2017, Vol. 15, No. 5

Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/5367

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Nüüd näidatakse 1 - 20 38

Anaerobic co-digestion of oil refinery wastewater and chicken manure to produce biogas, and kinetic parameters determination in batch reactors
(2017) Mehryar, E.; Ding, W.M.; Hemmat, A.; Hassan, M.; Bi, J.H.; Huang, H.Y.; Kafashan, J.
In order to improve the anaerobic fermentation of oil refinery wastewater (ORWW) via an appropriate nutrients pool for microbial and buffer capacity growth, a study was carried out on related anaerobic co-digestion (AcoD) with a rich organic carbon source, namely chicken manure (CM). The kinetic parameters were investigated (including cumulative biogas production, bio-methane content, retention time, and soluble chemical oxygen demand stabilisation rate) of batch AcoD experiments related to six ORWW:CM-ratio treatments (5:0, 4:1, 3:2, 2:3, 1:4, and 0:5) under mesophilic conditions. The highest soluble chemical oxygen demand removal rate was obtained for the 4:1-ratio treatment. However, the highest biogas production and bio-methane contents were achieved for the 1:4-ratio treatment. When taking into consideration the highest oil refinery wastewater portion in the AcoD mixtures and the statistical test results (LSD0.05) for the kinetic parameters, it can be seen that the 4:1-ratio treatment provided the maximum biogas production levels.
Analysis of Arabidopsis defensin-like genes and ovule development during fertilization and Fusarium infection
(2017) Spalvins, K.; Blumberga, D.
Defensins are small, highly stable antimicrobial peptides. Many defensin-like (DEFL) peptides found in flowering plant Arabidopsis thaliana are believed to have role in either natural immunity or cell-to-cell communication during fertilization. However, little is known about the DEFL peptides and their functions during these events. The goal of this work is to investigate the genes encoding selected DEFLs by observing their expression patterns during fertilization and Fusarium graminearum infection. According to the results 4 selected genes of interest (GOI) are downregulated after fertilization and infection and mock treatments are causing degradation and delay of development in treated ovules.
Influence of chemical composition on the biochemical methane potential of agro-industrial substrates from Estonia
(2017) Luna-del Risco, M.A.; Orupõld, Kaja; Diaz-Forero, I.; González-Palacio, M.; Estonian University of Life Sciences. Faculty of Agricultural and Environmental Sciences
Batch trials were carried out to evaluate the Biochemical Methane Potential (BMP) of 61 different substrates collected from agricultural farms and industrial sites in Estonia. Tests were performed in 500 mL plasma bottles at 36°C. The highest methane yield from all tested substrates was obtained from unconsumed dairy products (557 ± 101 L kg-1 VS) while the lowest was obtained from animal slurries (238 L kg-1 VS ± 42). From tested energy crops, foxtail millet achieved the highest methane yield (320 L kg-1 VS). Silages from different crops presented methane yields from 296 ± 31 L CH4 kg-1 VS to 319 ± 19 L CH4 kg-1 VS. The influence of chemical composition and kinetic rate constants (k) on methane potential was analyzed. Anaerobic digestibility of selected agro-industrial substrates was markedly influenced by their organic content, i.e. total proteins and lignin concentrations. Rate constants were found to correlate negatively with hemicellulose, cellulose and lignin (p < 0.05). Results from this study suggest that an appropriate characterization of the chemical composition of the substrates is important not only for predicting BMP and the kinetics rates, but also for identifying possible inhibitors during the anaerobic digestion process. Results on the BMP and national availability of studied substrates indicate that herbal biomass and agro-industrial residues are promising substrates for biogas production in agricultural biogas facilities in Estonia.
Requirements for inserting intercropping in aquaponics system for sustainability in agricultural production system
(2017) Puteri Edaroyati, M.W.; Siti Aishah, H.; Al-Tawaha, A.M.
