protection : pesticidal effects, soil improvement and environmental risks

The increased use of pesticides and their impacts on environment have become a matter of considerable concern in recent decades. The use of pesticides, especially synthetic ones, is suggested to be replaced by compensatory substances that exert a lower risk to the environment. At the same time, global climate change will lead to an increase in temperature and rainfall in some areas, which could enhance the growth of several pest populations. For example, populations of the molluscs Arianta arbustorum and Arion lusitanicus have increased in many parts of northern Europe in recent years. Plant-derived products may have a significant role in sustainable plant protection when functioning as compensatory substances for synthetic pesticides, or alternatively by affecting the behaviour of synthetic pesticides in the soil. This thesis research investigated the suitability of birch (Betula sp.) -derived slow pyrolysis products birch tar oil (BTO), wood vinegar (WV) and biochar in sustainable plant protection. The aims of the study were to (i) explore the efficiency of birch derived pyrolysis liquids in mollusc control and (ii) investigate the environmental risks related to their use. In addition, (iii) the effects of biochar and wood vinegar on the environmental fate of glyphosate, one of the most commonly used herbicide, was examined. BTO and WV proved to be ineffective in eliminating snails. Instead, BTO and the mixture of BTO and WV exhibited a clear repellent effect against molluscs. The effect of WV on non-target organisms was assessed in several toxicity tests and risk assessment calculations. Soil organisms were more tolerant of WV than aquatic organisms. No long-term effects on soil microbes, nematodes or enchytraeids were found. The initial risk assessment indicated the risks of WV (PIENEMPI 400 L ha-1) to soil and aquatic organisms to be negligible. Based on preliminary data, biochar reduced the leaching of glyphosate from the soil. The effects of WV on glyphosate leaching was inconsistent. Soils treated with a mixture of biochar and WV showed the lowest glyphosate leaching. Neither WV nor biochar alone had clear effects on glyphosate degradation in the soil. The results show, for the first time, that biochar has the potential to influence the fate of glyphosate in the soil by reducing its leaching from soil. This thesis provides strong evidence for the potential of birch-derived pyrolysis liquids as an effective, non-costly and environmental friendly method against molluscs. As WV is only slightly toxic or non-toxic to most non-target organisms, the environmental risk due to synthetic pesticides could be diminished by including WV as part of a pest control protocol. Biochar could also play a role in pesticide risk reduction, particularly in preventing contamination of the aquatic environment. Based on the results of this thesis, the birch-derived slow pyrolysis liquids and biochar appear to have potential for use in sustainable plant protection.Torjunta-aineiden käyttöä tulee vähentää ympäristölle ja ihmisten terveydelle aiheutuvien vaarojen vuoksi. Monien synteettisten torjunta-aineiden jäämiä ja hajoamistuotteita löytyy sekä maaperästä että pohja- ja pintavesistä. Samanaikaisesti ilmastonmuutos kiihdyttää monien kasvituholasten leviämistä, joten torjuntaa tarvitaan. Esimerkiksi lehtokotilot (Arianta arbustorum) ja espanjansiruetanat (Arion lusitanicus) ovat lisääntyneet viime vuosina runsaasti aiheuttaen ongelmia erityisesti kotipuutarhoissa. EU:n torjunta-ainestrategian tavoitteena on luonnon omien torjuntamekanismien laajempi käyttöönotto ja synteettisten kemikaalien osittainen korvaaminen helpommin hajoavilla tuotteilla. Kasviperäiset aineet ovat tärkeä ryhmä tavoiteltaessa synteettisten torjunta-aineiden aiheuttamien ympäristöriskien hallintaa. Kasviperäisillä yhdisteillä voidaan joko korvata osa synteettistä kemikaaleista tai vaihtoehtoisesti vaikuttaa niiden käyttäytymiseen ympäristössä. Tässä väitöskirjatutkimuksessa tutkittiin koivuperäisten hidaspyrolyysituotteiden - koivutervan, koivutisleen ja biohiilen käyttöä kasvinsuojelussa. Tavoitteena oli selvittää pyrolyysinesteiden tehokkuus nilviäistorjunnassa, sekä arvioida käytön aiheuttamat riskejä ympäristölle. Lisäksi tutkittiin voidaanko koivutisleen ja biohiilen avulla vaikuttaa glyfosaatin, Suomessa käytetyimmän herbisidin, kulkeutumiseen ympäristössä. Tutkimukset osoittivat että pyrolyysinesteet eivät tappaneet kotiloita. Sen sijaan niillä oli merkittävä kotiloita ja etanoita karkottava vaikutus. Tisleiden ympäristötoksisuutta selvitettiin lukuisilla kokeilla sekä riskinarviointilaskelmilla. Koivutisleellä ei havaittu olevan pitkäaikaisia vaikutuksia maaperän avainlajeihin. Riskinarviointiaineiston perusteella koivutisleen (PIENEMPI400 L ha-1) ympäristölle aiheuttamat riskit voidaan arvioida vähäisiksi. Alustavan aineiston perusteella biohiili vähensi glyfosaatin huuhtoutumista maaperästä 24-27%. Tisleen vaikutuksesta glyfosaatin liikkumiseen saatiin ristiriitaisia tuloksia. Biohiili ja tisle eivät vaikuttaneet glyfosaatin hajoamiseen maaperässä. Väitöskirjatutkimus osoittaa koivupuun pyrolyysineisteissä olevan potentiaalia tehokkaaseen, halpaan ja ympäristölle vähäriskiseen nilviäistorjuntaan. Koska koivutisle havaittiin ympäristön kannalta turvalliseksi ja vähäriskiseksi, synteettisten torjunta-aineiden aiheuttamia riskejä on mahdollista vähentää ottamalla koivutisle osaksi kasvinsuojelua. Myös biohiilellä voidaan vaikuttaa synteettisten torjunta-aineiden aiheuttamiin riskeihin mm. vähentämällä torjunta-aineiden kulkeutumista pelloilta vesistöihin. Tämän tutkimuksen tuloksiin perustuen voidaan koivuperäisillä hidaspyrolyysituotteilla todeta olevan useita käyttökohteita kestävän kasvinsuojelun edistämiseksi

