Effective and environmentally friendly methods of protection to reduce seed contamination from fungi are constantly sought. The use of thermal impulses of 100 °C wet water steam to reduce fungal contamination has not been sufficiently investigated, and the potential of this physical approach has not been estimated.The aim of the study was to investigate what impact 100 °C wet water steam with different time durations had on acorn contamination with fungi, acorn germination and biometric indicators of English oak (Quercus robur) seedlings during the first year of growth. Different treatment durations with wet water steam were used: 2, 4, 6, 8, 10, 12 and 14 s.Research showed that 6 seconds impact of wet steam on the surface of the oak acorn destroyed Alternaria spp., 8 seconds impact destroyed Penicillium spp. and 14 seconds impact destroyed Mucor spp. Using 14 seconds water steam treatment Penicillium, Alternaria and Mucor spp. fungi were eliminated.Wet water steam treatment for 2 - 4 seconds not only stimulated the acorns germination by 4.0 - 7.6%, but also had positive influence on the root collar diameter of seedlings. Wet water steam treatment for 2 - 12 seconds had a positive effect on the root development of oak seedlings, however, high temperature environment had a suppressive effect on the oak seedling height. Keywords: biological control, wet water steam, fungi, oak acorns, seedling production

No abstract

The experiment was conducted in the fields of farmers in Kaunas (in 2012), Vilkaviškis (in 2013) and Rietavas (in 2014) districts, Lithuania. The aim of the study was to ascertain the effects of water steam as a weed and fungal disease control method in the common onion (Allium cepa L.) stand. The trials were carried out according to the following design: 1) weeds were hand-weeded three times: the first hand-weeding was performed after mass emergence of weeds, 9-11 days after planting of onions; the second and third hand-weeding operations were carried out after emergence of weeds at a 2-3 leaf growth stage of weeds; 2) thermal weed control using water steam was carried out twice per growing season with the duration of weeds and onions exposure to steam of 2 seconds; thermal weed control was applied on the entire experimental plot, i.e. all over the plot, without protection of onion plants against exposure to steam; 3) thermal weed control using water steam was carried out twice per growing season with the duration of weed exposure to steam of 2 seconds. Thermal weed control was applied only in the inter-rows at a seedling stage of weeds. The impact of water steam on the onion bulbs was partial. The findings of the current study suggest that the application of water steam all over the trial plots, twice per growing season gave the most effective control of weeds in the stands of onion. Water steam treatment was found to reduce the occurrence of fungal diseases in the onion stand. The severity of downy mildew in the plots treated with water steam decreased by 52.5-739%, compared with the control plots. The steam treatment all over the trial plots reduced the severity of white rot of onion by 43.5-46.9%. Steaming all over the plots diminished the onion neck rot infection level on onion plants by 68.0-86.1%, while inter-row steaming reduced the disease pressure by 33.3-83.7%. The yield of common onion bulbs in our study ranged from 4.06 to 5.41 kg m-2. A statistically significantly higher yield of onion bulbs was produced in the treatment where steaming had been applied all over the plots compared with the hand-weeded plots.

Forest fire is an uncontrolled combustion of flammable materials in forested and non-forested areas. In Lithuania forest fires mainly occur in late spring and summer, mostly in young coniferous forests (Forest ..., 1987). The studies of herbaceous plants in fireplaces were carried out in 2016 in Jurbarkas SFE. Ground-level forest fire increased the projection coverage of herbaceous plants and their species composition in the fireplaces. According to the average data of the survey, 18 herbaceous plant species were ascertained in the fireplace and 14 species in the control stand. During the first year after fire, 9 new species were recorded in the fireplace and 5 species have disappeared, while in the seventh year -7 new species were recorded and 1 disappeared, as compared with the control stand. Summarizing the obtained data it can be stated that low-intensity ground-level forest fire in pine forest increased the number of herbaceous plant species, however, the number of new and extinct species has been gradually decreasing, suggesting that in the fireplaces the diversity of herbaceous plant species will be like in the control stand.

The usage of biodegradable waste as sewage sludge in a proper way for tree nurseries enable to seek for ecological, waste-less, alternative to mineral fertilization farming ways. The aim of this research is to investigate impact of sewage sludge fertilizers on Norway spruce (Picea abies) two years’ seedlings growth. Research has been done in 2013-2014 at Utena State Forest Enterprise nursery. The different fertilization rates (20, 40, 60, 80, 100 t/ha) of sewage sludge were investigated and compared with control – traditional fertilization with mineral fertilizers. The impact of sewage sludge was evaluated by seedlings biometric indicators, also dry mass of sample seedlings (medium seedlings by height and diameter). The bigger rates of sewage sludge showed almost better results in exception of seeds outlet. Sewage sludge has long lasting effect on seedlings growth and could successfully shift soil fertilization by mineral fertilizers. The obtained research results confirm the similar research carried out in 2011 in Rokiskis State Forest Enterprise nursery for first year Norway Spruce seedlings.