Volume 9 (2011)
  Number 1-2

Contents

Pages
273-280 A. Annuk, P. Pikk, E. Kokin, E. S. Karapidakis and T. Tamm
Performance of wind-solar integrated grid connected energy system
Abstract |
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Performance of wind-solar integrated grid connected energy system

A. Annuk¹, P. Pikk¹, E. Kokin¹, E. S. Karapidakis² and T. Tamm¹

¹Department of Energy Engineering, Institute of Technology, Estonian University of Life Sciences, 56 Kreutzwaldi Str., EE51014 Tartu, Estonia; e-mail: andres.annuk@emu.ee
²Department of Natural Resources & Environment (Chania), Technological Education Institute of Crete, P.O. Box 1939, GR 71004, Iraklio, Crete, Greece;
e-mail: karapidakis@chania.teicrete.gr

Abstract:

In this work the system of wind generator and PV panel connected to the grid is discussed. The unit wind generator and indicative solar data converted to relative values were used. The ratio between energy amount going to the grid and produced energy was analysed for different energy demands in case of varying wind power levels and solar irradiation intensities. In case of produced and consumed in site yearly energy is equal, the amount of energy supplied to grid and consumed is approximately equal to 50% of energy production. With the increase of wind energy part, this ratio diminishes. Wind – PV panels’ solution is most effective in case of energy selling to the grid at low demand periods. The possibility of Photovoltaic Geographical Information System ;PVGIS) database application for solar data modelling was also analysed. For summer months the differences between the PVGIS database and measured data from Estonian Meteorological and Hydrological Institute (EMHI) do not exceed 5%, though in winter months it reaches 25%. But as on the latitude of Estonia the PV panels’ energy production in winter is marginal compared to summer then its influence on the energy balance is very small.

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281-297 J. R. Gnepe, R. D. Tyagi, S. K. Brar, J. R. Valero and R. Y. Surampalli
Statistical optimization of agro-industrial diets for the rearing of Cydia pomonella using response surface methodology
Abstract |
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Statistical optimization of agro-industrial diets for the rearing of Cydia pomonella using response surface methodology

J. R. Gnepe¹, R. D. Tyagi¹*, S. K. Brar¹, J. R. Valero¹ and R. Y. Surampalli²

¹INRS Eau, Terre et Environnement (INRS-ETE), 490, de la Couronne, CP 7500,Québec, Canada G1K 9A9; Phone: (418) 654 2617; Fax: (418) 654 2600
²US EPA, P.O. Box-17-2141, Kansas City, Kansas, KS 66117e-mail: gnepej@yahoo.fr; satinder.brar@ete.inrs.ca; tyagi@ete.inrs.ca; josevalero@videotron.ca

Abstract:

In this study, apple pomace and brewery wastewater were used as nutritive agents and as alternative substitutes for the ingredients (soya flour, wheat germ and yeast extract) without affecting the production of the diet. The quantity of agro-industrial waste added during production was based on a regime where the different nutrients were maintained as a constant, such as proteins (3.71 ± 0.09 g), carbohydrates (4.2 ± 0.12 g) and lipids (2 ± 0.08 g) based on their concentration in the standard diet. Various diets produced using different concentrations of waste and ingredients were tested using the culture of Cydia pomonella in order to optimize the diet in terms of nutrition and optimal viscosity (to facilitate assimilation of nutrients). Optimization of the rearing parameters was carried out using response surface methodology. This demonstrated that the brewery wastewater (BWW-SF) diet provided the best results for insect-rearing (81% hatching, 76% larvae and 51% adults) which was closer to the control diet (90% hatching, 80% larvae and 65% adults) and was more significant than the other diets (40–70% hatching, 45–50% larvae and 9–30% adults). In addition, the viscosity was higher in diets where the solids content was higher. The increase in viscosity was in line with the solidification of agar, which evolved rapidly over time and in relation to the solids present in the diet.