In recent years, the recirculating aquaponics system has gained high attention and significant popularity for organic vegetables and fruits production which contributes to the sustainable aquaculture for tropical regions. This review aims to summarize the possibility for practicing intercropping in aquaponics to produce high-quality fruits, vegetables and fish without any chemical fertilizer and minimum ecological impact for a sustainable agriculture. Although many studies have addressed about aquaponics for producing high-value crops such as tomato, cucumber, and lettuce, there is still a lack of complete information to support the development of intercropping in aquaponics and limited focus on its commercial implementation. Moreover, this study will focus first on the requirements for inserting intercropping in aquaponics and technical improvements needed to adapt as potential for sustainable food production system to increase productivity around the world, especially in countries have deficiency in water and land resources as well as soil problem like salinity and reduce environmental emissions. Secondly, the insertion of intercropping in aquaponics must be for crops with high value and for crops that can complement together such as tomato with basil and tomato with lettuce. Thirdly, in technical improvement in this study will summarize the strategies and factors that affect the intercropping in aquaponics system such as the nutrients needed for crops under intercropping aquaponics, stocking density and feeding rate which are important to know the concentration of ammonia that is produced and converted to nitrate so that the plants can uptake it. Studying the requirements for inserting and improving intercropping in aquaponics will increase our understanding of needed for new agriculture technique that contributes to the sustainable aquaponics for tropical regions.
The content of weed seeds in the soil based on the management system
(2017) Kuht, Jaan; Eremeev, Viacheslav; Talgre, Liina; Madsen, Helena; Toom, Merili; Mäeorg, Erkki; Loit, Evelin; Luik, Anne; Estonian University of Life Sciences
In 2008 an experiment was set up on the field in Eerika experimental station (Estonian University of Life Sciences) as a 5-field crop rotation: barley (Hordeum vulgare L.) with undersown red clover, red clover (Trifolium pratense L.), winter wheat (Triticum aestivum L.), pea (Pisum sativum L.), potato (Solanum tuberosum L.). The objective of the study was to measure the content of weed seeds in the soil and to evaluate the diversity of the species at the beginning of the period of organic production in 2011. In conventional farming systems without fertilizer (Con I) and conventional farming with mineral fertilizer (Con II) herbicides were used for weed control. All the crops in Con II system received P 25 kg ha-1 and K 95 kg ha-1 , but the application rates of mineral nitrogen fertilizer differed. In organic systems (Org I – organic farming based on winter cover crop and Org II – organic farming based on winter cover crop and manure), the winter cover crops (ryegrass after winter wheat, winter oilseed rape after pea, winter rye after potato) were sown after the harvest and were ploughed into the soil as green manure in spring. Organic farming systems (Org II) had a negative effect on the content of weed seeds in the soil (2.0–22.7% less seeds than in other variants). The seeds of Chenopodium album were the most abundant among summer annual weeds and the seeds of Viola arvensis among winter weeds in the soil. Organic farming measures increased the domination of Chenopodium album – the dominance index D’ was increased by 0.09–0.14 compared to conventional variants. The content of seeds of winter weed Viola arvensis in Org II variant was decreased by 82%. The index of species evenness J’ and Shannon Wiener diversity index H’ were lower in organic plots by 0.10– 0.18 and 0.60–0.19, respectively. Org II variants showed the best results based on the decrease of soil weed seed bank and distribution of the weed species.
Dimethyl ether as a renewable fuel for diesel engines
(2017) Zeman, P.; Hönig, V.; Procházka, P.; Mařík, J.
The area of automotive fuel, or fuel components, which can be produced from biomass also includes dimethyl ether, otherwise known as DME. The issue of the use of DME as a fuel is one which has been monitored until recently. Biomass can also be used as the raw material for the production of DME. DME has therefore replaced the previously-used CFCs (chlorofluorocarbons), which are now banned for their role in dangerous levels of ozone depletion. With regard to its physical properties and combustion characteristics, it is currently expected that DME will soon apply significantly as a fuel in the municipal sector and in households, and as an alternative fuel for motor vehicles with diesel engines. DME is a suitable fuel for diesel engines and can be considered as one of the most promising diesel fuel replacements. DME is a suitable fuel for diesel engines mainly due to its low self-ignition temperature and good cetane figures. It is well miscible with most organic solvents and because the polar solvent is water-immiscible. The advantage is its high levels of purity, and its being free of sulphur, nitrogen, or metals. The physical properties of DME are very similar to the physical properties of LPG. DME requires relatively complex and costly fuel accessories, but the original compression ratio of the diesel engine is maintained. A diagram of the fuel system is illustrated in the paper. The paper analyses the dependence of vapour pressure on temperature, the dependence of the density on temperature, kinematic viscosity, the flash point, the boiling point, and the solubility of water. The objective is to evaluate this interesting energy source for applications in diesel engines.
AFLP-analysis of genetic diversity in soybean [Glycine max (l.) Merr.] cultivars Russian and foreign selection
(2017) Zargar, M.; Romanova, E.; Trifonova, A.; Shmelkova, E.; Kezimana, P.
