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Weather impact on the household electric energy consumption Texte intégral
2016
Jakusenoks, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Laizans, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim of the article is to ascertain the interaction between weather conditions and electric energy consumption in the Latvia household. The electric energy consumption data in the Saurieši village, Riga region, Latvia, for the year 2012 were collected, and the climate data for the same period including the duration of the sun-shine, ambient air temperature, precipitation intensity, and wind speed were obtained. The research hypothesis that there is strong relation between weather conditions and electric energy consumption was proved partially – there is rather strong correlation between household electric energy consumption and air temperature (r = 0.91), and medium correlation between household electric energy consumption and precipitation (r = 0.61), as well as between household electric energy consumption and duration of the sunshine (r = 0.67). Correlation found between weather conditions and electric energy consumption in the household allows to forecast the trends in energy consumption based on weather measurements, and even to use the weather forecasts for electric energy future demand trends development. The equations developed explain the household energy consumption patterns in Latvia with its geographical location and economic conditions, but the methodology developed can be applied for any region if necessary data are available.
Afficher plus [+] Moins [-]Impact of agroecological conditions on the Hagberg falling number of winter wheat grain Texte intégral
2015
Linina, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ruza, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Grain quality adversely affects price and consumer acceptance of finished products. Hagberg falling number (hereinafter falling number) is one of the most important grain quality indices of winter wheat (Triticum aestivum L.), especially in humid climate countries (Northern Europe). Field experiments with winter wheat cultivars ‘Bussard’ and ‘Zentos’ were conducted at the Latvia University of Agriculture, Study and Research farm ‘Peterlauki’ during a three year period (from 2009/2010 to 2011/2012). The aim of this investigation was to clarify variation of the falling number (FN) depending on cultivar, weather conditions and different rates of nitrogen (N) fertilizer applied (N 60, N 90, N 120, N 150) on fresh and stored grain (60, 120 and 360 days). During the investigation period, wheat ‘Zentos’ grain was characterised by a higher falling number compared with ‘Bussard’ grain. The falling number values for fresh grain for both wheat varieties studied were high: averagely 301 s for ‘Bussard’ and 359 s for ‘Zentos’, and reached demands set for grain suitable for bread baking. Differences in the falling number values were noted when freshly harvested winter wheat grain was compared with grain stored for 60 or 120 days and 360 days. During storage (60 – 360 days), α-amylase activity in winter wheat grain reduced and the FN increased on average up from 94 to 110 s. The falling number significantly depended on weather conditions, grain storage period and nitrogen fertilizer. The higher was the falling number of freshly harvested grain, the higher its increase during grain storage of compared to freshly harvested grain with a lower falling number value.
Afficher plus [+] Moins [-]The effect of planting density on potato (Solanum tuberosum L.) minituber number, weight and multiplication rate Texte intégral
2015
Dimante, I., State Priekuli Plant Breeding Inst., Priekuli, Priekuli parish, Priekuli Municipality (Latvia) | Gaile, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
The study was aimed to investigate the effect of potato (Solanum tuberosum L.) in vitro plantlets planting density under greenhouse conditions on obtained minitubers number per unit area, multiplication rate and their weight distribution. Three cultivars of different maturity (‘Monta’ – early maturity, ‘Prelma’ – medium early and ‘Mandaga’ – medium late maturity) were used for the study. In vitro plantlets were planted in a greenhouse of State Priekuli Plant Breeding Institute, Latvia in 2014 at four planting densities (PDs) 63 plants per square m, 95 plants per square m, 142 plants per m2 and 184 plants per square m respectively. Fertilized peat was used as a substratum. Significant effect of planting density (p is less than 0.001) and cultivar (p is less than 0.01) was found on analyzed yield parameters. Increased planting densities resulted in increased minitubers number per square m (from 272 minutubers mE-2 at PD 63 plants mE-2 to 414 minutubers mE-2 at PD 184 plants mE-2), decreased multiplication rate (4.3 to 2.7 minitubers per planted plant) and mean fresh weight of minitubers (from 20.26. g to 12.11 g). The highest increase of minitubers number per m2 was observed within size (weight) range 3 to 5 g. Minitubers number per m2 increase within bigger size ranges (5 to 10 g, 10 to 20 g) was less pronounced. Slight insignificant (p=0.330) decrease of minitubers number is greater than 20 g was observed in relation of planting density increase (112 minitubers mE-2 at PD 95 plants mE-2 to 84 minitubers mE-2 at PD 184 plants mE-2).
