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Enhancing biogas production predictions using ARIMAX models on mixed silages
No full textReceived: February 15th, 2025 ; Accepted: June 19th, 2025 ; Published: July 14th, 2025 ; Correspondence: [email protected] production as a renewable energy source is gaining more attention from different actors in the energy sector due to the use of different residual products for its generation. This interest also comes from the agricultural sector. A typical crop used for biogas production is maize, which poses environmental challenges related to soil erosion and nutrient depletion. Furthermore, land use changes can also reduce biodiversity and attract pests. An increasing number of strategies to diminish these issues rely on combining maize with other leguminous plants, improving the nutritional silage profiles, and potentially enhancing biogas production. Nonetheless, adopting these new approaches remains limited since the farmers hesitate to invest in new technologies without clear and quantifiable improvements. In this regard, in this study, we propose time-series-based models to predict biogas and methane production based on the silage features of crops and the time-series data. In particular, we fitted models based on Autoregressive Integrated Moving Average with eXogenous variables (ARIMAX) to capture the temporal dependencies, aiming to characterize the methane volume and methane concentration accurately. We used a previously validated measurement campaign, which included other anaerobic digestion variables like volatile solids, crude protein, cellulose, and hemicellulose, among others, from crops of maize and mixed maize-legume silages, along with the production of biogas and methane, with a sample period in days. The reactor was a 5 L fermenter operated at 40 °C with manual mixing daily. It used inoculum and silage, with a 21-day delay before measurement. Biogas volume was recorded using a measuring cylinder, and composition was analyzed with a Dräger X-am 8000. We tested our ARIMAX-based models regarding their goodness of fit using the determination coefficient R2 and the Root Mean Square Error (RMSE). In the case of the methane volume, we obtained an R2 of 0.92 and an RMSE of 0.001 liters, and for the case of methane concentration, our models exhibited an R2 of 0.908 and an RMSE of 0.85%. Our promising models help farmers, researchers, and policymakers to accurately characterize and forecast biogas and methane production as promising renewable energy generation technologies
Feeding and odor preferences of adult Colorado potato beetle (Leptinotarsa decemlineata)
No full textMagistritöö
Põllumajandussaaduste tootmise ja turustamise õppekavalKartulimardikas (Leptinotarsa decemlineata Say) on kõige ohtlikum ja suuremat
majanduslikku kahju tekitav kartulikahjur maailmas. Käesoleva magistritöö eesmärgiks
oli uurida erinevate kartulisortide ja maavitsaliste (Solanaceae) taimede sobivust
kartulimardika valmikute toidutaimena. Valiktoitumiskatsed kartulisortide (võrdlus- ehk
kontrollsort ‘Maret’) ja sekundaarsete (alternatiivsete) toidutaimedega (tomat, füüsal,
harilik ja kollane maavits) viidi läbi 2023. aasta suvel. Kartulimardikate lõhnaeelistust
mitmete kartulisortide suhtes uuriti neljaharulise olfaktomeetriga 2024. aasta suvel.
Katse tulemused olid järgnevad:
Kartulimardika valmikud eelistasid sorti ‘Maret’ sordile ‘Gala’.
Sordi ‘Maret’ lehepinna tarbimises võrreldes sortidega ‘Laura’ ja ‘Birgit’
erinevusi ei leitud, kuigi esines tendents, et sordi ‘Maret’ lehti söödi mõnevõrra
rohkem.
Kartulimardika valmikud eelistasid toituda kartulilehtedest mitte sekundaarsetest
(alternatiivsetest) toidutaimedest (harilik ja kollane maavits, füüsal, tomat).
Hariliku ja kollase maavitsa lõhn pärssis mardikate toitumist kartulil, sealjuures
olid isased enam mõjutatud.
Emased kartulimardikad sõid sekundaarsetest toidutaimedest kõige enam
tomatilehti ja kõige vähem hariliku maavitsa lehti. Isaste mardikate
toitumiskäitumine oli vastupidine – kõige enam söödi harilikku maavitsa lehti ja
kõige vähem tomatilehti.
