Sirvi Autor "Skoufogianni, E." järgi
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Kirje Comparison of two perennial energy crops for biomass production at the end of their life cycle(2020) Giannoulis, K.D.; Bartzialis, D.; Skoufogianni, E.; Charvalas, G.; Danalatos, N.G.Nowadays fossil fuels are decreasing, causing the world's interest in renewable energy sources to rapidly grow. One of the most interesting renewable and ecologically pure fuels is biomass, which is considered to be carbon neutral. Biomass is a promising source of energy, as it can be used directly as an energy resource. Its quality characteristics such as gross calorific value and ash content are of paramount importance so as to improve the combustion process. Furthermore, during the last three decades, there has been an increasing interest in the production of biomass pellets for domestic and industrial use. Alternative feed stocks will need to be sourced to meet the demand for biomass pellets. Investigation for new energy crops that produce high amounts of biomass under low inputs and of high energy efficiency are the main tasks of this field. Therefore, the aim of this study is to assess the biomass yield and the quality characteristics (gross calorific value and ash content) of two perennial energy crops (Cynara cardunculus L. and Panicum virgatum L.) growing in a typical soil (Fluventic Xerochrept) of the main agricultural land of central Greece. The comparison for both cultivated crops was made in order to show the results during their 8th growing year. The examined factors were the irrigation (two levels: irrigated and rainfed) and the nitrogen fertilization (two levels: 0 and 80 kg N ha-1 ) as well as their effect on the dry biomass yield and the gross calorific value. It was found that higher dry biomass yield was produced from cardoon (21.3 vs. 14.23 t ha-1 ), while the higher average gross calorific value was observed for switchgrass biomass (17.31 vs. 15.65 Mj kg-1 ). Finally, multiplying the dry biomass yield (t ha-1 ) with the gross calorific value (Mj kg-1 ) it was found that 334 and 245 Gj ha-1 from a cardoon and a switchgrass cultivation could be produced, respectively. Cardoon has better results than switchgrass probably due to the fact that switchgrass is growing from March till October; while cardoon’s growing period is from October to June and in such areas precipitation is in shortage during summer months. Both crops could achieve high amounts of energy per hectare and thus their introduction in future land use systems, for an environmentally friendly energy production should be seriously taken into consideration.Kirje Cost efficiency of different cropping systems encompassing the energy crop Helianthus annuus L.(2019) Skoufogianni, E.; Giannoulis, K.D.; Bartzialis, D.; Danalatos, N.G.Crop rotation and green manure are the most ancient and popular cropping systems. This study sought to analyze the economic efficiency of sunflower where pea (Pisum sativum L.) either harvested or incorporated at the flowering stage in the soil before the sowing of sunflower in Europe and the final agricultural profit of such a cultivation system. Therefore, the main objectiveof this paper is to report the production costs and to find out which of the tested cultivation system gets sunflower cultivation economically viable in Greece and in Mediterranean region. To assess the economic efficiency, three-year field experiments were established in two contrasting environments in central Greece (Trikala and Larisa) and contained three different cultivation practices using legumes comprised the main-factor (T1: control, T2: legume incorporated at the flowering stage, T3: legume incorporated after seed harvest), while nitrogen fertilization comprised the sub-factor (N1:0, N2:50, N3:100 and N4:150 kgNha-1).The results derived from this study revealed the positive effect of the legume incorporation treatment (T2:legume incorporated at the flowering stage) where the final yield increased up to 5tha-1regardless region. Moreover, depending on the year the T2 treatment increases the final yield 30–50%and a yield increase was also noticed to the treatment where the legume was harvested (T3: legume incorporated after seed harvest). Therefore the introduction of this scheme into future land use systems in Greece and more generally in Mediterranean basin should be seriously taken into consideration.Kirje Evaluation of soil properties, irrigation and solid waste application levels on Cu and Zn uptake by industrial hemp(2021) Golia, E.E.; Angelaki, A.; Giannoulis, K.D.; Skoufogianni, E.; Bartzialis, D.; Cavalaris, Ch.; Vleioras, S.Α three-year experiment was performed to study the alteration of copper and zinc levels in industrial hemp grown in different soils using elevated sewage slurry solid waste applications. Two soil samples, an acidic and an alkaline one, with different soil properties, such as percentage of CaCO3 and cation exchange capacity values, were used. Three treatments of waste solid with provided elevated concentrations of Cu and Zn were combined with two irrigation levels. The application of high doses of the solid residue as well as high irrigation level lead to an increase of the mobility of metals in hemp leaves in acidic soil in contrast to alkaline. On the contrary, in alkaline soil along with a reduced irrigation level, there is a decrease in the mobility of Cu and therefore its accumulation in the roots or stems was observed. Concluding, hemp seem to be a promising plant remediator, after the application of the proper irrigation level and taking into account the physico-chemical soil properties of moderately contaminated (with copper and zinc) soils.Kirje Sorghum dry biomass yield for solid bio-fuel production affected by different N-fertilization rates(2020) Bartzialis, D.; Giannoulis, K.D.; Skoufogianni, E.; Lavdis, A.; Zalaoras, G.; Charvalas, G.; Danalatos, N.G.The objective of this study was to examine the effect on the dry biomass yield of two dfferent sorghum hybrids (H1 and H2) under five different N-fertilization levels (0, 70, 140, 210 and 280 kg ha-1 ) in a soil which was formed by lacustrine deposits of Karla Lake and is characterized from the downward movement of calcium carbonate from the surface horizons due to leaching (Fluventic Xerochrept) during 2017. The results demonstrated a significant effect (P < 0.05) of fertilization only for one hybrid. Biomass yield ranged from 22.2 to 37.5 t ha−1. For both hybrids, sorghum accumulated a high amount of biomass in stems. Dry stem/total biomass ratio was rather constant throughout the different fertilization treatments achieving 81.6 and 77.5% for the first (H1) and the second hybrid (H2), respectively. The second hybrid (H2) had a higher percentage of leaf biomass (20.1 vs. 13.8%) than the first (H1), but lagged behind in seed production (2.4 vs. 4.6%). Biomass dry matter partitioning and total dry weight are important selection criteria for energy crops, due to different gross calorific value and ash content but also because of the different economic importance they may have e.g. the seed is also used as animal feed. The above high biomass yields of sorghum, confirming the high potential of this crop, should be taken into serious consideration regarding land use planning, but further investigation for the gross calorific value and the ash content is needed as well as biomass characteristics that are quite important in case to improve the combustion process.