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xxx S. Šēnhofa, M. Zeps, L. Ķēniņa, U. Neimane, R. Kāpostiņš, A. Kārkliņa and Ā. Jansons
Intra–annual height growth of hybrid poplars in Latvia. Results from the year of establishment
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Intra–annual height growth of hybrid poplars in Latvia. Results from the year of establishment

S. Šēnhofa, M. Zeps, L. Ķēniņa*, U. Neimane, R. Kāpostiņš, A. Kārkliņa and Ā. Jansons

Latvia State Forest Research Institute Silava, Rigas street 111, LV–2169 Salaspils, Latvia
*Correspondence: laura.kenina@silava.lv

Abstract:

Fast growing hybrid poplars (Populus spp.) could be successfully used for bioenergy as well as wood production. Productivity of clones had been studied in Baltic States recently, however, little is known about the impact of weather conditions on poplar height growth, thus the potential effect of climate change. Therefore, the aim of this study was to characterize the intra–annual height growth of hybrid poplar clones in Latvia. Height increment of 12 hybrid poplar clones was measured on average with an 11–day interval in the first vegetation season in 2016. Annual shoot height was on average 81.0 ± 6.8 cm, significantly (p < 0.001) depending on the poplar clone. Use of long (0.5 m) instead of short (0.3 m) cuttings leaded to larger annual height increment during the year of establishment of the plantation. From June to September the mean growth intensity was 10 to 15 mm day-1. The trend of height growth intensity, described by Gompertz model, indicated that the poplar clones with largest height had relatively fast increase of the growth intensity from June to July. Changes of growth intensity was linked both with the temperature and sum of precipitation. This tendency was not so pronounced for clones with largest height increment, emphasizing the importance of the phenotypic plasticity in selection of clones for plantations.

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xxx I. Laktionov, O. Vovna, O. Cherevko and T. Kozlovskaya
Mathematical model for monitoring carbon dioxide concentration in industrial greenhouses
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Mathematical model for monitoring carbon dioxide concentration in industrial greenhouses

I. Laktionov¹*, O. Vovna¹, O. Cherevko² and T. Kozlovskaya³

¹State Higher Educational Institution 'Donetsk National Technical University', Ministry of Education and Science of Ukraine, Department of Electronic Engineering, Shibankova sq., 2, UA85300 Pokrovsk, Ukraine
²State Higher Educational Institution 'Priazovsky State Technical University', Ministry of Education and Science of Ukraine, Department of Automation and Computer Technologies, University str., 7, UA87500 Mariupol, Ukraine
³Kremenchuk Mykhailo Ostohradskyi National University, Department of biotechnologies and bioengineering, Pershotravneva str., 20, UA39600, Kremenchuk, Ukraine
*Correspondence: ivan.laktionov@donntu.edu.ua

Abstract:

Processes of monitoring and control the industrial greenhouses microclimate play a decisive role in growing crops under protected cultivation. Providing optimal climatic conditions in the production process of greenhouse agricultural products requires solving the scientific and applied problem of developing and researching a mathematical model for monitoring carbon dioxide concentration in industrial greenhouses. The proposed model takes into account the processes of diffusion and absorption of carbon dioxide, the geometric parameters of greenhouses, as well as the types and vegetation periods of crops grown under protected cultivation. Time characteristics of the carbon dioxide dynamics process under greenhouse conditions are estimated. Quantitative estimates of the diffusion transfer duration and carbon dioxide absorption are made for indeterminate varieties of tomatoes during planting and fruiting periods. Recommendations are given on the development of an adaptive methodology for the functioning and structural and algorithmic organization of computerized monitoring and management system for carbon dioxide top-dressing modes for greenhouse crops. The necessity of improving the proposed mathematical model and confirming the adequacy of its implementation efficiency on yield indicators of greenhouse crops is substantiated.

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xxx K. Meile, A. Zhurinsh, L. Briede and A. Viksna
Investigation of the sugar content in wood hydrolysates with iodometric titration and UPLC-ELSD
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Investigation of the sugar content in wood hydrolysates with iodometric titration and UPLC-ELSD

K. Meile¹²*, A. Zhurinsh¹, L. Briede¹ and A. Viksna²

¹Latvian State Institute of Wood Chemistry, Dzerbenes 27, LV-1006 Riga, Latvia
²University of Latvia, Faculty of Chemistry, Department of Analytical Chemistry, Jelgavas 1, LV-1004 Riga, Latvia
*Correspondence: kristine.meile@inbox.lv

Abstract:

Autohydrolysis of birch wood is a mild pretreatment process, which gives a notable yield of sugars – monosaccharides and oligosaccharides – in the aqueous hydrolysate, while a solid lignocellulose fraction can be further processed into other valuable products within a biorefinery concept. In this work two analytical methods – iodometric titration and ultra-high performance liquid chromatography with evaporative light scattering detection (UPLC-ELSD) – have been optimized and compared for the determination of the sugar content in series of birch wood hydrolysates. The results of both methods were consistent and showed that the highest yield of sugars, mostly xylose, was obtained by hydrolysis at 180 °C after 75 min.

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xxx M. Gaworski, A. Leola, H. Kiiman, O. Sada, P. Kic and J. Priekulis
Assessment of dairy cow herd indices associated with different milking systems
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Assessment of dairy cow herd indices associated with different milking systems

M. Gaworski¹*, A. Leola², H. Kiiman², O. Sada², P. Kic³ and J. Priekulis⁴

¹Warsaw University of Life Sciences, Department of Production Management and Engineering, Nowoursynowska str. 164, PL02-787 Warsaw, Poland
²Estonian University of Life Sciences, Institute of Technology, Fr.R. Kreutzwaldi 56, 51014 Tartu, Estonia
³Czech University of Life Sciences Prague, Faculty of Engineering, Kamycka 129, CZ16521 Prague 6, Czech Republic
⁴Latvia University of Agriculture, Faculty of Engineering, Cakstes blvd. 5, LV-3001 Jelgava, Latvia
*Correspondence: marek_gaworski@sggw.pl

Abstract:

The objective of the research was to find whether any differences exist between cattle herds operated by certain milking installations. The cattle herds were studied not only by herd size but also by certain data, like annual milk yield, age and number of lactations. Data collected on dairy farms that operate pipeline milking systems, milking parlours and automatic milking systems were analysed. These farms are situated in three Baltic States. The investigated Estonian dairy farms indicated a decreased tendency in the prevalence of disease cases for udder diseases with an increase in cow herd size. An index of cow production potential was proposed to compare different (including number of lactations) group of cows in dairy farms.

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