Emaste kartulimardikate ööpäevane kehamassi juurdekasv oli tomatil toitudes
kõrgem kui teistel sekundaarsetel toidutaimedel.
Isaste mardikate ööpäevane kehamassi juurdekasv oli harilikul maavitsal toitudes
oluliselt madalam kui tomatil ja füüsalil.
Kollasel maavitsal toitumine kasvatas emaste ööpäevast kehamassi, aga pärssis
isaste kehamassi juurdekasvu.
Lõhnauuringus selgus, et kartulimardika mõlemast soost valmikutel on ilma
visuaalsete stiimuliteta raske orienteeruda. Isased mardikad eirasid
lõhnastiimulite alusel sorti ‘Maret’.The Colorado potato beetle (Leptinotarsa decemlineata Say) is the most dangerous and
economically damaging potato pest in the world. The aim of current Master's Thesis was to
investigate the suitability of different potato varieties and family Solanaceae plants as food
plants for potato beetle adults. Choice feeding tests with potato varieties (comparison/control
variety ‘Maret’) and secondary (alternative) food plants (tomato, physalis, bittersweet, hairy
nightshade) were conducted in the summer of 2023. The odour preference of potato beetles
for several potato varieties was studied using a four-arm olfactometer in the summer of 2024.
The results of the experiment were as follows:
Potato beetle adults preferred the variety ‘Maret’ to the variety ‘Gala’.
No differences were found in the consumption of the leaf area of the variety ‘Maret’
compared to the varieties ‘Laura’ and ‘Birgit’, although there was a tendency that the
leaves of the variety ‘Maret’ were eaten somewhat more.
Potato beetle adults preferred to feed on potato leaves rather than secondary
(alternative) food plants.
The smell of bittersweet and hairy nightshade inhibited beetles’ feeding on potatoes,
with males being more affected.
Female potato beetles ate the most tomato leaves and the least bittersweet leaves
among secondary food plants. The feeding behavior of male beetles was the opposite
– bittersweet leaves were the most and tomato leaves were eaten the least.
The daily body mass gain of female potato beetles was higher in the tomato variant
than in the other secondary food plants.
The daily body mass gain of male potato beetles was significantly lower when feeding
on bittersweet than on tomato and physalis.
Feeding on hairy nightshade increased the daily body mass of females, but inhibited
the body mass gain of males.
The odour study revealed that adult potato beetles of both sexes have difficulty
orienting themselves without visual stimuli. Male beetles ignored the ‘Maret’ variety
based on odour stimuli
The quality and fermentation of the total diet containing BRS capiaçu or sugarcane with or without urea
No full textReceived: April 3rd, 2025 ; Accepted: August 18th, 2025 ; Published: August 28st, 2025 ; Correspondence: [email protected] objective of this study was to evaluate total diet silages in PVC silos, containing BRS Capiaçu or sugarcane with or without urea. The experimental design was completely randomized with a 2x2 factorial arrangement with ten replicates, with one of the roughages (sugarcane or Capiaçu) being with or without urea (2% urea on a dry matter basis). No interaction was observed between the bulk and urea factors for the variables analyzed. Diets containing sugarcane presented greater gas losses and lower pH. In contrast, effluent losses and dry matter recovery were higher in diets containing BRS Capiaçu. Ammonia nitrogen levels were influenced by both the type of roughage and the addition of urea, being higher in diets with urea and those containing BRS Capiaçu. Diets with BRS Capiaçu also resulted in higher levels of ash, NDF, ADF, hemicellulose, cellulose, and lignin. The addition of urea, in turn, reduced lignin levels. The levels of ADIN and NDIN were higher in diets with BRS Capiaçu and lower in those with sugarcane, while urea reduced ADIN. For NFC, there was an effect of roughage and urea, with higher values observed in diets with sugarcane and with the addition of urea. The highest iNDF levels were found in