Effects of compost, biochar and ash mixed in till soil cover of mine tailings on plant growth and bioaccumulation of elements : A growing test in a greenhouse

Mine closures necessitate vegetation restoration to cover tailings fields and reduce environmental risks. Sole use of forest soil as growth medium provides only low fertility and slow plant growth especially in the harsh boreal climate conditions. This preliminary study examines the feasibility of recyclable waste materials added to forest till soil for improving vegetation success on reclaimed mine tailings. One compost type, three biochar types (Bc1-3) and two ash types (Ash1-2) were studied for physical and chemical properties as well as their effects on the growth and element accumulation of timothy (Phleum pratense L.), white clover (Trifolium repens L.) and Scot spine (Pinus sylvestris L.) during one growing period in a greenhouse. Oxidized surface tailings soil and Ash2 were the finest media components while compost and Ash1 were the coarsest. Tailings soil also had the highest salt contents and electrical conductivity, while in till soil they were at the lowest levels. Timothy and white clover germinated well in moist pure tailings soil but grew poorest in it. White clover grew poorly also in pure till soil. Best biomass growth was in the mixture of till, compost and Bc2 (from sewage sludge and woodchips). Planted pine seedlings grew relatively well in all media during the first growing season but Ash1 (from wood and peat) tended to promote height growth and pure till soil root biomass. In media containing Ash1, pine tissues accumulated B, Ca, Mg, K, Na and S. Elevated As content in tailings soil accumulated in plant shoot tissues slightly; only in the old needles of pine were As levels elevated. The results suggest that till and tailings media with compost added as a nitrogen source can promote adequate plant growth during initial growing seasons. Suitable types of biochar and ash amendments can further expedite plant establishment.Peer reviewe

Using biochar to purify runoff in road verges of urbanised watersheds: A large-scale field lysimeter study

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Addition of recyclable biochar, compost and fibre clay to the growth medium layer for the cover system of mine tailings : a bioassay in a greenhouse

Mine closures require landscape reclamation to reduce the environmental risks of tailings fields. However, information about the feasibility of recyclable waste materials as a growth medium layer for the cover systems of mine tailings and their effects on vegetation restoration and reforestation success is scant especially in the boreal climate. This study examines the use of various recyclable by-products in improving vegetation success on reclaimed mine tailings. The physical and chemical properties of two wood biochar types, fibre clay, compost, tailings soil and forest till soil as well as their effects as growth media on the growth of several plant species during one growing period in a greenhouse were examined. Marked differences in the properties (e.g. pH, element concentrations, water retention) as well as in plant growth among the growth media were found. Fresh non-oxidized tailings soil showed high salt contents and electrical conductivity which together with fine soil texture provided the poorest or nonexistent plant growth. Fibre clay was the coarsest and driest material and also showed poor plant growth. Root and shoot growth was greatest in pure compost. All media without compost additive showed relatively poor growth which indicates the lack of nitrogen. The results suggest that forest till soil and biochar are the most suitable growth media for the cover systems of mine tailings when added with compost or another nitrogen source. Scots pine container seedlings, willow cuttings and sown red clover showed to be the most feasible plant species to be grown on boreal tailings covers.Peer reviewe