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299-304 K. Jansen, L. Esko M. Luik, V. Viljasoo, J. Ereline, H. Gapeyeva, H. Aibast and M. Pääsuke
Workload assessment and its influence on a male tile layers working ability
Abstract |
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Workload assessment and its influence on a male tile layers working ability

K. Jansen¹, L. Esko² M. Luik², V. Viljasoo², J. Ereline¹, H. Gapeyeva¹, H. Aibast¹ and M. Pääsuke¹

¹Institute of Exercise Biology and Physiotherapy, University of Tartu, 5 Jakobi Street 51014 Tartu, Estonia, e-mail: jansen@ut.ee
²Institute of Technology, Estonian University of Life Sciences, 56 Kreutswaldi Street 51014 Tartu, Estonia, e-mail: pteh@emu.ee

Abstract:

The aim of this study was to evaluate tile layers workload at a construction site and its influence to their working ability. The subjects (n = 8) were male tile layers (mean ± SE) age of 36 ± 3.6 years. First the subjects completed a questionnaire and thereafter they performed before and after the working day a test of tile setting on a special wall, where was 3 stages and every stage they must set correctly 14 tiles. In the course of test the electromyographical (EMG) power spectral median frequency (MF) of biceps brachii, trapezius, deltoideus and erector spinae muscles was measured (both sides). The results of questionnaire indicate that the tile layer’s most burdened parts of the body were knees, lower back and upper back. Workers complained most about tiredness, skin irritations, dyscomfort in eyes, knee, leg, lower back and neck/shoulder pain. It is important emphasis that all tile layers were taking tiles from a left side. Objectively estimated muscle fatigue emerged before and after the working day when comparing EMG power spectral MF measured at the beginning and end of the tile setting test. The results indicated that the most burdened muscle was right erector spinae for all 3 stages. In case of physical work, it is advisable to make short breaks every hour, so as to avoid the problems caused by overload. The results of this study can be used by specialists of ergonomics and production managers.

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305-314 D. Lazdina, A. Bardule, A. Lazdins and J. Stola
Use of waste water sludge and wood ash as fertiliser for Salix cultivation in acid peat soils
Abstract |
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Use of waste water sludge and wood ash as fertiliser for Salix cultivation in acid peat soils

D. Lazdina, A. Bardule, A. Lazdins and J. Stola

‘Silava’ Latvian State Forest Research Institute, Riga iela 111, Salaspils, LV–2169, Latvia; e-mail: dagnija.lazdina@silava.lv

Abstract:

Two problems have become more topical in recent years – production of solid biofuel from wood and the utilisation of ash and organic waste, including waste water sludge. The purpose of this research is to model simultaneous solutions for both of these problems through their use as fertilizer and to identify useful indications for the use of waste water sludge and wood ash as fertilisers. Opportunities to boost the efficiency of the applications of waste water sludge by combined spreading with wood ash are addressed in this study. An experiment is carried out in vegetation pots with different proportions of peat, sludge and ash to determine the impact of stem and root system development related to chemical and nutrient availability. Due to these studies, it is determined that waste water sludge has a comparably small liming effect. The fertilising effect of sludge can be increased by the admixture of wood ash and dolomite. These materials reduce the acidity of the soil and provide additional nutrients. Using dolomite as a liming material in the amount of 10 t ha-1 secures a change in pH of 0.6–1.2 units in peat soil. Significant changes in pH were found just a few centimetres into the upper layer of the soil. The application of an equal amount of wood ash produces a faster effect in terms of neutralisation. The limiting element is phosphorus. However, the mineralisation of peat increases the percentile proportion of all mineral elements in substrates as well as heavy metals.

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315-329 M. Lonbani and A. Arzani
Morpho-physiological traits associated with terminal drought- stress tolerance in triticale and wheat
Abstract |
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Morpho-physiological traits associated with terminal drought- stress tolerance in triticale and wheat

M. Lonbani and A. Arzani*

*Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan 84156 83111, Iran; e-mail: a_arzani@cc.iut.ac.ir

Abstract:

