Warmer temperatures in the past 30 years have significantly influenced the seasonal development of insects throughout Europe. As a result of the outbreaks of black flies that have occurred in southeastern Lithuania since the 1970s it is hypothesized that this increase in black fly activity is due to the change in climate. To test this hypothesis the development of Simulium maculatum Meigen under different conditions was determined. This revealed that the time of hatching of S. maculatum eggs in Lithuania was influenced by winter air temperatures, especially those in March. Pupation in S. maculatum is associated with the increase in air and water temperatures that occur at the end of April and in May. The emergence of S. maculatum black flies occurs most often in May. At a water temperature of 13.2°C (1999), S. maculatum took 42 days to develop and half this time (21 days) when the water temperature was 18.8°C (2005). The number of black flies that emerged each year was determined by air temperature but unaffected by rainfall in June (either per month or per ten-day period). and Rasa Bernotienė, Galina Bartkevičienė.
Several alternative definitions of extreme events are proposed. As the first step a statistical analysis of daily precipitation measurement time series from the Hurbanovo SHMI Observatory and elaboration of potentially dangerous precipitation events is carried out. Then, combined characteristics based on daily temperature, daily air humidity and daily precipitation totals are computed. The drought index based on normalized deviations from long-term averages is defined. Alternatively, to define extreme events ''Data envelopment analysis'' (DEA) is employed with K-day periods of values of temperature, humidity and precipitation corresponding to decision making units. In this paper we have used the period of K = 10 days for both methodologies for identification of extreme events. The results of all definitions of extreme events are compared. and V článku navrhujeme niekoľko definícií extrémnych udalostí. Ako prvý krok je vypracovaná štatistická analýza denných úhrnov zrážok z observatória SHMÚ v Hurbanove, na základe ktorej označujeme extrémne udalosti. Následne počítame kombinované charakteristiky období sucha založené na denných údajoch teploty, vlhkosti vzduchu a denných úhrnoch zrážok. Index sucha je založený na normalizovaných odchýlkach od dlhodobých priemerov. Alternatívne definujeme extrémne udalosti na základe DEA analýzy, kde K-denné periódy teploty, vlhkosti a zrážok slúžia ako rozhodovacie jednotky. V tomto článku sme na identifikáciu extrémnych udalostí pre obe metodológie použili periódu K = 10 dní. Výsledky všetkých prístupov nakoniec porovnávame.
Nine years of seasonal δ18O values in precipitation, soilwater and groundwater were evaluated in the Uhlířská catchment between 2008 and 2016 and recharge winter/summer ratios were calculated using δ18O values. The longterm average 18O content in groundwater is lower than the mean weighted 18O content in precipitation. This is explained by more than 50% of winter- and snowmelt- induced groundwater recharge that occurs in all years except of 2010 and 2013. The recharge of the peat organic soil water is balanced between summer and winter, whereas the mineral hillslope soil is dominantly recharged by summer precipitation. The 67% portion of baseflow, dominantly generated in the winter season, is composed of groundwater and peat organic soil water, according to the hydrochemical distribution of runoff components. Isotopic mass balance of individual winters shows that precipitation in warmer winters is entirely transformed into outflow until the end of the winter season, generating no significant water storage for potential drought periods.
The aim of this study is to understand the seasonalities of runoff and precipitation and their controls along two transects in Peru and one transect in Austria. The analysis is based on daily precipitation data at 111 and 61 stations in Peru and Austria, respectively, and daily discharge data at 51 and 110 stations. The maximum Pardé coefficient is used to quantify the strength of the seasonalities of monthly precipitation and runoff. Circular statistics are used to quantify the seasonalities of annual maximum daily precipitation and annual maximum daily runoff. The results suggest that much larger spatial variation in seasonality in Peru is because of the large diversity in climate and topography. In the dry Peruvian lowlands of the North, the strength of the monthly runoff seasonality is smaller than that of precipitation due to a relatively short rainy period from January to March, catchment storage and the effect of upstream runoff contributions that are more uniform within the year. In the Peruvian highlands in the South, the strength of the monthly runoff seasonality is greater than that of precipitation, or similar, due to relatively little annual precipitation and rather uniform evaporation within the year. In the Austrian transect, the strength of the runoff seasonality is greater than that of precipitation due to the influence of snowmelt in April to June. The strength of monthly regime of precipitation and runoff controls the concentration of floods and extreme precipitation in Peruvian transects. The regions with strong monthly seasonality of runoff have also extreme events concentrated along the same time of the year and the occurrence of floods is mainly controlled by the seasonality of precipitation. In Austria, the monthly runoff maxima and floods occur in the same season in the Alps. In the lowlands, the flood seasonality is controlled mainly by summer extreme precipitation and its interplay with larger soil moisture.
The analyses of precipitation and runoff data along topographic gradients in Peru and Austria showed that, overall, in Peru the spatial variation in seasonality is much larger than in Austria. This is because of the larger diversity in climate and topography.
