ENERGY CROPS AS ALTERNATIVE AGRICULTURE CROPS FOR BIOMASS PRODUCTION IN MACEDONIA AND BULGARIA

In this review the focus is on few agricultural energy crops, which means crops that are grown exclusively or primarily for the purpose of producing biomass for energy purposes in an agricultural rather than a forestry context. However, cultivation of most of these crops is restricted to certain regions, e.g. by requirements for a certain climate zones. Having in mind the similar agro ecological conditions in R. Macedonia and Bulgaria, but also needs of the crops for successful growth and development, species as miscanthus, switch grass and sweet sorghum are introduced as a potentially used energetic plant species for this part of the Balkan region

RAPESEED (BRASSICA NAPUS, L.) – BIOLOGICAL REQUIREMENTS, GROWING CONDITIONS AND NEED FOR IRRIGATION

Rapeseed is one of the most important energy and food crops. The European agricultural producers are highly interested in it due to the obligations under the EU Directive for replacing the fossil fuels with biofuels as much as 20% by 2020, which has drawn the purchase prices considerably up. Rapeseed is widely used for production of cooking oil and rich in protein feed too. As regards to the environment, it contributes for restoration of degraded and contaminated lands owing to its capability for improving soil structure and leaving the area free of weeds. Rapeseed is one of the best pre-crops of winter wheat and contributes for some 20-30% increase of its yield. The paper contains an overview of different aspects of rapeseed growing: its biological requirements and the abiotic stressing factors in the Balkan geographic region; its sensibility to water and the impact of the water deficit on the yield and yield structural components; its yearly and monthly evapotranspiration and crop coefficients at different empirical evapotranspiration calculation methods; world data on its yields and the agricultural practices such as proper irrigation scheduling for its yield increase. The conclusions show that the soil and the climatic conditions on the Balkans are suitable for rapeseed growing and irrigation can contribute for obtaining sustainable yields from this crop

Antioxidative Defense, Suppressed Nitric Oxide Accumulation, and Synthesis of Protective Proteins in Roots and Leaves Contribute to the Desiccation Tolerance of the Resurrection Plant Haberlea rhodopensis

The desiccation tolerance of plants relies on defense mechanisms that enable the protection of macromolecules, biological structures, and metabolism. Although the defense of leaf tissues exposed to solar irradiation is challenging, mechanisms that protect the viability of the roots, yet largely unexplored, are equally important for survival. Although the photosynthetic apparatus in leaves contributes to the generation of oxidative stress under drought stress, we hypothesized that oxidative stress and thus antioxidative defense is also predominant in the roots. Thus, we aimed for a comparative analysis of the protective mechanisms in leaves and roots during the desiccation of Haberlea rhodopensis. Consequently, a high content of non-enzymatic antioxidants and high activity of antioxidant enzymes together with the activation of specific isoenzymes were found in both leaves and roots during the final stages of desiccation of H. rhodopensis. Among others, catalase and glutathione reductase activity showed a similar tendency of changes in roots and leaves, whereas, unlike that in the leaves, superoxide dismutase activity was enhanced under severe but not under medium desiccation in roots. Nitric oxide accumulation in the root tips was found to be sensitive to water restriction but suppressed under severe desiccation. In addition to the antioxidative defense, desiccation induced an enhanced abundance of dehydrins, ELIPs, and sHSP 17.7 in leaves, but this was significantly better in roots. In contrast to leaf cells, starch remained in the cells of the central cylinder of desiccated roots. Taken together, protective compounds and antioxidative defense mechanisms are equally important in protecting the roots to survive desiccation. Since drought-induced damage to the root system fundamentally affects the survival of plants, a better understanding of root desiccation tolerance mechanisms is essential to compensate for the challenges of prolonged dry periods

Proceedings: 3rd International Conference on Food and Agricultural Economics: EFFECT OF DRIP IRRIGATION MANAGEMENT ON YIELD AND WATER USE EFFICIENCY OF TOMATO GROWN IN AN UNHEATED POLYETHYLENE TUNNEL-TYPE GREENHOUSE

This study aims at investigating the impact of the irrigationmanagementfor tomato (Solanumlycopersicum 'Big Beef‘) grown under drip irrigation with mulch in an unheated polyethylene tunnel-type greenhouse.The experiment was carried out in the Chelopechene experimental field of the Institute of soil science, agrotechnologies and plant protection in town of Sofia, Bulgaria in 2018.Four different levels of irrigation have been served as treatment: T1 - full irrigation with application rate 100% of water requirements , T2 and T3 treatments – irrigationwith application rate 60% and 80% of the crop water requirements during the cluster fruit growing and cluster fruit ripening s and T4 - irrigation with 100% pan evaporation-based application rate.The total yield, yield per plant and irrigation water use efficiency (IWUE)were determined by treatments. The experimental results showed thatthe amount of water supplied for irrigation influencedfruit production of tomato grown in an unheated greenhouse.The highest tomato yield was obtained from the T1 and T4 treatments,89.205 t ha-1. и 88.11 t ha-1respectively. Reducing the irrigation application rate of 20% to 40% results in lower yield in T3 treatment by 10.5% and T2 treatment by 22% compared to the yield under full irrigation.The highest irrigation water use efficiency value of 27.03 kgm-3 was obtained for T2treatment the lowest irrigation level with. IWUE decreased in the other treatments as the amount of water applied for irrigation was larger.An economic analysis of the results was carried out