diets with BRS Capiaçu and without urea. Protein fractionation showed that the addition of urea increased fraction A and reduced fractions B1+B2 and C. Fraction B3 was higher in diets with sugarcane. Fraction C showed higher levels with BRS Capiaçu and when urea was not added. Sugarcane resulted in higher levels of fractions A+B1 and lower levels of B2 and C, a pattern opposite to that observed with BRS Capiaçu. Similarly, urea increased fractions A+B1 and decreased fractions B2 and C. The addition of urea to the diets promoted changes in the carbohydrate and protein fractions, improving the composition. Regarding the roughage used, sugarcane presented better fermentation parameters when purchased from Capiaçu
Assessing criteria for adopting sustainable subsoil management practices: an application of multinomial logit model
No full textReceived: July 13th, 2025 ; Accepted: October 20th, 2025 ; Published: October 23rd, 2025 ; Correspondence: [email protected] management practices are crucial for improving agricultural sustainability by enhancing resource use efficiency and soil health. This study focuses on two key methods: (a) the cultivation of deep-rooted crops like alfalfa, which enhances the accessibility of subsoil resources for subsequent crops, and (b) strip-wise loosening of the subsoil combined with compost addition (UEK)1, which is being developed and tested within the framework of the Soil³ project. A comprehensive model is developed to assess factors influencing the adoption of these practices using a Multinomial Logit model and survey data from stakeholders in Anhalt-Bitterfeld, Rhein-Sieg-Kreis, and Teltow-Fläming in Germany. Stakeholder responses are categorized into four groups: stakeholder characteristics, adoption factors, alfalfa cultivation and UEK method features. Statistical and econometric analyses reveal three critical factors: insufficient soil water storage capacity, business orientation, and ownership relationships. Through the identification of marginal effects, it appears that ‘business orientation’ is more influential in the adoption of the alfalfa cultivation method compared to the UEK method, whereas ‘ownership relationships’ have a greater marginal effect in the UEK method compared to alfalfa cultivation. Findings suggest that policy interventions should address method-specific barriers, promoting business incentives for alfalfa cultivation and resolving land ownership issues for the UEK method. Tailored, regionspecific approaches are essential for promoting subsoil management practices, contributing to resilient and resource-efficient farming systems
Maa- ja mullakasutuse, sh maahõive juhtimissüsteemi loomise jaoks tausta ja tervikpildi koondülevaate koostamine : lõpparuanne
No full textTellija esindajad: Madli Linder ja Janika Laht, Keskkonnaagentuur; Aire Rihe, Kliimaministeerium; Eike Lepmets, Regionaal- ja Põllumajandusministeerium.Projekti käigus viis uuringu läbi Eesti Maaülikooli uurimisrühm, koostöös projekti tellijapoolse juhtgrupi ning mitmete riigiasutuste töötajatega. Lõpparuanne käsitleb kestliku arengu põhimõtteid, mis on määratletud rahvusvaheliste konventsioonide ja ÜRO 2030. aasta tegevuskava alusel. Kestlik areng hõlmab majanduslikku, sotsiaalset ja keskkonnaalast tasakaalu, rõhutades maa ja mulla tähtsust toidutootmises, elurikkuse säilitamises ja kliimamuutuste leevendamises. Maapoliitika, maa- ja mullakasutuse juhtimine on kesksed teemad, mis hõlmavad maa ja mulla kui ressursside kasutamist erinevate tegevuste jaoks, nagu põllumajandus, metsandus, elamuehitus ja tööstus. Projekti aruanne toob välja vajaduse integreeritud ja koordineeritud maapoliitika järele, mis ühendaks erinevad sektorid ja tagaks kestliku maakasutuse. Aruandes analüüsitakse maakasutuse konfliktide ja kooskasutuse võimalusi, tuues esile erinevate huvigruppide vastandlikud huvid ja vajadused. Näiteks põllumajandusmaa ja elamuehituse vahelised konfliktid ning võimalused elurikkuse suurendamiseks põllumajandusmaadel. Aruandes