Genetic diversity of 11 cultivars of soybean (Glycine max) from a VIR (N.I. Vavilov Institute of Plant Genetic Resources) collection was analyzed by the AFLP (amplified fragment length polymorphism) technique. From 18 tested primer combinations, both of them were selected for further analysis. From these two primer combinations (E32/M60 and E32/M59), 90 DNA fragments were obtained, 39 (43%) of them were polymorphic. Unique DNA fragments were found in accessions SibNIISHoz 6, Soer-4, Determinant. The Jaccard's similarity indices varied from 0.79 (between Sonata and Ugra) to 0.94 (between Ugra and Garmoniya) with an average of 0.775. Cluster analysis placed the cultivars into the several groups but separation in groups was not related to their origin or biological characteristics, even though cultivars Nordik and Soer-4 (cultivars recommended for Central Black Earth region of Russia) clustered together on the dendrogram. The obtained high values of Jaccard genetic similarity index and low level of polymorphism and differentiation illustrated a relatively low genetic diversity in our studied cultivars, which correlated with different other studies on soybean genetic diversity with AFLP-analysis.
Chemical composition of seeds and green beans of common bean varieties, breeded in Omsk State Agrarian University under conditions of southern forest-steppe zone of Western Siberia
(2017) Kazydub, N.; Pinkal, A.; Marakayeva, Т.; Kuzmina, S.; Korobeinikova, M.; Kotsyubinskaya, O.
The article considers the biochemical composition of green beans and seeds of common beans varieties, breeded in Omsk State Agrarian University named after P.A. Stolypin (OmSAU). The research was conducted in 2014–2016. Varieties of locally breeded beans, in comparison with the standards, have advantages in the content of protein, zinc, iodine, calcium, iron, sugar; green bean technological properties and tenderizing of seeds during cooking, which becomes an indispensable component of the diet.
Assessment of different growing conditions for enhanced postharvest quality and shelf-life of leaf lettuce (Lactuca sativaL.)
(2017) Lee, J.-S.; Nath, U.K.; Goswami, G.; Nou, I.S.
Lettuce is the most important leafy vegetable. It is exclusively used as freshly raw form but sometime also as cooked. However, its quality depends on several pre- and postharvest factors. The effects of growing conditions and cultivars on the postharvest quality of leaf lettuce were investigated. In this experiment the interaction of variable factor; like growing conditions and fixed factor; cultivars are also observed. The leaf lettuce cultivars ‘Cheongchima’, ‘Cheongchuckmyeon’, ‘Geockchima’ and ‘Geockchuckmyeon’ were grown under favourable (natural condition) and unfavorable growing condition (with excess soil water and 50% shading) to evaluate their shelf-life and postharvest qualities. Plant height and the number of leaves were significantly varied in different growing conditions and by cultivars. In addition, fresh weight was affected by only growing condition, whereas leaf thickness was influenced by cultivars, growing conditions and the cultivars influenced the degree of fresh weight loss and respiration rate during postharvest storage. However, the postharvest storage qualities differed with cultivars and in combination with growing conditions.Leaf thickness and quality of leaf lettuce before and after harvest were also varied by cultivars and growing conditions. It could be concluded that postharvest leaf lettuce quality remains acceptable when growing under excess soil water with 50% shading.
Juvenile growth and frost damages of poplar clone OP42 in Latvia
(2017) Sēnhofa, S.; Neimane, U.; Grava, A.; Sisenis, L.; Lazdina, D.; Jansons, A.
Short rotation plantations in the northern Europe are commonly established using poplar clone OP42 (Populus maximowiczii Henry × P. trichocarpa Torr. and Gray). We assessed its growth and suitability to the climate in central part of Latvia at juvenile age. Trees that had formed single stem were significantly higher (121 ± 2.5 cm), thicker (7.1 ± 0.48 mm) and had longer branches (32 ± 1.5 cm) than trees that had formed multiple stems. In beginning of the second growing season all trees had died stems and 19.6% of them formed new shoots from the ground level. The sprouting trees had random spatial distribution in the field. Regardless of the number of stems, the sprouting trees were significantly lower (110 ± 3.9 cm) than the dead trees (119 ± 2.0 cm). During the repeated assessment about one month later, proportion of the sprouting trees increased up to 44%, but the detected relations between measured traits of sprouting and dead trees remained. Clone OP42 had serious frost induced damages also in autumn phenology experiment (96% trees with severely damaged leaves). Our results suggest that frost prone sites are not suitable for establishment of plantations of OP42 clone.
