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Gediminas Staugaitis Pranas Viškelis 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(2):176-181
Abstract The study investigates the effects of nitrogen fertilizers on the characteristics of the autumn crop of Chinese cabbage. The rates applied varied from 0 to 225 kg ha?1 (N0, N45, N90, N135, N180, N225); the supply of phosphorus and potassium fertilizers was similar in the all trials, 90 and 150 kg ha?1, respectively. It was found that the optimum nitrogen fertilization rate for the autumn crop of Chinese cabbage was N135. In the case of lower nitrogen rates the yield decreased and the cabbage heads were smaller. Further increase in fertilizer rate (>N135) resulted in a higher percentage of non-standard cabbage heads, while the yield remained almost unchanged compared with N135. The total plant mass of cabbage crop fertilized with N135 was 76 t ha?1; plant residues constituted 33 t ha?1 (43% of the total mass). The yield of market quality cabbage heads was 30 t ha?1 (70% of all the heads produced); the rest of heads were loose, not formed or rot-infected. The optimal amount of total mineral nitrogen (the sum of nitrogen present in the 0–60 cm soil layer and the nitrogen supplied with fertilizers) before planting was 260 kg ha?1. When nitrogen rates were higher than N180 the quality of cabbage heads in terms of the content of vitamin C, nitrates, soluble solids, total solids and sugars decreased. 相似文献
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Paulo Pereira Pranas Mierauskas Agata Novara 《Land Degradation \u0026amp; Development》2016,27(4):871-883
The aim of this work is to study Lithuanian stakeholders' perceptions of fire impacts in protected areas. For this study, the stakeholders consisted of foresters, ecologists and farmers. A clear understanding of the opinions of stakeholders about fire effects on environmental, social and economic aspects of Lithuanian protected areas will allow an assessment of the stakeholders' reaction to fire policy, including government measures towards fire prevention, suppression and application of prescribed fire to landscape management. The results showed that stakeholders in general think that fire is not a threat to Lithuania and to the ecological processes in the protected areas. However, they agree that fires have negative impacts on soil properties and fertility but are not to an irremediable or irrecoverable extent. Stakeholders disagree that fire has positive consequences for agricultural and cattle activities but agreed that vegetation recovers quickly. They do not see fire as a social and economic problem, do not agree that prescribed fire could be used to landscape management, and believe that mechanical thinning is a better management tool than prescribed fire. Stakeholders agree that fire does not have negative impacts on the biodiversity. These opinions depended on the age group of the respondent but especially on the respondent's professional occupation. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Baranauskiene R Venskutonis PR Viskelis P Dambrauskiene E 《Journal of agricultural and food chemistry》2003,51(26):7751-7758
The influence of nitrogen fertilizers on the yield of crop, as well as on the production and composition of the essential oil and some other chemical characteristics of thyme, was investigated. Different levels of fertilizers (N = 0, 45, 90, and 135 kg x ha(-)(1)) were applied. It was found that fertilizers increase thyme crop, but differences in the yield of essential oil were not remarkable. However, the use of certain amounts of nitrogen fertilizers resulted in higher yields of essential oil obtainable from the cultivation area unit (dm(3) ha(-)(1)). Totally, 61 constituents were identified in thyme essential oil by capillary GC and GC-MS. Thymol was the dominating compound in the all analyzed oils (44.4-58.1%), followed by p-cymene (9.1-18.5%), gamma-terpinene (6.9-18.9%), and carvacrol (2.4-4.2%). Differences in the percentage of these and other compounds in thyme herb cultivated under different fertilization doses were not significant; very slight changes in the percentage composition were detected after drying. Some variations in the amount of individual constituents expressed in arbitrary units per kilogram of herb (which is almost equivalent to mg x kg(-)(1)) were observed. The highest amounts of sugars and sucrose, in particular, were determined in the second year of thyme cultivation. Differences in the content of dry soluble substances were not meaningful, and there was no effect of nitrogen fertilizers on this chemical characteristic. Some effect of fertilization on the content of vitamin C and carotenes was observed in the first year of thyme cultivation. It was determined that nitrogen fertilizers influence the amount of nitrates, which was highest in the second-year-first-harvest. 相似文献
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Edita Baltr?nait? Arvydas Lietuvninkas Pranas Baltr?nas 《Water, air, and soil pollution》2012,223(7):4297-4306
To evaluate plant responses and compare metal uptake by different plants, several parameters and references have been used by researchers in the last few years. However, they express only the first-level comparison, i.e. biogeochemical comparison of different media (plant and soil) occurs in one place, at the same time and under the same circumstances. To integrate information about metal concentration in different media or plant organ and provide comparison of the process between control and treated cases, the second-level factors, the dynamic factors, are needed. Differently from the factors mentioned in the existing literature, they are able to show changes in processes under environmental changes rather than changes only in metal quantities. They are related both to internal (physiological) and external (ecological) factors. The paper introduces the use of dynamic factors for assessment of transfer and translocation of metals (Zn, Pb, Ni, Mn, Cu and Cr) in Scots pine (Pinus sylvestris L.), silver birch (Betula pendula) and black alder (Alnus glutinosa). Factor values and their implications are discussed in the paper. 相似文献
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Laima ?esonien? Remigijus Daubaras Pranas Vi?kelis Antanas ?arkinas 《Plant foods for human nutrition (Dordrecht, Netherlands)》2012,67(3):256-261
Viburnum opulus is a plant with fruits that are rich in biologically active substances, making it valuable to the food and pharmaceutical industries. Here, we present our study of the total phenolic and anthocyanin contents and antimicrobial activity in the fruit juice of six V. opulus L. accessions. The cultivar ??Krasnaya Grozd?? was notable for its exceptionally large amount of total phenolics, 1168?mg/100?g, with anthocyanins comprising 3?C5?% of the total phenolic content. The evaluation of the antimicrobial properties confirmed that the juice of V. opulus fruits strongly inhibited the growth of a wide range of human pathogenic bacteria, both Gram-negative (Salmonella typhimurium and S. agona) and Gram-positive (Staphylococcus aureus, Lysteria monocytogenes, and Enterococcus faecalis) organisms. Conversely, the yeasts Debaryomyces hansenii and Torulaspora delbrueckii showed complete resistance to the fruit juice, whereas a low sensitivity was demonstrated by Trichosporon cutaneum, Kluyveromyces marxianus var. lactis, Saccharomyces cerevisiae, S. cerevisiae 12R, and Candida parapsilosis. 相似文献
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