Browsing by master's degree program "Master's Programme in Agricultural Sciences"

Amerikankarpalo (Vaccinium macrocarpon Ait.) on Pohjois-Amerikasta kotoisin oleva terveysvaikutteinen marja, jota viljellään kotimaassaan allastyyppisillä turvesoilla. Myös Euroopassa amerikankarpaloa on viljelty käytöstä poistetuilla turpeennostoalueilla erityisesti Latviassa. Amerikankarpalon viljelyssä suurimpia haasteita on sen alttius useille eri sienitaudeille, jotka aiheuttavat marjojen pilaantumista jo viljelmillä, mutta myös varastoinnissa. Laajavaikutteisten fungisidien käyttö on yleinen käytäntö pohjoisamerikkalaisilla karpaloviljelmillä, kun taas Latviassa, missä niiden käyttö on vähäisempää, varastotaudit aiheuttavat merkittäviä sadonmenetyksiä. Amerikankarpalon viljelyä on tutkittu Helsingin yliopiston maataloustieteiden osastolla Viikissä vuodesta 2015 lähtien. Suomessa amerikankarpaloa on mahdollista viljellä kasvutunnelissa, jolla viljelyyn tarvittavaa lämpösummaa saadaan nostettua amerikankarpalon tarvitsemalle tasolle. Menetelmä on hyvin erilainen verrattuna turvesuoviljelyyn muualla maailmassa. Toistaiseksi tutkimuksissa ei ole havaittu merkittäviä kasvinsuojelullisia haasteita. Kasvutunneliviljelyn vaikutusta amerikankarpalon varastolaatuun ja -kestävyyteen ei ole aiemmin tutkittu. Tässä tutkimuksessa selvitettiin kolmen lajikkeen (’Pilgrim’, ’Stevens’ ja ’Early Black’) ja kahden kasvupaikan (kasvutunneli ja avomaa) vaikutusta marjojen varastolaadun muutokseen ja varastokestävyyteen, sekä eristettiin ja tunnistettiin morfologian perusteella sekä sekvensoimalla varastotauteja aiheuttavia sienipatogeeneja. Amerikankarpalon marjojen laatua arvioitiin pilaantumisprosentin, kiinteyden, happamuuden, liukoisten kuiva-aineiden määrän ja antosyaanipitoisuuden perusteella. Kaikilla lajikkeilla kasvutunnelissa kasvaneista marjoista pilaantui varastoinnin aikana huomattavasti pienempi osuus kuin avomaan marjoista. Tämä voi johtua kasvutunnelin antamasta suojasta ja kasvuston kuivemmasta mikroilmastosta. Varastointi laski kiinteyttä ja tunnelissa kasvatetut marjat olivat pääasiassa kiinteämpiä kuin avomaalla kasvaneet marjat. Liukoisten kuiva-aineiden pitoisuus laski varastoinnissa. Antosyaanipitoisuus kasvoi varastoinnin aikana ja oli suurempi avomaalla kasvaneissa marjoissa, mikä voi johtua eroista marjojen kypsyydessä sadonkorjuun aikana, sekä kasvupaikkojen välisistä eroista valo-olosuhteissa. Kokonaishappamuus laski varastoinnin aikana ja oli suurempi kasvutunnelissa kasvaneilla marjoilla. Tunnelikasvatuksella oli erityisen suuri positiivinen vaikutus ’Early Blackin’ marjojen varastokestävyyteen ja laatuun. Tutkimuksessa tautioireisista marjoista saatiin eristettyä viisi eri sienisukua tai -lajia, jotka aiheuttavat neljää eri varastotautia. Tunnistetut varastopatogeenit olivat Botrytis cinerea (keltamätä, yellow rot), Coleophoma -lajit (oranssimätä, ripe rot), Allantophomopsis lycopodina/Allantophomopsis cytisporea (mustamätä, black rot) ja Colletotrichum -lajit (kitkerämätä, bitter rot). Ne aiheuttavat vaihtelevasti varastotappioita Pohjois-Amerikassa ja Latviassa.