Some studies of responses of plants to elevated concentrations of carbon dioxide (EC) added CO2 only in the daytime, while others supplied CO2 continuously. I tested whether these two methods of EC treatments produced differences in the seed yield of soybeans. Tests were conducted for four growing seasons, using open top chambers, with soybeans rooted in the ground in field plots. One third of the chambers were flushed with air at the current ambient [CO2] (AC), one third had [CO2] 350 µmol mol-1 above ambient during the daytime (ECd), while one third had [CO2] 350 µmol mol-1 above ambient for 24 h per day (ECdn). ECdn increased seed yield by an average of 62 % over the four years compared with the AC treatment, while ECd increased seed yield by 34 %. Higher seed yield for ECdn compared with ECd occurred each year. In comparing years, the relative yield disadvantage of ECd decreased with increasing overall seed yield. On days with high water vapor pressure deficits, soybean canopies with ECd had smaller midday extinction coefficients for photosynthetically active radiation than canopies with ECdn, because of a more vertical leaf orientation. Hence the seed yield of soybean at EC varied depending on whether EC was also provided at night, with much greater yield stimulation for ECdn than for ECd in some years.
We established a multifactoral long-term field experiment at the Látókép experimental site of the University of Debrecen (Debrecen, Hungary), on mid-heavy calcareous chernozem soil in 1984, using experimental data from 17 years (1990-2008). We examined the extent to which soil fertility affects maize yield under natural conditions (without fertilisation). We analysed the effect of precipitation in the winter period (from the harvest of the previous crop (maize) until sowing (i.e. October-March)) and the growing season (i.e. April-September) on yield and we evaluated yield per FAO group. We examined the joint effect of crop year and hybrid maturity groups on maize yield; then we evaluated how hybrid maturity groups per crop year and wet and dry years per ripening group affected maize yield. It was shown that the pH value of soil significantly affected yield and also that there was a strong positive correlation between pH value and yield (r = 0.81) at a 1% significance level. The correlation between the two variables is described by a linear regression line. The slope shows that a 0.1 soil pH increase results in a 510 kg ha-1 maize yield increase on average. The correlation between the amount of precipitation during the growing season and maize yield is average, positive (r = 0.718) and linear. Based on the parameters of the estimated regression line - within non-fertilised conditions - 1 mm increase of precipitation resulted in a 9 kg ha-1 increase in yield. The analysis of the joint effect of hybrid maturity groups and crop year on yield showed that crop year determines standard deviation six times more than hybrid maturity groups, whereas the effect their interaction was not significant. and Práca bsahuje výsledky multifaktorového, dlhodobého pokusu na experimentálnej ploche Látókép, Univerzity v Debrecíne (Debrecen, Maďarsko). Experiment prebiehal od roku 1984, v tejto práci boli použité údaje z experimentu získané počas 17tich rokov (1990-2008). Pôda je stredne ťažká černozem. Bol skúmaný vplyv pôdnej úrodnosti na úrodu kukurice v prirodzených podmienkach, bez hnojenia. Študoval sa predovšetkým vplyv zrážok počas zimného obdobia (od zberu úrody kukurice až po nasledujúcu sejbu, t.j. od októbra do marca) a vplyv zrážok počas vegetačného obdobia (apríl -september) na úrodu kukurice. Okrem toho sa študoval vplyv ''sezóny'' a skupín skorosti hybridov na úrodu kukurice. Bolo vyhodnotený tiež vplyv skupiny skorosti hybridov počas suchých a mokrých rokov na úrodu kukurice. Bolo preukázané, že hodnota pH pôdy významne ovplyvňuje úrodu; súčiniteľ lineárnej korelácie medzi pH a úrodou na úrovni významnosti 1% bol r = 0,81. Z tejto korelácie vyplýva, že zvýšenie pH o 0,1 spôsobuje zvýšenie úrody kukurice priemerne o 510 kg ha-1. Korelácia medzi úrnom zrážok počas vegetačného obdobia kukurice a úrodou je pozitívna a lineárna (r = 0,718), z analýzy vyplýva, že zvýšenie úhrnu zrážok o 1 mm spôsobí priemerné zvýšenie úrody kukurice o 9 kg ha-1. Z výsledkov analýzy spoločného vplyvu skupín skorosti hybridov a sezóny vyplýva, že konkrétna sezóna ovplyvňuje tvorbu úrod 6-krát významnejšie, ako skupina skorosti hybridov; interakcia medzi skupinami skorosti hybridov a vlastnosťami sezóny nie je významná.
In the paper there the questions of selection of representative period for the hydrological characteristics assessment are discussed. Also the characteristics of runoff and precipitation for the periods 1931-1980 and 1961-2000 are presented. The main components of water balance in Slovakia are the basis for comparison of both periods. The assessment of development of runoff condition during the last decades is presented. and V referáte sa diskutujú otázky výberu reprezentatívneho obdobia pre stanovenie hydrologických charakteristík. Ďalej sa uvádzajú charakteristiky odtoku a zrážok za obdobia 1931-1980 a 1961-2000. Na základe hodnotenia hlavných komponentov hydrologickej bilancie Slovenska sa obidve obdobia porovnávajú a opisuje sa vývoj odtokových pomerov ostatného obdobia.