The objectives of this study were to evaluate the genotypic effects on tolerance to terminal drought stress in triticale and to compare it with that of durum and bread wheat under drought stress and normal field conditions using morpho-physiological traits. Five triticale ('Zoro', 'Moreno', 'Lasko', 'Prego' and 'Alamos 83'), one bread wheat ('Roshan') and one durum wheat ('Osta-Gata') cultivars were used. A randomized complete block design with three replications was used in each of the drought stress and well-watered (non-stress) experiments. Morpho-physiological traits including chlorophyll content, relative water content (RWC), excised leaf water retention (ELWR), rate of water loss (RWL), initial water content (IWC), leaf area, leaf angle, number of stomata, pollen viability, dry weight of awn and awn length were evaluated. Results of combined analyses of variances indicated the highly significant differences among genotypes for all traits and significant genotype × environmental interaction for all traits with the exception of leaf width, number of stomata and awn length. Overall performance of triticale cultivars was superior to wheat cultivars under both environmental conditions. Among triticale genotypes, 'Lasko' and 'Moreno' cultivars were the most drought tolerant and 'Prego' cultivar was the most sensitive genotype to water stress. Under drought stress conditions ELWR showed significant and negative correlation with grain yield, while their correlation was significant and positive under non-stress conditions. This relationship indicates that ELWR had an important impact on grain yield under both water stress and non-stress conditions.

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331-342 M. Luna-del Risco, A. Normak and K. Orupõld
Biochemical methane potential of different organic wastes and energy crops from Estonia
Abstract |
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Biochemical methane potential of different organic wastes and energy crops from Estonia

M. Luna-del Risco¹, A. Normak¹ and K. Orupõld¹²

¹Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences. Kreutzwaldi 5, 51014 Tartu, Estonia
²Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences
e-mail: 1 mario.luna@emu.ee, 1 argo.normak@emu.ee, 1,2 kaja.orupold@emu.ee

Abstract:

 The biochemical methane potential (BMP) of different Estonian substrates as alternative sources for biogas production was studied. For this purpose, the BMP test was carried out in batch mode at mesophilic temperature (36°C). Substrates were divided into 2 groups: agricultural substrates (silage, hay, cattle and pig slurry) and food industry residues (milk, brewery and cereal industry residues). Methane yields obtained were between 286–319 L kgVS-1 for silage and hay, 238–317 L kgVS-1 for animal slurry and 272–714 L kgVS-1 for agro-industrial wastes. The highest methane yield was obtained from sour cream (714    L kgVS-1), the lowest (238 L kgVS-1) from cattle slurry. In overall, our results suggest that all tested substrates can be treated anaerobically and are potential sources for the production of methane.

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343-356 J. Pozdíšek, B. Henriksen, A. Ponížil and A.-K. Løes
Utilizing legume-cereal intercropping for increasing self- sufficiency on organic farms in feed for monogastric animals
Abstract |
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Utilizing legume-cereal intercropping for increasing self- sufficiency on organic farms in feed for monogastric animals

J. Pozdíšek¹, B. Henriksen², A. Ponížil³ and A.-K. Løes²

¹Research Institute of Cattle Breeding, Rapotín s.r.o, Výzkumníků 267, 788 13 Vikýřovice, Czech Republic; e-mail:jan.pozdisek@vuchs.cz
²Bioforsk - Norwegian Institute for Agricultural and Environmental Research, Organic Food and Farming Division, Gunnars veg 6, NO-6630 Tingvoll, Norway; e-mail: britt.henriksen@bioforsk.no and anne-kristin.loes@bioforsk.no
³Agritec, research, breeding and services Ltd., Zemědělská 16, 787 01 Šumperk, Czech Republic; e-mail: ponizil@agritec.cz

Abstract:

In 2009, controlled field trials were conducted on three certified organic farms with field pea (leaf type), spring barley and spring wheat in monocultures and mixtures (pea:cereal ratio 60:40) to study the possibility of producing fodder for monogastric animals under Czech conditions. By grain harvest time, seed samples were collected and analysed for dry matter, ash, crude protein, fat and crude fiber, and content of organic matter and nitrogen-free extracts (NFE) were determined. Weed harrowing at various pea heights were included at one farm. Samples for analysis of tannins and trypsin-inhibitor activity (TIA) were taken from treatments with no weed harrowing (H0) and harrowings at 5 and 10 cm pea height (H2). Analyses of amino acids were conducted from H0-samples. To complement the data from the farm trials, samples of grains from treatments with the same pea and cereal varieties in plot trials conducted in 2008 and 2009 studying the effect of pea:cereal seed ratio and weed harrowing at various pea heights, were analysed. In cereals, the crude protein content increased by intercropping with pea. This increase was compensated for by a decrease in NFE. Wheat and barley grown in mixtures with peas seemed to contain more methionine than cereals in monoculture, and there tends to be higher threonine content in intercropped barley compared with barley monoculture. This is positive for the nutrition of monogastric animals.  There were no pronounced effects of intercropping on tannins or TIA or on the content of other analysed nutrients in the cereals. The chemical composition of peas was not significantly impacted by intercropping.

