**4. Propagation**

280 Sustainable Growth and Applications in Renewable Energy Sources

Hungary, under natural climatic conditions without any irrigation or fertilization. To evaluate threshold values of gas exchange parameters under different environmental regime, steady state and instantaneous field measurements by IRGA methods were

Among investigated abiotic environmental parameters photon flux density and air humidity turned out to have an essential role in gas exchange performance and regulation (Salamon-Albert & Molnár, 2009, 2010). Under non-stressed soil water conditions (P2, P3, P5) carbon fixation was the most favourable at the beginning of the growing period described by the assimilation capacity and light efficiency regulated by the air humidity (Fig. 10.A). After seasonal precipitation deficiency in late summer (P4), causing a decline in soil water content, hard reduction was detected in water use efficiency because of strong decrease in assimilation capacity and light efficiency, retaining a regular level of transpiration (Fig. 10.B,C). Effect of climatic air drought was significant for stomatal conductance, going shattered in seasonal response by a greater effectiveness to transpiration (Fig. 10.D). As for the other experimental soil types, overall and seasonal assimilation capacity and light efficiency was a little bit lower on Alfisol-Mollisol and significantly depressed on Aquic

Fig. 10. A) assimilation, B) transpiration, C) photosynthetic water use efficiency as a function of light and D) stomatal conductance for water vapour as a function of air humidity, derived from field measurement (instantaneous data, alfisol, unpublished). Fitted curves p<0.01, P2-

executed.

Mollisol.

P5 the vegetative phenophases.

Szarvasi-1 energy grass is propagated by seed. Since *E. elongatus* ssp. *ponticus* has evolved in regions of Europe that have long and severe winters, it germinates relatively late in the spring and by the time it develops its tussocks it is mid summer. This is why the suggested sowing time is in autumn, in the middle of September. Its germination needs no special circumstances. A period of only 7 consecutive days with approx. 16 hours dark each day and 18-20 °C air temperatures can maximize the germination success, up to 90 %. In different conditions the proportion of germinating seeds can vary between 52 and 90 %. Seedlings die rapidly without proper humidity conditions, but too much watering or a high water table are also poorly tolerated by Szarvasi-1 energy grass seedlings and juveniles. Similarly, strong competition of weeds can dramatically reduce seedling survival. The plant gets in full flower by the middle of June. The energy grass seeds belong to the transient seed bank-type, where the longevity of the seeds is shorter than a year. Hence, the seed bank of Szarvasi-1 energy grass fields contains seeds with the same age with no overlapping generations.