Production and analysis of non-traditional beer supplemented with sea buckthorn
(2017) Adadi, P.; Kovaleva, E.G.; Glukhareva, T.V.; Shatunova, S.A.; Petrov, A.S.
In recent years, there has been a growing demand for non-traditional beer (craft) with different flavours hence the main aim of this research is to produce beer with sea buckthorns (SBT). Brewing software BeerSmith was used to design the Kölch beer. After one month of primary fermentation, SBT were sanitised and crashed before adding into the green beer. Carbonation was done using keg with 1.8 bar of carbon dioxide. Physicochemical properties, microbial load and sensory evaluation of Kölch fruit beer (KFB) were determined. All the physiochemical parameters measured were significantly (P < 0.05) influenced by the fermentation time. The pH dropped from 5.8 ± 0.1 to 3.9 ± 0.1 toward the end of the fermentation. There was no microbial growth when KFB was inoculated in the media. °Brix likewise decreases from 13.3 ± 0.43 to 3.86 ± 0.25. There was a change in the colour of the wort throughout the fermentation from 11.2 ± 0.44 to 32.5 ± 0.56 EBC. A decrease from 1.48 ± 0.02 to 0.86 ± 0.02 mg maltose per 100 ml in the reducing sugar was observed during the entire period of fermentation. A total of 32 volatile compounds were identified. All assessed sensory variables of KFB were significantly different (P < 0.05) and preferred by the panellists, however, foaminess and clarity of KFB should have to be improved. KFB showed higher DPPH radical scavenging activity as compared to other types of beer examined due to biologically active substances contributed by SBT.
Carbon content of below–ground biomass of young Scots pines in Latvia
(2017) Jansons, Ā.; Bārdulis, A.; Ķēniņa, L.; Lazdiņa, D.; Džeriņš, E.; Kāpostiņš, R.
Forest ecosystems play crucial role in global carbon cycling, therefore, increasing afforestation of agricultural land in Europe has been recognized as important contribution of carbon sequestration. In carbon reporting systems, root carbon content (CC) default value has been set to 50%. The study aimed to estimate CC in below–ground biomass and in relation to tree age in young Scots pine stands on forest and former agricultural land. The below–ground CC of young (8 to 40 years) managed Scots pine (Pinus sylvestris L.) stands growing on nutrient poor mineral soils in Latvia was carried out. In total 62 sample trees (43 in forest land, 19 in former agricultural land) were randomly selected for destructive sampling to estimate the CC within below–ground biomass. Below–ground biomass weighted mean CC was 49.7 ± 0.4%, being slightly lower than the default CC value used to calculate carbon budgets. Root fractions stump, small roots (diameter 2–20 mm), coarse roots (diameter > 20 mm)) differed (p < 0.001) in their CC. Stumps (50.6 ± 0.6%) had highest (p < 0.001) CC in the below–ground biomass, followed by coarse (49.5 ± 0.4%) and small (49.1 ± 0.4%) roots, which did not differ from each other in their CC. Results demonstrated age–dependent increase of CC (p < 0.001) from 48.2 ± 0.3% to 51.7 ± 0.5%, indicating overestimation of the default value during the first two decades, but underestimation for older trees (24 to 40 years).
Through economic growth to the viability of rural space
(2017) Rivza, B.; Kruzmetra, M.; Zaluksne, V.
Rural areas as a living space for the population has been increasingly explored in official documents of various EU institutions and in research topics. Both the documents and the research papers stress the necessity to enhance and maintain the viability of rural areas. The viability of rural areas is ensured by employment opportunities and readiness of residents for active and innovative economic activities. The paper presents an analysis of vertical and horizontal changes in entrepreneurship in the period of 2009–2015 and their effect on changes in the living space of the analysed territories in Latvia’s regions. The processes in administrative territories of regions, municipalities were analysed, as the life of residents is influenced not only by national policies but also by on-going processes in the administrative territories of local governments. The data of LURSOFT for the period of 2009–2015 and the Central Statistical Bureau for the period of 2013–2015 were used as the sources of information. The data were processed by quantitative (growth) and qualitative (structural change) statistical analysis methods. The Eurostat methodology and the methodology developed by the authors for classification of industries were employed for the analysis of structural changes in the national economy. The development level-rate matrix method was used for an in-depth examination of the research results. The research results showed that, in spite of the global economic crisis, both vertical growth and positive horizontal change took place in the national economy of all five regions of Latvia, nine cities of national significance as well as all 110 municipalities that composed the rural areas of Latvia. The authors arrived at the conclusion that, first, performance trends contributing to economic growth were observed in the rural space; second, there was no direct causal relationship between the population density and economic activity in the rural territories; third, the economic growth in the rural territories was greatly affected by the quality of local governance and local community residents’ readiness for active, innovative and inclusive activities.