Agroforestry, a widespread land-use in tropics and especially in tropical drylands, is gaining increasing attention due its carbon sequestration and storage potential. Majority of African countries acknowledge agroforestry as a national climate change mitigation and adaptation strategy. Despite the large extent of African drylands and the commonness and importance of agroforestry systems to dryland livelihoods, these systems are scarcely studied and research on dryland African agroforestry carbon stocks are few. The aim of the study was to compare carbon stocks of three land-uses: Vitellaria paradoxa dominated parkland (PL), improved agroforestry system (IA) and, as a control, abandoned land (AL), to study carbon allocation between and within the land-uses and to examine the variability of biomass estimates of different allometric equations used in carbon inventory in West African Sahel. Study was conducted in two villages in Yorosso, Southern Mali. Carbon stocks accounted were woody above- and belowground biomass, litter and top-soil organic carbon. Allometric equations and root-to-shoot ratios were used for woody biomass measurement. Comparison of biomass estimations of different allometric equations and root-to-shoot-ratios was conducted by using multiple equations for the dataset. Total system carbon stocks were 24.7 MgC haˉ¹, 29.9 MgC haˉ¹ and 42.2 MgC haˉ¹, for PL, AL and IA, respectively, with statistically significant difference between PL and IA. Top-soil organic carbon (SOC) was important carbon pool, accounting 34.8 % of total system carbon in PL and IA, and 49.6 % in AL. There were no statistically significant differences on the SOC/biomass C ratios between the land-uses. PL had lower SOC stocks than IA or AL, difference being statistically significant. The reason for lower SOC stock of PL could not be explained in this study. IA had larger woody biomass carbon stocks (27.0 MgC haˉ¹) than PL (15.5 MgC haˉ¹ ) and AL (14.4 MgC haˉ¹), but the difference was not statistically significant due to the similar density of large mature trees in all of the land-uses and partly due to the large woody biomass variation within the land-uses. In all of the land-uses, most of biomass carbon was stored in large mature trees and in two species: V. paradoxa and Parkia biglobosa. Large woody individuals had major impact on the land-use level carbon stocks. For carbon conservation, these individuals should be preserved and spared even during land-use change. Despite relatively large density, young trees and shrubs stored diminutive amount of carbon compared to mature trees. As the currently young planted trees in IA will grow and mature in the future, the woody biomass carbon stocks of the system will increase significantly. Lack of regeneration observed in PL threatens the sustainability of the system and its carbon stocks. Future carbon storage potential of AL depends on the regeneration potential of large tree species. Comparison of different allometric equations for tree biomass estimation revealed substantial variation. The choice of allometric equation used affects the obtained results, hampering the comparison of studies using different equations. Commonly used root-to-shoot ratios vary on their estimations, and most probably by underestimating root biomass. There is a clear need for specialised and standard carbon inventory methods for drylands and agroforestry systems.

