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An advanced classification method for urban land cover classification
51-57Views:214This manuscript presents a detailed comparative analysis of three advanced classification techniques that were used between 2018 and 2020 to classify land cover using Landsat8 imagery, namely Support Vector Machine (SVM), Maximum Likelihood Classification (MLSC), and Random Forests (RF). The study focuses on evaluating the accuracy of these methods by comparing the classified maps with a higher-resolution ground truth map, utilising 500 randomly selected points for assessment.
The obtained results show that, compared to MLSC and RT, the Support Vector Machine (SVM) approach performs better. The SVM model demonstrates enhanced precision in land cover classification, showcasing its effectiveness in discerning subtle differences in landscape features.
Furthermore, using the precise classification results produced by the SVM method, this study examines the temporal variations in land cover between 2018 and 2020. The results provide insight into dynamic land cover changes and highlight the significance of applying reliable classification techniques for thorough temporal analysis with Landsat8 images.
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The Evaluation of Grazed Grasslands on the Hortobágy
50-54Views:137The sward composition of different grasslands on Puszta Hortobágy has been developed according to prevailing abiotic and biotic factors. The abiotic conditions have been more or less constans for long periods of time, and the abiotic factors are determined by ecological conditions (climate, soil, topography). Among biotic factors grazing of herbivores was important in the development of Hortobágy grasslands for centuries (Sipos and Varga, 1993). Result of three-year investigations on the sward composition of grasslands utilised in different ways are presented. Data on ground cover, number of plant species, representation of different plant groups (grasses, sedge and bent-grass, herbs, legumes) and weeds are reported from six different grazed grassland types from Puszta Hortobágy.
In 1999-2001 a sward composition survey was conducted. Sample areas of 2x2 m2 were marked out in three replicates: on temporarily waterlogged grassland grazed by cattle (A), on dry grassland grazed by cattle (B), on dry grassland grazed by sheep (C), on dry grassland grazed by buffaloes (D), on dry grassland grazed by buffaloes and geese (E), on dry grassland cut for hay in May then grazed by geese (F). On the sample areas sward composition of grasslands was estimated according to Balázs (1949).
The average ground cover of different grasslands ranged between 60 and 100% (Table 2). The lowest value was found for grasslands C and E, which are grazed by sheep (C) and buffaloes and geese alternately (E). In these grasslands were some open spaces, on the other grasslands completely closed swards covers were observed.
The species diversity of these natural grasslands are high (Table 2). The grassland F, which were cut for hay in May had the lowest diversity (17-21). The highest number of species was found on grassland A and B (32-51), on other grazed grasslands (C, D, E) had 29-48 species.
The different plant groups had different representation in the total ground cover (Table 3). The number of herbs was always higher then that of grasses, but the cover of herbs was lower then that of grasses. The legumes and the sedge and bent grasses were present in high abundance in grassland A, but in the other grasslands were not.
The composition of herbs should be a warning for future utilisation systems on some grasslands of Hortobágy. Some species of herbs, e.g. Achillea millefolium, Artemisia vulgaris, Carduus acanthoides, Cirsium arvense, Cirsium vulgare Eryngium campestre, Galium mollugo, Galium verum, Ononis spinosa, Rumex crispus, Verbascum phlomoideus, Phragmites australis can be invasive on short grasslands. -
Occurrence of woolly cupgrass (Eriochloa villosa /Thunb./ Kunth) in Hajdú-Bihar county, Hungary
119-123Views:104Woolly cupgrass (Eriochloa villosa /Thunb./ Kunth) is native to East Asia, it spreads in several parts of the World and causes difficulties in plant protection, especially in maize. Difficulties in control of Eriochloa villosa originated from several reasons: seeds continue to germinate later in the season, significant part of seeds emerges from a deep layer of the soil, and the species is less susceptible to some herbicides applied to maize than other annual grass weeds.
The first report on the occurrence of woolly cupgrass in Hungary was published in 2008, and it reported about the appearance of this species near to Gesztely village (Borsod-Abaúj-Zemplén county), however, no information has been added about spread of the weed in Hungary until now.
A significant population was discovered next to Debrecen (Hajdú-Bihar county) in summer, 2011, and then weed associations were examined in maize, sunflower and stubble-fields on several km2 in the area to estimate the Eriochloa villosa infection. The weed species was found on every maize field bordering with a ground cover of 0.5-4%. Woolly cupgrass occurred inside of the 50% of maize fields, and reached a ground cover of 76% in case of most infected area, in addition it was found in sunflower and stubble-fields.
The spread of woolly cupgrass is expected in this area, which requires the consideration of this species in the planning of weed management technologies. -
Stevia (Stevia rebaudiana B.) yield in the case of different production technologies
71-77Views:217Stevia rebaudiana B. offers a natural alternative of sweetening, potential health promotion plant, and our country shows increased interest about cultivation in Hungary in addition to the neighboring European countries. The agricultural production system installation necessary
understanding of the needs of the plant, as well as exploring the agronomic potential. Field experiments were conducted in 2015 with the aim to highlight some of the technological production parameters and correlations between them. We have reviewed the most important agronomic factors, the spacing (50×50 cm and 33×33 cm), ground covering (agro-cloth covered and uncovered/ control), their vegetative growth (first-,second-order branch), herb yield and quality in effect.
Based on empirical evidence, that the Hungarian climates also have the opportunity of 3 cuttings during a growing season, besides of early planting, optimal climatic conditions (in October didn’t reduce the daily minimum temperature below 0 °C, after cuttings the maximum interval values remain below 40 °C), and adequate water supply and crop protection facility. The 33×33 cm spacing evaporates more than 50×50 cm spacing, because of the dense population, the continuous canopy less able to breathe, so there are serious chances to the pathogen colonization.
Based on the results of our research to the wider 50×50 cm spacing favorable appreciate the stevia optimal progress in terms of qualitative and quantitative parameters of the yield. The stevia yields produced in the Northern Great Plains field cultivation can produce similar results as stevia crop yields in warmer climates, where the primary crops. Our research experience suggest that there is a viable domestic stevia cultivation, developing the necessary technology is still growing further investigation justifies. -
Effect of Water and Nutrient Supply on the Allelopathy of Abutilon theophrasti Medic. and Xanthium italicum Mor
102-105Views:82Velvetleaf (Abutilon theophrasti Medic.) and Cocklebur species (Xanthium spp.) are more and more dangerous and „difficult to control” weeds in several cultivated plants. The ground cover of these species have became larger in Hungary like other warm-philous species. There are several causes of danger of them, for example: large capability for competition, allelopathic effect, keeping on of emergence.
The allelopathic effect of these weeds were examined on sugarbeet (Beta vulgaris L.). Extracts of plants grown under different conditions have several effect on this species.
Abutilon theophrasti plants were grown in perlite to examine the effect of supplying with nutritive materials on production of inhibitors. The water soluble exudates of the shoots grown with no artificial fertilisers inhibit stronger than grown with them. Acid soluble exudates have contrary effect. The exudates made of roots inhibited the sugarbeet less than shoots.
Effect of drought stress on production of inhibitors was examined on Abutilon theophrasti and on Xanthium italicum. The species responded to missing of water different, and the water, acid and basic soluble exudates had different effect, as well.