tuuakse esile mitmeid probleeme, nagu puudulik seire maakasutuse muutuste osas, ebaselged mõisted ja määratlemiskriteeriumid ning vajadus mitmekihilise integratsioonivõimelise andmestruktuuri järele. Lahendusettepanekud hõlmavad süsteemse seire- ja hindamisraamistiku loomist, selgete määramiskriteeriumide ja metoodikate väljatöötamist ning kohalike omavalitsuste suutlikkuse suurendamist.Andmete kogumise aeg: 2025 jaanuar-aprill.Koondülevaade valmis osana maa- ja mullakasutuse teadus-arendusprojektist. Projekti toetab Eesti riik kasvuhoonegaaside lubatud heitkoguse ühikutega kauplemise tulust
Graduates of nature tourism as interpreters of nature in the labour market based on alumni survey data
No full textBakalaureusetöö
Loodusturismi õppekavalLoodusturismi eriala lõpetajate praktiline väärtus tööturul ning nende ettevalmistus on muutunud üha olulisemaks teemaks seoses turismi ja keskkonnahariduse valdkondade arenguga ning kasvava vajadusega looduse vahendajate järele. Looduse vahendaja on spetsialist, kes aitab inimestel looduskeskkonda paremini mõista ja väärtustada, rõhutades selle kaitsmise tähtsust ning pakkudes elamusi, mis tugevdavad sidet loodusega.
Käesolevas töös uuriti Eesti Maaülikooli loodusturismi eriala vilistlaste positsiooni tööturul keskkonnahariduse ja turismisektori valdkonnas ning õppekava vastavust tööturu vajadustele. Uuringu eesmärk oli välja selgitada, millised õppekava osad on vilistlasi kõige enam toetanud erialasel tööl ning koguda ettepanekuid loodusturismi õppekava arendamiseks. Uuring tugines kvantitatiivsele veebiküsitlusele, milles osales 81 loodusturismi eriala bakalaureuse- ja magistriõppe lõpetajat.
Küsitluse tulemused näitasid, et enamik vilistlasi töötab erialastes valdkondades, sealhulgas turismiettevõtluses, giidinduses ja hariduses. Kõige olulisemateks õppekava osadeks peeti looduse ja turismiga seotud teoreetilisi aineid ja praktilist õpet. Vilistlased tõid esile vajaduse arendada õppetöös ettevõtlus- ja digioskusi. Samuti rõhutati tihedamat koostöö vajalikkust tööandjatega, rahvusvaheliste kogemuste tähtsust ning selgemat eristust magistri- ja bakalaureuseõppe õppekavade vahel.
Töö järeldab, et loodusturismi eriala loob tugeva aluse tööturul hakkama saamiseks, kuid õppekava tuleks pidevalt arendada vastavalt vilistlaste kogemustele ja muutuvatele valdkonna vajadustele.The practical value and preparedness of graduates in the field of nature tourism have become increasingly important topics considering the development of the tourism and environmental education sectors, as well as the growing need for nature interpreters. A nature interpreter is a specialist who helps people better understand and appreciate the natural environment, emphasizing the importance of its protection and offering experiences that strengthen the connection with nature.
This study examined the position of graduates from the Estonian University of Life Sciences' nature tourism program in the labor market within the fields of environmental education and tourism, as well as the alignment of the curriculum with labor market needs. The aim of the study was to identify which parts of the curriculum have been most supportive for alumni in their professional work and to gather suggestions for developing the nature tourism curriculum. The research was based on a quantitative online survey, in which 81 bachelor's and master's graduates of the nature tourism program participated.
The results of the survey showed that most alumni work in fields related to their specialization, including tourism entrepreneurship, guiding, and education. The most important parts of the curriculum were subjects related to nature and tourism, as well as practical training. Graduates highlighted the need to develop entrepreneurship and digital skills within the studies. They also emphasized the importance of closer collaboration with employers, gaining international experience, and making a clearer distinction between the bachelor’s and master’s curricula.