Despite their immobile nature, their ability for adaptation allows plants to face harmful conditions from the environment to successfully survive and reproduce. Plant cells sense and integrate signals from the environment and activate response mechanisms. Participants in these mechanisms are the receptor-like protein kinases (RLKs) and a subgroup of RLKs, the cysteine-rich receptor-like kinases (CRKs). Members of this family have been associated with functions related to environmental stress responses in plants. CRK2 is one interesting member of the CRK clade of RLKs. While roles of CRK2 in the response to biotic and abiotic stimuli have been recently described, many aspects of the diverse functions of CRK2 remain elusive. The reduced size of the crk2 mutant suggests that developmental processes are affected by the absence of the protein. One of the objectives of this work was to analyse potential reasons for the smaller size of crk2. The difference in plant size could be due to a reduced number of cells. Results from the analysis of young cotyledons showed that the smaller plant size is not due to a reduced cell number in leaves when compared to Arabidopsis thaliana (Arabidopsis) ecotype Columbia (Col-0). Another way to understand the processes in which a protein is involved is to target possible interaction partners. Therefore, genotyping and analysis of growth phenotypes of T-DNA insertion mutant lines for candidate interaction partners for CRK2 was performed. The results revealed smaller phenotype for a nitrate transporter (NRT1.7) mutant in fresh weight and rosette area whereas for a protein kinase (QSK1) mutant, higher fresh weight but reduced rosette area was observed compared to Col-0. Generation of constructs for fusion protein expression and purification revealed the possibility of expressing tagged cytoplasmic regions of these proteins for further analysis of protein-protein interaction through kinase assays due to the kinase activity of CRK2. Generation of fluorescent-tagged proteins from the candidate interaction partners allowed for localization studies via confocal microscopy to determine the co-localization to the plasma membrane of these proteins with CRK2, which is located to plasma membrane under standard growth conditions. The co-localization results suggest that the proteins NRT1.7 and QSK1 colocalize with CRK2, which is a step forward in the verification of their possible interaction in planta. The smaller size of the nrt1.7 and qsk1 mutants indicates that the lack of these proteins affects plant development.

Weeds have been identified as a threat to arable crop production because crop-weed competition may result in considerable yield losses. Weeds and crops often possess similar characteristics, making weed control challenging. Chemical weed control may lead to environmental and health issues, as well as troubles in crop production. Nowadays the tendency is towards more sustainable agricultural practices to control weeds including mixed cropping systems. In earlier studies, mixed cropping systems were observed to reduce weed biomass, whereas weed diversity was affected by environmental and temporal factors. The present study was conducted at the Knehtilä organic farm in Hyvinkää to evaluate the competitive ability of mixed cropping systems against weeds. Crop stands were 50:50:50% and 33:33:33% oat, pea, and camelina mixtures, along with 100% oat, 100% pea, and 100% camelina stands. Plant sampling was conducted 24 Days after seeding (DAS), 38 DAS, 52 DAS, 66 DAS, and 97 DAS. Crops and weeds were separated and the number of plants in each species was counted. Weeds at the species level were identified. Dry biomass of crops and weeds was recorded at each sampling time. Weed species richness, Shannon-Weiner diversity index, species evenness, and species dominance were calculated. The most common weed species was Chenopodium album L., while the least common species was Cerastium fontanum Baumg. Crop stands accumulated in weed biomass until 52 DAS, followed by a gradual decline over sampling times. Weed biomass was lower in 50% and 33% mixes than sole crop stands in early growth stages. Significant differences in the Shannon-Weiner diversity index, species richness, evenness, and species dominance were found in crop stands at 24 DAS and 66 DAS. There was a positive correlation between weed evenness and crop biomass. The study proved that mixed crop stands (50% and 33% mixes) have effective weed control ability, indicating low weed biomasses compared to sole cropping systems. Weed diversity indices fluctuated at 24 DAS and 66 DAS, indicating that sampling time influences weed diversity. The positive correlation between weed evenness and crop biomass indicates the impact on species dominance and intraspecific competition. The study suggests that mixed cropping systems are effective at controlling weeds and highlights the importance of understanding temporal dynamics and weed-crop interactions in cropping systems to enhance crop yield. Future research should focus on understanding the fundamental mechanisms behind weed-crop interactions across cropping systems.

