The parameters determining the agronomic and economic performance of genetically modified maize hybrid MON 89034 × NK603 and conventional hybrids were compared under conditions that eliminated the herbicide tolerance in GM hybrid as well as the use of insecticides in conventional hybrids. The GM hybrid confirmed ability to protect itself against the European corn borer and its average grain yield was higher by 6.36-14.42% (i.e. 0.82-1.86 t/ha) in comparison with conventional hybrids. The year of cultivation statistically significant influenced agronomic parameters and the financial income of maize production. The maize genotype did not statistically significantly affected any evaluated parameter. The final income was statistically significant (P < 0.05) negatively influenced by all observed agronomic parameters with the exception of the seed price. The price of maize grains on the market was the only one factor that statistically significant (P < 0.05) influenced financial income of the maize production.

Influence of Soil Cultivation Technologies and Fertilisation on Productivity and Energy Production of Arable Crops The influence of three soil tillage technologies and two fertilisation levels on a productivity of crops and biomass for energy use, expressed in yield, cereal units (CU), energy acquired and indicative price of energy per hectare was evaluated at the experimental fields of Research Institute of Plant Production in Piešťany during 2007-2009. The highest yield of dry matter has been identified for maize for silage 19.41 t/ha, followed by winter oilseed rape 15.77 t/ha, triticale 15.39 t/ha and winter wheat 14.08 t/ha. Conventional tillage created soil condition for higher yield of dry matter in an average 17.92 t/ha, followed by minimum soil tillage 16.27 t/ha and no-till-age technology 14.3 t/ha. Nitrogen-based fertilisation (N120) has ensured a significantly higher yield of dry matter and a higher price of acquired energy €491.1 compared with €462.1 of zero-nitrogen fertilisation. The highest yield of cereal units has been identified for maize for silage 9.01 CU, followed by winter wheat 5.21 CU, triticale 4.70 CU and winter oilseed rape 4.55 CU. Energy of maize for silage has been calculated from biogas, winter oilseed rape from rape methyl ester, straw and crop residues, and for winter wheat and triticale from ethanol and straw. Average energy storage in plant biomass of crop rotation was 222.93 GJ/ha. The highest amount of energy acquired has been identified for winter oilseed rape 342.80 GJ/ha, followed by maize for silage with 236.99 GJ/ha, winter triticale 159.39 GJ/ha and winter wheat 152.52 GJ/ha.

Soil physical properties were investigated in two types of growing systems -integrated no-till system and conventional system with ploughing, in 1999 -2005 on chernozem in maize growing region. Bulk density decreased and total porosity increased during 7 years in both growing systems. In integrated system the improvement of soil physical properties could be explained by remaining of plant residues on soil surface. In conventional system the plant residues were incorporated into soil by ploughing. This led to the higher proportion of organic matter in soil. Soil cultivated conventionally had significantly higher value of reduced bulk density, significantly lower porosity and significantly higher values of soil moisture compared to soil in integrated no-till system. Maximum capillary water capacity was not significantly influenced by soil cultivation. Values of investigated soil physical properties in both systems were not markedly different from the typical values of cultivated chernozem. AbstraktPočas siedmich rokov 1999 -2005 boli na černozemi hnedozemnej, v kukuričnej výrobnej oblasti, sledované fyzikálne vlastnosti pôdy v dvoch pestovateľských systémochv integrovanom bezorbovom a v konvenčnom s orbou. Počas sedemročného obdobia došlo k zníženiu objemovej hmotnosti redukovanej a k zvýšeniu celkovej pórovitosti pôdy pri oboch spôsoboch obrábania pôdy. Zlepšenie fyzikálnych vlastností pôdy možno vysvetliť ponechávaním rastlinných zvyškov na povrchu pôdy v integrovanom systéme a ich zaorávaním v konvenčnom systéme pestovania plodín, čo zvýšilo podiel organickej hmoty v pôde. Pôda obrábaná konvenčným spôsobom sa vyznačovala štatisticky preukazne vyššou objemovou hmotnosťou redukovanou a štatisticky preukazne nižšou pórovitosťou. Tiež ju 254

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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...