Afficher plus [+] Moins [-]The effect of double inoculation on the broad beans (Vicia faba L.) yield quality Texte intégral
2015
Dubova, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Senberga, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Alsina, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Legumes (Leguminosae) are one of the most widely grown crops in the world after cereals (Poaceae). They are not only an important source of protein in food and feed, but also a significant component of different agrosystems. The N2 fixation by legumes is of great importance in nutrient management and sustainable economy of nitrogen. Legume productivity largely depends on a successful formation of symbiosis between the plant and soil microorganisms. The most important among those are rhizobia and mycorrhiza fungi. The field experiment was carried out at the Institute of Soil and Plant Sciences, Latvia University of Agriculture in 2014 to evaluate the influence of double inoculation using rhizobium leguminosarum and mycorrhiza fungi preparation on yield formation of broad bean V. faba L. var. major Harz ‘Bartek’. The bean seeds were treated with rhizobia and/or mycorrhiza fungi before sowing. Seeds were treated with rhizobia by soaking in bacteria suspension for 30 minutes directly before sowing. Mycorrhiza fungi preparation was added in soil under seeds before sowing. Plant height, fresh and dry weight and the weight of nodules were measured at the beginning of broad bean flowering (BBCH 60-61). rhizobium leguminosarum response to double inoculation differed between the strains. Rhizobium leguminosarum strain RL407, isolated from Vicia faba, was shown to be the most appropriate strain used for inoculation of broad bean seeds. Bean seed double inoculation increases the protein content significantly comparing to single inoculation using mycorrhiza fungi preparation.
Afficher plus [+] Moins [-]The changes in nitrogen content in soil depending on winter wheat (Triticum aestivum L.) fertilizing system Texte intégral
2015
Skudra, I., Latvia Univ. of Agriculture, Jelgava (Latvia);Latvian Rural Advisory and Training Centre, Ozolnieki parish, Ozolnieki Municipality (Latvia) | Ruza, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The objective of this study was to evaluate the main plant nutrient: mineral nitrogen (NH4 + -N and NO3 -N) dynamic in soil under fertilizing for obtaining high grain yields of winter wheat (Triticum aestivum L.) and to determine relationships between nutrient uptake and winter wheat productivity. The field study was carried out at the Research and Study farm ‘Vecauce’ of the Latvia University of Agriculture for two years 2012/2013 and 2013/2014 with winter wheat variety ‘Kranich’. Different nitrogen application rates (0, 85, 153, 150, 175, 180 and 187 kg haE-1) and timing were used for winter wheat. The content of nitrates NO3 -N and ammonium nitrogen NH4 -N was determined in the soil layers 0-0.20 m, 0.20-0.40 m, 0.40-0.60 m. Nitrogen management strategy during the plant growth period based on soil Nmin evaluating can improve N use efficiency and reduce environmental contamination. The maximum of mineral nitrogen content in soil in the vegetation period was observed at the beginning of stem elongation with a tendency to decrease. A significant impact (p is less than 0.05) of nitrogen fertilizer application was noted on the mineral nitrogen content in soil layer 0-0.20 m deep in both trial years. The increasing doses of nitrogen fertilizer raised the amount of mineral N in the soil profile. The significant impact (p is less than 0.001) of nitrogen application and year conditions was observed on grain yield. Close positive correlation significant at 99% probability level was observed between the grain protein content and nitrogen concentration mostly in all soil layers, but it was not found between the grain yield and nitrogen content.