Research on solid biofuels from cotton waste biomass – alternative for Tajikistan’s energy sector development
(2017) Akhmedov, S.; Ivanova, T.; Krepl, V.; Muntean, A.
An increasing awareness of the negative environmental cost associated with the combustion of fossil fuels and concerns over the geopolitical instability of the main oil producing regions is driving the development of renewable energy sources and biofuels. Use of solid biofuels made of different types of biomass became perspective alternative to conventional fuels in many countries. Such positive indicators as low cost of the final product that meets the quality of standards, not capital intensive production, possibility of producing briquettes/pellets from almost any agricultural waste or combination of raw materials are undoubted advantages of biomass based fuels. The main challenges for Tajikistan’s energy sector, which is depended on energy imports, are: to increase energy supply through better exploitation of hydropower and other renewable energy sources such as wind, solar and primary biofuels. Within the agricultural sector of Tajikistan, which is highly agrarian country, cotton accounts for 60% of agricultural output. According to the Ministry of Agriculture of Tajikistan 199,400 hectares of lands have been allocated to cotton cultivation in the year of 2014. Plenty of unused cotton residual biomass could be effectively utilized for winter heating in rural areas. The main focus of the research was to investigate and assess physical, chemical and mechanical properties of pellets and briquettes produced form cotton waste biomass.
Quality evaluation of local apple varieties: physicochemical and antioxidant proprieties at harvest and after cold storage
(2017) Bartolini, S.; Ducci, E.
A wide apple germplasm is present in Italy in which numerous local genotypes of specific cultivation environment have to be still evaluated for fruit quality attributes. This is the case of a long-established fruit area located in central Italy (Tuscany) where several ancient apple varieties survive with the perspective to be re-introduced for their excellent quality. The objective of this work was to determine over a 2-year period the physicochemical traits, total antioxidant capacity (TAC), and polyphenols (TP) content of three old local apple varieties: ‘Paganina’, ‘Paradisa’ and ‘Rosa’. These characteristics were also assessed after 90 and 150 days at 4 °C cold storage, in normal atmosphere refrigerated cellars. For comparison purpose, the commercial apple cultivar ‘Fuji’ was considered. In general, the old varieties showed valuable quality properties, particularly due to a greater antioxidant power of fruits, although a variability between the two crop seasons, characterized by different weather conditions, was observed. After a dry summer, ‘Rosa’ showed very high TAC and TP values (2-fold higher than other varieties) that, after longperiods of cold storage, markedly decreased. These losses were not so noticeable in the others, suggesting a tendency to maintain a major stability during storage. These findings could meet the preference of demanding consumers for healthier foods who appreciate fresh fruits with protective properties by free radicals scavenging activity. Moreover, farmers who are focused on nearby and niche markets could have interesting in these local varieties to promote their valorization.
Soil organic carbon in long–term experiments: comparative analysis in Slovakia and Serbia
(2017) Macák, M.; Đalović, I.; Turan, J.; Šeremešić, S.; Tyr, S.; Milošev, D.; Kulina, M.
Soil organic carbon plays an important role in a long-term agroecosystem productivity, in the global C cycle, maintaining a soil nutrient pool and improving its availability. The objective of this study is the assess the impacts of long–term cropping practices on SOC dynamics in Slovakia and Serbia. Soil C sequestration is a complex process that is influenced by many factors, such as agricultural practice, climatic and soil conditions. For the both location the initial SOC decline was followed with the C stabilization and possible increase where proper practices were used. More intensive crop management systems that maintained residue cover provided the greatest benefit towards increasing the quantity of mineralizable nutrients within the active fraction of soil organic carbon (SOC), as well as increasing C sequestration as SOC. Long–term field experiments have contributed significantly to our current knowledge of soil quality and have been used to study the influence of crop management, fertilizer application and tillage practices on SOC content.