The study concludes that the nature tourism program provides a strong foundation for succeeding in the labor market, but the curriculum should be continuously developed in response to alumni experiences and the evolving needs of the field
Integrating human factors into occupational accident investigation: a literature review of methodologies and their applications
No full textReceived: January 30th, 2025 ; Accepted: April 28th, 2025 ; Published: May 5th, 2025 ; Correspondence: [email protected]: Accident investigation is essential in safety management, aiming to identify causes and prevent recurrence. Despite various methodologies, gaps remain in information collection and human factors integration. Since data collection is the foundation of investigations, deficiencies can compromise conclusions. This study reviews literature on human factors, focusing on their integration into investigation of occupational accidents. The review explores the nature of human factors and investigation methods that address cognitive, psychological, and organisational dimensions. The study also proposes an integrated investigation flow that combines these methodologies to enhance the accuracy and effectiveness of accident investigations. Methods: A literature review was conducted using academic databases. Keywords included ‘accident investigation’, ‘human factors’, and ‘occupational safety’. Inclusion criteria focused on articles, books, and reports from 1990 to 2025, covering topics of interest and safety-critical industries. Relevant literature was screened and analysed based on its contributions to the research topic. Key investigation methodologies were analysed for their strengths and limitations. Results: The study revealed a multitude of methodologies available, each with its own set of strengths and limitations. HFACS, HEART and FMEA methods were analysed for their potential to systematically integrate human factor. While these methodologies demonstrate significant promise, their implementation remains inconsistent due to challenges related to training, organisational culture, and resource allocation. Conclusions: This review emphasizes the importance of integrating human factors into accident investigation methodologies to enhance workplace safety. While traditional methods remain valuable for their accessibility, systemic approaches are essential for addressing complex sociotechnical systems. Future efforts should prioritize investigator training and promotion of positive organisational culture to mitigate human factor challenges and improve investigative outcomes
Testing of plywood made from thermally treated birch veneer
No full textRakenduskõrgharidusõppe lõputöö
Puidutöötlemise tehnoloogia õppekavalTermiliselt töödeldud puit on kasutusel juba pikka aega. Termiliselt puitu töödeldes muutuvad puidu omadused: värv, struktuur ja niiskusele vastupidavus.
Lõputöö eesmärgiks oli katsetada termiliselt töödeldud spoonist valmistatud kasevineeri. Testiti vineeri paindetugevust, pinnakõvadust ja liimivuugi nihketugevust. Katsetamiseks kasutati viiel eri astmel termiliselt töödeldud ja töötlemata kasevineerist katsekehasid. Katsed viidi läbi Eesti Maaülikooli puidutehnoloogia laboris. Kokku tehti katseid 1188 katsekehal.
Pinnakõvaduse tulemuste analüüsist selgus, et vastupidavaimad ristikiudu katsekehad olid 3. astmel töödeldud (9476,3 N). Pikikiudu olid vastupidavaimad 2. astmel töödeldud katsekehad (9542,5 N). Suures pildis erinesid pinnakõvaduse katsete puhul tulemused risti- ja pikikiudu katsete puhul väga minimaalselt.Thermally treated wood has been used by humans for a long time. Thermal treatment of wood changes its characteristics, for example: color, texture and moisture resistance.
The aim of the practical thesis was to test the thermally treated birch plywood. For this, the flexural strength, surface hardness, and shear strength of plywood were studied. Tests were performed using five different levels of thermally treated plywood and non-thermally treated plywood. The tests were conducted in the wood technology laboratory of the Estonian University of Life Sciences. A total of 1188 test specimens were tested.
Analysis of the surface hardness results revealed that the most durable cross-grain specimens were those treated at level 3 (9476,3 N). The most durable long-grain specimens were those treated at level 2 (9542,5 N). In the big picture, the results for the surface hardness tests differed very minimally between the cross-grain and long-grain tests
Reflection of Various Environmental Impacts in Expert Assessment and Their Effect on Created Value
No full textBakalaureusetöö
Geodeesia, kinnisvara- ja maakorralduse õppekavalKäesolev bakalaureusetöö käsitleb keskkonnategurite mõju elamukinnisvara väärtusele Eestis, keskendudes professionaalsete kinnisvarahindajate hinnangutele. Probleemistik on seotud kinnisvaraturu jätkusuutlikkusega ja riskide adekvaatse arvestamisega hindamises, mida varasemates Eesti-põhistes uuringutes on vähe käsitletud.
