Research into the unsaturated zone and groundwater recharge can greatly improve understanding of hydrological processes and assist in sustainable groundwater management. Groundwater recharge of the ...Ljubljana Field aquifer, a coarse-gravel porous aquifer in Slovenia, was estimated with reference to soil characteristics, outflow data from a weighing lysimeter, and water-table fluctuation. The specific yield of the upper unsaturated zone determined from soil characteristics was 0.141 for the top soil layer (0–0.35 m), between 0.042 and 0.066 for the layer below the top soil (0.35–1.3 m), and between 0.239 and 0.219 for the underlying upper coarse layer. During long dry periods, especially in combination with times of high plant-water requirements, only substantial precipitation events directly contribute to considerable groundwater recharge, as ‘substantial precipitation’ is defined as those rainfall events that fill storage and exceed retention capacity of the upper soil layer. Lysimeter measurements show that 50% of the precipitation is lost by evapotranspiration and the other 50% contributes to groundwater recharge. Most infiltrated water was stored for a short time in the unsaturated zone and did not result in a significant discharge from the lysimeter. Average specific yield, calculated using the water-table fluctuation method, was 0.144. The nature of the gravely unsaturated zone is that once the retention buffer of the soil is exceeded, the water front travels through relatively quickly, which can be seen as an advantage for recharge or a disadvantage for prevention of groundwater pollution.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The objective of the study was to assess the concentration of egg yolk cholesterol in Czech Hen and Oravka breeds kept in two different breeding systems (cages and litter). Egg-yield, hen day egg ...production and feed mixtures consumption were observed during the experimental period. The eggs for laboratory analysis were collected during 4-week periods, at 34, 38, 42, 46 and 50 weeks of age of the laying hens. Sample extracts were analyzed by gas chromatography employing mass selective detector. Only daily consumption of feed mixtures was significantly affected by genotype, housing systems and their interaction. The cholesterol concentration was significantly affected by genotype and housing system of laying hens. The highest average concentration of cholesterol in egg yolk was determined on litter (Oravka 11.64 mg/g and Czech Hen 10.84 mg/g) compared to cages. Simultaneously, the influences of age of laying hens and its interaction with the housing system were also demonstrated. The highest concentration of cholesterol was measured at 34 weeks of age of hens bred on litter. Conversely, the lowest concentration was found at 42 weeks of age of hens housed in cages. Other parameters were inconclusive. The results showed that the selection of a suitable genotype and housing system can significantly affect the concentration of cholesterol in egg yolk.
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