The advantage of Decision Support System for managing spring barley disease in Estonia
(2017) Sooväli, Pille; Koppel, Mati; Lauringson, Enn; Talgre, Liina
A Decision Support System (DSS) I - Taimekaitse focusing on use of timely applied and reduced fungicide rates in control of cereal diseases has been tested in field trials since 2003 . We compared the conventional treatment and the DSS - based spray practices in 18 field trials in five agricultural locations over 7 - year period. Efficacy of the control of net blotch caused by Pyrenophora teres (Drechsler, am Drechlera teres Sacc. Shoem), the main fungal disease in spring barley has been tested to determine the economic advantage of DSS use. Compared with the conventional spray practices, the advantage I - Taimekaitse resulted in reduction of application doses by 30 to 60% of the registered rate. According to I - Taimekaitse , the fungicides were applied mainly between heading and flowering growth stages (GS 55 – 65), whereas traditional routine spraying is commonly made at booting (GS 37 – 49) . The experiment clarifies the cost - benefit of using DSS - based approach in barley disease management with average yield increase above the control in 12.8% and above the conventional treatment in 14.1%. I - Taimekaitse gave competitive disease control and average yield output reduction compared with conventional practice by 9%. In general the Treatment Frequency Index applied in conventional treatment was 0.65 and in DSS 0.41. Although the cost of treatment expense in DSS was 20% less compared with conv entional practice, the performance of conventional used spray practices was outstanding in economic return.
Effect of flame weed control on various weed species at various developmental stages
(2017) Mojžiš, M.; Vitázek, I.; Klúčik, J.
Physical methods of weed control as solarization, mulching, use of electricity, steam and flame are now an alternative in the organically grown crop. Flame weeder already has a wide range of practical use , particularly in the cultivation of vegetables in alternative form without any chemical treatment. Compared to chemical spraying, the use of flame weeder is more expensive, but we can compensate the costs by the added value of bioproducts. The issue of costs affects the wider use of the method in practice, but it may be offset by increased e fficiency of weed control. The correct parameters of flame weeder, such as burner angle, burner height, the gas pressure, speed of weeder as well as the growth stage of the weed, weed species, climate conditions etc., can increase the effectiveness of weed control. Field and laboratory tests carried out in Canada and Slovakia were aimed at verifying the influence of parameters on the effectiveness of flame weed control.
Determination of mechanical properties of poppy waste pellets
(2017) Kažimírová, V.; Kubík, Ľ; Chrastina, J.; Giertl, T.
The work deals with evaluation of mechanical properties three types of pellet samples produced fro m poppy waste. The pellets were submitted to compressive loading. The compressive loading curves of dependencies of force on strain and force on time were realised. Certain mechanical parameters were determined, namely the diameter of the sample, length of the sample, force at 10% of strain, force in the first maximum of the force – strain curve, strain in the first maximum of the force – strain curve, modulus of elasticity, force in the inflex point of the force – time and force – strain curves and strain and stress in the inflex point of the force – time and force – strain curves. The work lists correlations of mechanical parameters of individual pellet types. The pellet type 1 made only of ground poppy head mass has shown the best results, the pellet type 3 consisting of ground poppy heads after harvest and waste from sieving of poppy seeds in mass proportion 1 : 1 has shown the worst results.
Qualitative classification of mulchers
(2017) Hnilica, R.; Kotus, M.; Jankovský, M.; Hnilicová, M.; Dado, M.
Mulchers are helpful in forest establishment and tending. Numerous mulchers are available, so buyers can become disoriented when choosing one. This paper was aimed at creating a classification of mulchers based on the evaluation of the most important parameters: weight, required engine performance, and mulching diameter. Through ANOVA, and regression and correlation analyses of our database, we created six machine classes, devised their upper limits, and assigned mulchers to the classes. Class K1 (weight up to 1,300 kilograms; performance up to 75 kilowatts; mulching diameter up to 22 centimetres) was the most popular one with 88 mulchers. It was followed by class K2 (1,800 kilograms; 100 kilowatts; 27 centimetres) with 61 mulchers, class K4 (3,200 kilograms; 175 kilowatts; 41 centimetres) with 44 mulchers, class K3 (2,300 kilograms; 125 kilowatts; 31 centimetres) with 34 mulchers, class K5 (4,100 kilograms; 225 kilowatts; 51 centimetres) with 18 mulchers, and class K6 (no upper limit) with nine mulchers.

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