The research of this thesis was focused on anaerobic digestion of cow manure mixed with different types of biowaste, especially those material that are available in Finland. The research was conducted by search, collection, and analysis of different data in literature. Topic of the thesis was predetermined by the Co-Creation Lab project of Helsinki Institute of Sustainability Science (HELSUS), which was seeking solution to achieve carbon neutral cow milk production. The solution was co-approached by three participants conducting thesis from technological, economical, and legislative points of view, in which I was responsible for writing mainly the technological part, and general findings in economic efficiency and legislative terms by the other two co-creators were also included in this thesis. The research was mainly related with the whole cycle of biogas production, including basics about anaerobic digestion (AD), applications of the biogas and digestate as a product and by-product of AD. Substrates for AD were researched with a focus to find the best combination of cow manure (CM) and biowaste in regard with methane yield outcome, especially a mixture of CM and silage waste that suits the cow farming situation in Finland. Methane yields for mono-digestion of various types of biowaste and co-digestion of CM with different biomass were collected and analyzed. Premises for biogas plant establishment were researched briefly, including facility composition, and consideration of feasibility and raw material availability. CM with grass containing 75% timothy and 25% meadow fescue grass at 70%:30% mixing ratio could be the best combination of CM: grass co-digestion, followed by 0.5:0.5 mixed CM and perennial ryegrass. Furthermore, CM mixed with food waste at 52:48% ratio could be the best combination among co-digestion of CM with biowaste other than grass, followed by CM and food waste mixed with 68%:32% ratio, and CM with oat straw mixed at 1:2 ratio could be a considerable combination of CM and crop waste.

Crop monitoring in commercial indoor farming is a commonly used method in assessing the general productivity of the cultivated plants. This assessment practice is typically conducted manually by greenhouse workers and is sometimes supplemented by certain hand-held or stationary devices. An interesting example of novel device-assisted crop monitoring technologies utilizes digital imaging devices and computer-driven image analysis algorithms that have been prominently employed within the field of plant phenotyping. In the context of botanical studies, they have been used in e.g. characterizing various complex interactions between the genotypes of important food crops and their agronomic traits in specific prevailing environmental conditions. Additionally, image-based data acquisition technologies also present very interesting prospects for precision agriculture management practices. They could be harnessed to scan entire greenhouse compartments continuously and acquire massive amounts of data on multiple morphological and physiological aspects of crop growth and development in a non-destructive fashion. The acquired data could be implemented into mathematical greenhouse control models and utilized in a plethora of useful applications, including e.g. estimating and predicting biomass production and yield, detecting and localizing potential abiotic/biotic stress symptoms at an early stage, and ultimately enhancing overall crop production efficiency. In this thesis, these imaging technologies were explored in practice by designing and constructing a growth chamber embedded with automatic climate control and a low-cost multispectral imaging subsystem. The final assembly was tested by conducting a simple experiment involving drought-stressed sweet basil plants (Ocimum basilicum L. cv. ‘Genovese’) to determine how early drought-stress related symptoms could be detected purely from multispectral images. While the system carried out the tasks of automated climate control and continuous image capture adequately, the implemented approach in drought-stress detection was deemed unsuccessful. Significant differences between drought-stressed plants and their respective controls were not observed until visible symptoms were present. This was assumed to be due to incompatibility of the camera module’s spectral sensitivity in detecting changes in water content in plant tissue.

Onion (Allium cepa L.) is an important vegetable, which provides major nutritional benefits. In Finland, basal rot caused by Fusarium fungal species (FBR) has become the most destructive disease of onion in recent years. It causes damping off and stunted growth on onion seedlings and root death and abscission and bulb rot on mature onions. The average onion crop loss caused by basal rot has been up to 10% in conventional farming and as high as 30% in organic farming. In this study, a seedling assay was conducted to test the virulence of different Fusarium isolates on a commercial onion cultivar. The study goals were, primarily, to find out which of the Fusarium isolates, originating from onion and crop rotation plants grown in Finland, are pathogenic, and secondly, to compare the virulence of different isolates. Altogether 115 Fusarium isolates were tested for virulence on onion seedlings in a greenhouse. Fifty-five of the tested isolates of F. oxysporum, F. proliferatum and F. redolens were more or less virulent. 19.4% of F. oxysporum isolates, 35.3% of F. proliferatum isolates and 18.2% of F. redolens isolates showed high virulence. Among the aggressive pathogens isolated from onion samples, F. oxysporum f.sp. cepae is still the dominant onion pathogen, F. proliferatum is a new pathogen on onion in Finland, and relatively more aggressive than F. oxysporum. The F. solani and F. tricinctum isolates tested did not have any detrimental effects on the onion seedling health or growth. In order to control FBR in Finland, avoiding planting onion in the infested soils, growing onions from local seedlings to avoid new contamination and storing onions at cold temperatures are recommended.