Use of Botanical Pesticides in Modern Plant Protection

vokpuj puj ks

Soil organic matter, rather than temperature, determines the structure and functioning of subarctic decomposer communities

The impacts of climate change on ecosystem structure and functioning are likely to be strongest at high latitudes due to the adaptation of biota to relatively low temperatures and nutrient levels. Soil warming is widely predicted to alter microbial, invertebrate, and plant communities, with cascading effects on ecosystem functioning, but this has largely been demonstrated over short-term (Peer reviewe

Kasviperäiset pyrolyysituotteet lietelannan ravinnearvon turvaajina (PYSTI) – lainsäädäntöselvitys

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Effect of weather conditions, substrate pH, biochar amendment and plant species on two plant growth-promoting microbes on vegetated roofs and facades

Background Vegetated building envelopes (VBEs), such as vegetated roofs and facades, are becoming more frequent in urban planning nowadays. However, harsh growing conditions restrain the application of VBEs. Plant growth-promoting microbes (PGPMs) might help ease the stresses, but first, it is necessary to investigate how to ensure their survival and growth under VBE conditions. Methods We conducted three experiments to test the impact of various factors on the microbial populations of inoculated PGPMs in VBEs, a mycorrhizal fungus Rhizophagus irregularis and a bacterium Bacillus amyloliquefaciens. The first experiment was conducted by inoculating the two PGPMs separately in Sedum roof plots, and the microbial populations associated with Poa alpina was monitored for two consecutive years under local weather conditions. The second experiment was conducted in a laboratory testing the effect of substrate pH (substrates collected from balcony gardens) on R. irregularis population associated with Trifolium repens and Viola tricolor. The third experiment was conducted on a meadow roof testing the effect of biochar amendment on R. irregularis population associated with Thymus serpyllum and Fragaria vesca. Results In the first experiment, Bacillus was found to associate with P. alpina, but Rhizophagus wasn't. Yet, the fungus induced high Bacillus population density in the Rhizophagus treated plots in the first year. In the second experiment, Rhizophagus abundance in T. repens was higher in the neutral substrate (6–6.5), while V. tricolor was more colonized in acidic substrate (5–5.5), suggesting an important interactive effect of substrate pH and plant species on Rhizophagus abundance. The third experiment suggested a negligible impact of biochar amendment on Rhizophagus abundance for both host plants. Conclusion Three experiments demonstrate that PGPM inoculation on VBEs is feasible, and various factors and interactions affect the PGPM populations. This paper provides reference and inspiration for other VBE research involving substrate microbial manipulation.Peer reviewe

Lietteiden happokäsittely vähentää ammoniakkipäästöjä

Lehtiartikkeli (rinnakkaistallennusluvan asianumero: 2908/12 05 01 02/2020)202

Slow pyrolysis liquid in reducing NH3 emissions from cattle slurry-Impacts on plant growth and soil organisms

A substantial percentage of manure nitrogen (N) can be lost as gaseous ammonia (NH3) during storage and field spreading. Lowering slurry pH is a simple and accepted method for preserving its N. Efficiency of slow pyrolysis liquid (PL) produced from birch (Betula sp.) as an acidifying agent, and its ability to reduce NH3 emissions following surface application of cattle slurry, was studied in a field experiment. Untreated slurry (US) and slurries acidified with PL and sulfuric acid (SA) were applied to the second harvest of a grass ley. Immediate NH3 emissions, grass biomass, N-yield and possible toxic impacts on soil nematodes and enchytraeids were examined. Furthermore, the effects on soil respiration, nitrogen dynamics and seed germination were studied in subsequent laboratory experiments. In the field, over one third of the water-extractable ammonium-N (NH4-N) applied was lost through NH3 volatilization from US. SA and PL acidified slurries reduced NH3-N emission rate equally from 3.4 to (c) 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe