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Permanent grassland is the most complex natural ecosystem due to the biodiversity of the structural and functional elements that characterize the space and time unit of this ecosystem. From this point of view, in the case of this ecosystem, biodiversity is manifested by the richness of species as a result of the interactions between species and the biotope, the interspecific relations and the effects of the technology and usage applied to the improvement of these surfaces. The paper presents the results obtained in an experimental device placed on a permanent grassland of Festuca valesiaca + Festuca rupicola, from Caraş-Severin County, under conditions of mineral and organic fertilizers application (sheep manure and direct fertilization by sheep folding). [ABSTRACT FROM AUTHOR]

In any agricultural system based on legumes, nitrogen balance should take into account the flow of N2 by legume species. In this flow, the amount of N2 fixed by legumes is considered a reserve amount of nitrogen which, through harvesting, is removed from the nitrogen balance. The aim of the present paper is to assess the amount of nitrogen fixed biologically (NFB) in some legume species sowed in association and of the share of this amount of NFB of the total amount of nitrogen from the productions obtained. Thus, in the fodder system made up of Italian ryegrass + red clover cultivated for two years, the amount of NFB in the first year was 60 kg/ha. If we relate the amount of NFB to the amount of nitrogen exported through the fodder biomass, we see that the share of NFB varies between 22 and 42%. [ABSTRACT FROM AUTHOR]

Bird's-foot trefoil (Lotus corniculatus L.) is a perennial species with lower seed germination ability because of the large share of hard seeds. To increase germinating ability, the trial was based on treating bird's-foot trefoil seeds with ultrasounds (at different intensities and for different periods of time); they were then kept for a few days at -3 0°C. Treatment results show that the control variant (not treated) reached a germination level of 57.80%, while the variant treated with ultrasounds and thermally reached a germination level of 94.53% (i.e. 63.5% more). [ABSTRACT FROM AUTHOR]

The large variety of seed size at the Bird's-foot trefoil (Lotus corniculatus L.) affects their quality by the proportion of "hard" and "moldy" seeds. Studies found that germination energy, performed at a 5 days interval, varies depending on seed size: 71.8% at the class of medium seeds, 77% at small seeds, 82.2% at ungrouped seeds and 88.7% at large seeds. The average of results shows an increase in the proportion of "hard" seeds at the version with ungrouped seeds (3.11%) and a decrease in seeds grouped by size classes (1.77-2.42%). At the small and medium-sized groups of seeds there was no record of "moldy" seeds. [ABSTRACT FROM AUTHOR]