In agricultural soils, Nitrogen (N) is an essential nutrient in crop production, and its supply comes from various pools. Understanding the N pools in soil could help farmers make better decisions about N fertilisation, increase productivity, reduce costs, and decrease environmental impacts. N is a challenging element to track in soil due to its seven oxidation states that are large-ly cycled and intermediated by soil organisms between various organic, mineral, and gaseous forms. This thesis aims to find whether C farming practices accumulate N in soil through investi-gating the size of soil N pools and how they relate to each other through a literature survey and data from a four-year carbon (C) farming experiment. The thesis also investigates whether meas-uring the fast-cycling N pools and including them in fertilisation recommendation calculations results in financial savings from N fertiliser cuts. Twenty different Finnish farms were investigated, split between six C farming practices: subsoil-ing, undersown cover crops, ley farming, soil organic amendments, planned grazing, diverse grasses lay. Soil samples were collected at two different depths (0-17 and 17-30 cm) and ana-lysed for total N and C (Total N, Total C), mineral N, Illinois Soil N Test (ISNT N), autoclave citrate extractable protein N (ACE-Protein N), water extractable organic N and C (WSON and WSOC), and microbial activity derived N (PMN) from CO2 burst after rewetting of dry soil (Resp C).The analysis recovered on average 25% of total N, while 75% remained in the non-recovered pool. Clay%, C% and C:Clay explained the variation in Total N (r2=0.90), ISNT N (r2=0.90), pro-tein N (r2=0.93) and the non-recovered N (r2=0.83), but it did not for WSON (r2=0.50), PMN (r2=0.21) and inorganic N (r2=0.20). Four-year C farming management did not result in statisti-cally significant differences in the N pools, even though PMN and WSON were 19% and 11.6% higher in treatment than in control, respectively. The variation was high for both (SD=48 and 42), explaining the non-significance. Strong correlations (Spearman rho, ρ) were observed between Total N - ISNT N, Residual N, and WSON, indicating their predictive capability for total N, while protein N showed weaker correlations. PMN correlated strongly with bacterial respiration C (ρ = 0.94) and WSON (ρ = 0.75) and had a negative strong correlation with the WSOC:WSON ratio (ρ = -0.73). In conclusion, soil's non-recovered N fraction, likely associated with the mineral surfaces and undecomposed particulate organic matter (POM), is the largest portion of total N. Clay%, C% and C:Clay explains the variation in the slow-cycling N pools but not in the fast-cycling ones. The quality of soil organic matter (SOM) is better assessed using WSON, PMN, and the WSOC:WSON ratio. Utilising PMN as a predictor of N release from SOM results in lower N ferti-liser recommendations, leading to cost savings for farmers. This research shows that four years of C farming do not increase the N stock in soil. Further research is needed to determine if C farming practices in a long-term experiment would increase the soil N stocks, significantly affect soil N pool relationships and result in financial savings for farmers.

Biochar, produced by heating biomass in oxygen-limited environments, is known for its potential to reduce methane emissions, by altering rumen fermentation. However, the literature lacks exploration on how biochar affects nutrient digestibility and ruminal methane production across various diets. Therefore, we examined the effects of spruce (Picea abies) biochar on several forage plant species options and forage-to-concentrate (F:C) ratios. Two in vitro trials of 24 hours were conducted with Gas Endeavour® equipment at Animal Science laboratory of the University of Helsinki. There were three rumen fluid donor animals and the ratio of rumen fluid and McDougall’s buffer was 1:2 (vol:vol). The first trial tested biochar levels (0%, 0.25%, and 0.5% of diet dry matter (DM)) with four silage options that were pure grass (Phleum pratense – Festuca pratensis), grass mixed 1:1 in DM with red clover (Trifolium pratense), faba bean (Vicia faba), or maize (Zea mays L) at a fixed F:C ratio of 65:35. The concentrate consisted of oats and rapeseed meal. The second trial explored the effects of the biochar (0.5% of diet DM) and an alternative methane inhibitor (product X) alone or combined across 65:35 and 45:55 F:C ratios. Key parameters such as total gas and methane production, DM digestibility, rumen fluid pH, and volatile fatty acid (VFA) concentrations were analyzed. Grass silage (D-value 669, neutral detergent fiber (NDF) 523 g/kg DM) and red clover silage (D-value 626, NDF 362 g/kg DM) were harvested from the first cut. Maize silage was more digestible than faba bean silage (D-value 679 vs. 593 g/kg DM) and contained more starch (278 vs. 48 g/kg DM). High forage diet (65:35) had higher NDF content (453 vs 407 g/kg DM) and lower starch content (114 vs 179 g/kg DM) than low forage diet (45:55). Biochar's effect on DM digestibility and the production of rumen methane or carbon dioxide was not significant across different silage plant species and F:C ratios. Grass silage led to lower total methane production compared to silage mixtures (p<0.05), and the combination of biochar and product X in a low forage diet numerically reduced gas production. However, when methane production was calculated per digested DM, no differences were observed. Feeding maize silage increased the total production of methane and carbon dioxide in the rumen compared to faba bean silage (p<0.001), but gas productions per digested DM remained unaffected. Biochar did not significantly affect final rumen pH across silage species. Biochar with grass silage linearly reduced the total VFA content of the rumen fluid (p=0.003) and had tendency for smaller molar proportion of acetic acid in VFA (p= 0.075). In the second trial biochar or product X didn´t have significant effect on rumen fermentation pattern across forage levels. The effects of biochar, silage plant species and F:C ratios on in vitro rumen fermentation and methane production were minimal, despite differences in diet composition.

The feeding behavior of beef cattle is complex and varies depending on different factors such as the nutritive value of the feed, the individual and the environment. By optimizing and improving the feed efficiency, the economics of the production increases. Knowledge of feed intake and feeding behavior can be used to optimize the production and the health and well-being of the animals. The aim of this study was to determine how the cut of grass silage affects the feeding behaviour of bulls and thereby how to optimize the use of silage for animal growth. Simmental bulls got three different silage cuts. The first cut was taken on 25th June (ES1), the second cut on 11th August (ES2) and the third cut on 3rd October (ES3). The feeding was given as total mixed ration (TMR) ad libitum. Each TMR group had 15 bulls (TES1, TES2, TES3). Each TMR group had a diet based on grass silage (550 g/kg DM), the only difference being if the silage was of the first, second or third cut. That way the nutritive value differed among the TMR. Individual information about duration, when, and how much the bulls ate was recorded by the Growsafesystem. The average for the bulls in the feeding groups was calculated based on the individual data. This Master´s thesis researched feed intake, feeding frequency, time for head down, time for feed intake and feed intake rate during one month when the body weight of the bulls was on average 546 kg in the beginning and 607 kg at the end of the study. The dry matter for the three cuts was 201 g/kg for ES1, 298 g/kg for ES2 and 354 g/kg for ES3. D-value was 719, 685 and 739 g/kg DM, respectively. The bulls that ate ES3 had higher dry matter intake (12,1 kg DM/d) and eating rate (94,9 g DM/min) than the two other groups. The bulls that ate ES1 and ES2 had the same feed utilization, which was better than the feed utuilization of the bulls that were given ES3. Feeding frequency was about 15 times per day for all groups. The second cut had the lowest digestibility and the bulls eating the second cut had the longest feed intake time. The bulls that ate the third cut had the highest dry matter intake, but the lowest feed utilization. The study indicates that the D-value of the grass silage used in TMR has a clear impact on dry matter intake of the TMR and eating time and eating rate of the animal.