Afficher plus [+] Moins [-]Light - emitting diodes (LEDs) for higher nutritional quality of brassicaceae microgreens Texte intégral
2015
Vastakaite, V., Lithuanian Research Centre for Agriculture and Forestry, Akademija, Kedainiai distr. (Lithuania) | Virsile, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim of this study was to investigate the effect of industrially designed light-emitting diode (LED) lamp lighting on the nutritional quality of Brassicaceae microgreens. Red pak choi (Brassica rapa var. chinensis ‘Rubi F1 ’), tatsoi (Brassica rapa var. rosularis) and mustard (Brassica juncea L. ‘Red Lion’) were grown in a greenhouse (20±2/18±2 °C) during winter season, and the solar daily integral (DLI) was ~3.46±1.16 mol mE-2 dE-1. The light spectra of lamp consist of 8 violet (420-430), 16 blue (460-470 nm), 8 orange (610-615 nm), 3 red (620-630 nm), 56 red (660-670 nm), 8 white (contain blue (400-500 nm), green (500-600 nm) and red (600-700 nm)) LEDs. The treatments of ~150 and ~250 µmol m-2 sE-1 LED irradiance levels (LED 150 and LED 250) for 16 h dE-1 in comparison with high pressure sodium (HPS) lamps (~150 µmol mE-2 sE-1) as a control were performed. Photophysiological response to the artificial light varied among Brassicaceae species. Microgreens treated with LED 150 and LED 250 were significantly (P is less than or equal to 0.05) shorter and formed smaller hypocotyls. The photooxidative changes were evoked by both lighting treatments and led to higher phytochemical (phenols, ascorbic acid, flavonols, anthocyanins) and mineral element (Ca, K, Mg, Na, P, Fe, Zn) contents, and the DPPH and ABTS free radicals scavenging activities in all microgreens. Significantly lower content of nitrate was obtained with LED 150 treatment. Finally, LED lamps have the potential to be used as the main light source for growing high nutritional quality microgreens in greenhouses.
Afficher plus [+] Moins [-]The effect of growing systems on the quality of carrots Texte intégral
2015
Bender, I., Estonian Crop Research Inst., Jogeva, Jogeva parish (Estonia) | Moor, U., Estonian Univ. of Life Sciences, Tartu (Estonia) | Luik, A., Estonian Univ. of Life Sciences, Tartu (Estonia)
The aim of the research was to evaluate how the quality of carrots is affected by organic and conventional production systems. The experiment was carried out at the Estonian Crop Research Institute in 2009. Conventional treatment received the following amount of nutrients via mineral fertilizers: N 115, P 40 and K 152 kg haE-1. For plant protection, the following pesticides were used: Fenix, Fastac 50, Agil and Signum. In organic cultivation system compost and humic acid solution Humistar were used for fertilization and polypropylene non-woven fabric Agryl P-17 for plant protection. Marketable yield of organic carrots was 8% lower compared to the conventional carrots. Conventional carrots contained pesticide residues and had significantly higher nitrate concentration than organic carrots. The contents of total sugars, phosphorus, potassium, calcium and magnesium did not differ significantly between carrots from different cultivation systems. At harvest, dry matter (DM) content of organically grown carrots was significantly higher, whereas vitamin C and ß-carotene content was significantly lower in organically grown carrots. However, after 5-months of storage, the organic carrots had significantly higher total soluble solids (TSS) and β-carotene content compared to the conventional ones indicating that organically grown carrots were less susceptible to storage conditions.