Töö eesmärk oli välja selgitada, milliseid keskkonnategureid Eesti kutselised kinnisvarahindajad elamukinnisvara väärtuse kujunemisel oluliseks peavad. Uuringu andmed koguti struktureeritud küsimustiku abil ning analüüsiti kvantitatiivsete ja kvalitatiivsete meetoditega.
Tulemused näitavad, et hindajad peavad kõige olulisemateks keskkonnateguriteks elukeskkonna kvaliteeti, müra ja jääkreostust, samas kui näiteks radoonirisk ja kliimamuutuste mõjud on hetkel alahinnatud. Võrreldes varasemate rahvusvaheliste uuringutega ilmnes, et Eestis teadvustatakse keskkonnariskide mõju kinnisvarale alles osaliselt. Töö tulemused pakuvad väärtuslikku sisendit edasisteks uuringuteks ja võivad olla aluseks hindamisstandardite ning koolituste arendamisel.This bachelor's thesis examines the impact of environmental factors on residential property value in Estonia, focusing on the perspectives of professional property valuers. The topic relates to the sustainability of the real estate market and the proper consideration of environmental risks in valuation, an area with limited prior research in Estonia.
The aim of the study was to identify which environmental factors certified property valuers when assessing residential property value consider most significant. Data was collected through a structured questionnaire and analysed using both quantitative and qualitative methods.
The results show that valuers regard living environment quality, noise, and residual pollution as the most influential factors, while risks such as radon exposure and climate change impacts are currently underestimated. Compared to previous international studies, awareness of environmental risks in property valuation is still developing in Estonia. The findings provide valuable input for future research and can support the development of valuation standards and professional training programs
EUDR and its impact on the Estonian timber sector
No full textRakenduskõrgharidusõppe lõputöö
Puidutöötlemise tehnoloogia õppekavalMetsade raadamine ja degradeerumine on globaalse suurusega probleemid, mille tõttu
hävivad liikide elupaigad ja looduslik mitmekesisus. Käesoleva lõputöö eesmärk oli
uurida Euroopa Liidu raadamisvabade toodete määruse ehk EUDR-i mõju Eesti
puidusektoris tegutsevatele ettevõtetele. EUDR loob süsteemi, mille kohaselt ei tohi
Euroopa Liidu turule lubada materjali, mis on toodetud metsade raadamise või
degradeerumise tulemusena. Töös uuriti EUDR-i olemust ja vajalikkust ning viidi läbi
intervjuud Eesti puidusektori ettevõtetega. Saadud vastuseid analüüsiti ja tehti järeldused.
Vastanud nõustusid vajalikkusega EUDR-i järele, kuid ei usu, et määruse kehtestamisest
tuleneb Euroopa turule olulisi positiivseid tagajärgi. 2025. aasta kevadel on EUDR-i
nõuete täitmise osas valdav segadus. Leitakse, et praegusel kujul on süsteem poolik.Deforestation and forest degradation are global problems that destroy species' habitats and
natural diversity. The aim of this thesis was to examine the impact of the European Union
Deforestation-Free Products Regulation (EUDR) on companies operating in the Estonian
timber sector. The EUDR creates a system according to which material produced as a
result of deforestation or forest degradation may not be allowed on the European Union
market. The work examined the nature and necessity of the EUDR and conducted
interviews with companies in the Estonian timber sector. The responses received were
analyzed and conclusions were drawn. Respondents agreed with the necessity of the
EUDR, but do not believe that the introduction of the regulation will have significant
positive consequences for the European market. In the spring of 2025, there is widespread
confusion regarding the compliance with the EUDR requirements. It is considered that the
system is incomplete in its current form