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357-364 V. Vasileva and A. Ilieva
Chemical composition, nitrate reductase activity and plastid pigments content in lucerne under the influence of ammonium and nitrate form mineral nitrogen
Abstract |
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Chemical composition, nitrate reductase activity and plastid pigments content in lucerne under the influence of ammonium and nitrate form mineral nitrogen

V. Vasileva and A. Ilieva

Institute of Forage Crops, 89 Gen. “Vladimir Vazov” Str., Pleven 5800, Bulgaria, E-mail: viliana.vasileva@gmail.com

Abstract:

A pot trial was carried out at the Institute of Forage Crops, town of Pleven, Bulgaria (2003–04). Whereas ammonium and nitrate forms of mineral nitrogen are assimilated for the plants, the influence of these two forms of mineral nitrogen on the chemical composition, nitrate reductase activity and plastid pigments content of lucerne in conditions of optimum moisture and water deficiency stress was tested. Urea as a source of ammonium nitrogen and potassium nitrate as a source of nitrate nitrogen were used. Rates of 70, 140 and 210 mg N kg-1soil were applied. It was found that mineral nitrogen in ammonium form, applied at the doses of 140 and 210 mg N kg-1 soil at optimum moisture increased crude protein content by 5–13%, and in the nitrate form at the same doses, by 3–7%. Crude protein content under water deficiency stress increased by 4–21% for ammonium, and by 3–12% for the nitrate form of mineral nitrogen. When the plants were supplied insufficiently with nitrogen, water deficiency stress more strongly deteriorated the chemical composition of lucerne, crude protein decreased by 6% and crude fiber increased by 10%. The application of mineral nitrogen under optimum moisture decreased calcium and phosphorus content, and the decrease was bigger for the nitrate form (up to 10% for calcium, and 23% for phosphorus). Under water deficiency stress the content of calcium and phosphorus decreased, but there were no differences for two forms of mineral nitrogen. At the optimum moisture and water deficiency stress, there was a similar tendency to reduce nitrate reductase activity in leaves, when applied mineral nitrogen at a dose of 70 mg N kg-1 soil in both forms, and to increase at the doses of 140 and 210 mg N kg-1 soil. The total content of plastid pigments increased as compared to unfertilized control, when mineral nitrogen was applied in both forms.

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365-369 E. Veromann and M. Toome
Pollen beetle (Meligethes aeneus Fab) susceptibility to synthetic pyretroids – pilot study in Estonia
Abstract |
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Pollen beetle (Meligethes aeneus Fab) susceptibility to synthetic pyretroids – pilot study in Estonia

E. Veromann and M. Toome

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1 Tartu 51014 Estonia e-mail: eve.veromann@emu.ee

Abstract:

Pollen beetle (Meligethes aeneus Fab) is a common pest of oilseed rape. The development of resistance to pyrethroids in M. aeneus is widespread in northern Europe. In Estonia, the majority of farmers apply insecticides against pollen beetles without considering the threshold levels of the pest. This creates good preconditions for development of resistance in  M. aeneus. To date the susceptibility tests of pollen beetles have not been conducted in Estonia and it is unknown whether the local pest population has any resistance to pyrethroids. Therefore a pilot study was conducted to ascertain the state of resistance inthe Estonian pollen beetle population. Approximately 200 adult beetles were collected from two intensively managed spring oilseed rape fields in Jõgeva and Tartu County. The susceptibility test was conducted according to IRAC test method No 11, with lamda-cyhalothrin as a standard for testing the synthetic pyrethroid resistance. In 20% lamda-cyhalothrin solution the majority of insects were affected and at the normal field rate (100%) all studied insects were affected which demonstrates that they were not resistant. These results suggest that the pollen beetles are susceptible to synthetic pyrethroids in these monitored regions in Estonia. However, additional studies are necessary to make conclusions about the extent of resistance or susceptibility to pyrethroids in the Estonian beetle population.

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