Afficher plus [+] Moins [-]Diversity of lactic acid bacteria in raw milk Texte intégral
2015
Bluma, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ciprovica, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
In this study we described the diversity of lactic acid bacteria and their representatives in raw and thermally treated milk, focusing on their potential in cheese production influencing cheese quality. The aim of the present study was to analyse the concentrations and representatives of lactic acid bacteria in raw milk and to detect the changes of lactic acid bacteria microflora during thermal treatment of cheese milk at a dairy processing plant. The analysis carried out in the study showed a seasonal variation in the microbial composition and quantity of raw milk. The most frequently isolated lactic acid bacteria: lactococci, lactobacilli, leuconostoc were found at low level in raw milk (mean 9.27×103 CFU mLE-1) and the most frequently identified species were Lactococcus lactis, Lactobacillus brevis and Lactobacillus fermentum. The microflora of raw and pasteurised milk is similar to the analysed lactic acid bacteria representatives in the samples. Interestingly, we found the same species in raw milk and pasteurised milk, for example, Lactobacillus brevis and Lactobacillus fermentum were detected in the same samples in raw milk and pasteurised milk. Our study showed that lactic acid bacteria concentration was quite low in pasteurised milk (0-76 CFU mLE-1), but they grow rapidly in cheese during ripening; therefore the definition of limits of the non–starter lactic acid bacteria colony forming units in milk should be reasonable for selection of appropriate raw milk quality for cheesemaking.
Afficher plus [+] Moins [-]Probiotic and prebiotic influence on haematological values of goat kids Texte intégral
2015
Otzule, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ilgaza, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Blood haematology is one of the indicators that shows if a goat (Capra hircus) kid gets a sufficient quantity of liquid, has a good supply of oxygen in the body, as well as an indication of inflammatory processes. Our aim of this research was to find out how feed additives (probiotics (Enterococcus faecium), prebiotics (Jerusalem artichoke (Helianthus tuberosus L.)) and symbiotics (Enterococcus faecium+ Jerusalem artichoke)) influence on haematological parameters of kids. Research was performed in Latvia in 2014. The blood samples were analyzed for leucocytes (WBC), erythrocyte number (RBC), haemoglobin (HGB) concentration, packed cell volume (HCT), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentrations (MCHC). Since the blood indicators have not significantly changed in all examination times, we analyzed the results of the age of 4, 8 and 12 weeks. HCT downward trend in blood sample MRG + PRO, MRG + PRE and MRG + SIM group of kids was observed from the fourth week up to the eighth week and then it gradually increased. The results showed that the HCT, HGB, RBC, MCHC and WBC number was comparable (p is greater than 0.05) between groups. Our results prove that the use of Jerusalem artichoke powder as an additive to food not only improves digestion and metabolism of ruminant, but also helps to maintain constant haematological values. In the control group and the kids who received probiotics, prebiotics or symbiotics - significant differences are evident in all haematological parameters (p is less than 0.05) at the age of 12 weeks.
Afficher plus [+] Moins [-]Corticosteroid-induced hepatopathy in dogs Texte intégral
2015
Kondratjeva, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Birgele, E., Latvia Univ. of Agriculture, Jelgava (Latvia)
Corticosteroid therapy is often used on dogs (Canis lupus familiaris) to treat different kinds of diseases. One of the most common complications of corticosteroid use is steroid hepatopathy, a specific pathology only in dogs. The objective of this study was to determine whether and how significant the liver functional changes after one administration of different kinds of corticosteroids in standard dosages are. The study took place in private veterinary clinics in Riga, Latvia, during 2013 - 2014, with the permission of dogs’ owners. Twenty animals, which received corticosteroids due to present diagnosis, were divided into four groups. To reach the aim such corticosteroids as dexamethasone sodium phosphate, prednisolone acetate, methylprednisolone acetate and hydrocortisone aceponate were used in standard dosage one time to these dogs, respectively. Then, such blood serum enzymes as alaninaminotransferase (ALAT) and alkaline phosphatase (AP) were determined 24, 48 and 96 hours after the use of corticosteroids. It was discovered that the only one administration of dexamethasone sodium phosphate and methylprednisolone acetate in standard dosage can significantly increase (p is less than 0.05) ALAT and AP mean values in dogs. The corticosteroid prednisolone acetate was used once in standard dosage and hydrocortisone aceponate spray was used once and did not statistically significantly (p is greater than 0.05) change the values of alaninaminotransferase (ALAT) and alkaline phosphatase (AP) in dogs’ blood serum during this study.
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