Throughout Europe, grasslands are managed primarily for agricultural production but also provide a range of ecosystem services, the magnitude of which is influenced by their area, management and the abiotic properties of the ecosystem. The grassland area in Europe has been affected by significant changes in recent decades, including abandonment and conversion to arable land. This study presents an assessment of changes in the permanent grassland area with reference to Slovakia and provides an assessment of the bioenergy potential of permanent grassland surplus to agricultural needs. In 2015, of the total permanent grassland area (868,000 ha) 42% had ceased to be used as feed for milk or meat production and had been abandoned. Results from field experiments show that low-level improvement of permanent grasslands, e.g., by oversowing commonly sown agricultural grassland species and low-dose fertilization (up to 30 kg N ha À1 year À1) could provide herbage biomass of 1.7 million tonnes of herbage dry matter per year. This would be sufficient to generate an energy output of approximately 31.3-31.9 PJ/year (4.5% of the current gross inland energy consumption of Slovakia). Low-intensity use of the currently surplus permanent grassland is also considered to have potential beneficial outcomes in terms of delivery of ecosystem services. Results are also discussed in the context of countries beyond the case-study area.

The left descending coronary artery (LAD) of mongrel dogs was ligated for one month to evaluate the effect of a dihydroquinoline-type antioxidant (MTDQ-DA) during the healing process of myocardial infarction. Thirty animals were divided into three groups: I) control animals (10 dogs) were treated with saline infusion during operation and postoperative days; II) 10 dogs were treated with intravenous MTDQ-DA during the operation followed by postoperative oral treatment, and III) 10 animals were treated with preoperative and postoperative oral treatment plus intraoperative MTDQ-DA infusion. The antioxidant effects were evaluated by measurements of the lipid peroxidation and product malondialdehyde (MDA) and of endogenous scavengers: reduced glutathione (GSH) and superoxide dismutase (SOD) in the ischemic and in intact areas. Ultrathin sections were investigated by JEOL 100 C electron microscope. Elevation of lipid peroxidation (LPO) was present in each group. The most remarkable changes were seen in the control ischemic areas (152 +/- 6.7%). GSH was depleted in the infarcted areas of the control hearts (60 +/- 5.6%), in the antioxidant treated animals this thiol compound was only slightly decreased (81 +/- 5.6%). SOD activity showed a sharp decline (group I) in both ischemic (52 +/- 8.3 U/g) and non-ischemic parts of the left ventricle (78 +/- 7 U/g). After MTDQ-DA treatment (groups II, III) SOD activity diminished only in the ischemic area (83 +/- 8.5 U/g); other parts showed normal (123 +/- 7.2 U/g) activity. According to ultrastructural examinations, MTDQ-DA diminished the degree of structural injury.

The aim of the present work was to assess and compare energy inputs and outputs of various crop managements in 2011-2012. Two main crops on arable land and three permanent grasslands were investigated. Silage maize (Zea mays L.) and winter wheat (Triticum aestivum L.) were grown on lowland, whilst two semi-natural grasslands and grassland infested by tufted hair-grass (Deschampsia caespitose (L.) P. Beauv) were located in mountainous regions of Slovakia. In these crops and grasslands the dry matter yield was measured and subsequently the supplementary energy, energy gain and unifying energy value -tonne of oil equivalent (TOE) -were calculated. Silage maize with 233.37 GJ*ha -1 has provided the highest energy gain. In the group of grasslands, grassland infested by tufted hair-grass has offered the highest energy gain (59.77 GJ*ha -1 ). And this grassland had the lowest requirement on the supplementary energy (3.66 GJ*ha -1 ), contrary to silage maize with highest one (12.37 GJ*ha -1 ). The total energy potential of the crop biomasses was confronted with energy consumption in Slovakia. Winter wheat has the biggest energy potential, but it could cover only 19.6% and 11.3% total consumption of electricity or natural gas, respectively. Large area of permanent grasslands and their spatial location make them an important energy reservoir for bioenergy production. But, it is not possible to replace all consumed fossil fuels by bioenergy from these tested renewable energy sources. AbstraktCieľom predkladanej štúdie bolo zhodnotiť a porovnať vstupy a výstupy energie pre pestovateľské technológie silážnej kukurice (Zea mays L.) a pšenice letnej (Triticum aestivum L.) v nížinnej oblasti a troch trvalých trávnych porastov (dva poloprírodné a porast osídlený metlicou trstnatou, Deschampsia caespitose (L.) P. Beauv) v horských oblastiach Slovenska počas obdobia 2011-2012. Plodiny boli porovnávané z hľadiska úrod sušiny, dodatkovej energie a energetického zisku prevedením na zjednocujúcu energetickú veličinu -tona ropného ekvivalentu (TOE). Najvyšší energetický zisk bol dosiahnutý pri silážnej kukurici (233.37 GJ*ha -1 ). V skupine trvalých trávnych porastov dominoval porast osídlený metlicou trstnatou so ziskom energie (59.77 GJ*ha -1 ). Tento trávny porast vyžadoval na svoju prevádzku veľmi nízky vklad dodatkovej energie (3.66 GJ*ha -1 ) v porovnaní so silážnou kukuricou (12.37 GJ*ha -1 ). Celkový potenciál rastlinnej biomasy bol konfrontovaný so spotrebou energie na Slovensku. Najpriaznivejší energetický potenciál poskytla pšenica, ale aj napriek tomu by dokázala pokryť iba 19,6% spotreby elektrickej energie a 11,3% spotreby zemného plynu. Vysoká výmera plôch trvalých trávnych porastov a oblasti kde sa nachádzajú, sú dôvodom, prečo sa pokladajú za významný rezervoár bioenergie. Nie je však možné nahradiť spotrebu fosílnych palív energiou biomasy testovaných plodín.Kľúčové slová: energetický potenciál, kukurica, metlica trstnatá, obnoviteľná energia, pšenica letná, tona ropného ekvivatentu, trvalý trávny porast Deta...